Calorie restriction or dietary restriction: how far they can protect the brain against neurodegenerative diseases?

Numerous studies have identified microbial sequences or epitopes in pathological and non-pathological human brain samples. It has not been resolved if these observations are artifactual, or truly represent population of the brain by microbes. Given the tempting speculation that resident microbes could play a role in the many neuropsychiatric and neurodegenerative diseases that currently lack clear etiologies, there is a strong motivation to determine the “ground truth” of microbial existence in living brains. Here I argue that the evidence for the presence of microbes in diseased brains is quite strong, but a compelling demonstration of resident microbes in the healthy human brain remains to be done. Dedicated animal models studies may be required to determine if there is indeed a “brain microbiome.”

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Safety profile of the transcription factor EB (TFEB)-based gene therapy through intracranial injection in mice

Translational Neuroscience ◽

10.1515/tnsci-2020-0132 ◽

2020 ◽

Vol 11 (1) ◽

pp. 241-250

Author(s):

Zhenyu Li ◽

Guangqian Ding ◽

Yudi Wang ◽

Zelong Zheng ◽

Jianping Lv

Keyword(s):

Gene Therapy ◽

Transcription Factor ◽

Neurodegenerative Diseases ◽

Brain Tissue ◽

Inflammatory Responses ◽

Tissue Samples ◽

Protein Levels ◽

Virus Serotype ◽

Transcription Factor Eb ◽

The Brain

AbstractTranscription factor EB (TFEB)-based gene therapy is a promising therapeutic strategy in treating neurodegenerative diseases by promoting autophagy/lysosome-mediated degradation and clearance of misfolded proteins that contribute to the pathogenesis of these diseases. However, recent findings have shown that TFEB has proinflammatory properties, raising the safety concerns about its clinical application. To investigate whether TFEB induces significant inflammatory responses in the brain, male C57BL/6 mice were injected with phosphate-buffered saline (PBS), adeno-associated virus serotype 8 (AAV8) vectors overexpressing mouse TFEB (pAAV8-CMV-mTFEB), or AAV8 vectors expressing green fluorescent proteins (GFPs) in the barrel cortex. The brain tissue samples were collected at 2 months after injection. Western blotting and immunofluorescence staining showed that mTFEB protein levels were significantly increased in the brain tissue samples of mice injected with mTFEB-overexpressing vectors compared with those injected with PBS or GFP-overexpressing vectors. pAAV8-CMV-mTFEB injection resulted in significant elevations in the mRNA and protein levels of lysosomal biogenesis indicators in the brain tissue samples. No significant changes were observed in the expressions of GFAP, Iba1, and proinflammation mediators in the pAAV8-CMV-mTFEB-injected brain compared with those in the control groups. Collectively, our results suggest that AAV8 successfully mediates mTFEB overexpression in the mouse brain without inducing apparent local inflammation, supporting the safety of TFEB-based gene therapy in treating neurodegenerative diseases.

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Mechanisms of Neurodegeneration in Various Forms of Parkinsonism—Similarities and Differences

Cells ◽

10.3390/cells10030656 ◽

2021 ◽

Vol 10 (3) ◽

pp. 656

Author(s):

Dariusz Koziorowski ◽

Monika Figura ◽

Łukasz M. Milanowski ◽

Stanisław Szlufik ◽

Piotr Alster ◽

...

Keyword(s):

Neurodegenerative Diseases ◽

Tau Protein ◽

Protein Gene ◽

Clinical Presentation ◽

Neuronal Loss ◽

Corticobasal Degeneration ◽

Inflammatory Factors ◽

Parkinsonian Disorders ◽

Genetic Features ◽

The Brain

Parkinson's disease (PD), dementia with Lewy body (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA) belong to a group of neurodegenerative diseases called parkinsonian syndromes. They share several clinical, neuropathological and genetic features. Neurodegenerative diseases are characterized by the progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra- and intracellular accumulation of misfolded proteins. The parkinsonian diseases affect distinct areas of the brain. PD and MSA belong to a group of synucleinopathies that are characterized by the presence of fibrillary aggregates of α-synuclein protein in the cytoplasm of selected populations of neurons and glial cells. PSP is a tauopathy associated with the pathological aggregation of the microtubule associated tau protein. Although PD is common in the world's aging population and has been extensively studied, the exact mechanisms of the neurodegeneration are still not fully understood. Growing evidence indicates that parkinsonian disorders to some extent share a genetic background, with two key components identified so far: the microtubule associated tau protein gene (MAPT) and the α-synuclein gene (SNCA). The main pathways of parkinsonian neurodegeneration described in the literature are the protein and mitochondrial pathways. The factors that lead to neurodegeneration are primarily environmental toxins, inflammatory factors, oxidative stress and traumatic brain injury.

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Molecular mechanisms of cell death in neurological diseases

Cell Death and Differentiation ◽

10.1038/s41418-021-00814-y ◽

2021 ◽

Author(s):

Diane Moujalled ◽

Andreas Strasser ◽

Jeffrey R. Liddell

Keyword(s):

Cell Death ◽

Neurodegenerative Diseases ◽

Molecular Mechanisms ◽

Neuronal Development ◽

Neurological Diseases ◽

Treatment Strategies ◽

Current Treatment ◽

Response To Therapy ◽

Signalling Cascades ◽

The Brain

AbstractTightly orchestrated programmed cell death (PCD) signalling events occur during normal neuronal development in a spatially and temporally restricted manner to establish the neural architecture and shaping the CNS. Abnormalities in PCD signalling cascades, such as apoptosis, necroptosis, pyroptosis, ferroptosis, and cell death associated with autophagy as well as in unprogrammed necrosis can be observed in the pathogenesis of various neurological diseases. These cell deaths can be activated in response to various forms of cellular stress (exerted by intracellular or extracellular stimuli) and inflammatory processes. Aberrant activation of PCD pathways is a common feature in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, resulting in unwanted loss of neuronal cells and function. Conversely, inactivation of PCD is thought to contribute to the development of brain cancers and to impact their response to therapy. For many neurodegenerative diseases and brain cancers current treatment strategies have only modest effect, engendering the need for investigations into the origins of these diseases. With many diseases of the brain displaying aberrations in PCD pathways, it appears that agents that can either inhibit or induce PCD may be critical components of future therapeutic strategies. The development of such therapies will have to be guided by preclinical studies in animal models that faithfully mimic the human disease. In this review, we briefly describe PCD and unprogrammed cell death processes and the roles they play in contributing to neurodegenerative diseases or tumorigenesis in the brain. We also discuss the interplay between distinct cell death signalling cascades and disease pathogenesis and describe pharmacological agents targeting key players in the cell death signalling pathways that have progressed through to clinical trials.

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High-Cholesterol Diet Decreases the Level of Phosphatidylinositol 4,5-Bisphosphate by Enhancing the Expression of Phospholipase C (PLCβ1) in Rat Brain

International Journal of Molecular Sciences ◽

10.3390/ijms21031161 ◽

2020 ◽

Vol 21 (3) ◽

pp. 1161 ◽

Cited By ~ 2

Author(s):

Yoon Sun Chun ◽

Sungkwon Chung

Keyword(s):

Neurodegenerative Diseases ◽

Rat Brain ◽

Phospholipase C ◽

Cultured Cells ◽

Cell Interaction ◽

High Cholesterol Diet ◽

Cholesterol Diet ◽

High Cholesterol ◽

Amyloid Aβ ◽

The Brain

Cholesterol is a critical component of eukaryotic membranes, where it contributes to regulating transmembrane signaling, cell–cell interaction, and ion transport. Dysregulation of cholesterol levels in the brain may induce neurodegenerative diseases, such as Alzheimer’s disease, Parkinson disease, and Huntington disease. We previously reported that augmenting membrane cholesterol level regulates ion channels by decreasing the level of phosphatidylinositol 4,5-bisphosphate (PIP2), which is closely related to β-amyloid (Aβ) production. In addition, cholesterol enrichment decreased PIP2 levels by increasing the expression of the β1 isoform of phospholipase C (PLC) in cultured cells. In this study, we examined the effect of a high-cholesterol diet on phospholipase C (PLCβ1) expression and PIP2 levels in rat brain. PIP2 levels were decreased in the cerebral cortex in rats on a high-cholesterol diet. Levels of PLCβ1 expression correlated with PIP2 levels. However, cholesterol and PIP2 levels were not correlated, suggesting that PIP2 level is regulated by cholesterol via PLCβ1 expression in the brain. Thus, there exists cross talk between cholesterol and PIP2 that could contribute to the pathogenesis of neurodegenerative diseases.

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A Destruction Model of the Vascular and Lymphatic Systems in the Emergence of Psychiatric Symptoms

Biology ◽

10.3390/biology10010034 ◽

2021 ◽

Vol 10 (1) ◽

pp. 34

Author(s):

Kohei Segawa ◽

Yukari Blumenthal ◽

Yuki Yamawaki ◽

Gen Ohtsuki

Keyword(s):

Neurodegenerative Diseases ◽

Lymphatic System ◽

Psychiatric Symptoms ◽

Neurological Diseases ◽

Immune Surveillance ◽

Brain Network ◽

Cellular Mechanisms ◽

Postmortem Brains ◽

New Interpretation ◽

The Brain

The lymphatic system is important for antigen presentation and immune surveillance. The lymphatic system in the brain was originally introduced by Giovanni Mascagni in 1787, while the rediscovery of it by Jonathan Kipnis and Kari Kustaa Alitalo now opens the door for a new interpretation of neurological diseases and therapeutic applications. The glymphatic system for the exchanges of cerebrospinal fluid (CSF) and interstitial fluid (ISF) is associated with the blood-brain barrier (BBB), which is involved in the maintenance of immune privilege and homeostasis in the brain. Recent notions from studies of postmortem brains and clinical studies of neurodegenerative diseases, infection, and cerebral hemorrhage, implied that the breakdown of those barrier systems and infiltration of activated immune cells disrupt the function of both neurons and glia in the parenchyma (e.g., modulation of neurophysiological properties and maturation of myelination), which causes the abnormality in the functional connectivity of the entire brain network. Due to the vulnerability, such dysfunction may occur in developing brains as well as in senile or neurodegenerative diseases and may raise the risk of emergence of psychosis symptoms. Here, we introduce this hypothesis with a series of studies and cellular mechanisms.

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