140 research outputs found
Ergosterol promotes neurite outgrowth, inhibits amyloid-beta synthesis, and extends longevity: In vitro neuroblastoma and in vivo Caenorhabditis elegans evidence
No full textAims: Alzheimer's disease (AD), the most common neurodegenerative disorder associated with aging, is characterized by amyloid-beta (A beta) plaques in the hippocampus. Ergosterol, a mushroom sterol, exhibits neuroprotective activities; however, the underlying mechanisms of ergosterol in promoting neurite outgrowth and preventing A beta associated aging have never been investigated. We aim to determine the beneficial activities of ergosterol in neuronal cells and Caenorhabditis elegans (C. elegans). Materials and methods: The neuritogenesis and molecular mechanisms of ergosterol were investigated in wildtype and A beta precursor protein (APP)-overexpressing Neuro2a cells. The anti-amyloidosis properties of ergosterol were determined by evaluating in vitro A beta production and the potential inhibition of A beta-producing enzymes. Additionally, AD-associated transgenic C. elegans was utilized to investigate the in vivo attenuating effects of ergosterol. Key findings: Ergosterol promoted neurite outgrowth in Neuro2a cells through the upregulation of the transmembrane protein Teneurin-4 (Ten-4) mRNA and protein expressions, phosphorylation of the extracellular signal-regulated kinases (ERKs), activity of cAMP response element (CRE), and growth-associated protein-43 (GAP-43). Furthermore, ergosterol enhanced neurite outgrowth in transgenic Neuro2A cells overexpressing either the wild-type APP (Neuro2a-APPwt) or the Swedish mutant APP (Neuro2a-APPswe) through the Ten-4/ ERK/CREB/GAP-43 signaling pathway. Interestingly, ergosterol inhibited A beta synthesis in Neuro2a-APPwt cells. In silico analysis indicated that ergosterol can interact with the catalytic sites of beta- and gamma-secretases. In A beta-overexpressing C. elegans, ergosterol decreased A beta accumulation, increased chemotaxis behavior, and prolonged lifespan. Significance: Ergosterol is a potential candidate compound that might benefit AD patients by promoting neurite outgrowth, inhibiting A beta synthesis, and enhancing longevity
Dipentylammonium Binds to the Sigma-1 Receptor and Protects Against Glutamate Toxicity, Attenuates Dopamine Toxicity and Potentiates Neurite Outgrowth in Various Cultured Cell Lines
No full textAlzheimer’s disease is a neurodegenerative disease that affects 44 million people worldwide, costing the world $605 billion to care for those affected not taking into account the physical and psychological costs for those who care for Alzheimer’s patients. Dipentylammonium is a simple amine, which is structurally similar to a number of other identified sigma-1 receptor ligands with high affinities such as (2R-trans)-2butyl-5-heptylpyrrolidine, stearylamine and dodecylamine. This study investigates whether dipentylammonium is able to provide neuroprotective effects similar to those of sigma-1 receptor agonists such as PRE-084. Here we identify dipentylammonium as a sigma-1 receptor ligand with nanomolar affinity. We have found that micromolar concentrations of dipentylammonium protect from glutamate toxicity and prevent NFκB activation in HT-22 cells. Micromolar concentrations of dipentylammonium also protect stably expressing amyloid precursor protein Swedish mutant (APP/Swe) Neuro2A cells from toxicity induced by 150 μM dopamine, suggesting that dipentylammonium may be useful for the treatment of Parkinsonian symptoms in Alzheimer’s patients which are often associated with a more rapid deterioration of cognitive and physical ability. Finally, we found that low micromolar concentrations of dipentylammonium could out preform known sigma-1 receptor agonist PRE-084 in potentiating neurite outgrowth in Neuro2A cells, further suggesting that dipentylammonium has a potential use in the treatment of neurodegenerative diseases and could be acting through the sigma-1 receptor
Turmeric Toxicity in A431 Epidermoid Cancer Cells Associates with Autophagy Degradation of Anti-apoptotic and Anti-autophagic p53 Mutant
No full textThe keratinocyte-derived A431 Squamous Cell Carcinoma cells express the p53R273H mutant, which has been reported to inhibit apoptosis and autophagy. Here, we show that the crude extract of turmeric (Curcuma longa), similarly to its bioactive component Curcumin, could induce both apoptosis and autophagy in A431 cells, and these effects were concomitant with degradation of p53. Turmeric and curcumin also stimulated the activity of mTOR, which notoriously promotes cell growth and acts negatively on basal autophagy. Rapamycin-mediated inhibition of mTOR synergized with turmeric and curcumin in causing p53 degradation, increased the production of autophagosomes and exacerbated cell toxicity leading to cell necrosis. Small-interference mediated silencing of the autophagy proteins BECLIN 1 or ATG7 abrogated the induction of autophagy and largely rescued p53 stability in Turmeric-treated or Curcumin-treated cells, indicating that macroautophagy was mainly responsible for mutant p53 degradation. These data uncover a novel mechanism of turmeric and curcumin toxicity in chemoresistant cancer cells bearing mutant p53
Acanthus ebracteatus leaf extract provides neuronal cell protection against oxidative stress injury induced by glutamate
No full textAbstract Background Acanthus ebracteatus (AE), an herb native to Asia, has been recognized in traditional folk medicine not only for its antioxidant properties and various pharmacological activities but also as an ingredient of longevity formulas. However, its anti-neurodegenerative potential is not yet clearly known. This work aimed to evaluate the protective effect of AE leaf extract against glutamate-induced oxidative damage in mouse hippocampal HT22 cells, a neurodegenerative model system due to a reduction in glutathione levels and an increase in reactive oxygen species (ROS). Methods Cell viability, apoptosis, and ROS assays were performed to assess the protective effect of AE leaf extract against glutamate-induced oxidative toxicity in HT22 cells. The antioxidant capacity of AE was evaluated using in vitro radical scavenging assays. The subcellular localization of apoptosis-inducing factor (AIF) and the mRNA and protein levels of genes associated with the nuclear factor erythroid 2–related factor 2 (Nrf2) antioxidant system were determined to elucidate the mechanisms underlying the neuroprotective effect of AE leaf extract. Results We demonstrated that AE leaf extract is capable of attenuating the intracellular ROS generation and HT22 cell death induced by glutamate in a concentration-dependent manner. Co-treatment of glutamate with the extract significantly reduced apoptotic cell death via inhibition of AIF nuclear translocation. The increases in Nrf2 levels in the nucleus and gene expression levels of antioxidant-related downstream genes under Nrf2 control were found to be significant in cells treated with the extract. Conclusions The results suggested that AE leaf extract possesses neuroprotective activity against glutamate-induced oxidative injury and may have therapeutic potential for the treatment of neurodegenerative diseases associated with oxidative stress
Citrus hystrix Extracts Protect Human Neuronal Cells against High Glucose-Induced Senescence
No full textCitrus hystrix (CH) is a beneficial plant utilized in traditional folk medicine to relieve various health ailments. The antisenescent mechanisms of CH extracts were investigated using human neuroblastoma cells (SH-SY5Y). Phytochemical contents and antioxidant activities of CH extracts were analyzed using a gas chromatograph–mass spectrometer (GC-MS), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assay. Effects of CH extracts on high glucose-induced cytotoxicity, reactive oxygen species (ROS) generation, cell cycle arrest and cell cycle-associated proteins were assessed using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) assay, non-fluorescent 2′, 7′-dichloro-dihydrofluorescein diacetate (H2DCFDA) assay, flow cytometer and Western blot. The extracts protected neuronal senescence by inhibiting ROS generation. CH extracts induced cell cycle progression by releasing senescent cells from the G1 phase arrest. As the Western blot confirmed, the mechanism involved in cell cycle progression was associated with the downregulation of cyclin D1, phospho-cell division cycle 2 (pcdc2) and phospho-Retinoblastoma (pRb) proteins. Furthermore, the Western blot showed that extracts increased Surtuin 1 (SIRT1) expression by increasing the phosphorylation of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Collectively, CH extracts could protect high glucose-induced human neuronal senescence by inducing cell cycle progression and up-regulation of SIRT1, thus leading to the improvement of the neuronal cell functions
Rhinacanthus nasutus Protects Cultured Neuronal Cells against Hypoxia Induced Cell Death
No full textRhinacanthus nasutus (L.) Kurz (Acanthaceae) is an herb native to Thailand and Southeast Asia, known for its antioxidant properties. Hypoxia leads to an increase in reactive oxygen species in cells and is a leading cause of neuronal damage. Cell death caused by hypoxia has been linked with a number of neurodegenerative diseases including some forms of dementia and stroke, as well as the build up of reactive oxygen species which can lead to diseases such as Huntington’s disease, Parkinson’s disease and Alzeheimer’s disease. In this study we used an airtight culture container and the Mitsubishi Gas Company anaeropack along with the MTT assay, LDH assay and the trypan blue exlusion assay to show that 1 and 10 µg mL−1 root extract of R. nasutus is able to significantly prevent the death of HT-22 cells subjected to hypoxic conditions, and 0.1 to 10 µg mL−1 had no toxic effect on HT-22 under normal conditions, whereas 100 µg mL−1 reduced HT-22 cell proliferation. We also used H2DCFDA staining to show R. nasutus can reduce reactive oxygen species production in HT-22 cells
ฤทธิ์ของสารสกัดจากขมิ้นชันต่อการแสดงออกของ RAGEในเซลล์มะเร็ง
No full textThesis (M.Sc.)--Chulalongkorn University, 2006The purpose of this study was to determine the effects of turmeric (Curcuma longa Linn.) extracts on the receptor for advanced glycation end products (RAGE) gene expression in human cancer cells (HeLa and SW480). The cells were incubated with turmeric extract at various concentrations (0-80 ug/ml) for 48 and 72 hours. Percentage of cell viability was determined by MTS assay. The results showed that turmeric extract inhibited cell proliferation at 48 and 72 hours of incubation with IC50 of 19.29 and 16.93 ug/ml against HeLa, and 15.60 and 15.62 ug/ml against SW480, respectively. To investigate the anti-invasion effect of turmeric extract, cells were treated with 0-20 ug/ml of turmeric extract and evaluated by matrigel invasion assay. At the concentration of 20 ug/ml, turmeric extract inhibited invasion ability of HeLa and SW480 by 48.72±3.7.76% (p=0.000) and 47.02±10.37% (p=0.000) respectively. Moreover, the expression of RAGE gene was determined by RT-PCR. In HeLa cells, the level of RAGE gene expression was significantly decreased with 20 ug/ml of turmeric extract, at 24 hours incubation period (p=0.002). However, RAGE gene expression in SW480 cells did not show significant difference as compared to the control group (p>0.05). We conclude that turmeric extract has anti-proliferation and anti-invasion activity. In addition, it also reduced RAGE gene expression in HeLa cells that may be involved with these effects.งานวิจัยนี้มีจุดมุ่งหมายเพื่อศึกษาฤทธิ์ของสารสกัดของขมิ้นชันต่อการแสดงออกของยีน RAGE ในเซลล์มะเร็งเพาะเลี้ยง 2 ชนิด (HeLa และ SW480) เมื่อทดสอบเซลล์มะเร็งทั้งสองกับสารสกัดขมิ้นชันที่ความเข้มข้นต่างๆ (ตั้งแต่ 0-80 ug/ml) เป็นเวลา 48 และ 72 ชั่วโมง วิเคราะห์เปอร์เซนต์เซลล์มีชีวิตด้วยวิธี MTS พบว่า สารสกัดขมิ้นชันมีฤทธิ์ต้านการเพิ่มจำนวนเซลล์ของเซลล์มะเร็งทั้งสองโดยมีค่า IC50 ของ HeLa เท่ากับ 19.29 และ 16.93 ug/ml เมื่อบ่มเซลล์กับสารสกัดเป็นเวลา 48 และ 72 ชั่วโมง ตามลำดับ สำหรับค่า IC50 ของ SW480 เท่ากับ 15.60 และ 15.62 ug/ml เมื่อบ่มเซลล์กับสารสกัดเป็นเวลา 48 และ 72 ชั่วโมง ตามลำดับ จากนั้น ทดสอบฤทธิ์ของสารสกัดขมิ้นชันต่อการลุกลามของเซลล์มะเร็งด้วยวิธี matrigel invasion assay โดยบ่มเซลล์กับสารสกัดขมิ้นชันที่ความเข้มข้น 0-20 ug/ml พบว่า สารสกัดขมิ้นชันมีฤทธิ์ต้านการลุกลามของเซลล์มะเร็งทั้งสองเมื่อเทียบกับกลุ่มควบคุม โดยที่ความเข้มข้น 20 ug/ml สารกสัดสามารถต้านการลุกลามของเซลล์ HeLa และเซลล์ SW480 ได้ที่ 48.72±3.76% (P=0.000) และ 47.02±10.37% (p=0.000) ตามลำดับ นอกจากนี้ จากการศึกษาฤทธิ์ของสารสกัดขมิ้นชัน (0-20 ug/ml) ต่อการแสดงออกของยีน RAGE โดยวิธี RT-PCR ในเซลล์ HeLa พบว่าสารสกัดขมิ้นชันที่ 20 ug/ml สามารถยับยั้งการแสดงของยีน RAGE ได้อย่างมีนัยสำคัญทางสถิติ (p=0.002) เมื่อบ่มเป็นเวลา 24 ชั่วโมง แต่ในเซลล์ SW480 การแสดงออกยีน RAGE ไม่พบความแตกต่างอย่างมีนัยสำคัญเมื่อเทียบกับกลุ่มควบคุม (p>0.05) จากผลการทดสอบทั้งหมดสรุปได้ว่า สารสกัดขมิ้นชันมีฤทธิ์ยับยั้งการเพิ่มจำนวนเซลล์และการลุกลามของเซลล์มะเร็ง นอกจากนี้ ยังลดระดับการแสดงออกของยีน RAGE ในเซลล์ HeLa ซึ่งมีความเกี่ยวข้องในการเกิดผลดังกล่า
Effects of Thai Medicinal Herb Extracts with Anti-Psoriatic Activity on the Expression on NF-κB Signaling Biomarkers in HaCaT Keratinocytes
No full textPsoriasis is a chronic inflammatory skin disorder characterized by rapid proliferation of keratinocytes and incomplete keratinization. Discovery of safer and more effective anti-psoriatic drugs remains an area of active research at the present time. Using a HaCaT keratinocyte cell line as an in vitro model, we had previously found that ethanolic extracts from three Thai medicinal herbs, namely Alpinia galanga, Curcuma longa and Annona squamosa, possessed anti-psoriatic activity. In the current study, we aimed at investigating if these Thai medicinal herb extracts played a molecular role in suppressing psoriasis via regulation of NF-κB signaling biomarkers. Using semi-quantitative RT-PCR and report gene assays, we analyzed the effects of these potential herbal extracts on 10 different genes of the NF-κB signaling network in HaCaT cells. In accordance with our hypothesis, we found that the extract derived from Alpinia galanga significantly increased the expression of TNFAIP3 and significantly reduced the expression of CSF-1 and NF-kB2. Curcuma longa extract significantly decreased the expression of CSF-1, IL-8, NF-kB2, NF-kB1 and RelA, while Annona squamosa extract significantly lowered the expression of CD40 and NF-kB1. Therefore, this in vitro study suggested that these herbal extracts capable of functioning against psoriasis, might exert their activity by controlling the expression of NF-κB signaling biomarkers
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