Ginkgolide B‑induced AMPK pathway activation protects astrocytes by regulating endoplasmic reticulum stress, oxidative stress and energy metabolism induced by Aβ1‑42

Temporin-GHaR Peptide Alleviates LPS-Induced Cognitive Impairment and Microglial Activation by Modulating Endoplasmic Reticulum Stress

Neuroinflammation is considered an important factor that leads to cognitive impairment. Microglia play a crucial role in neuroinflammation, which leads to cognitive impairment. This study aimed at determining whether temporin-GHaR peptide (GHaR) could improve cognitive function and at uncovering the underlying mechanisms. We found that GHaR treatment alleviated LPS-induced cognitive impairment and inhibited activation of microglia in LPS-induced mice. Furthermore, GHaR inhibited activation of endoplasmic reticulum stress (ERS) and the NF-κB signaling pathway in LPS-induced mice. In vitro, GHaR inhibited M1 polarization of BV2 cells and suppressed TNF-α and IL-6 secretion. Additionally, GHaR neuronal cell viability and apoptosis were induced by LPS-activated microglia-conditioned medium. Moreover, in LPS-induced BV2 cells, GHaR inhibited activation of ERS and the NF-κB signaling pathway. In summary, GHaR improved LPS-induced cognitive and attenuated inflammatory responses via microglial activation reversal. In conclusion, the neuroprotective effects of GHaR were mediated via the ERS signaling pathway.

[Ginkgolide B: mechanisms of neurobiological effects, prospects for use in the therapy of Alzheimer's disease]

The review presents an analysis of experimental data on the study of neurobiological effects of ginkgolide B, which may find application in the therapy of Alzheimer's disease (AD). Ginkgolide B is a diterpene trilactone isolated from the leaves of the relict woody plant Ginkgo biloba L., which has been used for thousands of years in traditional Chinese medicine as a neuroprotective agent. In recent years, this compound has attracted attention because of its wide range of neurobiological effects. The neuroprotective effect of ginkgolide B on brain neurons when exposed to various neurotoxins has been established. This compound has also been shown to effectively protect neurons from the effects of beta-amyloid. Studies have revealed the ability of ginkgolide B to reduce microglia activity and regulate neurotransmitter release. In vivo experiments have shown that this substance significantly increases the expression of brain-derived neurotrophic factor (BDNF) and improves cognitive functions, including memory and learning. It is concluded that ginkgolide B, apparently, may find application in the future as a multi-targeted agent of complex therapy of AD.

Radioprotective effect of Ginkgolide B on brain: the mediating role of DCC/MST1 signaling

PURPOSE

The risk of brain exposure to ionizing radiation increases gradually due to the extensive application of nuclear technology in medical, industrial, and aerospace fields. Radiation-induced brain injury (RBI) is highly likely to cause a wide range of neurological complications, including schizophrenia, Alzheimer's disease (AD), depression. Ginkgolide B (GB) is one of the effective active components extracted from ginkgo biloba leaves, exerts protective effects on CNS, which is involved in the regulation of the Hippo signaling pathway. MST1, as one of the core kinases of the Hippo pathway, participated in regulating cell proliferation, differentiation, and apoptosis. However, it remains unclear whether GB attenuates radiation brain injury (RBI) and whether the radioprotective effect of GB refers to MST1 signaling. Hence, our study aimed to explore the radiation protection effect and the potential mechanism of GB.

MATERIALS AND METHODS

C57BL/6 mice were stimulated with an X-ray (20 Gy) to establish an RBI model. Then, morris water maze test (MWM) and step-down passive avoidance test (SDPAT) were used to assess the learning and memory function of mice. The open field test (OFT), tail suspension test (TST), and forced swimming test (FST) were used to assess changes in locomotor activity and hopelessness. Besides, X-ray-stimulated SH-SY5Y cells were used to verify the radioprotective effect of GB. Immunofluorescence double staining, Dihydroethidium (DHE), western blot, and flow cytometry were used to explore the role of DCC/MST1 signaling in RBI.

RESULTS

In this study, X-ray-treated mice exhibited cognitive impairment and depression-like behavior, which was ameliorated by GB treatment. GB also reduced the ROS production and the number of TUNEL-positive cells in the hippocampus. Moreover, GB increased the protein levels of p-AKT and Bcl2, while decreased the protein levels of MST1, p-p38, p-JNK, cleaved-caspase-3 and Bax both in vivo and in vitro. Additionally, exogenous Netrin-1 alleviated X-ray-induced ROS production and apoptosis, whereas knockout of Netrin-1 receptor DCC abolished the protective effect of GB.

CONCLUSION

Oxidative stress and MST1-mediated neuronal apoptosis participated in radiation-induced cognitive impairment and depression-like behaviors, and modulation of DCC by GB was an effective intervention against RBI.

Ginkgo biloba extracts protect human retinal Müller glial cells from t-BHP induced oxidative damage by activating the AMPK-Nrf2-NQO-1 axis

OBJECTIVES

Retinal Müller glial cell loss is almost involved in all retinal diseases, especially diabetic retinopathy (DR). Oxidative stress significantly contributes to the development of Müller glial cell loss. Ginkgo biloba extracts (GBE) have been reported to possess antioxidant property, beneficial in treating human retinal diseases. However, little is known about its role in Müller glial cells. This study investigated the protective effect of GBE (prepared from ginkgo biloba dropping pills) in human Müller glial cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress and its underlying molecular mechanism.

METHODS

MIO-M1 cells were pretreated with or without GBE prior to the exposure to t-BHP-induced oxidative stress. Cell viability, cell death profile and lipid peroxidation were subsequently assessed. Protein expression of the key anti-oxidative signalling factors were investigated.

KEY FINDINGS

We showed that GBE can effectively protect human MIO-M1 cells from t-BHP-induced oxidative injury by improving cell viability, reducing intracellular ROS accumulation and suppressing lipid peroxidation, which effect is likely mediated through activating AMPK-Nrf2-NQO-1 antioxidant respondent axis.

CONCLUSIONS

Our study is the first to reveal the great potentials of GBE in protecting human retinal Müller glial cell loss against oxidative stress. GBE might be used to prevent human retinal diseases particularly DR.

Protective effect of Huangpu Tongqiao capsule against Alzheimer's disease through inhibiting the apoptosis pathway mediated by endoplasmic reticulum stress in vitro and in vivo

Objectives

Huangpu Tongqiao Capsule (HPTQC) is a traditional Chinese medicine (TCM) that has been used to treat Alzheimer's disease (AD). This study was to explore the pharmacological action and molecular mechanism of HPTQC in the treatment of AD.

Methods

The possible targets of HTPQC were predicted by the molecular docking technique. Intraperitoneal injection of D-galactose and bilateral injection of Aβ25-35 in hippocampus induced AD rat model. Morris water maze was used to observe learning and memory function. The primary hippocampal neurons were induced by Aβ25-35. Moreover, the apoptosis rate of hippocampal nerve cells was detected through AnnexinV/PI double standard staining. The mRNA and protein levels of GRP78, CHOP, Caspase 12, Caspase 9, and Caspase 3 were detected by PCR and western blot.

Results

The prediction results suggest that HPTQC may act on GRP78. HPTQC significantly improved the learning and memory function, and decreased neuronal apoptosis in vivo and in vitro. In addition, HPTQC could decrease the mRNA and protein expression levels of GRP78, CHOP, Caspase12, Caspase9, and Caspase3, and the effect trend was consistent with the specific inhibitor of GRP78.

Conclusions

HPTQC has a neuroprotective effect against AD by inhibiting the apoptosis pathway mediated by endoplasmic reticulum stress.

Ginkgolide C slows the progression of osteoarthritis by activating Nrf2/HO-1 and blocking the NF-κB pathway

Osteoarthritis (OA) is driven by chronic low-grade inflammation and subsequent cartilage degradation. OA is the most prevalent degenerative joint disease worldwide, and its treatment remains a challenge. The aim of this study was to explore the potential effects and mechanism underlying the anti-OA properties of ginkgolide C (GC). Protective effects of GC on hydrogen peroxide (H2O2)-treated rat chondrocytes were evaluated using ELISA, qPCR, western blot analysis, flow cytometry, ROS detection and immunofluorescence in vitro. Ameliorating effects of GC on cartilage degeneration in rats were evaluated through behavioral assays, microcomputed tomography, histopathological analysis, western blot analysis and ELISA in vivo. In vitro, GC treatment inhibited the release of pro-apoptotic factors induced by H2O2 and promoted the release of the anti-apoptotic proteins. In addition, GC decreased the expression of matrix metalloproteinase (MMP3 and MMP13), thrombospondin motifs 4 (ADAMTS4), and inflammatory mediators inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and SOX9 thereby inhibiting extracellular matrix (ECM) degradation. Mechanistically, GC exerts its anti-apoptotic and anti-inflammatory effects by upregulating the oxidative stress signaling Nrf2/HO-1 pathway and preventing p65 from binding to DNA. Similarly, In a rat model with post-traumatic OA (PTOA) induced by anterior cruciate ligament transection (ACLT), GC inhibited joint pain, cartilage destruction, and abnormal bone remodeling of subchondral bone. GC inhibited H2O2-induced chondrocyte apoptosis through Nrf2/HO-1 and NF-κB axis, exerted anti-inflammatory effects, and inhibited cartilage degeneration in rat OA. Our findings advanced the concept that GC may contribute to cartilage metabolism through anti-inflammatory and anti-apoptotic effects, and the identified GC is a potential therapeutic agent for the treatment of OA.

Exendin-4 alleviates β-Amyloid peptide toxicity via DAF-16 in a Caenorhabditis elegans model of Alzheimer's disease

Epidemiological analyses indicate that type 2 diabetes mellitus (T2DM) is a risk factor for Alzheimer's disease (AD). They share common pathophysiological mechanisms. Thus, it has been increasingly suggested that several anti-T2DM drugs may have therapeutic potential in AD. Exendin-4, as a glucagon-like peptide-1 (GLP-1) receptor agonist, is an approved drug used to treat T2DM. In this research, the neuroprotective effect of Exendin-4 was investigated for the first time using transgenic Caenorhabditis elegans. Our results demonstrated that Exendin-4 attenuated the amyloid-β (1-42) (Aβ1-42) toxicity via multiple mechanisms, such as depressing its expression on protein and mRNA and reducing Aβ (1-42) accumulation. Exendin-4 at 0.5 mg/ml had been shown to extend life by 34.39% in CL4176 and delay the onset of paralysis in CL4176 and CL2006 which were increased by 8.18 and 8.02%, respectively. With the treatment of Exendin-4, the nuclear translocation of DAF-16 in the transgenic nematode TJ356 was enhanced. Superoxide dismutase-3 (SOD-3), as a downstream target gene regulated by DAF-16, was upregulated on mRNA level and activity. The reactive oxygen species (ROS) level was decreased. In contrast, we observed that the ability of Exendin-4 to regulate SOD was decreased in CL4176 worms with the DAF-16 gene silenced. The activity of SOD and the mRNA level of sod-3 were downregulated by 30.45 and 43.13%, respectively. Taken together, Exendin-4 attenuated Aβ (1-42) toxicity in the C. elegans model of AD via decreasing the expression and the accumulation of Aβ (1-42). Exendin-4 exhibited the ability of antioxidant stress through DAF-16. With continuous research, Exendin-4 would become a potential therapeutic strategy for treating AD.

Ginkgolide B Protects Against Ischemic Stroke via Targeting AMPK/PINK1

Introduction: Ginkgolide B (GB), which is an active constituent derived from Ginkgo biloba leaves, has been reported to ameliorate Alzheimer’s disease (AD), ischemic stroke, as well as other neurodegenerative diseases due to its viable immunosuppressive and anti-inflammatory functions. However, it has yet to be proven whether GB inhibits neuronal apoptosis in ischemic stroke.

Methods: In the present research, the inhibition function of GB on neuronal apoptosis and its underpinning process(s) after cerebral ischemia were studied through transient middle cerebral artery occlusion (t-MCAO) in an in vivo rat model as well as in cultured SH-SY5Y cells subjected to oxygen and glucose deprivation (OGD)/reoxygenation in vitro. The neurological score was calculated and Nissl and TUNEL staining were performed to evaluate the stroke outcome, neuronal loss, and neuronal apoptosis. Subsequently, the western blot was utilized to detect Bcl2 and p-AMPK/AMPK expression.

Results: Compared to t-MCAO rats, rats receiving GB treatment showed a significant reduction of neuronal loss and apoptosis and improved neurological behavior at 72 h after MCAO. GB treatment also upregulated the expression of Bcl2 and p-AMPK. In vitro, GB suppressed the apoptosis in OGD/reoxygenation-challenged neuronal SH-SY5Y cells through AMPK activation.

Conclusions: Our observations suggest that GB enhanced AMPK activation in neural cells, reducing neuronal apoptosis, thus eventually preventing ischemic stroke.

Current Progress on Neuroprotection Induced by Artemisia, Ginseng, Astragalus, and Ginkgo Traditional Chinese Medicines for the Therapy of Alzheimer's Disease

Aging is associated with the occurrence of diverse degenerative changes in various tissues and organs and with an increased incidence of neurological disorders, especially neurodegenerative diseases such as Alzheimer's disease (AD). In recent years, the search for effective components derived from medicinal plants in delaying aging and preventing and treating neurodegenerative diseases has been increasing and the number of related publications shows a rising trend. Here, we present a concise, updated review on the preclinical and clinical research progress in the assessment of the therapeutic potential of different traditional Chinese medicines and derived active ingredients and their effect on the signaling pathways involved in AD neuroprotection. Recognized by their multitargeting ability, these natural compounds hold great potential in developing novel drugs for AD.

Calcitriol ameliorates renal injury with high-salt diet-induced hypertension by upregulating GLIS2 expression and AMPK/mTOR-regulated autophagy

The goal of the present study was to investigate the protective effect of calcitriol on high-salt diet-induced hypertension. The hypertension rat model was established by a long-term high-salt diet (8% NaCl). Rats were treated with calcitriol, losartan, or their combination. Histological staining was used to confirm renal pathology. Global transcriptome analysis of renal tissues was performed, and the mechanism of the therapeutic effect of calcitriol was analysed by functional annotation and pathway analysis of the differentially expressed genes (DEGs) as well as by Western blotting analysis. The core genes for potential therapeutic regulation were identified through the coexpression gene network. For in vitro HK-2 cell experiments, small interfering RNA (siRNA) was used to knockdown key a transcription factor (TF) Glis2 to validate the therapeutic target of calcitriol. MAPK1 and CXCL12 expression was downregulated and the apoptosis pathway was significantly enriched by calcitriol treatment. The western blotting results showed that calcitriol treatment increased AMPK phosphorylation and decreased downstream mTOR phosphorylation, which was accompanied by a decrease in autophagy protein p62 expression and an increase in LC3-II/I expression. GLIS2 was identified as a specific therapeutic target for calcitriol. GLIS2 expression was upregulated by calcitriol and confirmed by HK-2 cells in vitro. Our omics data show that calcitriol can alleviate oxidative stress and fibrosis. Moreover, calcitriol can regulate the CXCL12/ERK1/2 cascade to inhibit the inflammatory response and renal cell apoptosis and induce renal autophagy through the AMPK/mTOR pathway. Our study partially elucidate the pathogenesis and treatment mechanism underlying hypertension, and provide new insights into the treatment of hypertension.

Protective Effects of Ginkgolide on a Cellular Model of Alzheimer's Disease via Suppression of the NF-κB Signaling Pathway

NF-κB signaling has been reported to play a key regulatory role in the pathogenesis of Alzheimer’s disease (AD). The purpose of this study is to investigate the effects of ginkgolide on cell viability in an AD cellular model involving an APP/PS1 double gene-transfected HEK293 cell line (APP/PS1-HEK293) and further explore the mechanisms of action related to NF-κB signaling. The optimal time point and concentration of ginkgolide for cell proliferation were screened using a cell counting kit-8 assay. Based on the results, an in vitro study was performed by co-culture of APP/PS1-HEK293 with different dosages of ginkgolide, followed by an enzyme-linked immunosorbent assay to measure the levels of supernatant tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, as well as western blotting and real-time polymerase chain reaction to detect intracellular protein and mRNA expression of NF-κB p65, IκBa, Bcl-2, and Bax. APP/PS1-HEK293 cells exhibited the highest cell viability at a concentration of 100 µg/ml after 48 h of treatment with ginkgolide. The supernatant levels of TNF-α, IL-1β, and IL-6 in the high-dosage ginkgolide-treated groups were lower than those in the control group. Compared with the control group, there were decreased intracellular protein and mRNA expression of NF-κB p65 and Bax, but increased protein and mRNA expression of IκBa in both high-dosage and low-dosage groups. Ginkgolide may enhance cell viability, indicative of its neuroprotective effects on AD, at least partially via suppression of the NF-κB signaling pathway involving anti-apoptosis and anti-inflammation mechanisms. Therefore, ginkgolide might be a promising therapeutic agent against AD.

Protective Effect of Ginkgolide B against Cognitive Impairment in Mice via Regulation of Gut Microbiota

Ginkgolide B (GB) is one of the main bioactive components of Ginkgo biloba leaf extracts with neuroprotective activity. However, the neuroprotective mechanism link between the anti-Alzheimer's disease (AD) efficiency of GB and gut microbiota have remained elusive. Here, we elucidated the effect and possible mechanism of GB against cognitive impairment in mice. Male mice were induced with d-galactose and aluminum chloride to establish an AD animal model, and then intragastrically treated with GB. Cognitive function was assessed by an object recognition test and an open-field test. Amyloid deposition and neuropathological change were detected. The levels of receptor for advanced glycation end products (RAGE), Bcl-2, and Bax were detected. Moreover, microbial compositions were measured by 16s rRNA sequencing. Our results showed that GB significantly alleviated cognitive dysfunction, neurodegeneration, and neuropathological changes in AD model mice. Moreover, GB treatment remarkably reduced the levels of RAGE and Bax and increased the level of Bcl-2 in AD model mice. GB treatment reversed the decreased abundance of Lactobacillus and the increased abundance of Bacteroidales, Muribaculaceae, and Alloprevotella, which led to reconstruction of gut microbiota. These findings demonstrated the neuroprotective effects of GB in AD mice, which were partly mediated by modulating gut dysbiosis, indicating that GB might be a potentially active supplement to alleviate AD.