Inhibition of autophagy via activation of PI3K/Akt pathway contributes to the protection of ginsenoside Rb1 against neuronal death caused by ischemic insults

Regulation of Autophagy Signaling Pathways by Ginseng Saponins: A Review

Ginseng saponins (ginsenosides), bioactive compounds derived from ginseng, are widely used natural products with potent therapeutic properties in the management of various ailments, particularly tumors, cardiovascular and cerebrovascular diseases, and immune system disorders. Autophagy, a highly regulated and multistep process involving the breakdown of impaired organelles and macromolecules by autophagolysosomes and autophagy-related genes (ATGs), has gained increasing attention as a potential target for ginsenoside-mediated disease treatment. This review aims to provide a comprehensive overview of recent research advances in the understanding of autophagy-related signaling pathways and the role of ginsenoside-mediated autophagy regulation. By delving into the intricate autophagy signaling pathways underpinning the pharmacological properties of ginsenosides, we highlight their therapeutic potential in addressing various conditions. Our findings serve as a comprehensive reference for further investigation into the medicinal properties of ginseng or ginseng-related products.

Ginsenoside Rb1 alleviates lipopolysaccharide-induced inflammation in human dental pulp cells via the PI3K/Akt, NF-κB, and MAPK signalling pathways

AIM

Among numerous constituents of Panax ginseng, a constituent named Ginsenoside Rb1 (G-Rb1) has been studied to diminish inflammation associated with diseases. This study investigated the anti-inflammatory properties of G-Rb1 on human dental pulp cells (hDPCs) exposed to lipopolysaccharide (LPS) and aimed to determine the underlying molecular mechanisms.

METHODOLOGY

The KEGG pathway analysis was performed after RNA sequencing in G-Rb1- and LPS-treated hDPCs. Reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis were used for the assessment of cell adhesion molecules and inflammatory cytokines. Statistical analysis was performed with one-way ANOVA and the Student-Newman-Keuls test.

RESULTS

G-Rb1 did not exhibit any cytotoxicity within the range of concentrations tested. However, it affected the levels of TNF-α, IL-6 and IL-8, as these showed reduced levels with exposure to LPS. Additionally, less mRNA and protein expressions of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were shown. With the presence of G-Rb1, decreased levels of PI3K/Akt, phosphorylated IκBα and p65 were also observed. Furthermore, phosphorylated ERK and JNK by LPS were diminished within 15, 30 and 60 min of G-Rb1 exposure; however, the expression of non-phosphorylated ERK and JNK remained unchanged.

CONCLUSIONS

G-Rb1 suppressed the LPS-induced increase of cell adhesion molecules and inflammatory cytokines, while also inhibiting PI3K/Akt, phosphorylation of NF-κB transcription factors, ERK and JNK of MAPK signalling in hDPCs.

The advancement of polysaccharides in disease modulation: Multifaceted regulation of programmed cell death

Programmed cell death (PCD), also known as regulatory cell death (RCD), is a process that occurs in all organisms and is closely linked to both normal physiological processes and disease states. Various signaling pathways, such as TP53, KRAS, NOTCH, hypoxia, and metabolic reprogramming, have been found to regulate RCD. Polysaccharides, which are essential natural products, have been the subject of extensive research in the fields of food, nutrition, and medicine due to their wide range of pharmacological effects. Studies have shown that polysaccharides have biological activities and the potential to target signal transduction pathways for the treatment of diseases. This paper provides a review of the mechanisms through which polysaccharides exert their therapeutic effects at different levels and explores the relationship between different types of RCD and human diseases. The aim of this review is to provide a theoretical basis for the further clinical use and application of polysaccharide bioactivities.

Progress of Ginsenoside Rb1 in neurological disorders

Ginseng is frequently used in traditional Chinese medicine to treat neurological disorders. The primary active component of ginseng is ginsenoside, which has been classified into more than 110 types based on their chemical structures. Ginsenoside Rb1 (GsRb1)-a protopanaxadiol saponin and a typical ginseng component-exhibits anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-autophagy properties in the nervous system. Neurological disorders remain a leading cause of death and disability globally. GsRb1 effectively treats neurological disorders. To contribute novel insights to the understanding and treatment of neurological disorders, we present a comprehensive review of the pharmacokinetics, actions, mechanisms, and research development of GsRb1 in neurological disorders.

How ginseng regulates autophagy: Insights from multistep process

BACKGROUND

Although autophagy is a recognized contributor to the pathogenesis of human diseases, chloroquine and hydroxychloroquine are the only two FDA-approved autophagy inhibitors to date. Emerging evidence has revealed the potential therapeutic benefits of various extracts and active compounds isolated from ginseng, especially ginsenosides and their derivatives, by mediating autophagy. Mechanistically, active components from ginseng mediate key regulators in the multistep processes of autophagy, namely, initiation, autophagosome biogenesis and cargo degradation.

AIM OF REVIEW

To date, a review that systematically described the relationship between ginseng and autophagy is still lacking. Breakthroughs in finding the key players in ginseng-autophagy regulation will be a promising research area, and will provide positive insights into the development of new drugs based on ginseng and autophagy.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Here, we comprehensively summarized the critical roles of ginseng-regulated autophagy in treating diseases, including cancers, neurological disorders, cardiovascular diseases, inflammation, and neurotoxicity. The dual effects of the autophagy response in certain diseases are worthy of note; thus, we highlight the complex impacts of both ginseng-induced and ginseng-inhibited autophagy. Moreover, autophagy and apoptosis are controlled by multiple common upstream signals, cross-regulate each other and affect certain diseases, especially cancers. Therefore, this review also discusses the cross-signal transduction pathways underlying the molecular mechanisms and interaction between ginseng-regulated autophagy and apoptosis.

Protective potential of hydroxysafflor yellow A in cerebral ischemia and reperfusion injury: An overview of evidence from experimental studies

Ischemic stroke, mostly caused by thromboembolic or thrombotic arterial occlusions, is a primary leading cause of death worldwide with high morbidity and disability. Unfortunately, no specific medicine is available for the treatment of cerebral I/R injury due to its limitation of therapeutic window. Hydroxysafflor yellow A, a natural product extracted from Carthamus tinctorius, has been extensively investigated on its pharmacological properties in cerebrovascular diseases. However, review focusing on the beneficial role of HSYA against cerebral I/R injury is still lacking. In this paper, we reviewed the neuroprotective effect of HSYA in preclinical studies and the underlying mechanisms involved, as well as clinical data that support the pharmacological activities. Additionally, the sources, physicochemical properties, biosynthesis, safety and limitations of HSYA were also reviewed. As a result, HSYA possesses a wide range of beneficial effects against cerebral I/R injury, and its action mechanisms include anti-excitotoxicity, anti-oxidant stress, anti-apoptosis, anti-inflammation, attenuating BBB leakage and regulating autophagy. Collectively, HSYA might be applied as one of the promising alternatives in ischemic stroke treatment.

Involvement of Autophagy in the Protective Effects of Ginsenoside Rb1 in a Rat Model of Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

No treatment modalities have been identified to prevent neuron damage induced by traumatic brain injury (TBI). The objective of this study was to investigate whether ginsenoside Rb1 (GS-Rb1) could be utilized to exert neuroprotective effects in TBI.

METHODS

Lateral fluid percussion injury (LFPI) was used to induce an experimental TBI model. Lewis rats were divided into a GS-Rb1 group (5, 10, 20 mg/kg, intraperitoneally injected daily), a sham group, and a vehicle group. Neurological impairments were assessed with brain water content, Evans blue extravasation, neurological deficit scores, and Morris water maze test. TUNEL and NeuN staining were utilized to detect neuron apoptosis. The relative expression of apoptosis- and autophagy-relevant molecules were assayed with real-time PCR and western blot.

RESULTS

GS-Rb1 inhibited TBI-induced brain edema and Evans blue extravasation in a dose-dependent manner. Furthermore, GS-Rb1 improved neurological impairments with diminished neurological deficit scores, decreased escape latencies, increased time in the target quadrant, and increased number of platform site crossings. GS-Rb1 protected against neuron apoptosis with downregulated Bax expression and upregulated Bcl-2 expression. It was worth noting that TBI increased the LC3II/LC3I ratio and upregulated the relative expression of Beclin-1, Atg-7, and Atg-3; moreover, TBI downregulated the relative expression of P62. The administration of GS-Rb1 further strengthened the relative expression of autophagy-related molecules.

CONCLUSIONS

GS-Rb1 alleviates neurological impairments induced by TBI with upregulated autophagy.

Mechanisms of ginsenosides exert neuroprotective effects on spinal cord injury: A promising traditional Chinese medicine

Spinal cord injury (SCI) is a devastating disorder of the central nervous system (CNS). It is mainly caused by trauma and reduces the quality of life of the affected individual. Ginsenosides are safe and effective traditional Chinese medicines (TCMs), and their efficacy against SCI is being increasingly researched in many countries, especially in China and Korea. This systematic review evaluated the neuroprotective effects of ginsenosides in SCI and elucidated their properties.

Neuroprotection of Triptolide against Amyloid-Beta1-42-induced toxicity via the Akt/mTOR/p70S6K-mediated Autophagy Pathway

Triptolide is a natural active compound that has significant neuroprotective properties and shows promising effects in the treatment of Alzheimer's disease (AD). Recent studies have shown that autophagy occurs in AD. In this study, we determined whether autophagy regulated by triptolide ameliorates neuronal death caused by amyloid-Beta1-42 (Aβ1-42). We examined the effects of triptolide on cell viability, autophagy, apoptosis, and the protein kinase B/mammalian target of the rapamysin/70 kDa ribosomal protein S6 kinase (Akt/mTOR/p70S6K) signaling pathway in PC12 cells. The results indicated that triptolide treatment exhibited a cytoprotective effect against cell injury induced by Aβ1-42. Triptolide also reduced apoptosis and enhanced cell survival by decreasing autophagosome accumulation and inducing autophagic degradation. Furthermore, our results also showed that activating the Akt/mTOR/p70S6K mechanism was one reason for the protection of triptolide. Triptolide treatment protected against Aβ1-42-induced cytotoxicity by decreasing autophagosome accumulation, and inducing autophagic degradation in PC12 cells. These findings also suggest that the reduction of autophagosome accumulation observed in triptolide-treated cells was Akt/mTOR/p70S6K pathway dependent. Overall, triptolide exhibits a neuron protective effect and this study provides new insight into AD prevention and treatment.

A Review of Neuroprotective Effects and Mechanisms of Ginsenosides From Panax Ginseng in Treating Ischemic Stroke

Ischemic stroke has been considered one of the leading causes of mortality and disability worldwide, associated with a series of complex pathophysiological processes. However, effective therapeutic methods for ischemic stroke are still limited. Panax ginseng, a valuable traditional Chinese medicine, has been long used in eastern countries for various diseases. Ginsenosides, the main active ingredient of Panax ginseng, has demonstrated neuroprotective effects on ischemic stroke injury during the last decade. In this article, we summarized the pathophysiology of ischemic stroke and reviewed the literature on ginsenosides studies in preclinical and clinical ischemic stroke. Available findings showed that both major ginsenosides and minor ginsenosides (such as Rg3, Rg5, and Rh2) has a potential neuroprotective effect, mainly through attenuating the excitotoxicity, Ca²⁺ overload, mitochondria dysfunction, blood-brain barrier (BBB) permeability, anti-inflammation, anti-oxidative, anti-apoptosis, anti-pyroptosis, anti-autophagy, improving angiogenesis, and neurogenesis. Therefore, this review brings a current understanding of the mechanisms of ginsenosides in the treatment of ischemic stroke. Further studies, especially in clinical trials, will be important to confirm the clinical value of ginseng and ginsenosides.

The effects of Ginsenosides on PI3K/AKT signaling pathway

Ginsenosides belong to a group of steroid glycosides that are extracted from the plant genus Panax (ginseng). This plant has been used for a long time for the treatment of a variety of disorders in traditional medicine. Recent studies have assessed the biological impact of Ginsenosides in cell culture or animal models. Animal studies have shown their beneficial impacts in the remedy of pathological conditions in different tissues. The ameliorating effects of Ginsenosides in diverse pathogenic conditions can be attributed to their effects on the production of reactive oxygen species. These substances mainly affect the activity of AMPK/AKT and PI3K/AKT pathways. The beneficial effects of Ginsenosides have been appraised in diabetes-related complications, spinal cord injury, cerebral ischemia, myocardial ischemia, and other disorders which are associated with oxidative stress. Moreover, these substances have been shown to interfere with the pathologic conditions during carcinogenesis. In the current study, we explain these impacts in two distinct sections including non-neoplastic conditions and neoplastic conditions.

Neuroprotective Mechanisms of Ginsenoside Rb1 in Central Nervous System Diseases

Panax ginseng and Panax notoginseng, two well-known herbs with enormous medical value in Asian countries, have a long usage history in China for the therapy of some diseases, such as stroke. Ginsenoside Rb1 is one of most important active ingredients in Panax ginseng and Panax notoginseng. In the last two decades, more attention has focused on ginsenoside Rb1 as an antioxidative, anti-apoptotic and anti-inflammatory agent that can protect the nervous system. In the review, we summarize the neuroprotective roles of ginsenoside Rb1 and its potential mechanisms in central nervous system diseases (CNSDs), including neurodegenerative diseases, cerebral ischemia injury, depression and spinal cord injury. In conclusion, ginsenoside Rb1 has a potential neuroprotection due to its inhibition of oxidative stress, apoptosis, neuroinflammation and autophagy in CNSDs and may be a promising candidate agent for clinical therapy of CNSDs in the future.

Bioactives and functional food ingredients with promising potential for the management of cerebral and myocardial ischemia: a comprehensive mechanistic review

Ischemia is a deadly disease featured by restricted perfusion to different organs in the body. An increase in the accumulation of reactive oxygen species and cell debris is the driving force for inducing many oxidative, inflammatory and apoptotic signaling pathways. However, the number of therapeutics existing for ischemic stroke patients is limited and there is insufficient data on their efficiency, which warrants the search for novel therapeutic candidates from natural sources. Herein, a comprehensive survey was done on the reported functional food bioactives (ca. 152 compounds) to manage or protect against health consequences of myocardial and cerebral ischemia. Furthermore, we reviewed the reported mechanistic studies for their anti-ischemic potential. Subsequently, network pharmacology- and in silico-based studies were conducted using the reported myocardial and cerebral ischemia-relevant molecular targets to study their complex interactions and highlight key targets in disease pathogenesis. Subsequently, the most prominent 20 compounds in the literature were used in a comprehensive in silico-based analysis (inverse docking, ΔG calculation and molecular dynamics simulation) to determine other potential targets for these compounds and their probable interactions with different signaling pathways relevant to this disease. Many functional food bioactives, belonging to different chemical classes, i.e., flavonoids, saponins, phenolics, alkaloids, iridoids and carotenoids, were proven to exhibit multifactorial effects in targeting the complex pathophysiology of ischemic conditions. These merits make them valuable therapeutic agents that can outperform the conventional drugs, and hence they can be utilized as add-ons to the conventional therapy for the management of different ischemic conditions; however, their rigorous clinical assessment is necessary.

Neuroprotective Mechanisms of Ginsenoside Rb1 in Central Nervous System Diseases

Panax ginseng and Panax notoginseng, two well-known herbs with enormous medical value in Asian countries, have a long usage history in China for the therapy of some diseases, such as stroke. Ginsenoside Rb1 is one of most important active ingredients in Panax ginseng and Panax notoginseng. In the last two decades, more attention has focused on ginsenoside Rb1 as an antioxidative, anti-apoptotic and anti-inflammatory agent that can protect the nervous system. In the review, we summarize the neuroprotective roles of ginsenoside Rb1 and its potential mechanisms in central nervous system diseases (CNSDs), including neurodegenerative diseases, cerebral ischemia injury, depression and spinal cord injury. In conclusion, ginsenoside Rb1 has a potential neuroprotection due to its inhibition of oxidative stress, apoptosis, neuroinflammation and autophagy in CNSDs and may be a promising candidate agent for clinical therapy of CNSDs in the future.

Potentilla anserine L. polysaccharide protects against cadmium-induced neurotoxicity

Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway.

Mechanistic Insight on Autophagy Modulated Molecular Pathways in Cerebral Ischemic Injury: From Preclinical to Clinical Perspective

Cerebral ischemia is one of the most devastating brain injuries and a primary cause of acquired and persistent disability worldwide. Despite ongoing therapeutic interventions at both the experimental and clinical levels, options for stroke-related brain injury are still limited. Several evidence suggests that autophagy is triggered in response to cerebral ischemia, therefore targeting autophagy-related signaling pathways can provide a new direction for the therapeutic implications in the ischemic injury. Autophagy is a highly conserved lysosomal-dependent pathway that degrades and recycles damaged or non-essential cellular components to maintain neuronal homeostasis. But, whether autophagy activation promotes cell survival against ischemic injury or, on the contrary, causes neuronal death is still under debate. We performed an extensive literature search from PubMed, Bentham and Elsevier for various aspects related to molecular mechanisms and pathobiology involved in autophagy and several pre-clinical studies justifiable further in the clinical trials. Autophagy modulates various downstream molecular cascades, i.e., mTOR, NF-κB, HIF-1, PPAR-γ, MAPK, UPR, and ROS pathways in cerebral ischemic injury. In this review, the various approaches and their implementation in the translational research in ischemic injury into practices has been covered. It will assist researchers in finding a way to cross the unbridgeable chasm between the pre-clinical and clinical studies.

YiQiFuMai lyophilized injection attenuates cerebral ischemic injury with inhibition of neuronal autophagy through intervention in the NMMHC IIA-actin-ATG9A interaction

BACKGROUND

YiQiFuMai lyophilized injection (YQFM) is derived from a traditional Chinese medicine prescription termed Shengmai San.YQFM is clinically applied to the treatment of cardiovascular and cerebrovascular diseases. It has been found that critical components of YQFM affect non-muscle myosin heavy chain IIA (NMMHC IIA), but its regulation in the excessive autophagy and the underlying mechanism has yet to be clarified.

PURPOSE

To evaluate whether YQFM has neuroprotective effects on cerebral ischemia/reperfusion-induced injury by inhibiting NMMHC IIA-actin-ATG9A interaction for autophagosome formation.

METHODS

The neuroprotective effects of YQFM were investigated in vivo in mice with middle cerebral artery occlusion/reperfusion (MCAO/R) (n = 6) by detecting neurological deficits, infarct volume, and histopathological changes. The NMMHC IIA-actin-ATG9A interaction was determined using immunofluorescence co-localization, co-immunoprecipitation, and proximity ligation assay. Rat pheochromocytoma (PC12) cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) were used to mimic neurons in in vitro experiments.

RESULTS

In MCAO/R model mice, YQFM (1.342 g/kg) attenuated brain ischemia/reperfusion-induced injury by regulating NMMHC IIA-actin-mediated ATG9A trafficking. YQFM (400 μg/ml) also exerted similar effects on OGD/R-induced PC12 cells. Furthermore, RNAi of NMMHC IIA weakened the NMMHC IIA-F-actin-dependent ATG9A trafficking and, therefore, attenuated the neuroprotective activities of YQFM in vitro.

CONCLUSION

These findings demonstrated that YQFM exerted neuroprotective effects by regulating the NMMHC IIA-actin-ATG9A interaction for autophagosome formation. This evidence sheds new light on the potential mechanism of YQFM in the treatment of cerebral ischemia/reperfusion.

Autophagy in vascular dementia and natural products with autophagy regulating activity

Chronic Cerebral Hypoperfusion(CCH)-induced vascular dementia(VD) is a common neurodegenerative disease which seriously affects the patient's quality of life. Therefore, it is critical to find an effective treatment of VD. Autophagy is a natural regulated mechanism that can remove dysfunctional proteins and organelles, however, over-activation or under-activation can of autophagy can induce the apoptosis of cells. Although autophagy plays a role in the central nervous system is unquestionable, the effects of autophagy in the ischemic brain are still controversial. Some autophagy regulators have been tested, suggesting that both activation and inhibition of autophagy can improve the cognitive function. This article reviews the role of autophagy in CCH-induced VD to discuss whether autophagy has the potential to become a target for drug development and provides several potential compounds for treating vascular dementia.

Protective Effects and Network Analysis of Ginsenoside Rb1 Against Cerebral Ischemia Injury: A Pharmacological Review

Ischemic stroke is a leading cause of death and disability worldwide. Currently, only a limited number of drugs are available for treating ischemic stroke. Hence, studies aiming to explore and develop other potential strategies and agents for preventing and treating ischemic stroke are urgently needed. Ginseng Rb1 (GRb1), a saponin from natural active ingredients derived from traditional Chinese medicine (TCM), exerts neuroprotective effects on the central nervous system (CNS). We conducted this review to explore and summarize the protective effects and mechanisms of GRb1 on cerebral ischemic injury, providing a valuable reference and insights for developing new agents to treat ischemic stroke. Our summarized results indicate that GRb1 exerts significant neuroprotective effects on cerebral ischemic injury both in vivo and in vitro, and these network actions and underlying mechanisms are mediated by antioxidant, anti-inflammatory, and antiapoptotic activities and involve the inhibition of excitotoxicity and Ca2⁺ influx, preservation of blood–brain barrier (BBB) integrity, and maintenance of energy metabolism. These findings indicate the potential of GRb1 as a candidate drug for treating ischemic stroke. Further studies, in particular clinical trials, will be important to confirm its therapeutic value in a clinical setting.

Potentilla anserine L. polysaccharide inhibits cadmium-induced neurotoxicity by attenuating autophagy

Cadmium (Cd), a heavy metal with cytotoxicity, can activate autophagy. This study aimed to explore the effects and mechanisms of Potentilla anserine L. polysaccharide (PAP) on autophagy in N2a cells, primary neurons, and the brain of BALB/c mice exposed to Cd. The CCK-8 assay results showed that the cell viability decreased and the number of acidic vesicular organelles, autophagic vacuoles, lysosomes, and dysfunctional mitochondria increased in the cytoplasm of Cd-exposed N2a cells and primary neurons, as revealed by acridine orange staining, monodansylcadaverine staining, and transmission electron microscopy. PAP mitigated Cd-induced neuronal death and characteristic changes in autophagy. The expression of LC3 IILC3 II, Bcl-2, p62, Beclin-1, and PI3K class III was examined by Western blot analysis. Furthermore, the PI3K inhibitor (LY294002 or 3-MA) and/or PAP reversed the Cd-induced upregulated expression of LC3 II, Beclin-1, and PI3K class III, with a synergy between PI3K inhibitor and PAP against Cd-induced autophagy. The findings suggested that PAP partially prevented Cd-induced autophagic cell death in neurons by inhibiting the PI3K class III/Beclin-1 signaling pathway in vitro and in vivo.

Lycopene prevents oxygen-glucose deprivation-induced autophagic death in SH-SY5Y cells via inhibition of the oxidative stress-activated AMPK/mTOR pathway

Lycopene has been reported to exert a protective effect on the brain against transient ischemia‑induced damage; however, whether it could regulate autophagic neuronal death remains elusive. The present study aimed to investigate the role of autophagy in the protective effects of lycopene against neuronal damage and its underlying mechanism. Oxygen‑glucose deprivation (OGD) was used to simulate neuronal ischemic injury in human SH‑SY5Y cells. Lactate dehydrogenase (LDH) release assay revealed that OGD induced SH‑SY5Y cell death. Western blotting demonstrated that OGD upregulated the expression levels of the autophagy marker proteins autophagy protein 5 (ATG5) and LC3II, but downregulated the autophagy substrate p62 in a time‑dependent manner. By contrast, OGD‑induced cell death was significantly inhibited by the autophagy inhibitors 3‑methyladenine or bafilomycin A1 or by knockdown of ATG5, indicating that OGD may induce autophagic death in SH‑SY5Y cells. Notably, lycopene was shown not only to prevent OGD‑induced SH‑SY5Y cell death, but was also able to effectively inhibit OGD‑induced upregulation of ATG5 and LC3II, and downregulation of p62 in a dose‑dependent manner. Mechanistically, it was suggested that lycopene inhibited OGD‑induced activation of the AMPK/mTOR pathway via attenuation of oxidative stress by maintaining the intracellular antioxidant glutathione (GSH). Furthermore, the inhibitory role of lycopene in GSH depletion was found to be associated with the prevention of OGD‑induced depletion of intracellular cysteine and downregulation of xCT. Collectively, the present study demonstrated that lycopene protected SH‑SY5Y cells against OGD‑induced autophagic death by inhibiting oxidative stress‑dependent activation of the AMPK/mTOR pathway.

Hesperidin protects liver and kidney against sodium fluoride-induced toxicity through anti-apoptotic and anti-autophagic mechanisms

AIM

High dose of fluoride intake is associated with toxic effects on liver and kidney tissues. One approach to tackle these toxicities is using natural antioxidants as supplements. This study evaluated the ameliorative effects of hesperidin (HSP) against sodium fluoride (NaF)-induced hepatotoxicity and nephrotoxicity in wistar albino rats.

MATERIALS AND METHODS

In the present study, the rats were randomly allocated into five groups of seven male rats each group: control, NaF (600 ppm), HSP-200, NaF + HSP-100 and NaF + HSP 200.

KEY FINDINGS

Hepatic and renal injuries induced by NaF were confirmed by the alteration in kidney function parameters in the serum (urea and creatinine), levels of liver enzymes (ALT, ALP and AST), activities of the antioxidant enzymes (SOD, CAT and GPx) and levels of inflammatory markers (NF-κB, IL-1β and TNF-α). NaF also inhibited PI3K/Akt/mTOR pathway, increased levels of autophagic markers (Beclin-1, LC3A and LC3B) and expression levels of apoptotic and anti-apoptotic proteins (Bax, Bcl-2, cytochrome c, p53 and procaspase-3) in the liver and kidney tissues. Administration of HSP concurrently with NaF significantly ameliorated the deviation in the above-studied parameters.

SIGNIFICANCE

The results of the current study revealed that HSP could be used as a beneficial adjuvant that confers protection against NaF-induced liver and kidney damage through antioxidant, anti-inflammatory, anti-apoptotic and anti-autophagic mechanisms.

Paving the Road Toward Exploiting the Therapeutic Effects of Ginsenosides: An Emphasis on Autophagy and Endoplasmic Reticulum Stress

Programmed cell death processes such as apoptosis and autophagy strongly contribute to the onset and progression of cancer. Along with these lines, modulation of cell death mechanisms to combat cancer cells and elimination of resistance to apoptosis is of great interest. It appears that modulation of autophagy and endoplasmic reticulum (ER) stress with specific agents would be beneficial in the treatment of several disorders. Interestingly, it has been suggested that herbal natural products may be suitable candidates for the modulation of these processes due to few side effects and significant therapeutic potential. Ginsenosides are derivatives of ginseng and exert modulatory effects on the molecular mechanisms associated with autophagy and ER stress. Ginsenosides act as smart phytochemicals that confer their effects by up-regulating ATG proteins and converting LC3-I to -II, which results in maturation of autophagosomes. Not only do ginsenosides promote autophagy but they also possess protective and therapeutic properties due to their capacity to modulate ER stress and up- and down-regulate and/or dephosphorylate UPR transducers such as IRE1, PERK, and ATF6. Thus, it would appear that ginsenosides are promising agents to potentially restore tissue malfunction and possibly eliminate cancer.

Ginsenoside Rb1 attenuates microglia activation to improve spinal cord injury via microRNA-130b-5p/TLR4/NF-κB axis

Ginsenoside Rb1 (GRb1), a major ingredient of ginseng, has been found to be a potential protective agent in spinal cord injury (SCI) and in activated microglia-induced neuronal injury. This study discovered that GRb1 could facilitate miR-130b-5p expression in SCI rats and Toll-like receptor 4 (TLR4; a crucial player in inflammation) was a potential target of miR-130b-5p. Hence, we further investigated whether GRb1 could relieve SCI by reducing microglia-mediated inflammatory responses and neuronal injury via miR-130b-5p/TLR4 pathways. The results showed that GRb1 alleviated SCI through inhibiting neuronal apoptosis and proinflammatory factor expression via increasing miR-130b-5p.GRb1 weakened the damage of activated microglia to neurons through upregulating miR-130b-5p. miR-130b-5p attenuated activated microglia-induced neuron injury via targeting TLR4. GRb1 inactivated TLR4/nuclear factor-κB (NF-κB) activation and inhibited proinflammatory cytokine secretion by increasing miR-130b-5p in activated microglia. As a conclusion, GRb1 alleviated SCI through reducing activated microglia-induced neuronal injury via miR-130b-5p/TLR4/NF-κB axis, providing a deep insight into the molecular basis of GRb1 in the treatment of SCI.

Apelin-13 inhibits apoptosis and excessive autophagy in cerebral ischemia/reperfusion injury

Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor, and it may be neuroprotective against cerebral ischemia injury. However, the precise mechanisms of the effects of apelin-13 remain to be elucidated. To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury, a rat model was established by middle cerebral artery occlusion. Apelin-13 (50 μg/kg) was injected into the right ventricle as a treatment. In addition, an SH-SY5Y cell model was established by oxygen-glucose deprivation/reperfusion, with cells first cultured in sugar-free medium with 95% N₂ and 5% CO₂ for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours. This SH-SY5Y cell model was treated with 10^–7 M apelin-13 for 5 hours. Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury. Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression. In addition, apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3B, p62, and Beclin1. Furthermore, the expression of Bcl-2 and the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway was markedly increased. Both LY294002 (20 μM) and rapamycin (500 nM), which are inhibitors of the PI3K/Akt/mTOR pathway, significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13. In conclusion, the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy. These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury, both in vivo and in vitro. The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University, China (approval No. 2018-JS-001) in February 2018.

The co-treatment of rosuvastatin with dapagliflozin synergistically inhibited apoptosis via activating the PI3K/AKt/mTOR signaling pathway in myocardial ischemia/reperfusion injury rats

Objective

The purpose of the present study was to evaluate the role of co-treatment of rosuvastatin (RSV) and dapagliflozin (DGZ) preconditioning in myocardium ischemia/reperfusion (I/R) injury and to further investigate the underlying mechanism.

Methods

Sprague-Dawley (SD) rats (n = 25) were divided into five groups randomly: (1) Sham, (2) I/R, (3) I/R + RSV (10 mg/kg), (4) IR + DGZ (1 mg/kg), and (5) I/R + RSV (10 mg/kg) + DGZ (1 mg/kg). The I/R model was induced with 30 min of left anterior descending occlusion followed by 120 min of reperfusion.

Results

In vivo pretreatment with RSV and DGZ, respectively, showed a significant reduction of infarction size, a significant increase in the levels of left ventricular systolic pressure, and maximal rate increase in left ventricular pressure (+dp/dt_max), decrease in the levels of left ventricular end-diastolic pressure (LVEDP), maximal rate of decrease of left ventricular pressure (−dp/dt_max) and activity of cardiac enzymes of creatine kinase (CK), creatine kinase MB isoenzymes (CK-MB), and hyper-tensive cardiac troponin I compared with the I/R group. H9C2 cells were exposed to hypoxia/reoxygenation to simulate an I/R model. In vitro administration of 25 µM RSV and 50 µM DGZ significantly enhanced cell viability, upregulated the expression levels of p-PI3K, p-Akt, p-mTOR, and Bcl-2, whereas it downregulated cleaved-caspase3, Bax. TUNEL assay indicated that pretreatment with RSV and DGZ decreased the apoptosis of H9C2 cells.

Conclusion

The combination of RSV and DGZ significantly enhances the cardioprotective effects compared with RSV or DGZ alone. RSV and DGZ have the potential cardioprotective effects against I/R injury by activating the PI3K/AKt/mTOR signaling pathway.

Yi-Zhi-Fang-Dai Formula Exerts a Protective Effect on the Injury of Tight Junction Scaffold Proteins in Vitro and in Vivo by Mediating Autophagy through Regulation of the RAGE/CaMKKβ/AMPK/mTOR Pathway

Alzheimer's disease (AD) is a chronic neurodegeneration disease that is closely related to the abnormal tight junction scaffold proteins (TJ) proteins of the blood-brain barrier (BBB). Recently, Yi-Zhi-Fang-Dai Formula (YZFDF) had exerted a neuronal protective effect against amyloid peptide (Aβ) toxicity. Still, the therapeutic mechanism of YZFDF in restoring Aβ-induced injury of TJ proteins (ZO-1, Occludin, and Claudin-5) remains unclear. This study aimed to explore the underlying mechanism of YZFDF in alleviating the injury of TJ proteins. We examined the impacts of YZFDF on autophagy-related proteins and the histopathology of Aβ in the APP/PS1 double-transgenic male mice. We then performed the free intracellular calcium levels [Ca²⁺]i analysis and the cognitive behavior test of the AD model. Our results showed that YZFDF ameliorated the injury of TJ proteins by reducing the mRNA transcription and expression of the receptor for advanced glycation end-products (RAGE), the levels of [Ca²⁺]i, calmodulin-dependent protein kinase β (CaMKKβ), phosphorylated AMP-activated protein kinase (AMPK). Accordingly, YZFDF increased the expression of the phosphorylated mammalian targets of rapamycin (mTOR), leading to inhibition of autophagy (downregulated LC3 and upregulated P62). Moreover, the Aβ_1-42 oligomers-induced alterations of autophagy in murine mouse brain capillary (bEnd.3) cells were blocked by RAGE small interfering RNA (siRNA). These results suggest that YZFDF restored TJ proteins' injury by suppressing autophagy via RAGE signaling. Furthermore, YZFDF reduced the pathological precipitation of Aβ in the hippocampus, and improved cognitive behavior impairment of the AD model suggested that YZFDF might be a potential therapeutic candidate for treating AD through RAGE/CaMKKβ/AMPK/mTOR-regulated autophagy pathway.

Ginsenoside Rb1 ameliorates autophagy via the AMPK/mTOR pathway in renal tubular epithelial cells in vitro and in vivo

Although ginsenoside Rb1 (G-Rb1) has exerted an inhibitory effect on renal fibrosis and progression of chronic kidney disease (CKD), its mechanism remains unknown. This study aims to explore the anti-fibrosis effect of G-Rb1 in unilateral ureter obstruction (UUO) mouse model and underlying mechanisms in HBSS-induced HK-2 cells. In vivo, renal function, kidney histological pathology, and autophagy-related protein molecules were assessed. Additionally, rapamycin, Deptor overexpression plasmid, Akt inhibitor, metformin, and a p38-MAPK inhibitor, as well as an ERK-MAPK inhibitor were used to evaluate the effect of AMPK/mTOR, Akt and MAPK signal pathways on the protective effect of G-Rb1 in HK-2 cells. Treatment with G-Rb1 significantly improved renal dysfunction. G-Rb1 reversed UUO-induced downregulation of p62, and upregulation of LC3 and the ratio of LC3 I/II, indicating that G-Rb1 restrained UUO-induced activation of autophagy. Furthermore, we found that treatment of HBSS-induced HK-2 cells with G-Rb1 resulted in AMPK/mTOR and ERK, p38 MAPKs signaling pathways regulated autophagy inhibition. These findings may explain, in part, the molecular mechanisms by which G-Rb1 could be applied in the treatment of patients with CKD, further suggesting that autophagy and its associated molecular signaling pathway may be new targets for the treatment of renal fibrosis and CKD.

Taurine and Ginsenoside Rf Induce BDNF Expression in SH-SY5Y Cells: A Potential Role of BDNF in Corticosterone-Triggered Cellular Damage

This study shows that taurine and ginsenoside Rf act synergistically to increase the expression of brain-derived neurotrophic factor (BDNF) in SH-SY5Y human neuroblastoma cells in a dose- and time-dependent manner. The increase of BDNF mRNA by taurine and ginsenoside Rf was markedly attenuated by inhibitors of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase. In addition, taurine and ginsenoside Rf protected cells from corticosterone-induced BDNF suppression and reduced cell viability and lactate dehydrogenase release. The results from this study showed that combined treatment with both taurine and ginsenoside Rf enhanced BDNF expression and protected cells against corticosterone-induced damage.

Pancreas protective effects of Urolithin A on type 2 diabetic mice induced by high fat and streptozotocin via regulating autophagy and AKT/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Urolithin A (UroA), the main intestinal microflora metabolite of ellagic acid of berries, pomegranate,and some other traditional chinese herbals such as emblica officinalis,etc,has been reported to exhibit anti-inflammatory, anti-oxidative, anti-tumor and pro-autophagy effects.

AIM OF THE STUDY

This study evaluated the anti-diabetic and pancreas-protective effects of UroA using a mice model of type 2 diabetes and preliminarily explored its effect on autophagy as well as the mechanism involved.

MATERIALS AND METHODS

Type 2 diabetes model was induced by high-fat diet (HFD; 60% energy as fat) and low-dose streptozotocin (85 mg/kg) injection. Mice were administered with UroA (50 mg/kg/d) alone or UroA-chloroquine (autophagy inhibitor) combination for 8 weeks.

RESULTS

UroA improved symptoms of diabetic mice such as high water intake volume, high urine volume, significantly decreased fasting blood glucose (FBG), after-glucose-loading glucose, glycated hemoglobin (GHb) levels, plasma C-peptide, malondialdehyde (MDA) and interleukin-1 β level, increased reduced glutathione (GSH), interleukin-10 content, and glucose tolerance. UroA also improved pancreatic function indexes such as HOMA-β as evidenced by improved pathological and ultrastructural features of the pancreas assessed by light microscopy and transmission electron microscopy (TEM). Accordingly, UroA decreased mitochondrial swelling and myelin-like cytoplasmic inclusions. UroA significantly upregulated the protein levels of microtubule-associated protein 1 light chain 3-II (LC3II) and beclin1, downregulated sequestosome 1 (p62) accompanied by decreased expression of apoptotic protein cleaved caspase3 in pancreas of diabetic mice. In addition, it increased the phosphorylation level of protein kinase B (p-Akt) and mammalian target of rapamycin (p-mTOR). Most of these effects of UroA were reversed by treatment with autophagy inhibitor chloroquine.

CONCLUSIONS

Our findings reveal that the pancreas protective effects of UroA against diabetes were partially mediated by its regulation of autophagy and AKT/mTOR signal pathway.

Insulin-Like Growth Factor Binding Protein-Related Protein 1 Activates Primary Hepatic Stellate Cells via Autophagy Regulated by the PI3K/Akt/mTOR Signaling Pathway

BACKGROUND

Autophagy is a self-degrading process. Previously, we showed that insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) is a novel transforming growth factor β1 (TGFβ1)-interacting factor in liver fibrosis; the role of TGFβ1-mediated autophagy in hepatic stellate cells (HSCs) activation has been investigated. However, whether autophagy is regulated by IGFBPrP1 remains unknown.

AIMS

We investigated the interactions among IGFBPrP1, autophagy, and activation of primary rat HSCs.

METHODS

Primary HSCs were separated from Sprague Dawley rats by two-step enzymatic digestion, and then, we overexpressed or inhibited IGFBPrP1 expression in HSCs under serum-starved condition. Autophagy inducer rapamycin or inhibitor 3-methyladenine (3MA) was used to assess the relationship between autophagy and HSCs activation.

RESULTS

We observed the expression of activation marker α-SMA and autophagy markers such as LC3B and Beclin1, which were significantly increased in HSCs treated with adenovirus vector harboring the IGFBPrP1 gene (AdIGFBPrP1) compared to cells cultured under serum-starved. In comparison, HSCs treated with shIGFBPrP1 showed opposite results. Furthermore, HSCs activation and autophagy increased when cells were treated with rapamycin, whereas opposite results were obtained when cells were treated with 3MA. AdIGFBPrP1 treatment downregulated the phosphorylation of Akt and mTOR.

CONCLUSION

Autophagy was induced in IGFBPrP1-treated primary HSCs, and IGFBPrP1-induced autophagy promoted the activation of HSCs and extracellular matrix expression, the underlying mechanism of which may involve the phosphatidylinositide 3-kinase/Akt/mTOR signaling pathway.

Urolithin B, a gut microbiota metabolite, protects against myocardial ischemia/reperfusion injury via p62/Keap1/Nrf2 signaling pathway

Ischemia/reperfusion (IR) induces additional damage during the restoration of blood flow to ischemic myocardium. Urolithin B (UB) is one of the gut metabolites of ellagitannins, a class of antioxidant polyphenols, which was found to be protective against oxidative stress in multiple organs. However, the role of UB in cardiovascular disease remains elusive. Adult Sprague Dawley rats were subjected to left anterior descending artery ligation for 30 min followed by 120 min of reperfusion, with or without UB treatment. In vitro, the H9c2 cardiomyocytes were subjected to hypoxia (94 %N₂/5 %CO₂/1 %O₂) for 3 h, followed by reoxygenation (74 %N₂/5 %CO₂/21 %O₂) for 3 h (HR). UB was found to decrease myocardial infarct size and attenuate the cardiac dysfunction in the rats after IR, and protect against HR injury in H9c2 cardiomyocytes. Mechanistically, UB inhibited autophagy by activating Akt/mTOR/ULK1 pathway and protected against oxidative stress and caspase 3-dependent cell apoptosis. In particular, UB induced accumulation of p62 and its interaction with Keap1, which promoted Nrf2 nuclear translocation during HR insult. Of note, the protection of UB against superoxide production and apoptotic cell death was compromised with Nrf2 gene silencing. Taken together, our findings suggested that UB protected against myocardial IR injury at least partially via the p62/Keap1/Nrf2 signaling pathway, which highlights the potential of UB as a novel therapy for ischemic heart disease.

Schizandrol A protects against Aβ1-42-induced autophagy via activation of PI3K/AKT/mTOR pathway in SH-SY5Y cells and primary hippocampal neurons

Autophagy, a lysosomal degradative pathway, is crucial for the pathogenesis of Alzheimer's disease (AD). Schizandrol A (SchA) shows multiple pharmacological effects. However, the potential effects and mechanisms of SchA on amyloid-β (Aβ)-induced autophagy remain unclear. In this study, differentiated SH-SY5Y cells or primary hippocampal neurons were pretreated with SchA (2 μg/ml) for 1 h before subjected to Aβ_1-42 (10 μM) for 24 h to test its effects on cell viability, apoptosis, oxidative stress, and autophagy. Then an mTOR inhibitor (rapamycin) and a PI3K inhibitor (LY294002) were employed to explore the role of PI3K/AKT/mTOR pathway. The results showed that SchA significantly inhibited Aβ_1-42-triggered reduction of viable cells, increases of apoptotic cell number and pro-apoptotic protein expressions, as well as alterations of oxidative stress markers. In addition, the increases of LC3-II/LC3-I and Beclin-1 and decrease of p62 were suppressed by SchA. At the molecular level, we found that the inactivation of PI3K/AKT/mTOR pathway was ameliorated by SchA. Inhibition of PI3K/AKT/mTOR pathway deteriorated the protective effects of SchA against Aβ_1-42-induced autophagy activation, cell death, and apoptosis. In conclusion, we demonstrate that SchA attenuates Aβ_1-42-induced autophagy through activating PI3K/AKT/mTOR signaling pathway. SchA may be a novel drug for the prevention and treatment of AD.

Co-enzyme Q10 protects primary chicken myocardial cells from heat stress by upregulating autophagy and suppressing the PI3K/AKT/mTOR pathway

In this study, we investigated the function of co-enzyme Q10 (Q10) in autophagy of primary chicken myocardial cells during heat stress. Cells were treated with Q10 (1 μΜ, 10 μΜ, and 20 μM) before exposure to heat stress. Pretreatment of chicken myocardial cells with Q10 suppressed the decline in cell viability during heat stress and suppressed the increase in apoptosis during heat stress. Treatment with 20 μM Q10 upregulated autophagy-associated genes during heat stress. The expression of LC3-II was highest in cells treated with 20 μM Q10. Pretreatment with Q10 decreased reactive oxygen species (ROS) levels during heat stress. The number of autophagosomes was significantly increased by 20 μM Q10 treatment, as demonstrated by electron microscopy or monodansylcadaverine (MDC) fluorescence. SQSTM1 accumulation was diminished by Q10 treatment during heat stress, and the number of LC3II puncta was increased. Treatment with 20 μM Q10 also decreased the activation of the PI3K/Akt/mTOR pathway. Our results showed that co-enzyme Q10 can protect primary chicken myocardial cells by upregulating autophagy and suppressing the PI3K/Akt/mTOR pathway during heat stress.

Total ginsenosides extract induce autophagic cell death in NSCLC cells through activation of endoplasmic reticulum stress

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng (Panax ginseng C. A. Mey) has been widely used in Asian countries for thousands of years. It has auxiliary anticancer efficacy and its derived preparations (e.g. Shenmai injection) are prescribed for cancer patients as Traditional Chinese Medicines clinically in China.

AIM OF THE STUDY

The involved adjuvant anticancer mechanisms of ginseng are still unknown. The present study evaluated the anti-cancer effect of total ginsenosides extract (TGS) and determined the anticancer mechanisms of TGS-induced cell death in human non-small cell lung cancer (NSCLC) cells.

MATERIALS AND METHODS

The anti-cancer effect of TGS was evaluated in NSCLC by cell proliferation assay. The autophagy flux induction of TGS were tested and validated by Western blot, immunofluorescence and transmission electron microscope. The mechanisms of TGS in inducing autophagic cell death were validated by Western blot, gene knockdown and quantitative real time PCR assay.

RESULTS

We found TGS could induce cell death in concentration and time dependent manners, and the cell morphology of NSCLC changed from cobblestone shape to elongated spindle shape after treated with TGS. In the study of cell autophagy, we confirm that TGS could upregulate autophagy flux and induce autophagic cell death through activation endoplasmic reticulum stress. Further investigations demonstrated this process was mediated by the ATF4-CHOP-AKT1-mTOR axis in NSCLC cells.

CONCLUSION

Our findings suggested that TGS could induce autophagic cell death in NSCLC cells through activation of endoplasmic reticulum stress, disclosing another characteristic of TGS-induced cell death and a novel mechanism of TGS and its derived preparations in clinical treatment of cancer patients.

Disocin prevents postmenopausal atherosclerosis in ovariectomized LDLR-/- mice through a PGC-1α/ERα pathway leading to promotion of autophagy and inhibition of oxidative stress, inflammation and apoptosis

Atherosclerosis (AS) is one of the major causes leading to mortality of dysfunctional cardiovascular events in the menopausal women, which has long-term deficiency of estrogen. At present, the primary treatment for postmenopausal AS is hormone replacement therapy (HRT). However, it can increase the risks of ovarian and uterine cancers with long-term therapy. So seeking for a phytoestrogen which can overcome the disadvantages of HRT is a great mission. Dioscin, a traditional Chinese medicine, extracted from the roots of dioscorea nipponica, has anti-inflammatory, anti-tumor and anti-apoptosis activities. Especially, it also has estrogenic activity. Thus, this study aims to investigate the effects of dioscin on postmenopausal AS. Currently, ovariectomy (OVX) is the accepted model for AS associated with estrogen deficiency, and it can mimic the cessation of ovarian function that occurs in postmenopausal women as well. We used the high fat diet and ovariectomy(HFD-OVX)model to induce postmenopausal AS in the low-density lipoprotein receptor- deficient (LDLR-/-) mice. (1) The levels of TG, TC, LDL-C, HDLC, MDA, GSH, MDA and GSH in serum of HFD-OVX induced LDLR-/- mice were measured by colorimetric assay. (2) The artery injury of HFD-OVX induced LDLR-/- mice was detected with Oil Red O staining. (3) The protein expressions of NOX4, P22phox, IκB, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, bcl-2, PGC-1α, ERα, ERβ in the arterial tissue of HFD-OVX induced LDLR-/- mice were detected by Western blot analysis. In vitro, the model of human aortic endothelial cells (HAECs) induced by oxidized low-density lipoprotein (ox-LDL) (150 μg /ml) was established, and the molecular mechanism of dioscin on atherosclerosis in postmenopausal women was investigated. (1) The levels of MDA, GSH, MDA and GSH in ox-LDL induced HAECs were measured by colorimetric assay. (2) Reactive Oxygen Species (ROS) of ox-LDL induced HAEC cells was detected by fluorescence staining. (3) The protein expressions of PGC-1α, ERα, ERβ, NOX4, P22phox, IκB, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, bcl-2 and LC3 in ox-LDL induced HAECs were detected by Western blot analysis. (4) The autophagy level of ox-LDL induced HAECs was measured by transmission electron microscopy. (5) The applications of si-RNA transfection were used to explore whether dioscin could activate PGC-1α/ERα pathway to inhibit postmenopausal atherosclerosis. In vivo, we found that dioscin decreased the level of TG, TC, LDL-C and increased the level of HDLC in serum of HFD-OVX induced LDLR-/- mice, and it has protective effects to maintain the lipid homeostasis; The Oil Red O staining study showed that dioscin could significantly inhibit the formation of atherosclerotic plaques in HFD-OVX-treated LDLR-/- mice; Dioscin decreased the levels of NOX4, P22phox, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, but increased the levels of HDL-C, GSH, SOD, PGC-1α, ERα, ERβ, IκB, Bcl-2 and elevated the autophagy level in arterial tissues of HFD-OVX induced LDLR-/- mice. It is particularly worth mentioning that the up-regulating effect of dioscin on ERα is stronger than ERβ in OVX treated mice. In vitro, the results of colorimetric assay showed that dioscin decreased the level of MDA and LDH, increased the level of SOD and GSH in ox-LDL-induced HAEC cells; Dioscin also suppressed the release of ROS in ox-LDL-induced HAECs by fluorescence staining; Dioscin decreased the levels of NOX4, P22phox, p-p65, n-p65, ICAM-1, VCAM-1, caspase-3, caspase-9, but increased the levels of PGC-1α, ERα, ERβ, IκB, Bcl-2 and the ratio of LC3-II/LC3-I in ox-LDL-induced HAECs; Dioscin significantly elevated the autophagy level of ox-LDL-induced HAECs by transmission electron microscopy analysis; In addition, by si-RNA transfection, we found that the inhibitory effects of dioscin on oxidative stress, inflammatory response and apoptosis might partly through PGC-1α/ERα pathway in ox-LDL induced HAECs. The data of dual-Luciferase reporter assay revealed that dioscin activated ERα at least partly through PGC-1α pathway. Dioscin significantly inhibited oxidative stress, inflammatory response, apoptosis and increased the level of autophagy in vivo and vitro. In addition, dioscin could regulate the balance of lipid metabolism. Moreover, we proved that the effects of dioscin attenuating postmenopausal atherosclerosis by inhibiting oxidative stress, inflammation and apoptosis were partly dependent on PGC-1α/ERα pathway. Therefore, dioscin, as a phytoestrogen, might become a drug for the treatment of atherosclerosis in postmenopausal women.

Rapamycin improves sevoflurane‑induced cognitive dysfunction in aged rats by mediating autophagy through the TLR4/MyD88/NF‑κB signaling pathway

The present study was aimed to observe the protective effect of rapamycin on cognitive dysfunction induced by sevoflurane in aged rats and its effect on autophagy-related proteins, and to investigate the regulatory mechanism of the Toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor-κB (TLR4/MyD88/NF-κB) signaling pathway. Fifty Sprague-Dawley rats were randomly assigned to a control group, a sevoflurane group, a rapamycin pretreatment group, a TLR4 inhibitor group and a 3MA autophagy inhibitor group. A water maze test was used to evaluate the cognition and memory of rats. Hematoxylin and eosin (H&E) staining was performed to observe pathological changes of brain tissue. A TUNEL assay was used to detect the apoptosis of brain tissue. ELISA was used to assess changes in brain injury markers and inflammatory factors. A western blot assay or quantitative reverse transcription PCR (RT-qPCR) were performed to determine the expression of autophagy-related proteins and the TLR4/MyD88/NF-κB signaling pathway in brain tissue. The results revealed that rapamycin could improve cognitive dysfunction of aged rats induced by sevoflurane. Rapamycin was identified to play a therapeutic role, including mitigating brain tissue damage, inhibiting apoptosis, and activating autophagy in a sevoflurane-treated aged rat model. This function of rapamycin was demonstrated to depend on the TLR4/MyD88/NF-κB signaling pathway.

Sense Ginsenosides From Ginsengs: Structure-Activity Relationship in Autophagy

The term ginseng refers to the dried roots of several plants belonging to the genus Panax of the Araliaceae family. The 3 major commercial ginsengs are Panax notoginseng (Burk.) F.H. Chen (Notoginseng), P. ginseng C.A. Meyer (Ginseng), and P. quinquefolius L. (American ginseng), which have been used as herbal medicines. Over 18,000 papers on ginsengs have been published on the basis of their structural diversity and biological activities. Many reviews have summarized the phytochemistry, pharmacology, and clinical use of ginsengs, but the structure-activity relationship (SAR) of ginsenosides from ginsengs in autophagy is unavailable. Herein, we review the structural diversity of ginsenosides, especially the ones in notoginseng, and the SAR in autophagic activity is discussed in detail.

Efficacy and Mechanism of Panax Ginseng in Experimental Stroke

Stroke is one of the leading causes of death and long-term disability worldwide. However, effective therapeutic approaches are still limited. The disruption of blood supply triggers complicated temporal and spatial events involving hemodynamic, biochemical, and neurophysiologic changes, eventually leading to pathological disturbance and diverse clinical symptoms. Ginseng (Panax ginseng), a popular herb distributed in East Asia, has been extensively used as medicinal and nutritional supplements for a variety of disorders worldwide. In recent years, ginseng has displayed attractive beneficial effects in distinct neurological disorders including stroke, involving multiple protective mechanisms. In this article, we reviewed the literature on ginseng studies in the experimental stroke field, particularly focusing on the in vivo evidence on the preventive or therapeutic efficacy and mechanisms of ginseng and ginsenosides in various stroke models of mice and rats. We also summarized the efficacy and underlying mechanisms of ginseng and ginsenosides on short- and long-term stroke outcomes.

Quantitative Proteomics Combined with Affinity MS Revealed the Molecular Mechanism of Ginsenoside Antitumor Effects

Ginsenosides have previously been demonstrated to effectively inhibit cancer cell growth and survival in both animal models and cell lines. However, the specific ginsenoside component that is the active ingredient for cancer treatment through interaction with a target protein remains unknown. By an integrated quantitative proteomics approach via affinity mass spectrum (MS) technology, we deciphered the core structure of the ginsenoside active ingredient derived from crude extracts of ginsenosides and progressed toward identifying the target protein that mediates its anticancer activity. The Tandem Mass Tag (TMT) labeling quantitative proteomics technique acquired 55620 MS/MS spectra that identified 5499 proteins and 3045 modified proteins. Of these identified proteins, 224 differentially expressed proteins and modified proteins were significantly altered in nonsmall cell lung cancer cell lines. Bioinformatics tools for comprehensive analysis revealed that the Ras protein played a general regulatory role in many functional pathways and was probably the direct target protein of a compound in ginsenosides. Then, affinity MS screening based on the Ras protein identified 20(s)-protopanaxadiol, 20(s)-Ginsenoside Rh2, and 20(s)-Ginsenoside Rg3 had affinity with Ras protein under different conditions. In particular, 20(s)-protopanaxadiol, whose derivatives are the reported antitumor compounds 20(s)-Ginsenoside Rh2 and 20(s)-Ginsenoside Rg3 that have a higher affinity for Ras via a low KD of 1.22 μM and the mutation sites of G12 and G60, was demonstrated to play a core role in those interactions. Moreover, the molecular mechanism and bioactivity assessment results confirmed the identity of the chemical ligand that was directly acting on the GTP binding pocket of Ras and shown to be effective in cancer cell bioactivity profiles.

The progress of neuronal autophagy in cerebral ischemia stroke: Mechanisms, roles and research methods

There is increasing evidence indicating that autophagy may be a new target in the treatment of ischemic stroke. Moderate autophagy can clear damaged organelles, thereby protecting cells against various injuries. However, long-term excessive autophagy brings redundant degradation of cell contents, leading to cell death and eventually serious damage to tissues and organs. A number of different animal models of ischemic brain injury shows that autophagy is activated and involved in the regulation of neuronal death during ischemic brain injury. This article summarizes the role of autophagy, its underlying regulators and mechanisms in ischemic neuronal injury. We briefly introduce the relationship between apoptosis and autophagy and give a summary of research methods and modulators of autophagy.

Gambogic acid prevents angiotensin II‑induced abdominal aortic aneurysm through inflammatory and oxidative stress dependent targeting the PI3K/Akt/mTOR and NF‑κB signaling pathways

Gamboge is the dry resin secreted by Garcinia hanbaryi Hook.f, with the function of promoting blood circulation and anti‑cancer effects, detoxification, hemostasis and killing insects. It is also used for the treatment of cancer, brain edema and other diseases. Gambogic acid is the main effective constituent of Gamboge. The present study tested the hypothesis that the effect of Gambogic acid prevents angiotensin II‑induced abdominal aortic aneurysm (AAA), and explored its underlying mechanism. It was demonstrated that gambogic acid significantly inhibited AAA incidence rate, and reduced edge leading aortic diameter and aortic wall thickness in AAA mice. Gambogic acid treatment markedly decreased the levels of proinflammatory cytokines and oxidative stress factors, and transforming growth factor‑β (TGF‑β) and matrix metalloproteinase (MMP)‑2 and MMP‑9 protein expression in AAA mice. Furthermore, Gambogic acid decreased expression of phosphatidylinositol 3‑kinase (PI3K), and phosphorylation of protein kinase B (Akt), mechanistic target of rapamycin (mTOR) and p70‑S6 kinase 1. It also suppressed nuclear factor (NF)‑κB protein expression in AAA mice. The findings of the present study indicated that Gambogic acid prevents angiotensin II‑induced AAA through inflammatory and oxidative stress‑dependent targeting of the PI3K/Akt/mTOR and NF‑κB signaling pathways.

Anti-microRNA-132 causes sevoflurane‑induced neuronal apoptosis via the PI3K/AKT/FOXO3a pathway

In the present study, the mechanisms underlying the protective effects of microRNA‑132 (miRNA‑132) on sevoflurane‑induced neuronal apoptosis were investigated. Reverse transcription‑quantitative polymerase chain reaction and gene microarray hybridization were used to analyze alterations in microRNA levels. Cell viability, apoptosis and caspase‑3/9 activity were measured using MTT, flow cytometry and caspase‑3/9 activity kits. Immunofluorescence staining and western blot analysis were used to measure protein expression of phosphoinositide 3‑kinase (PI3K) and phosphorylated (p‑)AKT, forkhead box O3a (FOXO3a). In sevoflurane‑induced rats, the expression of miRNA‑132 was downregulated, compared with that in negative control rats. The downregulation of miRNA‑132 increased neuronal apoptosis and the upregulation of miRNA‑132 inhibited neuronal apoptosis in the sevoflurane‑induced in vitro model. The downregulation of miRNA‑132 suppressed the protein expression of PI3K and p‑AKT, and suppressed the protein expression of FOXO3a in the sevoflurane‑induced in vitro model. The PI3K inhibitor increased the effects of anti‑miRNA‑132 on neuronal apoptosis through the AKT/FOXO3a pathway in the sevoflurane‑induced in vitro model. The promotion of FOXO3a inhibited the effects of anti‑miRNA‑132 on neuronal apoptosis through the AKT/FOXO3a pathway in the sevoflurane‑induced in vitro model. These data suggested that miRNA‑132 caused sevoflurane‑induced neuronal apoptosis via suppression of the PI3K/AKT/FOXO3a pathway.

High-Mobility Group Box 1 Protein Regulates Autophagy in LO2 Cells Following Anoxia-Reoxygenation Injury

The mechanisms of autophagy during liver ischemia-reperfusion injury are not completely understood. This study aimed to assess the role of high-mobility group box 1 protein (HMGB1) in autophagy in LO2 cells following anoxia-reoxygenation injury. LO2 cells were pretreated with the HMGB1 inhibitor ammonium glycyrrhizinate (1000 μmol/L) or the HMGB1 agonist recombinant HMGB1 (rHMGB1, 10 ng/mL) at proper concentrations before induction of anoxia-reoxygenation injury. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and cell viability were evaluated. Then, the expression levels of LC3 and Beclin-1, which are classical autophagy markers, were assessed by Western blot. Autophagosomes were detected by electron microscopy. Our results showed that rHMGB1-treated cells had increased AST and ALT levels in the culture medium, aggravated cell injury, enhanced expression of beclin-1 and LC3 proteins, and increased number of autophagosomes. However, glycyrrhizinate treatment alleviated ALT and AST levels in culture medium, relieved cell injury, reduced beclin-1 and LC3 protein expression levels, and decreased autophagosome number. These findings indicated that HMGB1 likely regulates autophagy in LO2 cells exposed to anoxia-reoxygenation injury.

Protective Effects of Oleuropein Against Cerebral Ischemia/Reperfusion by Inhibiting Neuronal Apoptosis

BACKGROUND In this study, we investigated the potential neuroprotective effect of oleuropein (OLE) on apoptotic changes via modulating Akt/glycogen synthase kinase 3 beta (Akt/GSK-3b) signaling in a rat model of cerebral ischemia/reperfusion injury (IRI). MATERIAL AND METHODS Sprague-Dawley male rats (12 weeks, n=200) were randomly assigned to 5 groups: sham group, vehicle (IRI+ vehicle) group, OLE (IRI+OLE) group, OLE+LY294002 (IRI+OLE+LY294002) group, and LY294002(IRI+LY294002) group. The rats were subjected to cerebral ischemia/reperfusion injury (IRI) model and treated once daily for 5 days with vehicle and OLE (100 mg/kg via intraperitoneal injection) after IRI injury. LY294002 (0.3 mg/kg) was intraperitoneally injected once at 30 min after IRI injury. Brain edema, neurological deficit, rotarod latencies, and Morris water maze (MWM) performance were evaluated after IRI. The number of dead cells were assayed by TUNEL staining. Western blot was used to detect the expression of Bcl-2, Bax, cleaved caspase-3 (CC3), neurotrophic factors, and the phosphorylation levels of Akt and GSK-3β. RESULTS Compared with the vehicle group, brain water content, neurological deficits, rotarod latencies, and escape latency following IRI were reduced in the OLE group. Cell apoptosis and reduced neurotrophic factor caused by IRI was also attenuated by OLE. Furthermore, increased p-Akt and decreased p-GSK-3β were caused by OLE, which were associated with decrease of Bax/Bcl-2 ratio and the suppression of Caspase-3 activity after IRI. Importantly, all the beneficial effects of OLE in the vehicle group were abrogated by PI3K inhibitor LY294002. CONCLUSIONS Cerebral ischemia was protected by OLE via suppressing apoptosis through the Akt/GSK-3β pathway and upregulating neurotrophic factor after IRI.

Effects of Ginsenoside Rb1 on Expressions of Phosphorylation Akt/Phosphorylation mTOR/Phosphorylation PTEN in Artificial Abnormal Hippocampal Microenvironment in Rats

Artificial abnormal microenvironment caused by microperfusion of L-glutamate (Glu) and Ca²⁺ in the hippocampus results in neuron damage, which is closely related to cerebral ischemia. Ginsenoside Rb1, a compound from Panax notoginseng, was previously used to counter the artificial abnormal hippocampal environment in a microperfusion model. In addition, while the Akt/mTOR/PTEN signaling pathway has been shown to mediate neuronprotection in cerebral ischemia, whether this pathway is involved in the neuroprotection of ginsenoside Rb1 is unknown. Here SH-SY5Y cells exposed to OGD/R injury in treated with LY294002, ginsenoside Rb1, ginsenoside Rb1+ LY294002. Expressions of phosphorylation (P-)Akt/P-mTOR/P-PTEN (24 h after OGD/R) were detected by Western blotting. Effects were examined via the memory function of rats (by Morris water maze test), morphological changes in pyramidal cell (by histology), and mRNA expression (by qRT-PCR) and phosphorylation (P-) (by Western blotting and immunohistochemical staining) of Akt, P-mTOR, and P-PTEN in the hippocampus. The memory deficit of rats and pyramidal cellular necrosis and apoptosis in the CA1 region of hippocampus after microperfusion of Glu and Ca²⁺ were dose dependently alleviated by ginsenoside Rb1.Moreover,Western blot showed that ginsenoside Rb1 increased the expressions of P-Akt, P-mTOR and reduced P-PTEN in vivo and vitro. Thus, the potent neuroprotection of ginsenoside Rb1 in artificial abnormal microenvironment is, at least partially, related to the activation of P-AKT/P-mTOR signaling pathway and inhibition of P-PTEN protein.

Inhibition of autophagy via activation of PI3K/Akt/mTOR pathway contributes to the protection of hesperidin against myocardial ischemia/reperfusion injury

Hesperidin has been reported to attenuate myocardial ischemia/reperfusion (I/R) injury; however, its effect on autophagy during myocardial I/R and the underlying mechanism remains unknown. The present study aimed to investigate whether hesperidin inhibited I/R-induced excessive myocardial autophagy through activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway. Male adult rats were pretreated with hesperidin for a total of 3 days prior to ischemia in the absence or presence of LY294002, a PI3K inhibitor, and then subjected to ischemia for 30 min followed by reperfusion for 4 h. Myocardial infarct size was measured by Evans blue/triphenyltetrazolium chloride staining. Hematoxylin and eosin staining was used for observing the histological changes in the heart, and the serum levels of creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) were measured by enzyme-linked immunosorbent assay. Additionally, the protein levels of light chain (LC) 3II, Beclin1, phosphorylated (p)-mTOR, p-Akt and p-PI3K were determined by western blot analysis. Hesperidin pretreatment significantly decreased the myocardial infarct size, myocardial damage and serum levels of CK-MB and cTnI. Furthermore, the expression levels of LC3II and Beclin1 were significantly downregulated and the expression levels of p-mTOR, p-Akt and p-PI3K were markedly upregulated by hesperidin. However, the aforementioned effects as a result of hesperidin were significantly reversed by the presence of LY294002. These results demonstrated that hesperidin reduced myocardial I/R injury by suppressing excessive autophagy. Activation of the PI3K/Akt/mTOR pathway contributed to the inhibitory effect of hesperidin on excessive autophagy.