scholarly journals Fluoxetine Potentiates Phagocytosis and Autophagy in Microglia

2021 ◽  
Vol 12 ◽  
Author(s):  
Sung Hee Park ◽  
Young-Sun Lee ◽  
Hyun-Jeong Yang ◽  
Gyun Jee Song
Keyword(s):  
Molecular Mechanisms ◽  
Antidepressant Drug ◽  
Amyloid Β ◽  
Regulatory Effect ◽  
Immunomodulatory Effects ◽  
Autophagy Flux ◽  
Neuroprotective Effects ◽  
Microglia Cell ◽  
Primary Mouse ◽  
And Oxidative Stress

Fluoxetine is a classic antidepressant drug, and its immunomodulatory effects have recently been reported in many disease models. In addition, it has strong antineuroinflammatory effects in stroke and neurodegenerative animal models. However, the effect of fluoxetine on microglia phagocytosis and its molecular mechanisms have not yet been studied. In this study, we investigated whether fluoxetine has a regulatory effect on microglial function. Microglia cell lines and primary mouse microglia were treated with fluoxetine, and the production of inflammatory cytokines and neurotrophic factors and the phagocytosis of amyloid β were measured. Fluoxetine significantly attenuated the production of lipopolysaccharide-induced proinflammatory cytokines and oxidative stress in microglia. Fluoxetine also significantly potentiated microglia phagocytosis and autophagy. In addition, autophagy flux inhibitors attenuated fluoxetine-induced phagocytosis. In conclusion, fluoxetine induces autophagy and potentiates phagocytosis in microglia, which can be a novel molecular mechanism of the neuroinflammatory and neuroprotective effects of fluoxetine.

Sulforaphane Reverses the Amyloid-β Oligomers Induced Depressive-Like Behavior

2020 ◽  
Vol 78 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Wei Wang ◽  
Cuibai Wei ◽  
Meina Quan ◽  
Tingting Li ◽  
Jianping Jia
Keyword(s):  
Oxidative Stress ◽  
Memory Impairment ◽  
Molecular Mechanisms ◽  
Psychological Symptoms ◽  
Amyloid Β ◽  
Serotonergic System ◽  
Inflammatory Factors ◽  
The Relationship ◽  
The Brain ◽  
And Oxidative Stress

Background: Depression is one of the most common behavioral and psychological symptoms in people with Alzheimer’s disease (AD). To date, however, the molecular mechanisms underlying the clinical association between depression and AD remained elusive. Objective: Here, we study the relationship between memory impairment and depressive-like behavior in AD animal model, and investigate the potential mechanisms. Methods: Male SD rats were administered amyloid-β oligomers (AβOs) by intracerebroventricular injection, and then the depressive-like behavior, neuroinflammation, oxidative stress, and the serotonergic system were measured in the brain. Sulforaphane (SF), a compound with dual capacities of anti-inflammation and anti-oxidative stress, was injected intraperitoneally to evaluate the therapeutic effect. Results: The results showed that AβOs induced both memory impairment and depressive-like behavior in rats, through the mechanisms of inducing neuroinflammation and oxidative stress, and impairing the serotonergic axis. SF could reduce both inflammatory factors and oxidative stress parameters to protect the serotonergic system and alleviate memory impairment and depressive-like behavior in rats. Conclusion: These results provided insights into the biological mechanisms underlying the clinical link between depressive disorder and AD, and offered new drug options for the treatment of depressive symptoms in dementia.

scholarly journals Vanillic Acid, a Bioactive Phenolic Compound, Counteracts LPS-Induced Neurotoxicity by Regulating c-Jun N-Terminal Kinase in Mouse Brain

2020 ◽  
Vol 22 (1) ◽  
pp. 361
Author(s):  
Rahat Ullah ◽  
Muhammad Ikram ◽  
Tae Ju Park ◽  
Riaz Ahmad ◽  
Kamran Saeed ◽  
...  
Keyword(s):  
Glial Cells ◽  
Vanillic Acid ◽  
Molecular Mechanisms ◽  
Biological Activities ◽  
Interleukin 1 ◽  
Amyloid Β ◽  
Treated Group ◽  
Expression Level ◽  
Neuroprotective Effects ◽  
Necrosis Factor Alpha

The receptor for advanced glycation end products (RAGE), a pattern recognition receptor signaling event, has been associated with several human illnesses, including neurodegenerative diseases, particularly in Alzheimer’s disease (AD). Vanillic acid (V.A), a flavoring agent, is a benzoic acid derivative having a broad range of biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects. However, the underlying molecular mechanisms of V.A in exerting neuroprotection are not well investigated. The present study aims to explore the neuroprotective effects of V.A against lipopolysaccharides (LPS)-induced neuroinflammation, amyloidogenesis, synaptic/memory dysfunction, and neurodegeneration in mice brain. Behavioral tests and biochemical and immunofluorescence assays were applied. Our results indicated increased expression of RAGE and its downstream phospho-c-Jun n-terminal kinase (p-JNK) in the LPS-alone treated group, which was significantly reduced in the V.A + LPS co-treated group. We also found that systemic administration of LPS-injection induced glial cells (microglia and astrocytes) activation and significantly increased expression level of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-KB) and secretion of proinflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1 β (IL1-β), and cyclooxygenase (COX-2). However, V.A + LPS co-treatment significantly inhibited the LPS-induced activation of glial cells and neuroinflammatory mediators. Moreover, we also noted that V.A treatment significantly attenuated LPS-induced increases in the expression of AD markers, such as β-site amyloid precursor protein (APP)–cleaving enzyme 1 (BACE1) and amyloid-β (Aβ). Furthermore, V.A treatment significantly reversed LPS-induced synaptic loss via enhancing the expression level of pre- and post-synaptic markers (PSD-95 and SYP), and improved memory performance in LPS-alone treated group. Taken together; we suggest that neuroprotective effects of V.A against LPS-induced neurotoxicity might be via inhibition of LPS/RAGE mediated JNK signaling pathway; and encourage future studies that V.A would be a potential neuroprotective and neurotherapeutic candidate in various neurological disorders.

scholarly journals Amyloid β-protein oligomers promote the uptake of tau fibril seeds potentiating intracellular tau aggregation

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Woo Shik Shin ◽  
Jing Di ◽  
Qin Cao ◽  
Binsen Li ◽  
Paul M. Seidler ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Amyloid Β ◽  
Tau Proteins ◽  
Amyloid Β Protein ◽  
Dependent Manner ◽  
Aβ Oligomers ◽  
Human Neuroblastoma ◽  
Primary Mouse ◽  
Tau Aggregation ◽  
Aβ Oligomer

Abstract Background Repeated failure of drug candidates targeting Alzheimer’s disease (AD) in clinical trials likely stems from a lack of understanding of the molecular mechanisms underlying AD pathogenesis. Recent research has highlighted synergistic interactions between aggregated amyloid-β (Aβ) and tau proteins in AD, but the molecular details of how these interactions drive AD pathology remain elusive and speculative. Methods Here, we test the hypothesis that Aβ potentiates intracellular tau aggregation, and show that oligomeric Aβ specifically exacerbates proteopathic seeding by tau. Using tau-biosensor cells, we show that treatment with sub-toxic concentrations of Aβ oligomers, but not monomers or fibrils, “primes” cells, making them more susceptible to tau seeding. The treatment with Aβ oligomers enhances intracellular tau aggregation in a dose-dependent manner when the cells are seeded with either recombinant or brain-derived tau fibrils, whereas little or no aggregation is observed in the absence of Aβ-oligomer priming. Results Priming by Aβ oligomers appears to be specific to tau, as α-synuclein seeding is unaffected by this treatment. Aβ oligomer-enhanced tau seeding also occurs in primary mouse neurons and human neuroblastoma cells. Using fluorescently labeled tau seeds, we find that treatment with Aβ oligomers significantly enhances the cellular uptake of tau seeds, whereas a known tau-uptake inhibitor blocks the effect of Aβ on tau uptake. Conclusion The ability of Aβ to promote tau seeding suggests a specific and plausible mechanism by which extracellular Aβ initiates a deleterious cascade that is unique to AD. These data suggest that the Aβ-mediated potentiation of tau uptake into cells should also be taken into account when designing Aβ-targeted therapeutics.

scholarly journals Huperzine A and Its Neuroprotective Molecular Signaling in Alzheimer’s Disease

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6531
Author(s):  
María Jesús Friedli ◽  
Nibaldo C. Inestrosa
Keyword(s):  
Molecular Mechanisms ◽  
Acetylcholinesterase Inhibitor ◽  
Amyloid Β ◽  
Huperzine A ◽  
Amyloid Β Peptide ◽  
Molecular Signaling ◽  
Neuroprotective Effects ◽  
App Processing

Huperzine A (HupA), an alkaloid found in the club moss Huperzia serrata, has been used for centuries in Chinese folk medicine to treat dementia. The effects of this alkaloid have been attributed to its ability to inhibit the cholinergic enzyme acetylcholinesterase (AChE), acting as an acetylcholinesterase inhibitor (AChEI). The biological functions of HupA have been studied both in vitro and in vivo, and its role in neuroprotection appears to be a good therapeutic candidate for Alzheimer´s disease (AD). Here, we summarize the neuroprotective effects of HupA on AD, with an emphasis on its interactions with different molecular signaling avenues, such as the Wnt signaling, the pre- and post-synaptic region mechanisms (synaptotagmin, neuroligins), the amyloid precursor protein (APP) processing, the amyloid-β peptide (Aβ) accumulation, and mitochondrial protection. Our goal is to provide an integrated overview of the molecular mechanisms through which HupA affects AD.

Neuroprotective Effects of Ellagic Acid in Alzheimer's Disease: Focus on Underlying Molecular Mechanisms of Therapeutic Potential

2020 ◽  
Vol 26 ◽  
Author(s):  
Nimra Javaid ◽  
Muhammad Ajmal Shah ◽  
Azhar Rasul ◽  
Zunera Chauhdary ◽  
Uzma Saleem ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Ellagic Acid ◽  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Therapeutic Potential ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Acetylcholinesterase Activity ◽  
Neuroprotective Effects

: Neurodegeneration is a multifactorial process involved the different cytotoxic pathways that lead towards neuronal cell death. Alzheimer’s disease (AD) is a persistent neurodegenerative disorder that normally has a steady onset yet later on it worsens. The documented evidence of AD neuropathology manifested the neuro-inflammation, increased reactive oxygen, nitrogen species and decreased antioxidant protective process; mitochondrial dysfunction as well as increased level of acetylcholinesterase activity. Moreover, enhanced action of proteins leads towards neural apoptosis which have a vital role in the degeneration of neurons. The inability of commercial therapeutic options to treat AD with targeting single mechanism leads the attraction towards organic drugs. Ellagic acid is a dimer of gallic acid, latest studies expressed that ellagic acid can initiate the numerous cell signaling transmission and decrease the progression of disorders, involved in the degeneration of neurons. The influential property of ellagic acid to protect the neurons in neurodegenerative disorders is due to its antioxidant effect, iron chelating and mitochondrial protective effect. The main goal of this review is to critically analyze the molecular mode of action of ellagic acid against neurodegeneration.

LncRNA SNHG12 Improves Cerebral Ischemic-reperfusion Injury by Activating SIRT1/FOXO3a Pathway through I nhibition of Autophagy and Oxidative Stress

2020 ◽  
Vol 17 (4) ◽  
pp. 394-401
Author(s):  
Yuanhua Wu ◽  
Yuan Huang ◽  
Jing Cai ◽  
Donglan Zhang ◽  
Shixi Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanisms ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Cell Activity ◽  
Ht22 Cells ◽  
Cerebral Ischemic ◽  
Cerebral Ischemic Reperfusion ◽  
And Oxidative Stress

Background: Ischemia/reperfusion (I/R) injury involves complex biological processes and molecular mechanisms such as autophagy. Oxidative stress plays a critical role in the pathogenesis of I/R injury. LncRNAs are the regulatory factor of cerebral I/R injury. Methods: This study constructs cerebral I/R model to investigate role of autophagy and oxidative stress in cerebral I/R injury and the underline regulatory mechanism of SIRT1/ FOXO3a pathway. In this study, lncRNA SNHG12 and FOXO3a expression was up-regulated and SIRT1 expression was down-regulated in HT22 cells of I/R model. Results: Overexpression of lncRNA SNHG12 significantly increased the cell viability and inhibited cerebral ischemicreperfusion injury induced by I/Rthrough inhibition of autophagy. In addition, the transfected p-SIRT1 significantly suppressed the release of LDH and SOD compared with cells co-transfected with SIRT1 and FOXO3a group and cells induced by I/R and transfected with p-SNHG12 group and overexpression of cells co-transfected with SIRT1 and FOXO3 further decreased the I/R induced release of ROS and MDA. Conclusion: In conclusion, lncRNA SNHG12 increased cell activity and inhibited oxidative stress through inhibition of SIRT1/FOXO3a signaling-mediated autophagy in HT22 cells of I/R model. This study might provide new potential therapeutic targets for further investigating the mechanisms in cerebral I/R injury and provide.

Berberine nanoencapsulation attenuates hallmarks of scoplomine induced Alzheimer's-like disease in rats

2020 ◽  
Vol 15 ◽  
Author(s):  
Samar R. Saleh ◽  
Mariam M. Abady ◽  
Mohammed Nofal ◽  
Nashwa W. Yassa ◽  
Mohamed S. Abdel-latif ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Histopathological Examination ◽  
Memory Function ◽  
Amyloid Β ◽  
Active Pharmaceutical Ingredient ◽  
Isoquinoline Alkaloid ◽  
Drug Uptake ◽  
Male Rats ◽  
Morris Water Maze Test ◽  
Neuroprotective Effects

Background: Berberine (BBR), an isoquinoline alkaloid, acts as a multipotent active pharmaceutical ingredient to counteract several types of dementia based on its numerous pharmacological actions including antioxidant, antiinflammatory, cholesterol-lowering effect, and inhibition of Aβ production and AChE. However, BBR suffers from poor absorption, bioavailability and brain drug uptake. The present study is directed for the formulation and characterization of Chitosan BBR-nanoparticles (BBR-NPs) as well as the estimation of its neuroprotective effects against scopolamine induced cognitive impairments. Methods: BBR-NPs were formulated using ionic gelation method and tripolyphosphate was chosen as a cross linker. Nanoparticles size, zeta potential, encapsulation efficiency and releasing profile were estimated. To investigate the neuroprotective effects, adult fifty six Wistar male rats were randomly distributed into: three control groups, received saline, polyethylene glycol or chitosan- NPs respectively; induced group, received scopolamine (2 mg/ kg, i.p.) and three treated groups were orally administrated BBR (50 mg/ kg), BBR- NP (7 mg/ kg) and donepezil (2.25 mg/ kg, as positive control) followed by scopolamine injection after 40 min, daily for 4 weeks. Morris water maze test, oxidative stress parameters, cholinergic and amyloid-β processing intermediates as well as neuroplasticity markers and histopathological examination were assessed. Results: Our results showed that BBR- NPs were better than BBR and donepezil as BBR- NPs were powerful inhibitory ligands toward AChE and Aβ42 formation and significantly down regulated Tau, iNOS and BACE gene expression in rats’ hippocampus. BBR-NPs administration, at 1/6 of BBR therapeutic recommended dose, significantly improved learning and memory function. This could be accredited to the diminution of oxidative stress and amyloid-β toxicity in addition to the improvement of the neuroplasticity markers. Conclusions: The enhancing effect of BBR- NPs could be related to the enhancing of its bioavailability, absorption and brain drug uptake which need more investigation in future work.

Formononetin Ameliorates Cognitive Disorder via PGC-1α Pathway in Neuroinflammation Conditions in High-Fat Diet-Induced Mice

2019 ◽  
Vol 18 (7) ◽  
pp. 566-577 ◽  
Author(s):  
Xinxin Fu ◽  
Tingting Qin ◽  
Jiayu Yu ◽  
Jie Jiao ◽  
Zhanqiang Ma ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
High Fat Diet ◽  
Trifolium Pratense ◽  
Amyloid Β ◽  
Cognitive Disorder ◽  
Mechanism Study ◽  
High Fat ◽  
Neuroprotective Effects ◽  
Underlying Mechanisms

Background: Alzheimer’s disease is one of the most common neurodegenerative diseases in many modern societies. The core pathogenesis of Alzheimer’s disease includes the aggregation of hyperphosphorylated Tau and abnormal Amyloid-β generation. In addition, previous studies have shown that neuroinflammation is one of the pathogenesis of Alzheimer’s disease. Formononetin, an isoflavone compound extracted from Trifolium pratense L., has been found to have various properties including anti-obesity, anti-inflammation, and neuroprotective effects. But there are very few studies on the treatment of Alzheimer’s disease with Formononetin. Objective: The present study focused on the protective activities of Formononetin on a high-fat dietinduced cognitive decline and explored the underlying mechanisms. Methods: Mice were fed with HFD for 10 weeks and intragastric administrated daily with metformin (300 mg/kg) and Formononetin (20 and 40 mg/kg). Results: We found that Formononetin (20, 40 mg/kg) significantly attenuated the learning and memory deficits companied by weight improvement and decreased the levels of blood glucose, total cholesterol and triglyceride in high-fat diet-induced mice. Meanwhile, we observed high-fat diet significantly caused the Tau hyperphosphorylation in the hippocampus of mice, whereas Formononetin reversed this effect. Additionally, Formononetin markedly reduced the levels of inflammation cytokines IL-1β and TNF-α in high-fat diet-induced mice. The mechanism study showed that Formononetin suppressed the pro-inflammatory NF-κB signaling and enhanced the anti-inflammatory Nrf-2/HO-1 signaling, which might be related to the regulation of PGC-1α in the hippocampus of high-fat diet -induced mice. Conclusion: Taken together, our results showed that Formononetin could improve the cognitive function by inhibiting neuroinflammation, which is attributed to the regulation of PGC-1α pathway in HFD-induced mice.

scholarly journals Molecular Mechanisms of Obesity-Linked Cardiac Dysfunction: An Up-Date on Current Knowledge

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 629
Author(s):  
Jorge Gutiérrez-Cuevas ◽  
Ana Sandoval-Rodriguez ◽  
Alejandra Meza-Rios ◽  
Hugo Christian Monroy-Ramírez ◽  
Marina Galicia-Moreno ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cardiac Dysfunction ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Peroxisome Proliferator ◽  
White Adipocyte ◽  
Peroxisome Proliferator Activated Receptors ◽  
And Oxidative Stress

Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.

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