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Fulltext Asymptomatic neurotoxicity of amyloid β-peptides (Aβ1-42 and Aβ25-35) on mouse embryonic stem cell-derived neural cells

Mansor NI, Ntimi CM, Abdul-Aziz NM, Ling KH, Adam A, Rosli R, et al.

Bosn J Basic Med Sci, 2021 Feb 01;21(1):98-110.
PMID: 32156249 DOI: 10.17305/bjbms.2020.4639

One of the strategies in the establishment of in vitro oxidative stress models for neurodegenerative diseases, such as Alzheimer's disease (AD), is to induce neurotoxicity by amyloid beta (Aβ) peptides in suitable neural cells. Presently, data on the neurotoxicity of Aβ in neural cells differentiated from stem cells are limited. In this study, we attempted to induce oxidative stress in transgenic 46C mouse embryonic stem cell-derived neurons via treatment with Aβ peptides (Aβ1-42 and Aβ25-35). 46C neural cells were generated by promoting the formation of multicellular aggregates, embryoid bodies in the absence of leukemia inhibitory factor, followed by the addition of all-trans retinoic acid as the neural inducer. Mature neuronal cells were exposed to different concentrations of Aβ1-42 and Aβ25-35 for 24 h. Morphological changes, cell viability, and intracellular reactive oxygen species (ROS) production were assessed. We found that 100 µM Aβ1-42 and 50 µM Aβ25-35 only promoted 40% and 10%, respectively, of cell injury and death in the 46C-derived neuronal cells. Interestingly, treatment with each of the Aβ peptides resulted in a significant increase of intracellular ROS activity, as compared to untreated neurons. These findings indicate the potential of using neurons derived from stem cells and Aβ peptides in generating oxidative stress for the establishment of an in vitro AD model that could be useful for drug screening and natural product studies.

Matched MeSH terms: Peptide Fragments/toxicity*
Fulltext Neuroprotective Effects of Biochanin A against β-Amyloid-Induced Neurotoxicity in PC12 Cells via a Mitochondrial-Dependent Apoptosis Pathway

Tan JW, Kim MK

Molecules, 2016 Apr 25;21(5).
PMID: 27120593 DOI: 10.3390/molecules21050548

Alzheimer's disease is considered one of the major neurodegenerative diseases and is characterized by the production of β-amyloid (Aβ) proteins and progressive loss of neurons. Biochanin A, a phytoestrogen compound found mainly in Trifolium pratense, was used in the present study as a potential alternative to estrogen replacement therapy via the investigation of its neuroprotective effects against Aβ25-35-induced toxicity, as well as of its potential mechanisms of action in PC12 cells. Exposure of these cells to the Aβ25-35 protein significantly increased cell viability loss and apoptosis. However, the effects induced by Aβ25-35 were markedly reversed in the present of biochanin A. Pretreatment with biochanin A attenuated the cytotoxic effect of the Aβ25-35 protein by decreasing viability loss, LDH release, and caspase activity in cells. Moreover, we found that expression of cytochrome c and Puma were reduced, alongside with the restoration of Bcl-2/Bax and Bcl-xL/Bax ratio in the presence of biochanin A, which led to a decrease in the apoptotic rate. These data demonstrate that mitochondria are involved in the protective effect of biochanin A against Aβ25-35 and that this drug attenuated Aβ25-35-induced PC12 cell injury and apoptosis by preventing mitochondrial dysfunction. Thus, biochanin A might raise a possibility as a potential therapeutic agent for Alzheimer's disease and other related neurodegenerative diseases.

Matched MeSH terms: Peptide Fragments/toxicity*
Report: Antibacterial activity of a peptide derived from HIV-1 MN strain gp41 envelope glycoprotein against methicillin-resistant Staphylococcus aureus

Teow SY, Ali SA

Pak J Pharm Sci, 2016 Nov;29(6):2119-2124.
PMID: 28375134

Peptides derived from HIV-1 transmembrane proteins have been extensively studied for antimicrobial activities, and they are known as antimicrobial peptides (AMPs). These AMPs have also been reported to potently combat the drug-resistant microbes. In this study, we demonstrated that peptide #6383 originated from HIV-1 MN strain membrane-spanning domain of gp41 was active (2-log reductions) at 100βg/mL (56.5βM) against methicillin-resistant Staphylococcus aureus (MRSA) in 10% and 50% human plasma-supplemented phosphate buffered saline (PBS). The activity was further enhanced (3-log reductions) in the presence of 5% human serum albumin (HSA) alone. All bactericidal activities were achieved within 6 hours. At 100μg/mL, the peptide showed only 13% toxicity against human erythrocytes. This peptide can serve as an attractive template for a design of a novel peptide antibiotic against drug-resistant bacteria. By sequence-specific engineering or modifications, we anticipated that the bactericidal activity and the reduced toxicity against human erythrocytes will be improved.

Matched MeSH terms: Peptide Fragments/toxicity
Modulation of LOX and COX pathways via inhibition of amyloidogenesis contributes to mitoprotection against β-amyloid oligomer-induced toxicity in an animal model of Alzheimer's disease in rats

Kalra J, Kumar P, Majeed AB, Prakash A

Pharmacol. Biochem. Behav., 2016 Jul-Aug;146-147:1-12.
PMID: 27106205 DOI: 10.1016/j.pbb.2016.04.002

Several lines of evidence indicate that beta amyloid (β-A) production, neurofibrillary tangles and neuroinflammation are interrelated in the pathogenesis of Alzheimer's disease (AD). AD is associated with enhanced β-A production and accumulation resulting in neuroinflammation probably via activation of lipoxygenase (LOX) and cyclooxygenase (COX) pathways. Therefore, the present study was designed to investigate the role of LOX and COX inhibitors (zafirlukast and valdecoxib) in amyloidogenesis in β-A1-42 oligomer induced experimental AD in rats. The behavioral activities were assessed using actophotometer, novel object recognition test (ORT), Morris water maze (MWM) followed by biochemical assessments, determination of proinflammatory cytokines and mediators (TNF-α, IL-1β and PGE2), β-A1-42 levels and histopathological analysis. ICV administration of β-A1-42 oligomer produced significant impairment in memory consolidation. In addition to this significant increase in mito-oxidative stress, neuroinflammatory markers, acetylcholinesterase (AChE) toxicity, β-A1-42 level, neuronal cell death and neuroinflammation are more profound in β-A1-42 oligomer treated AD rats. Administration of zafirlukast (15 and 30mg/kg), and valdecoxib (5 and 10mg/kg) significantly improved the behavioral performances and showed significant reversal of mito-oxidative damage declining the neuroinflammation in β-A1-42 oligomer treated rats. Furthermore, more profound effects were observed at the sub-therapeutic dose combination of zafirlukast (15mg/kg) and valdecoxib (5mg/kg). The results of the present study indicate that protective effects of zafirlukast and valdecoxib are achieved through the blockade of release of LOX and COX metabolites therefore, representing a new therapeutic target for treating AD and other neurodegenerative disorders.

Matched MeSH terms: Peptide Fragments/toxicity*
Piper sarmentosum Roxb. confers neuroprotection on beta-amyloid (Aβ)-induced microglia-mediated neuroinflammation and attenuates tau hyperphosphorylation in SH-SY5Y cells

Yeo ETY, Wong KWL, See ML, Wong KY, Gan SY, Chan EWL

J Ethnopharmacol, 2018 May 10;217:187-194.
PMID: 29462698 DOI: 10.1016/j.jep.2018.02.025

ETHNOPHARMACOLOGICAL RELEVANCE: Piper sarmentosum Roxb. (PS), belonging to Piperaceae family, is an edible plant with medicinal properties. It is traditionally used by the Malays to treat headache and boost memory. Pharmacological studies revealed that PS exhibits anti-inflammatory, anti-oxidant, anti-acetylcholinesterase, and anti-depressant-like effects. In view of this, the present study aimed to investigate the anti-inflammatory actions of PS and its potential neuroprotective effects against beta-amyloid (Aβ)-induced microglia-mediated neurotoxicity.
MATERIALS AND METHODS: The inhibitory effects of hexane (LHXN), dichloromethane (LDCM), ethyl acetate (LEA) and methanol (LMEOH) extracts from leaves of PS on Aβ-induced production and mRNA expression of pro-inflammatory mediators in BV-2 microglial cells were assessed using colorimetric assay with Griess reagent, ELISA kit and real-time RT-PCR respectively. Subsequently, MTT reduction assay was used to evaluate the neuroprotective effects of PS leaf extracts against Aβ-induced microglia-mediated neurotoxicity in SH-SY5Y neuroblastoma cells. The levels of tau proteins phosphorylated at threonine 231 (pT231) and total tau proteins (T-tau) were determined using ELISA kits.
RESULTS: Polar extracts of PS leaves (LEA and LMEOH) reduced the Aβ-induced secretion of pro-inflammatory cytokines (IL-1β and TNF-α) in BV-2 cells by downregulating the mRNA expressions of pro-inflammatory cytokines. The inhibition of nitric oxide (NO) production could be due to the free radical scavenging activity of the extracts. In addition, conditioned media from Aβ-induced BV-2 cells pre-treated with LEA and LMEOH protected SH-SY5Y cells against microglia-mediated neurotoxicity. Further mechanistic study suggested that the neuroprotective effects were associated with the downregulation of phosphorylated tau proteins.
CONCLUSIONS: The present study suggests that polar extracts of PS leaves confer neuroprotection against Aβ-induced microglia-mediated neurotoxicity in SH-SY5Y cells by attenuating tau hyperphosphorylation through their anti-inflammatory actions and could be a potential therapeutic agent for Alzheimer's disease.

Matched MeSH terms: Peptide Fragments/toxicity*
Neurorestorative effect of FTY720 in a rat model of Alzheimer's disease: comparison with memantine

Hemmati F, Dargahi L, Nasoohi S, Omidbakhsh R, Mohamed Z, Chik Z, et al.

Behav Brain Res, 2013 Sep 1;252:415-21.
PMID: 23777795 DOI: 10.1016/j.bbr.2013.06.016

Alzheimer's disease (AD) as a neurodegenerative brain disorder is the most common cause of dementia. To date, there is no causative treatment for AD and there are few preventive treatments either. The sphingosine-1-phosphate receptor modulator FTY720 (fingolimod) prevents lymphocytes from contributing to an autoimmune reaction and has been approved for multiple sclerosis treatment. In concert with other studies showing the anti-inflammatory and protective effect of FTY720 in some neurodegenerative disorders like ischemia, we have recently shown that FTY720 chronic administration prevents from impairment of spatial learning and memory in AD rats. Here FTY720 was examined on AD rats in comparison to the only clinically approved NMDA receptor antagonist, Memantine. Passive avoidance task showed significant memory restoration in AD animals received FTY720 comparable to Memantine. Upon gene profiling by QuantiGene Plex, this behavioral outcomes was concurrent with considerable alterations in some genes transcripts like that of mitogen activated protein kinases (MAPKs) and some inflammatory markers that may particularly account for the detected decline in hippocampal neural damage or memory impairment associated with AD. From a therapeutic standpoint, our findings conclude that FTY720 may suggest new opportunities for AD management probably based on several modulatory effects on genes involved in cell death or survival.

Matched MeSH terms: Peptide Fragments/toxicity