P38 Initiates Diabetic Neurodegeneration Through Glutamatergic and GABAergic Neurons

Abstract Background: Diabetes mellitus may cause neurodegeneration, but the exact mechanism by which diabetic conditions induce neuronal cell death remains unclear. Tau protein hyperphosphorylation is considered to be a major pathological hallmark of neurodegeneration and can be triggered by diabetes. Various tau-directed kinases, including P38, can be activated upon diabetic stress and induce tau hyperphosphorylation. Despite extensive research efforts and the known importance of tau pathology in neurodegeneration, the exact tau specie(s) and kinases driving neurodegeneration in diabetes mellitus have not been clearly elucidated. Methods: We herein employed protein expression data analysis as well as immunofluorescence and immunoblotting techniques to determine the exact molecular mechanism of tau pathology triggered by diabetes in both in vitro and in vivo systems.Results: We found that P38, a major tau kinase, was increased in Glutamatergic & GABAergic neuron subtypes under diabetic conditions. This rendered them more responsive to oxidative stress caused by diabetes. We observed that oxidative stress activated P38, which in turn directly and indirectly drove tau pathology in the brainstem (enriched by Glutamatergic & GABAergic neurons), which gradually spread to neighboring brain areas. Notably, P38 inhibition suppressed tau pathogenicity and neurodegeneration in diabetic mouse models. Conclusion: The data establish P38 as a central mediator of diabetes mellitus induced tau pathology. Furthermore, the inhibition of P38 at early stages of diabetes-induced stress can inhibit tau pathology. Our findings provide mechanistic insight on the consequences of this metabolic disorder on the nervous system.

Download Full-text

Inhibition of Oxidative Neurotoxicity and Scopolamine-Induced Memory Impairment by γ-Mangostin: In Vitro and In Vivo Evidence

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/3640753 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Youngmun Lee ◽

Sunyoung Kim ◽

Yeonsoo Oh ◽

Young-Mi Kim ◽

Young-Won Chin ◽

...

Keyword(s):

Oxidative Stress ◽

Memory Impairment ◽

Neuronal Damage ◽

Biological Activities ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Ros Generation ◽

Garcinia Mangostana

Among a series of xanthones identified from mangosteen, the fruit of Garcinia mangostana L. (Guttifereae), α- and γ-mangostins are known to be major constituents exhibiting diverse biological activities. However, the effects of γ-mangostin on oxidative neurotoxicity and impaired memory are yet to be elucidated. In the present study, the protective effect of γ-mangostin on oxidative stress-induced neuronal cell death and its underlying action mechanism(s) were investigated and compared to that of α-mangostin using primary cultured rat cortical cells. In addition, the effect of orally administered γ-mangostin on scopolamine-induced memory impairment was evaluated in mice. We found that γ-mangostin exhibited prominent protection against H2O2- or xanthine/xanthine oxidase-induced oxidative neuronal death and inhibited reactive oxygen species (ROS) generation triggered by these oxidative insults. In contrast, α-mangostin had no effects on the oxidative neuronal damage or associated ROS production. We also found that γ-mangostin, not α-mangostin, significantly inhibited H2O2-induced DNA fragmentation and activation of caspases 3 and 9, demonstrating its antiapoptotic action. In addition, only γ-mangostin was found to effectively inhibit lipid peroxidation and DPPH radical formation, while both mangostins inhibited β-secretase activity. Furthermore, we observed that the oral administration of γ-mangostin at dosages of 10 and 30 mg/kg markedly improved scopolamine-induced memory impairment in mice. Collectively, these results provide both in vitro and in vivo evidences for the neuroprotective and memory enhancing effects of γ-mangostin. Multiple mechanisms underlying this neuroprotective action were suggested in this study. Based on our findings, γ-mangostin could serve as a potentially preferable candidate over α-mangostin in combatting oxidative stress-associated neurodegenerative diseases including Alzheimer’s disease.

Download Full-text

Bacopa monnierias an Antioxidant Therapy to Reduce Oxidative Stress in the Aging Brain

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/615384 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 24

Author(s):

Tamara Simpson ◽

Matthew Pase ◽

Con Stough

Keyword(s):

Oxidative Stress ◽

Cognitive Function ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Bacopa Monnieri ◽

Aging Brain ◽

Resonance Spectroscopy ◽

Age Related

The detrimental effect of neuronal cell death due to oxidative stress and mitochondrial dysfunction has been implicated in age-related cognitive decline and neurodegenerative disorders such as Alzheimer’s disease. The Indian herbBacopa monnieriis a dietary antioxidant, with animal andin vitrostudies indicating several modes of action that may protect the brain against oxidative damage. In parallel, several studies using the CDRI08 extract have shown that extracts ofBacopa monnieriimprove cognitive function in humans. The biological mechanisms of this cognitive enhancement are unknown. In this review we discuss the animal studies andin vivoevidence forBacopa monnierias a potential therapeutic antioxidant to reduce oxidative stress and improve cognitive function. We suggest that future studies incorporate neuroimaging particularly magnetic resonance spectroscopy into their randomized controlled trials to better understand whether changes in antioxidant statusin vivocause improvements in cognitive function.

Download Full-text

The Potential Neuroprotective Role of Free and Encapsulated Quercetin Mediated by miRNA against Neurological Diseases

Nutrients ◽

10.3390/nu13041318 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1318

Author(s):

Tarek Benameur ◽

Raffaella Soleti ◽

Chiara Porro

Keyword(s):

Inflammatory Responses ◽

Pathological Condition ◽

Neurological Diseases ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

In Vivo Studies ◽

Innovative Drug ◽

Chronic Neuroinflammation

Chronic neuroinflammation is a pathological condition of numerous central nervous system (CNS) diseases such as Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis and many others. Neuroinflammation is characterized by the microglia activation and concomitant production of pro-inflammatory cytokines leading to an increasing neuronal cell death. The decreased neuroinflammation could be obtained by using natural compounds, including flavonoids known to modulate the inflammatory responses. Among flavonoids, quercetin possess multiple pharmacological applications including anti-inflammatory, antitumoral, antiapoptotic and anti-thrombotic activities, widely demonstrated in both in vitro and in vivo studies. In this review, we describe the recent findings about the neuroprotective action of quercetin by acting with different mechanisms on the microglial cells of CNS. The ability of quercetin to influence microRNA expression represents an interesting skill in the regulation of inflammation, differentiation, proliferation, apoptosis and immune responses. Moreover, in order to enhance quercetin bioavailability and capacity to target the brain, we discuss an innovative drug delivery system. In summary, this review highlighted an important application of quercetin in the modulation of neuroinflammation and prevention of neurological disorders.

Download Full-text

Selective Release of Calpain Produced αII-Spectrin (α-Fodrin) Breakdown Products by Acute Neuronal Cell Death

Biological Chemistry ◽

10.1515/bc.2002.082 ◽

2002 ◽

Vol 383 (5) ◽

pp. 785-791 ◽

Cited By ~ 38

Author(s):

Satavisha Dutta ◽

Yuk Chun Chiu ◽

Albert W. Probert ◽

Kevin K.W. Wang

Keyword(s):

Cell Death ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Neuronal Injury ◽

Nmda Receptor Antagonist ◽

Breakdown Product ◽

Calpain Inhibitor ◽

Neural Cells

Abstract Activation of calpain results in the breakdown of α II spectrin (αfodrin), a neuronal cytoskeleton protein, which has previously been detected in various in vitro and in vivo neuronal injury models. In this study, a 150 kDa spectrin breakdown product (SBDP150) was found to be released into the cellconditioned media from SHSY5Y cells treated with the calcium channel opener maitotoxin (MTX). SBDP150 release can be readily quantified on immunoblot using an SBDP150- specific polyclonal antibody. Increase of SBDP150 also correlated with cell death in a timedependent manner. MDL28170, a selective calpain inhibitor, was the only protease inhibitor tested that significantly reduced MTXinduced SBDP150 release. The cellconditioned media of cerebellar granule neurons challenged with excitotoxins (NMDA and kainate) also exhibited a significant increase of SBDP150 that was attenuated by pretreatment with an NMDA receptor antagonist, R()-3-(2-carbopiperazine-4-yl)propyl-1- phosphonic acid (CPP), and MDL28170. In addition, hypoxic/hypoglycemic challenge of cerebrocortical cultures also resulted in SBDP150 liberation into the media. These results support the theory that an antibody based detection of SBDP150 in the cellconditioned media can be utilized to quantify injury to neural cells. Furthermore, SBDP150 may potentially be used as a surrogate biomarker for acute neuronal injury in clinical settings.

Download Full-text

Cylindromatosis mediates neuronal cell death in vitro and in vivo

Cell Death and Differentiation ◽

10.1038/s41418-017-0046-7 ◽

2018 ◽

Vol 25 (8) ◽

pp. 1394-1407 ◽

Cited By ~ 6

Author(s):

Goutham K. Ganjam ◽

Nicole Angela Terpolilli ◽

Sebastian Diemert ◽

Ina Eisenbach ◽

Lena Hoffmann ◽

...

Keyword(s):

Cell Death ◽

Neuronal Cell Death ◽

Neuronal Cell

Download Full-text

Overexpression of Mitochondrial Calcium Uniporter Causes Neuronal Death

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/1681254 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 7

Author(s):

Veronica Granatiero ◽

Marco Pacifici ◽

Anna Raffaello ◽

Diego De Stefani ◽

Rosario Rizzuto

Keyword(s):

Cell Fate ◽

Neuronal Death ◽

Cortical Neurons ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Neuronal Loss ◽

Calcium Uniporter ◽

Organelle Morphology

Neurodegenerative diseases are a large and heterogeneous group of disorders characterized by selective and progressive death of specific neuronal subtypes. In most of the cases, the pathophysiology is still poorly understood, although a number of hypotheses have been proposed. Among these, dysregulation of Ca2+ homeostasis and mitochondrial dysfunction represent two broadly recognized early events associated with neurodegeneration. However, a direct link between these two hypotheses can be drawn. Mitochondria actively participate to global Ca2+ signaling, and increases of [Ca2+] inside organelle matrix are known to sustain energy production to modulate apoptosis and remodel cytosolic Ca2+ waves. Most importantly, while mitochondrial Ca2+ overload has been proposed as the no-return signal, triggering apoptotic or necrotic neuronal death, until now direct evidences supporting this hypothesis, especially in vivo, are limited. Here, we took advantage of the identification of the mitochondrial Ca2+ uniporter (MCU) and tested whether mitochondrial Ca2+ signaling controls neuronal cell fate. We overexpressed MCU both in vitro, in mouse primary cortical neurons, and in vivo, through stereotaxic injection of MCU-coding adenoviral particles in the brain cortex. We first measured mitochondrial Ca2+ uptake using quantitative genetically encoded Ca2+ probes, and we observed that the overexpression of MCU causes a dramatic increase of mitochondrial Ca2+ uptake both at resting and after membrane depolarization. MCU-mediated mitochondrial Ca2+ overload causes alteration of organelle morphology and dysregulation of global Ca2+ homeostasis. Most importantly, MCU overexpression in vivo is sufficient to trigger gliosis and neuronal loss. Overall, we demonstrated that mitochondrial Ca2+ overload is per se sufficient to cause neuronal cell death both in vitro and in vivo, thus highlighting a potential key step in neurodegeneration.

Download Full-text

Degradation of mutant huntingtin via the ubiquitin/proteasome system is modulated by FE65

Biochemical Journal ◽

10.1042/bj20112175 ◽

2012 ◽

Vol 443 (3) ◽

pp. 681-689 ◽

Cited By ~ 15

Author(s):

Wan Ning Vanessa Chow ◽

Hon Wing Luk ◽

Ho Yin Edwin Chan ◽

Kwok-Fai Lau

Keyword(s):

Cell Death ◽

Degradation Mechanism ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Adaptor Protein ◽

Ubiquitin Proteasome System ◽

Exon 1 ◽

Ubiquitin Proteasome

An unstable expansion of the polyglutamine repeat within exon 1 of the protein Htt (huntingtin) causes HD (Huntington's disease). Mounting evidence shows that accumulation of N-terminal mutant Htt fragments is the source of disruption of normal cellular processes which ultimately leads to neuronal cell death. Understanding the degradation mechanism of mutant Htt and improving its clearance has emerged as a new direction in developing therapeutic approaches to treat HD. In the present study we show that the brain-enriched adaptor protein FE65 is a novel interacting partner of Htt. The binding is mediated through WW–polyproline interaction and is dependent on the length of the polyglutamine tract. Interestingly, a reduction in mutant Htt protein level was observed in FE65-knockdown cells, and the process requires the UPS (ubiquitin/proteasome system). Moreover, the ubiquitination level of mutant Htt was found to be enhanced when FE65 is knocked down. Immunofluroescence staining revealed that FE65 associates with mutant Htt aggregates. Additionally, we demonstrated that overexpression of FE65 increases mutant Htt-induced cell death both in vitro and in vivo. These results suggest that FE65 facilitates the accumulation of mutant Htt in cells by preventing its degradation via the UPS, and thereby enhances the toxicity of mutant Htt.

Download Full-text

The Therapeutic Potential of Rosemary (Rosmarinus officinalis) Diterpenes for Alzheimer’s Disease

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2016/2680409 ◽

2016 ◽

Vol 2016 ◽

pp. 1-14 ◽

Cited By ~ 50

Author(s):

Solomon Habtemariam

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Therapeutic Potential ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Rosmarinus Officinalis ◽

Brain Inflammation ◽

Important Species

Rosemary (Rosmarinus officinalisL.) is one of the most economically important species of the family Lamiaceae. Native to the Mediterranean region, the plant is now widely distributed all over the world mainly due to its culinary, medicinal, and commercial uses including in the fragrance and food industries. Among the most important group of compounds isolated from the plant are the abietane-type phenolic diterpenes that account for most of the antioxidant and many pharmacological activities of the plant. Rosemary diterpenes have also been shown in recent years to inhibit neuronal cell death induced by a variety of agents bothin vitroandin vivo. The therapeutic potential of these compounds for Alzheimer’s disease (AD) is reviewed in this communication by giving special attention to the chemistry of the compounds along with the various pharmacological targets of the disease. The multifunctional nature of the compounds from the general antioxidant-mediated neuronal protection to other specific mechanisms including brain inflammation and amyloid beta (Aβ) formation, polymerisation, and pathologies is discussed.

Download Full-text