Allicin protects against H2O2-induced apoptosis of PC12 cells via the mitochondrial pathway

Therapeutic potentials of allicin in cardiovascular disease: advances and future directions

Cardiovascular disease (CVD) remains the predominant cause of mortality and disability worldwide. Against this backdrop, finding effective drugs for the pharmacological treatment of CVD has become one of the most urgent and challenging issues in medical research. Garlic (Allium sativum L.) is one of the oldest plants and is world-renowned for its dietary and medicinal values. Allicin (diallyl thiosulfinate) is one of the primary natural active ingredients in garlic, which has been proven to have powerful cardioprotective effects and mediate various pathological processes related to CVD, such as inflammatory factor secretion, myocardial cell apoptosis, oxidative stress, and more. Therefore, allicin holds a promising application prospect in the treatment of CVD. This review summarized the biological functions of allicin and its potential mechanisms in CVD, including antioxidation, anti-inflammation, and anti-apoptosis effects. Reckoning with these, we delved into recent studies on allicin's cardioprotective effects concerning various CVDs, such as atherosclerosis, hypertension, myocardial infarction, arrhythmia, cardiac hypertrophy, heart failure, and cardiotoxicity. Further, considering the tremendous advancement in nanomedicine, nanotechnology-based drug delivery systems show promise in addressing limitations of allicin's clinical applications, including improving its solubility, stability, and bioavailability. Through this review, we hope to provide a reference for further research on allicin in cardioprotection and drug development.

Allicin Alleviates Mitochondrial Dysfunction in Acrylamide-Induced Rat Kidney Involving the Regulation of SIRT1

Acrylamide (AA), commonly formed in carbohydrate-rich thermally processed foods, exerts harmful effects on the kidney. Allicin, from crushed garlic cloves, exhibits strong biological activities. In the current study, the protection mechanisms of allicin against AA-caused nephrotoxicity were comprehensively examined using an in vivo rat model based on previous research that allicin plays a key role in improving renal function. The results showed that allicin attenuated histological changes of the kidney and ameliorated renal function. Damaged mitochondrial structures, upregulated voltage-dependent anion channel 1 expression, and decreased membrane potential and adenosine 5'-triphosphate levels were observed after AA treatment. Surprisingly, allicin notably reversed the adverse effects. Further, allicin effectively restored mitochondrial function via modulating mitochondrial biogenesis and dynamics, which might be associated with the upregulated expression of sirtuin 1 (SIRT1). Meanwhile, allicin dramatically activated the SIRT1 activity and subsequently inhibited p53 acetylation, prevented the translocation of cytochrome c to the cytoplasm, and reduced the caspase expression, thus further inhibiting mitochondrial apoptosis caused by AA. In summary, the relieving effect of allicin on AA-caused nephrotoxicity lies in its inhibition of mitochondrial dysfunction and mitochondrial apoptosis.

Neuroprotective Effects of Zerumbone on H2O2-Induced Oxidative Injury in Human Neuroblastoma SH-SY5Y Cells

Oxidative stress is recognized as one of the main reasons for cellular damage and neurodegenerative diseases. Zerumbone is one of the sesquiterpenoid compounds in the essential oil of Zingiber zerumbet Smith. Zerumbone exhibits various physiological activities, such as anticancer, antioxidant, and antibacterial effects. However, studies on the neuroprotective efficacy of zerumbone and the mechanism behind it are lacking. In this study, we explored the neuroprotective efficacy of zerumbone and its mechanism in hydrogen peroxide-treated human neuroblastoma SH-SY5Y cells. H2O2 treatment (400 μM) for 24 h enhanced the generation of intracellular reactive oxygen species (ROS) compared to untreated cells. By contrast, zerumbone treatment significantly suppressed the production of intracellular ROS. Zerumbone significantly inhibited H2O2-induced nitric oxide production and expression of inflammation-related genes. Moreover, zerumbone decreased H2O2-induced mitogen-activated protein kinase (MAPK) protein expression. Various hallmarks of apoptosis in H2O2-treated cells were suppressed in a dose-dependent manner through downregulation of the Bax/Bcl-2 expression ratio by zerumbone. Since activation of AMP-activated kinase (AMPK) is a promising therapeutic target for neurodegenerative diseases, we also investigated the mammalian target of rapamycin (mTOR) as part of the autophagy mechanism in H2O2-treated SH-SY5Y cells. In this study, zerumbone upregulated the expression of Sirtuin 1 (SIRT1) and p-AMPK (which were downregulated by the H2O2 treatment) and downregulated p-mTOR. Altogether, our results propose that inhibition of apoptosis and inflammation by autophagy activation plays an important neuroprotective role in H2O2-treated SH-SY5Y cells. Zerumbone may thus be a potent dietary agent that reduces the onset and progression, as well as prevents neurodegenerative diseases.

The role of Nrf2/HO-1 signal pathway in regulating aluminum-induced apoptosis of PC12 cells

BACKGROUND

Aluminum has definite neurotoxicity and can lead to apoptosis of nerve cells, but the specific mechanism remains to be further explored. The aim of this study was to investigate the role of Nrf2/HO-1 signaling pathway in neural cell apoptosis induced by aluminum exposure.

METHODS

In this study, PC12 cells were used as the research object, aluminum maltol [Al(mal)₃] was used as the exposure agent, and tert-butyl hydroquinone (TBHQ), an agonist of Nrf2, was used as the intervention agent to construct an in vitro cell model. Cell viability was detected by CCK-8 method, cell morphology was observed by light microscope, cell apoptosis was measured by flow cytometry, and expression of Bax and Bcl-2 proteins and Nrf2/HO-1 signaling pathway proteins were investigated by western blotting.

RESULTS

With the increase of Al(mal)₃ concentration, PC12 cell viability decreased, the early apoptosis rate and total apoptosis rate increased, the ratio of Bcl-2 and Bax protein expression decreased, and Nrf2/HO-1 pathway protein expression decreased. The use of TBHQ could activate the Nrf2/HO-1 pathway and reverse the apoptosis of PC12 cells induced by aluminum exposure.

CONCLUSION

Nrf2/HO-1 signaling pathway plays a neuroprotective role in the apoptosis of PC12 cells caused by Al(mal)₃, which provides a possible target for the intervention of aluminum induced neurotoxicity.

The Pharmacological Activity of Garlic (Allium sativum) in Parkinson's Disease: From Molecular Mechanisms to the Therapeutic Potential

Parkinson's disease (PD), one of the most common neurological diseases worldwide, is mainly characterized neuropathologically by the dopaminergic neurodegeneration in the substantia nigra pars compacta of the brainstem. Genetic and environmental factors contribute to PD pathophysiology through modulation of pleiotropic cellular mechanisms. The currently available treatment options focus only on replenishing dopamine and do not alter disease progression. Interestingly, garlic (Allium sativum), globally famed for its flavor and taste-enhancing properties, has shown protective activity in different PD models. Numerous chemical constituents of garlic, mainly the organosulfur compounds, have been shown to exhibit anti-Parkinsonian effects by targeting oxidative stress, mitochondrial impairment, and neuroinflammation-related signaling. However, despite its therapeutic potential against PD, the major bioactive components of garlic display some stability issues and some adverse effects. In the present review, we explore the therapeutic potential of garlic and its major constituents in PD, the molecular mechanisms responsible for its pharmaceutical activity, and the associated limitations that need to be overcome for its future potential use in clinical practice.

Mitochondrial Modulators: The Defender

Mitochondria are widely considered the "power hub" of the cell because of their pivotal roles in energy metabolism and oxidative phosphorylation. However, beyond the production of ATP, which is the major source of chemical energy supply in eukaryotes, mitochondria are also central to calcium homeostasis, reactive oxygen species (ROS) balance, and cell apoptosis. The mitochondria also perform crucial multifaceted roles in biosynthetic pathways, serving as an important source of building blocks for the biosynthesis of fatty acid, cholesterol, amino acid, glucose, and heme. Since mitochondria play multiple vital roles in the cell, it is not surprising that disruption of mitochondrial function has been linked to a myriad of diseases, including neurodegenerative diseases, cancer, and metabolic disorders. In this review, we discuss the key physiological and pathological functions of mitochondria and present bioactive compounds with protective effects on the mitochondria and their mechanisms of action. We highlight promising compounds and existing difficulties limiting the therapeutic use of these compounds and potential solutions. We also provide insights and perspectives into future research windows on mitochondrial modulators.

Evolutionarily Ancient Caspase-9 Sensitizes Immune Effector Coelomocytes to Cadmium-Induced Cell Death in the Sea Cucumber, Holothuria leucospilota

Heavy-metal pollution has increasingly jeopardized the habitats of marine organisms including the sea cucumber, a seafloor scavenger vital to seawater bio-decontamination, ocean de-acidification and coral-reef protection. Normal physiology including immune functions of sea cucumbers is toxicologically modulated by marine metal pollutants such as cadmium (Cd). The processes underpinning Cd's toxic effects on immune systems in the sea cucumber, Holothuria leucospilota, are still poorly understood. To this end, we cloned and characterized a full-length caspase-9 (Hl-CASP9) cDNA in the sea cucumber, Holothuria leucospilota. Hl-CASP9 mRNA levels evolved dynamically during embryonic development. Coelomocytes, a type of phagocytic immune effectors central to H. leucospilota immunity, were found to express Hl-CASP9 mRNA most abundantly. Hl-CASP9 protein structurally resembles caspases-2 and -9 in both invertebrate and vertebrate species, comprising a CARD domain and a CASc domain. Remarkably, Hl-CASP9 was transcriptionally sensitive to abiotic oxidative stress inducers including hydrogen peroxide (H₂O₂), nitric oxide (^•NO) and cadmium (Cd), but insensitive to immunostimulants including lipopolysaccharide (LPS), and poly(I:C). Overexpression of Hl-CASP9 augmented mitochondria-dependent apoptosis in HEK293T cells, while knock-down of Hl-CASP9 blunted Cd-induced coelomocyte apoptosis in vivo. Overall, we illustrate that an evolutionarily ancient caspase-9-dependent pathway exists to sensitize coelomocytes to premature cell death precipitated by heavy metal pollutants, with important implications for negative modulation of organismal immune response in marine invertebrates.

Allicin mitigates hepatic injury following cyclophosphamide administration via activation of Nrf2/ARE pathways and through inhibition of inflammatory and apoptotic machinery

Treatment with anti-neoplastic agents, including cyclophosphamide (CP), is associated with several adverse reactions. Here, we distinguished the potential protective effect of allicin against CP-mediated hepatotoxicity in rats. To assess the effect of allicin, four experimental groups were used, with 7 rats per group, including control, allicin (10 mg/kg), CP (200 mg/kg), and allicin + CP-treated groups. All groups were treated for 10 days. Blood and liver samples were collected for biochemical, molecular, and histological analyses. Treatment with CP led to deformations in the liver tissue that were associated with higher liver function markers (alanine transaminase, aspartate transaminase, and alkaline phosphatase). Additionally, a disturbance in the redox balance was observed after CP exposure, as indicated by increased levels of oxidants, including malondialdehyde and nitric oxide, and the decreased levels of endogenous antioxidants, including glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase. At the molecular level, CP treatment resulted in reduced expression of the Nrf2/ARE pathway and other genes related to this pathway, including NAD(P)H quinone dehydrogenase 1 and glutamate-cysteine ligase catalytic subunit. CP also led to a hyper-inflammatory response in hepatic tissue, with increased production of pro-inflammatory cytokines, including tumor necrosis factor-alpha and interlukin-1beta, and upregulation of nitric oxide synthase 2. CP also enhanced the immunoreactivity of the profibrogenic cytokine, transforming growth factor-beta, in liver tissue. Upregulation of caspase 3 and Bcl-2-associated X protein and downregulation of B-cell lymphoma 2 were also observed in response to CP treatment. Treatment with allicin reversed the molecular, biochemical, and histological changes that occurred with CP exposure. These results suggest that allicin can be used in combination with CP to avoid hepatotoxicity.

Suppression of TRPV1/TRPM8/P2Y Nociceptors by Withametelin via Downregulating MAPK Signaling in Mouse Model of Vincristine-Induced Neuropathic Pain

Vincristine (VCR) is a widely used chemotherapy drug that induced peripheral painful neuropathy. Yet, it still lacks an ideal therapeutic strategy. The transient receptor potential (TRP) channels, purinergic receptor (P2Y), and mitogen-activated protein kinase (MAPK) signaling play a crucial role in the pathogenesis of neuropathic pain. Withametelin (WMT), a potential Phytosteroid isolated from datura innoxa, exhibits remarkable neuroprotective properties. The present investigation was designed to explore the effect of withametelin on VCR-induced neuropathic pain and its underlying molecular mechanism. Initially, the neuroprotective potential of WMT was confirmed against hydrogen peroxide (H₂O₂)-induced PC12 cells. To develop potential candidates for neuropathic pain treatment, a VCR-induced neuropathic pain model was established. Vincristine (75 μg/kg) was administered intraperitoneally (i.p.) for 10 consecutive days (day 1-10) for the induction of neuropathic pain. Gabapentin (GBP) (60 mg/kg, i.p.) and withametelin (0.1 and 1 mg/kg i.p.) treatments were given after the completion of VCR injection on the 11th day up to 21 days. The results revealed that WMT significantly reduced VCR-induced pain hypersensitivity, including mechanical allodynia, cold allodynia, and thermal hyperalgesia. It reversed the VCR-induced histopathological changes in the brain, spinal cord, and sciatic nerve. It inhibited VCR-induced changes in the biochemical composition of the myelin sheath of the sciatic nerve. It markedly downregulated the expression levels of TRPV1 (transient receptor potential vanilloid 1); TRPM8 (Transient receptor potential melastatin 8); and P2Y nociceptors and MAPKs signaling, including ERK (Extracellular Signal-Regulated Kinase), JNK (c-Jun N-terminal kinase), and p-38 in the spinal cord. It suppressed apoptosis by regulating Bax (Bcl2-associated X-protein), Bcl-2 (B-cell-lymphoma-2), and Caspase-3 expression. It considerably attenuated inflammatory cytokines, oxidative stress, and genotoxicity. This study suggests that WMT treatment suppressed vincristine-induced neuropathic pain by targeting the TRPV1/TRPM8/P2Y nociceptors and MAPK signaling.

Neuroprotective effects of allocryptopine-rich alkaloid extracts against oxidative stress-induced neuronal damage

BACKGROUND

Oxidative stress is a significant feature in the pathomechanism of neurodegenerative diseases. Thus, the search for an effective and safe novel antioxidant agent with neuroprotective properties has increased the interest in medicinal plant products as a bioactive phytochemical source. However, little is known about the potential effects of the medically important Glaucium corniculatum as a natural antioxidant.

OBJECTIVE

In the present study, it was aimed to investigate the anti-oxidative, anti-apoptotic, and cell cycle regulatory mechanisms underlying the neuroprotective effects of alkaloid extracts (chloroform, methanol, and water) from G. corniculatum, which was profiled for major alkaloid/alkaloids, against H₂O₂-induced neuronal damage in differentiated PC12 cells.

MATERIALS AND METHODS

The profiles of the alkaloid extracts were analyzed by GC-MS. The effects of the alkaloid extracts on intracellular ROS production, level of apoptotic cells, and cell cycle dysregulation were analyzed by flow cytometry; the effects on mRNA expression of apoptosis-related genes were also analyzed by qRT-PCR.

RESULTS

The same alkaloid components, allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide were obtained in all three solvents, but the ratios of the components differed according to the solvents. Allocryptopine was determined to be the major alkaloid ingredient in the alkaloid extracts, with the highest amount of allocryptopine (497 μg/mg) being found in the chloroform alkaloid extract (CAE) (*p < 0.05). The best results were obtained from CAE, which has the highest amount of allocryptopine among alkaloid extracts in all studies. CAE suppressed intracellular ROS production (5.7-fold), percentage of apoptotic cells (3.0-fold), and cells in the sub G1 phase (6.8-fold); additionally, it increased cells in the G1 phase (1.5-fold) (**p < 0.01). CAE remarkably reduced the expressions of Bax, Caspase-9/-3 mRNA (2.4-3.5-fold) while increasing the expression of Bcl-2 mRNA (3.0-fold) (*p < 0.05).

CONCLUSIONS

Our results demonstrated that alkaloid extracts from G. corniculatum, which contain allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide suppressed oxidative stress-induced neuronal apoptosis, possibly by suppressing the mitochondrial apoptotic pathway and regulating the cell cycle. These results are the first report that related alkaloids have played a neuroprotective role by regulating multiple mechanisms. Thus, our study indicated that these alkaloids especially allocryptopine could offer an efficient and novel strategy to explore novel drugs for neuroprotection and cognitive improvement.

(-)-Syringaresinol-4-O-β-D-glucopyranoside from Cortex Albizziae inhibits corticosterone-induced PC12 cell apoptosis and relieves the associated dysfunction

The neuroprotective effects and potential mechanisms of (-)-Syringaresinol-4-O-β-D-glucopyranoside (SRG), a natural lignan glycoside extracted from Cortex Albizziae, were investigated using corticosterone (CORT)-induced PC12 cells as an in vitro anxiety model. PC12 cells were treated with 100 μM CORT and 5, 10, or 20 μM SRG for 48 h. Cell viability and lactate dehydrogenase (LDH) leakage were measured. Apoptosis were detected using FITC-coupled Annexin V (AV) and propidium iodide (PI) staining flow cytometric analyses and TUNEL assays. Rhodamine 123 and Fluo-3-AM staining flow cytometric analyses were used to detect mitochondrial membrane potential (ΔΨm) and intracellular calcium concentration ([Ca²⁺]_i), respectively. Western blot was used to detect brain-derived neurotrophic factor (BDNF), Bax, Bcl-2, cAMP-response element binding protein (CREB), cytosolic cytochrome c (Cyt c), caspase-3, and cleaved caspase-3. Experimental data showed that SRG promoted cell proliferation, reduced LDH release, inhibited apoptosis, improved ΔΨm values, decreased [Ca²⁺]_i, up-regulated CREB, BDNF, and Bcl-2, down-regulated Bax and Cyt c protein expression levels, and reduced caspase-3 activity. This suggests that SRG has neuroprotective and antiapoptotic effects in the pathogenesis of anxiety disorders, and its mechanisms are partly connecte to inhibition of the mitochondrial apoptotic pathway and activation of pathways involving CREB and BDNF.

Salidroside mitigates hydrogen peroxide-induced injury by enhancement of microRNA-27a in human trabecular meshwork cells

Salidroside (Sal) exerted widely pharmacological effects in multitudinous diseases had been certified. The actual study clarified the protective activity of Sal in H₂O₂-injured human trabecular meshwork (HTM) cells. HTM cells were disposed with H₂O₂ to construct an oxidative damage model in vitro. Then, Sal was utilized to administrate HTM cells, and cell viability, apoptosis, apoptosis-interrelated proteins and ROS production were appraised using CCK-8, flow cytometry, western blot and DCFH-DA staining. MiR-27a inhibitor and its control were transfected into HTM cells, and the influences of miR-27a inhibition in HTM cells stimulated with H₂O₂ and Sal were detected. PI3K/AKT and Wnt/β-catenin pathways were ultimately investigated to uncover the underlying mechanism. We found that H₂O₂ evoked HTM cells oxidative damage, as evidenced by repressing cell viability, inducing apoptosis, activating cleaved-caspase-3/-9 expression and increasing ROS production. Sal significantly lightened H₂O₂-evoked oxidative damage in HTM cells. Additionally, miR-27a was up-regulated by Sal, and miR-27a suppression significantly reversed the protective effect of Sal on H₂O₂-injured HTM cells. Finally, Sal activated PI3K/AKT and Wnt/β-catenin pathways through enhancement of miR-27a in H₂O₂-injured HTM cells. In conclusion, these discoveries suggested that Sal could protect HTM cells against H₂O₂-evoked oxidative damage by activating PI3K/AKT and Wnt/β-catenin pathways through enhancement of miR-27a. Highlights H₂O₂ evokes HTM cells oxidative damage; Sal relieves H₂O₂-induced oxidative damage in HTM cells; Sal enhances miR-27a expression in H₂O₂-injured HTM cells; Repressed miR-27a reverses the protective impacts of Sal on H₂O₂-injured HTM cells; Sal activates PI3K/AKT and Wnt/β-catenin pathways by increasing miR-27a.

Neuroprotective and Memory-Enhancing Effects of Antioxidant Peptide From Walnut (Juglans regia L.) Protein Hydrolysates

Peptides have been reported to possess interesting biological properties. The present study was designed to evaluate neuroprotective and memory-enhancing effects of antioxidant peptide from walnut ( Juglans regia L.) protein hydrolysates. The neuroprotective effect of walnut peptide (WP) against oxidative stress on PC12 cells was evaluated. And zebrafish was used as the model to corroborate the effect. Its effect on learning and memory of mice using the Morris water maze and the step-down passive avoidance tests were performed. Moreover, the acute toxicity of WP was carried out to assess its safety profile. It was found that WP was able to suppress H2O2-induced cell death in PC12 cells. In the zebrafish model, WP had an obvious neuroprotective effect, and the ratio reached 42% at 222 µg/mL. The mechanism study revealed that WP could inhibit the activity of caspases 3/7 and 8, reduce the mRNA expression levels of Bax and glial cell line-derived neurotrophic factor, and improve the mRNA expression level of brain-derived neurotrophic factor significantly. Besides, the treatment of mice with WP shortened the escape latency and exhibited much longer target time and more crossing times significantly, compared with untreated control groups in the Morris water maze test. Similarly, the step-down passive avoidance test showed that WP could ameliorate memory impairments. The administrated dose (20.1 g/kg body weight [BW]) did not produce mortality or treatment-related adverse effects with regard to BW, general behavior, or relative organ weights of the tested male and female mice. The current results indicated that WP could exert neuroprotective effect, and attenuated learning and memory impairments. These ameliorating effects of WP may be useful for treatment of memory impairment in Alzheimer’s and its related diseases.

Crocin protects against dexamethasone‑induced osteoblast apoptosis by inhibiting the ROS/Ca2+‑mediated mitochondrial pathway

Osteoblast apoptosis has been identified as an important event in the development of glucocorticoid (GC)-induced osteoporosis and osteonecrosis of the femoral head. Crocin, a bioactive ingredient of saffron, has been demonstrated to induce antiapoptotic effects on numerous types of cell in vitro; however, the effects of crocin on the dexamethasone (Dex)-induced apoptosis of osteoblasts remain unclear. In the present study, the protective effects of crocin during Dex-induced apoptosis of MC3T3-E1 osteoblasts, and the underlying mechanisms, were investigated. MTT and Annexin V-FITC/PI flow cytometry assays were performed to evaluate the viability and apoptosis of cells, respectively. The mitochondrial transmembrane potential, reactive oxygen species (ROS), intracellular Ca²⁺ levels and apoptosis-associated protein expression were assessed via flow cytometry, fluorescence microscopy and western blotting. It was demonstrated that crocin pretreatment inhibited Dex-induced apoptosis of osteoblasts in a dose-dependent manner. Crocin reversed Dex-induced decreases in the mitochondrial transmembrane potential, and increases in ROS and intracellular Ca²⁺ levels. Furthermore, crocin upregulated the expression levels of B-cell lymphoma-2 (Bcl-2) and mitochondrial cytochrome c (Cyt C), and downregulated those of cleaved caspase-9, cleaved caspase-3, Bcl-2-associated X protein and cytoplasmic Cyt C. N-acetylcysteine, a ROS inhibitor, and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, a calcium chelator, attenuated Dex-induced osteoblast apoptosis, whereas H₂O₂ and ionomycin, a calcium ionophore that increases intracellular calcium levels, reversed the antiapoptotic effects of crocin on Dex-treated osteoblasts. These results indicated that crocin may protect osteoblasts from Dex-induced apoptosis by inhibiting the ROS/Ca²⁺-mediated mitochondrial pathway, thus suggesting that crocin has potential value as a treatment for GC-induced bone diseases.

Trametenolic acid B protects against cerebral ischemia and reperfusion injury through modulation of microRNA-10a and PI3K/Akt/mTOR signaling pathways

Trametenolic acid B (TAB) was a lanostane-type triterpenoid isolated from the trametes lactinea (Berk.) Pat. We have previously reported that extract from trametes lactinea (Berk.) Pat and TAB could efficiently improve learning and memory ability of the cerebral ischemia injury rats and suppress mitochondrial-mediated apoptosis in hydrogen peroxide damaged SH-SY5Y cells. However, the potential mechanisms have not been fully understood yet. The current study was to further investigate the protective effect of TAB on oxygen glucose deprivation/reoxygenation (OGD/R)-damaged SH-SY5Y cells and cerebral ischemia/reperfusion (I/R) injury rats, as well as its mechanisms involved. Cell experiments demonstrated that TAB (10, 20 and 40 μg/mL) protected OGD/R-induced SH-SY5Y cell injury by promoting cell proliferation and suppressing LDH leakage; Meanwhile, the results in vivo showed that TAB (20, 40 and 80 mg/kg) might significantly ameliorate the neurological deficit score, cerebral edema, neuronal cell loss and apoptosis, suppress cerebral infarction volume of the cerebral I/R injury rats. Further studies in vitro and in vivo indicated TAB could efficiently reduce OGD/R-damaged SH-SY5Y cell and cerebral I/R rat serum ROS, LDH and MDA levels, elevate SOD, GSH-Px and CAT activities, downregulate miR-10a mRNA and Bax, cytochrome C, cleaved-caspase-3 and cleaved-caspase-9 protein expressions, upregulate p-PIK3CA, p-Akt, p-mTOR, Bcl-2, pro-caspase-9 and pro-caspase-3 protein expressions and p-PIK3CA/PIK3CA, p-Akt/Akt, p-mTOR/mTOR ratios (P < 0.05 or P < 0.01, respectively). Our present study indicated that TAB possessed neuroprotective property against ODG/R and I/R injury by suppressing miR-10a expression, activating PI3K/Akt/mTOR signaling pathway, thereby reducing mitochondrial-mediated apoptosis, which provided a new insight for interpreting the underlying mechanisms of TAB' neuroprotective effect and a candidate agent to treat cerebral I/R injury.

Gastroprotective effect of araloside A on ethanol- and aspirin-induced gastric ulcer in mice: involvement of H+/K+-ATPase and mitochondrial-mediated signaling pathway

The aim of this study was to elucidate the gastroprotective activity and possible mechanism of involvement of araloside A (ARA) against ethanol- and aspirin-induced gastric ulcer in mice. The experimental mice were randomly divided into control, model, omeprazole (20 mg/kg, orally) and ARA (10, 20 and 40 mg/kg, orally). Gastric ulcer in mice was induced by intragastric administration of 80% ethanol (10 mL/kg) containing 15 mg/mL aspirin 4 h after drug administration on day 7. The results indicated that ARA could significantly raise gastric juice volume and acidity; ameliorate gastric mucosal blood flow, gastric binding mucus volume, ulcer index and ulcer inhibition rate; suppress H⁺/K⁺-ATPase activity, which was confirmed by computer-aided docking simulations; inhibit the release of mitochondrial cytochrome c into the cytoplasm; inhibit caspase-9 and caspase-3 activities and down-regulate mRNA expression levels; down-regulate the mRNA and protein expressions of apoptosis protease-activating factor-1 and protein expression of cleaved poly(ADP ribose) polymerase-1; and up-regulate Bcl-2 mRNA and protein expressions and down-regulate Bax mRNA and protein expressions, thus elevating the Bcl-2/Bax ratio in a dose-dependent manner. Histopathological observations further provided supportive evidence for the aforementioned results. The results demonstrated that ARA exerted beneficial gastroprotective effects on alcohol- and aspirin-induced gastric ulcer in mice, which was related to suppressing H⁺/K⁺-ATPase activity as well as pro-apoptotic protein expression, and promoting anti-apoptotic protein expression, thus alleviating gastric mucosal injury and cell death.

Orexin-A protects SH-SY5Y cells against H2O2-induced oxidative damage via the PI3K/MEK1/2/ERK1/2 signaling pathway

Orexin-A elicits multiple potent effects on a variety of tumor cells via different signaling pathways. However, it is unknown whether it has a neuroprotective effect on SH-SY5Y human neuroblastoma cells. This study investigated the neuroprotective effect of Orexin-A against hydrogen peroxide (H₂O₂)-induced oxidative damage in SH-SY5Y cells and the underlying mechanism. H₂O₂ treatment decreased the viability of SH-SY5Y cells, induced apoptosis, and decreased superoxide dismutase activity. Orexin-A attenuated these effects, indicating that it protects SH-SY5Y cells against H₂O₂-induced oxidative damage. Pre-treatment with Orexin-A also attenuated H₂O₂-induced increases in phosphorylation of MEK_1/2 and ERK_1/2. Moreover, these effects of Orexin-A were reduced in the presence of the PI3K inhibitor LY294002. Finally, pre-treatment with LY294002 abrogated attenuation of the H₂O₂-induced decrease in cell viability and increase in caspase-3/7 activity by Orexin-A. These results show that the PI3K/MEK_1/2/ERK_1/2 signaling pathway is involved in the neuroprotective effects of Orexin-A against H₂O₂-induced oxidative damage in SH-SY5Y cells. Our findings provide insight into the neuroprotective effects of Orexin-A and the underlying mechanism, which will be useful for the treatment of nervous system diseases.

miR-146a down-regulation alleviates H2O2-induced cytotoxicity of PC12 cells by regulating MCL1/JAK/STAT pathway : miR-146a down-regulation relieves H2O2-induced PC12 cells cytotoxicity by MCL1/JAK/STAT

Oxidative stress and miRNAs have been confirmed to play an important role in neurological diseases. The study aimed to explore the underlying effect and mechanisms of miR-146a in H₂O₂-induced injury of PC12 cells. Here, PC12 cells were stimulated with 200 μM of H₂O₂ to construct oxidative injury model. Cell injury was evaluated on the basis of the changes in cell viability, migration, invasion, apoptosis, and DNA damage. Results revealed that miR-146a expression was up-regulated in H₂O₂-induced PC12 cells. Functional analysis showed that down-regulation of miR-146a alleviated H₂O₂-induced cytotoxicity in PC12 cells. Dual-luciferase reporter and western blot assay verified that MCL1 was a direct target gene of miR-146a. Moreover, anti-miR-146a-mediated suppression on cell cytotoxicity was abated following MCL1 knockdown in H₂O₂-induced PC12 cells. Furthermore, MCL1 activated JAK/STAT signaling pathway and MCL1 overexpression attenuated H₂O₂-induced cytotoxicity in PC12 cells by JAK/STAT signaling pathway. In conclusion, this study suggested that suppression of miR-146a abated H₂O₂-induced cytotoxicity in PC12 cells via regulating MCL1/JAK/STAT pathway.