Anthocyanin Extracts from Black Soybean (Glycine max L.) Protect Human Glial Cells Against Oxygen-Glucose Deprivation by Promoting Autophagy

Prevention of motor relapses and associated trigeminal pain in experimental autoimmune encephalomyelitis by reducing neuroinflammation with a purple corn extract enriched in anthocyanins

Multiple sclerosis (MS) is the leading cause of disability in young adults, with about 2.5-3 million cases currently diagnosed. Pain is a common comorbid symptom of MS, and develops independently from motor impairments. Currently utilized drugs bear severe side effects; thus, new therapeutic strategies are needed, and nutraceutical supplements represent innovative and safe opportunities. We have selected a variety of anthocyanin-enriched purple corn, from which a water-soluble extract (Red extract) has been obtained and administered to male rats exposed to experimental autoimmune encephalomyelitis (EAE). Animals developed relapsing-remitting motor symptoms, accompanied by early onset trigeminal allodynia. The preventive administration of Red extract facilitated the remission of motor symptoms, prevented the development of relapses, and delayed and reduced the development of EAE-associated trigeminal pain. An overall inhibition of neuroinflammation, blunted microgliosis and astrogliosis, activation of autophagy and reduced immune cell infiltration in the brainstem, cervical and lumbar spinal cord were observed. Yellow corn extract, lacking anthocyanins, had no behavioral effects, despite a limited anti-inflammatory action. Therapeutic Red extract administration did not affect EAE motor symptoms, only partially reduced the development of trigeminal pain but maintained its ability to reduce neuroinflammation and glial cell activation and to promote autophagy. Overall, our data suggest that a nutraceutical supplement from anthocyanin-enriched purple corn represents an interesting option to limit the development of motor relapses and the chronicization of multiple sclerosis-associated pain, through the mitigation of neuroinflammation, of the infiltration of immune cells and the promotion of autophagy.

Unveiling the nutrient-wealth of black soybean: A holistic review of its bioactive compounds and health implications

Legumes, an essential component of staple diets, hold a prominent place in global cuisines. Soybean stands out as a widely cultivated legume and is valued for its high protein content, dietary fiber, and rich micronutrients. Several varieties of soybean are available, of which black and yellow varieties show dominance in varied countries and cultures. Over time, the cultivation and consumption of black soybeans have markedly reduced compared to the yellow variety. Despite its rich nutritional and therapeutic indices, it has lost its usage over time. Traditionally, it was utilized in oriental medicine for detoxification and anti-inflammatory potential. However, the antinutrients present in black soybean limit its utilization in the food sector due to their interference with overall nutrient absorption. Several studies in the last few decades have focused on reducing the content of antinutritional factors. However, the information on the use of different processing techniques, both singly and in blends, to reduce antinutrients and enhance the bioaccessibility, bioavailability, and bioactivity of bioactive compounds and varied nutrients is limited and fragmented. Furthermore, studies have highlighted black soybeans' protective effects against various degenerative diseases. However, the studies on the effect of processing to enhance its antioxidative properties to make them a sought-after food commodity with nutraceutical potential and therapeutic efficacy are limited and widely scattered. The review aims to consolidate knowledge of diverse processing methods to improve their nutritional and bioactive profile for wider applications in the food and pharmaceutical industries. Further, it has also highlighted its nutraceutical properties for developing varied functional foods against degenerative diseases to have better therapeutic efficacy.

Astrocyte modulation in cerebral ischemia-reperfusion injury: A promising therapeutic strategy

Cerebral ischemia-reperfusion injury (CIRI) poses significant challenges for drug development due to its complex pathogenesis. Astrocyte involvement in CIRI pathogenesis has led to the development of novel astrocyte-targeting drug strategies. To comprehensively review the current literature, we conducted a thorough analysis from January 2012 to December 2023, identifying 82 drugs aimed at preventing and treating CIRI. These drugs target astrocytes to exert potential benefits in CIRI, and their primary actions include modulation of relevant signaling pathways to inhibit neuroinflammation and oxidative stress, reduce cerebral edema, restore blood-brain barrier integrity, suppress excitotoxicity, and regulate autophagy. Notably, active components from traditional Chinese medicines (TCM) such as Salvia miltiorrhiza, Ginkgo, and Ginseng exhibit these important pharmacological properties and show promise in the treatment of CIRI. This review highlights the potential of astrocyte-targeted drugs to ameliorate CIRI and categorizes them based on their mechanisms of action, underscoring their therapeutic potential in targeting astrocytes.

Tactics with Prebiotics for the Treatment of Metabolic Dysfunction-Associated Fatty Liver Disease via the Improvement of Mitophagy

Mitophagy/autophagy plays a protective role in various forms of liver damage, by renovating cellular metabolism linking to sustain liver homeostasis. A characterized pathway for mitophagy is the phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1)/Parkin-dependent signaling pathway. In particular, PINK1-mediated mitophagy could play an indispensable role in improving the metabolic dysfunction-associated fatty liver disease (MAFLD) which could precede to steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma. In addition, the PI3K/AKT/mTOR pathway might regulate the various characteristics of cellular homeostasis including energy metabolism, cell proliferation, and/or cell protection. Therefore, targeting mitophagy with the alteration of PI3K/AKT/mTOR or PINK1/Parkin-dependent signaling to eliminate impaired mitochondria might be an attractive strategy for the treatment of MAFLD. In particular, the efficacy of prebiotics for the treatment of MAFLD has been suggested to be useful via the modulation of the PI3K/AKT/mTOR/AMPK pathway. Additionally, several edible phytochemicals could activate mitophagy for the improvement of mitochondrial damages, which could also be a promising option to treat MAFLD with providing liver protection. Here, the potential therapeutics with several phytochemicals has been discussed for the treatment of MAFLD. Tactics with a viewpoint of prospective probiotics might contribute to the development of therapeutic interventions.

Potential Diets to Improve Mitochondrial Activity in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, the pathogenesis of which is based on alternations in the mitochondria of motor neurons, causing their progressive death. A growing body of evidence shows that more efficient mitophagy could prevent and/or treat this disorder by suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. Mitophagy has been considered one of the main mechanisms responsible for mitochondrial quality control. Since ALS is characterized by enormous oxidative stress, several edible phytochemicals that can activate mitophagy to remove damaged mitochondria could be considered a promising option to treat ALS by providing neuroprotection. Therefore, it is of great significance to explore the mechanisms of mitophagy in ALS and to understand the effects and/or molecular mechanisms of phytochemical action, which could translate into a treatment for neurodegenerative diseases, including ALS.

Research progress on astrocyte autophagy in ischemic stroke

Ischemic stroke is a highly disabling and potentially fatal disease. After ischemic stroke, autophagy plays a key regulatory role as an intracellular catabolic pathway for misfolded proteins and damaged organelles. Mounting evidence indicates that astrocytes are strongly linked to the occurrence and development of cerebral ischemia. In recent years, great progress has been made in the investigation of astrocyte autophagy during ischemic stroke. This article summarizes the roles and potential mechanisms of astrocyte autophagy in ischemic stroke, briefly expounds on the crosstalk of astrocyte autophagy with pathological mechanisms and its potential protective effect on neurons, and reviews astrocytic autophagy-targeted therapeutic methods for cerebral ischemia. The broader aim of the report is to provide new perspectives and strategies for the treatment of cerebral ischemia and a reference for future research on cerebral ischemia.

The dual roles of autophagy and the GPCRs-mediating autophagy signaling pathway after cerebral ischemic stroke

Ischemic stroke, caused by a lack of blood supply in brain tissues, is the third leading cause of human death and disability worldwide, and usually results in sensory and motor dysfunction, cognitive impairment, and in severe cases, even death. Autophagy is a highly conserved lysosome-dependent process in which eukaryotic cells removal misfolded proteins and damaged organelles in cytoplasm, which is critical for energy metabolism, organelle renewal, and maintenance of intracellular homeostasis. Increasing evidence suggests that autophagy plays important roles in pathophysiological mechanisms under ischemic conditions. However, there are still controversies about whether autophagy plays a neuroprotective or damaging role after ischemia. G-protein-coupled receptors (GPCRs), one of the largest protein receptor superfamilies in mammals, play crucial roles in various physiological and pathological processes. Statistics show that GPCRs are the targets of about one-fifth of drugs known in the world, predicting potential values as targets for drug research. Studies have demonstrated that nutritional deprivation can directly or indirectly activate GPCRs, mediating a series of downstream biological processes, including autophagy. It can be concluded that there are interactions between autophagy and GPCRs signaling pathway, which provides research evidence for regulating GPCRs-mediated autophagy. This review aims to systematically discuss the underlying mechanism and dual roles of autophagy in cerebral ischemia, and describe the GPCRs-mediated autophagy, hoping to probe promising therapeutic targets for ischemic stroke through in-depth exploration of the GPCRs-mediated autophagy signaling pathway.

Targeting autophagy in ischemic stroke: From molecular mechanisms to clinical therapeutics

Stroke constitutes the second leading cause of death and a major cause of disability worldwide. Stroke is normally classified as either ischemic or hemorrhagic stroke (HS) although 87% of cases belong to ischemic nature. Approximately 700,000 individuals suffer an ischemic stroke (IS) in the US each year. Recent evidence has denoted a rather pivotal role for defective macroautophagy/autophagy in the pathogenesis of IS. Cellular response to stroke includes autophagy as an adaptive mechanism that alleviates cellular stresses by removing long-lived or damaged organelles, protein aggregates, and surplus cellular components via the autophagosome-lysosomal degradation process. In this context, autophagy functions as an essential cellular process to maintain cellular homeostasis and organismal survival. However, unchecked or excessive induction of autophagy has been perceived to be detrimental and its contribution to neuronal cell death remains largely unknown. In this review, we will summarize the role of autophagy in IS, and discuss potential strategies, particularly, employment of natural compounds for IS treatment through manipulation of autophagy.

Natural compounds modulate the autophagy with potential implication of stroke

Stroke is considered a leading cause of mortality and neurological disability, which puts a huge burden on individuals and the community. To date, effective therapy for stroke has been limited by its complex pathological mechanisms. Autophagy refers to an intracellular degrading process with the involvement of lysosomes. Autophagy plays a critical role in maintaining the homeostasis and survival of cells by eliminating damaged or non-essential cellular constituents. Increasing evidence support that autophagy protects neuronal cells from ischemic injury. However, under certain circumstances, autophagy activation induces cell death and aggravates ischemic brain injury. Diverse naturally derived compounds have been found to modulate autophagy and exert neuroprotection against stroke. In the present work, we have reviewed recent advances in naturally derived compounds that regulate autophagy and discussed their potential application in stroke treatment.

Total flavones of Dracocephalum moldavica L. protect astrocytes against H2O2-induced apoptosis through a mitochondria-dependent pathway

BACKGROUND

The active components of Dracocephalum moldavica L. (TFDM) can inhibit myocardial ischemia by inhibiting oxidative stress. However, the effects of TFDM on astrocytes have not been investigated in vitro. The current study aimed to explore whether TFDM protects astrocytes against H₂O₂-induced apoptosis through a mitochondria-dependent pathway.

METHODS

The human glioma cell line U87 was used to investigate the ability of TFDM to protect astrocytes against H₂O₂-induced apoptosis. The cell counting kit-8 assay and flow cytometry were used to detect cell viability, apoptosis, MMP, Ca²⁺ influx and reactive oxygen species (ROS). Lactate dehydrogenase (LDH) and malonic dialdehyde (MDA) levels were measured by ELISA. In addition, protein and mRNA expression changes were detected by Western blotting and qRT-PCR.

RESULTS

TFDM (0.78~200 μg/ml) had limited cytotoxic effects on the viability of U87 cells. Compared with the model group (treated with H2O2 only), cells treated with medium- and high-dose TFDM exhibited reduced MDA concentrations (P < 0.05) and ROS production (P < 0.05) and decreased MMP (P < 0.05) and reduced apoptosis (P < 0.05). The percentage of annexin V-FITC-stained cells was markedly suppressed by TFDM, confirming its anti-apoptotic properties. WB results showed that protein expression of Bcl-2-associated X protein (BAX), Caspase-3, Caspase-9, Caspase-12, and B-cell leukemia/lymphoma 2 (Bcl2) was reduced in the TFDM group compared with that in the model group (P < 0.05) and that expression of these proteins was normalized by TFDM treatment in a dose-dependent manner. According to RT-qPCR results, TFDM pretreatment resulted in reduced mRNA expression of BAX, Caspase-9, Caspase-12, p38MAPK, and CaMKII and increased mRNA expression of mTOR compared with the model group.

CONCLUSIONS

The current study revealed the protective effects of TFDM on U87 cells under oxidative stress conditions through the inhibition of a mitochondria-dependent pathway that is associated with the CaMKII/P38MAPK/ERK1/2 and PI3K/AKT/mTOR pathways.

Dietary Anthocyanins and Stroke: A Review of Pharmacokinetic and Pharmacodynamic Studies

Cerebrovascular accidents are currently the second major cause of death and the third leading cause of disability in the world, according to the World Health Organization (WHO), which has provided protocols for stroke prevention. Although there is a multitude of studies on the health benefits associated with anthocyanin (ACN) consumption, there is no a rigorous systematization of the data linking dietary ACN with stroke prevention. This review is intended to present data from epidemiological, in vitro, in vivo, and clinical studies dealing with the stroke related to ACN-rich diets or ACN supplements, along with possible mechanisms of action revealed by pharmacokinetic studies, including ACN passage through the blood-brain barrier (BBB).

The Impact of O-Glycosylation on Cyanidin Interaction with RBCs and HMEC-1 Cells-Structure⁻Activity Relationships

With the aim of contributing to the knowledge about their potential therapeutic activity, we determined the biological activities of cyanidin and its selected O-glycosides in relation to erythrocytes (RBCs) and human dermal vascular endothelial cells (HMEC-1). Furthermore, on the basis of changes in the physical/functional properties of the cells, the structure–activity relationships of the compounds were determined. Concerning erythrocytes, we analyzed the antioxidant activity of the compounds and their impact on the RBCs’ shape and transmembrane potential. The compounds’ cytotoxic activity, ability to modulate apoptosis, cell cycle, and intracellular ROS generation, as well as inhibitory activity against AAPH-inducted oxidative stress, were determined in relation to HMEC-1 cells. We demonstrated that biological activity of cyanidin and its O-glycosides strongly depends on the number and type of sugar substituents, and varies depending on the extracellular environment and type of cells. The compounds are practically non-cytotoxic, and do not induce apoptosis or disturb the progression of the cell cycle. Additionally, the compounds alter the shape of RBCs, but they do not affect their transmembrane potential. They effectively protect erythrocytes against free radicals and affect intracellular reactive oxygen spices (ROS) generation under physiological and AAPH-induced oxidative stress conditions. Our results suggest a potential beneficial effect of cyanidin on the cardiovascular system.

Effect of polysaccharide from Undaria pinnatifida on proliferation, migration and apoptosis of breast cancer cell MCF7

Sulfated polysaccharide from Undaria pinnatifida (SPUP) has significant anti-breast cancer activity. However, its anticarcinogenic mechanism still remains unclear. The aim of this article is to observe the effect of SPUP on proliferation, migration and apoptosis of human breast cancer cell line MCF7. Firstly, the effect of SPUP on proliferation was evaluated through MTT assay, plate clonality assay and immunofluorescence test of PCNA. The results showed that SPUP could significantly reduce MCF7 cells proliferation in a time- and dose-dependent manner. Based on transwell and scratch wound healing assays, then, inhibitory action of SPUP for MCF7 cells migration was observed. Finally, apoptosis and cycle arrest of SPUP for MCF7 cells also were found by the results from both flow cytometry analysis and Hoechst 33342 staining of apoptotic cells. Overall, these results showed anti-breast cancer mechanism of SPUP could be possibly related to inhibit migration, proliferation and induce apoptosis of cancer cells.

Purple sweet potato color protects against high-fat diet-induced cognitive deficits through AMPK-mediated autophagy in mouse hippocampus

Prevention of obesity-induced cognitive decline is an important public health goal. Purple sweet potato color (PSPC), a class of naturally occurring anthocyanins, has beneficial potentials including antioxidant and neuroprotective activity. Evidence shows that anthocyanins can activate AMP-activated protein kinase (AMPK), a critical mediator of autophagy induction. This study investigated whether PSPC could improve cognitive function through regulating AMPK/autophagy signaling in HFD-fed obese mice. Our results showed that PSPC significantly ameliorated obesity, peripheral insulin resistance and memory impairment in HFD-fed mice. Moreover, enhanced autophagy was observed, along with the decreased levels of protein carbonyls, malondialdehyde and reactive oxygen species (ROS) in the hippocampus of HFD-fed mice due to PSPC administration. PSPC also promoted hippocampal brain-derived neurotrophic factor (BDNF) expression and neuron survival in HFD-fed mouse. These improvements were mediated, at least in part, by the activation of AMPK, which was confirmed by metformin treatment. It is concluded that PSPC has great potential to improve cognitive function in HFD-fed mice via AMPK activation that restores autophagy and protects against hippocampal apoptosis.

Autophagy in glioma cells: An identity crisis with a clinical perspective

Over the last decade, autophagy has emerged as one of the critical cellular systems that control homeostasis. Besides management of normal homeostatic processes, autophagy can also be induced by tissue damage stress or by rapidly progressing tumors. During tumor progression, autophagy mediates a cellular reaction to the changes inside and outside of cells, which leads to tumor adaptation. Even though the regulation of autophagy seems universal and is a well-described process, its dysregulation and role in glioma progression remain an important topic of investigation. In this review, we summarize recent evidence of autophagy regulation in brain tumor tissues and possible interconnection between signaling pathways that govern cellular responses. This perspective may help to assess the qualitative differences and various outcomes in response to autophagy stimulation.

Phytochemicals as potent modulators of autophagy for cancer therapy

The dysregulation of autophagy is involved in the pathogenesis of a broad range of diseases, and accordingly universal research efforts have focused on exploring novel compounds with autophagy-modulating properties. While a number of synthetic autophagy modulators have been identified as promising cancer therapy candidates, autophagy-modulating phytochemicals have also attracted attention as potential treatments with minimal side effects. In this review, we firstly highlight the importance of autophagy and its relevance in the pathogenesis and treatment of cancer. Subsequently, we present the data on common phytochemicals and their mechanism of action as autophagy modulators. Finally, we discuss the challenges associated with harnessing the autophagic potential of phytochemicals for cancer therapy.

Radioprotective effects of delphinidin on normal human lung cells against proton beam exposure

BACKGROUND/OBJECTIVES

Exposure of the normal lung tissue around the cancerous tumor during radiotherapy causes serious side effects such as pneumonitis and pulmonary fibrosis. Radioprotectors used during cancer radiotherapy could protect the patient from side effects induced by radiation injury of the normal tissue. Delphinidin has strong antioxidant properties, and it works as the driving force of a radioprotective effect by scavenging radiation-induced reactive oxygen species (ROS). However, no studies have been conducted on the radioprotective effect of delphinidin against high linear energy transfer radiation. Therefore, this study was undertaken to evaluate the radioprotective effects of delphinidin on human lung cells against a proton beam.

MATERIALS/METHODS

Normal human lung cells (HEL 299 cells) were used for in vitro experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay assessed the cytotoxicity of delphinidin and cell viability. The expression of radiation induced cellular ROS was measured by the 2′-7′-dicholordihydrofluorescein diacetate assay. Superoxide dismutase activity assay and catalase activity assay were used for evaluating the activity of corresponding enzymes. In addition, radioprotective effects on DNA damage-induced cellular apoptosis were evaluated by Western blot assay.

RESULTS

Experimental analysis, including cell survival assay, MTT assay, and Western blot assay, revealed the radioprotective effects of delphinidin. These include restoring the activities of antioxidant enzymes of damaged cells, increase in the levels of pro-survival protein, and decrease of pro-apoptosis proteins. The results from different experiments were compatible with each to provide a substantial conclusion.

CONCLUSION

Low concentration (2.5 µM/mL) of delphinidin administration prior to radiation exposure was radioprotective against a low dose of proton beam exposure. Hence, delphinidin is a promising shielding agent against radiation, protecting the normal tissues around a cancerous tumor, which are unintentionally exposed to low doses of radiation during proton therapy.

Neuroprotective properties of anthocyanidin glycosides against H2O2-induced glial cell death are modulated by their different stability and antioxidant activity in vitro

The neuroprotective effect of several anthocyanins in combination with their stability and antioxidant/pro-oxidant activity has been investigated against H₂O₂-induced oxidative stress in C6 glial cells. First it was found that delphinidin (Dp) 3-O-glucoside and 3-O-rutinoside were degraded within an hour, and at the same time stimulated the production of H₂O₂ in the micromolar concentration range. The stability of peonidin, pelargonidin (Pg), malvidin (Mv) and cyanidin (Cy) 3-O-glucosides and Cy 3-O-rutinoside was significantly higher than that of Dp 3-O-glycosides, with Pg3G showing the highest percent recovery over time. Based on these findings and chemical difference (according to the set of functional groups on the B-ring) of tested anthocyanins Cy3G, Mv3G and Pg3G were selected as candidates for the protection of glial cells against H₂O₂-induced oxidative stress. It was revealed that Cy3G (5-20μM) and Mv3G (10-20μM) but not Pg3G protected glial cells against H₂O₂-induced necrotic cell death. Moreover, these anthocyanins sustained the glutathione antioxidant defence system. Finally, to the extent of our knowledge we were the first to demonstrate the protective effect of Cy3G on the resting mitochondrial respiration rate in H₂O₂-affected glial cells. The results suggest that Cy3G, as the most prominent antioxidant among tested anthocyanins, could be a potential adjuvant for the prevention or reduction of necrotic glial cell death during the oxidative stress conditions met in neurodegenerative diseases. However, further elucidation of other possible mechanisms for anthocyanins to protect the nervous system is encouraged.

A Critical Review on Polyphenols and Health Benefits of Black Soybeans

Polyphenols are plant secondary metabolites containing antioxidant properties, which help to protect chronic diseases from free radical damage. Dietary polyphenols are the subject of enhancing scientific interest due to their possible beneficial effects on human health. In the last two decades, there has been more interest in the potential health benefits of dietary polyphenols as antioxidant. Black soybeans (Glycine max L. Merr) are merely a black variety of soybean containing a variety of phytochemicals. These phytochemicals in black soybean (BSB) are potentially effective in human health, including cancer, diabetes, cardiovascular diseases, cerebrovascular diseases, and neurodegenerative diseases. Taking into account exploratory study, the present review aims to provide up-to-date data on health benefit of BSB, which helps to explore their therapeutic values for future clinical settings. All data of in vitro and in vivo studies of BSB and its impact on human health were collected from a library database and electronic search (Science Direct, PubMed, and Google Scholar). The different pharmacological information was gathered and orchestrated in a suitable spot on the paper.

Health benefits of anthocyanins and molecular mechanisms: Update from recent decade

Anthocyanins are one of the most widespread families of natural pigments in the plant kingdom. Their health beneficial effects have been documented in many in vivo and in vitro studies. This review summarizes the most recent literature regarding the health benefits of anthocyanins and their molecular mechanisms. It appears that several signaling pathways, including mitogen-activated protein kinase, nuclear factor κB, AMP-activated protein kinase, and Wnt/β-catenin, as well as some crucial cellular processes, such as cell cycle, apoptosis, autophagy, and biochemical metabolism, are involved in these beneficial effects and may provide potential therapeutic targets and strategies for the improvement of a wide range of diseases in future. In addition, specific anthocyanin metabolites contributing to the observed in vivo biological activities, structure-activity relationships as well as additive and synergistic efficacy of anthocyanins are also discussed.

Time-Dependent Changes in Apoptosis Upon Autophagy Inhibition in Astrocytes Exposed to Oxygen and Glucose Deprivation

Recent studies have implicated the role of autophagy in brain ischemia pathophysiology. However, it remains unclear whether autophagy activation is protective or detrimental to astrocytes undergoing ischemic stress. This study evaluated the influence of ischemia-induced autophagy on cell death and the course of intrinsic and extrinsic apoptosis in primary cultures of rat cortical astrocytes exposed to combined oxygen-glucose deprivation (OGD). The role of autophagy was assessed by pharmacological inhibition with 3-methyladenine (3-MA). Cell viability was evaluated by measuring LDH release and through the use of the alamarBlue Assay. Apoptosis and necrosis were determined by fluorescence microscopy after Hoechst 33,342 and propidium iodide staining, respectively. The levels of apoptosis-related proteins were analyzed by immunoblotting. The downregulation of autophagy during OGD resulted in decreased cell viability and time-dependent changes in levels of apoptosis and necrosis. After short-term OGD (1, 4 h), cells treated with 3-MA showed higher level of cleaved caspase 3 compared with control cells. This result was consistent with an evaluation of apoptotic cell number by fluorescence microscopy. However, after prolonged exposure to OGD (8, 24 h), the number of apoptotic astrocytes (microscopically evaluated) did not differ or was even lower (as marked by caspase 3) in the presence of the autophagy inhibitor in comparison to the control. A higher level of necrosis was observed in 3-MA-treated cells compared to non-treated cells after 24 h OGD. The downregulation of autophagy caused time-dependent changes in both extrinsic (cleaved caspase 8, TNFα) and intrinsic (cleaved caspase 9) apoptotic pathways. Our results strongly indicate that the activation of autophagy in astrocytes undergoing ischemic stress is an adaptive mechanism, which allows for longer cell survival by delaying the initiation of apoptosis and necrosis.

Anthocyanins in the black soybean (Glycine max L.) protect U2OS cells from apoptosis by inducing autophagy via the activation of adenosyl monophosphate-dependent protein kinase

Anthocyanins (ATCs) have been reported to induce apoptosis in various types of cancer cells, stimulating the development of ATCs as a cancer chemotherapeutic or chemopreventive agent. It was recently reported that ATCs can induce autophagy, however, the mechanism for this remains unclear. In the present report, we carried out mechanistic studies of the mechanism involved in ATC-induced autophagy using ATCs extracted from black soybeans (cv. Cheongja 3, Glycine max L.). ATCs clearly induced hallmarks of autophagy, including LC3 puncta formation and the conversion of LC3-I to LC3-II in U2OS human osteosarcoma cells. The induction of autophagy was accompanied by the phosphorylation of multiple protein kinases including extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), protein kinase B (AKT) and adenosyl mono-phosphate-dependent protein kinase (AMPK). While chemical inhibitors against ERK1/2, p38 MAPK, JNK and AKT failed to inhibit ATC-induced autophagy, the suppression of AMPK by compound C (CC) as well as siRNA against AMPK reduced ATC-induced autophagy. The treatment of ATCs resulted in a decrease in intracellular ATP contents and the activation of AMPK by AICAR treatment also induced autophagy. It is noteworthy that the reduction of autophagy via the inhibition of AMPK resulted in enhanced apoptosis in ATC-treated cells. In addition, siRNA against forkhead box O3A (FOXO3a), a downstream target of AMPK, suppressed ATC-induced autophagy and p27KIP1 siRNA increased apoptosis in ATC-treated cells. Collectively, it can be concluded that ATCs induce autophagy in U2OS cells via activation of the AMPK-FOXO3a pathway and protect cells from ATC-induced apoptosis via the AMPK-p27KIP1 pathway. These results also suggest that autophagy-modulating agents could contribute to the efficient development of ATCs as anticancer therapy.

Decreased vulnerability of hippocampal neurons after neonatal hypoxia-ischemia in bis-deficient mice

The Bcl-2-interacting death suppressor (Bis) protein is involved in antiapoptosis and antistress pathways. However, its roles after neonatal hypoxia-ischemia remain obscure. Therefore, we investigated the effects of Bis deletion on hippocampal cell death following neonatal hypoxia-ischemia. We transected the right common carotid artery of bis(+/+) and bis(-/-) mice at postnatal Day 7 and subjected them to hypoxia for 35 min. Cresyl violet staining showed that hypoxia-ischemia induced progressive cell death in the hippocampi of bis(+/+) mice. Moreover, Bis was expressed in astrocytes, not microglia, in sham-manipulated hippocampi of bis(+/+) mice, and was markedly enhanced after hypoxia-ischemia. Immunoblotting showed that Bis expression significantly increased 3 and 7 days following hypoxia-ischemia. Unexpectedly, 7 days after hypoxia-ischemia, the number of hippocampal NeuN-positive cells was higher in the bis(-/-) mice than in the bis(+/+) mice. We subsequently performed transcriptomic analysis and quantitative real time polymerase chain reaction to search for the underlying genes responsible for resistance to hypoxia-ischemia in the bis(-/-) hippocampus. These studies showed that 6 h after hypoxia-ischemia, galectin 3 and filamin C levels increased to a lesser extent in the bis(-/-) hippocampi compared with the bis(+/+) hippocampi. Finally, our in vitro hypoxia-ischemia model, using A172 glioma cells and primary astrocytes, showed that downregulation of Bis blocked the enhanced expression of galectin 3 after oxygen-glucose deprivation. This study demonstrated that Bis was upregulated in the astrocytes after hypoxia-ischemia. In addition, we showed that hippocampal neurons are less vulnerable to hypoxia-ischemia in mice lacking Bis, possibly because of the modulation of galectin 3 induction.