scholarly journals Regulation of Brain Cholesterol: What Role Do Liver X Receptors Play in Neurodegenerative Diseases?

2019 ◽  
Vol 20 (16) ◽  
pp. 3858 ◽  
Author(s):  
Kevin Mouzat ◽  
Aleksandra Chudinova ◽  
Anne Polge ◽  
Jovana Kantar ◽  
William Camu ◽  
...  

Liver X Receptors (LXR) alpha and beta are two members of nuclear receptor superfamily documented as endogenous cholesterol sensors. Following conversion of cholesterol in oxysterol, both LXR isoforms detect intracellular concentrations and act as transcription factors to promote expression of target genes. Among their numerous physiological roles, they act as central cholesterol-lowering factors. In the central nervous system (CNS), cholesterol has been shown to be an essential determinant of brain function, particularly as a major constituent of myelin and membranes. In the brain, LXRs act as cholesterol central regulators, and, beyond this metabolic function, LXRs have additional roles such as providing neuroprotective effects and lowering neuroinflammation. In many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD), and multiple sclerosis (MS), dysregulations of cholesterol and oxysterol have been reported. In this paper, we propose to focus on recent advances in the knowledge of the LXRs roles on brain cholesterol and oxysterol homeostasis, neuroinflammation, neuroprotection, and their putative involvement in neurodegenerative disorders. We will discuss their potential use as candidates for both molecular diagnosis and as promising pharmacological targets in the treatment of ALS, AD, or MS patients.

2020 ◽  
Vol 20 (13) ◽  
pp. 1142-1153 ◽  
Author(s):  
Sreyashi Chandra ◽  
Md. Tanjim Alam ◽  
Jhilik Dey ◽  
Baby C. Pulikkaparambil Sasidharan ◽  
Upasana Ray ◽  
...  

Background: The central nervous system (CNS) known to regulate the physiological conditions of human body, also itself gets dynamically regulated by both the physiological as well as pathological conditions of the body. These conditions get changed quite often, and often involve changes introduced into the gut microbiota which, as studies are revealing, directly modulate the CNS via a crosstalk. This cross-talk between the gut microbiota and CNS, i.e., the gut-brain axis (GBA), plays a major role in the pathogenesis of many neurodegenerative disorders such as Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS) and Huntington’s disease (HD). Objective: We aim to discuss how gut microbiota, through GBA, regulate neurodegenerative disorders such as PD, AD, ALS, MS and HD. Methods: In this review, we have discussed the present understanding of the role played by the gut microbiota in neurodegenerative disorders and emphasized the probable therapeutic approaches being explored to treat them. Results: In the first part, we introduce the GBA and its relevance, followed by the changes occurring in the GBA during neurodegenerative disorders and then further discuss its role in the pathogenesis of these diseases. Finally, we discuss its applications in possible therapeutics of these diseases and the current research improvements being made to better investigate this interaction. Conclusion: We concluded that alterations in the intestinal microbiota modulate various activities that could potentially lead to CNS disorders through interactions via the GBA.


Medicines ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 126 ◽  
Author(s):  
Miora Rakotoarisoa ◽  
Angelina Angelova

Neurodegenerative diseases have become a major challenge for public health because of their incurable status. Soft nanotechnology provides potential for slowing down the progression of neurodegenerative disorders by using innovative formulations of neuroprotective antioxidants like curcumin, resveratrol, vitamin E, rosmarinic acid, 7,8-dihydroxyflavone, coenzyme Q10, and fish oil. Curcumin is a natural, liposoluble compound, which is of considerable interest for nanomedicine development in combination therapies. The neuroprotective effects of combination treatments can involve restorative mechanisms against oxidative stress, mitochondrial dysfunction, inflammation, and protein aggregation. Despite the anti-amyloid and anti-tau potential of curcumin and its neurogenesis-stimulating properties, the utilization of this antioxidant as a drug in neuroregenerative therapies has huge limitations due to its poor water solubility, physico-chemical instability, and low oral bioavailability. We highlight the developments of soft lipid- and polymer-based delivery carriers of curcumin, which help improve the drug solubility and stability. We specifically focus on amphiphilic liquid crystalline nanocarriers (cubosome, hexosome, spongosome, and liposome particles) for the encapsulation of curcumin with the purpose of halting the progressive neuronal loss in Alzheimer’s, Parkinson’s, and Huntington’s diseases and amyotrophic lateral sclerosis (ALS).


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyuk Sung Kwon ◽  
Seong-Ho Koh

AbstractNeuroinflammation is associated with neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Microglia and astrocytes are key regulators of inflammatory responses in the central nervous system. The activation of microglia and astrocytes is heterogeneous and traditionally categorized as neurotoxic (M1-phenotype microglia and A1-phenotype astrocytes) or neuroprotective (M2-phenotype microglia and A2-phenotype astrocytes). However, this dichotomized classification may not reflect the various phenotypes of microglia and astrocytes. The relationship between these activated glial cells is also very complicated, and the phenotypic distribution can change, based on the progression of neurodegenerative diseases. A better understanding of the roles of microglia and astrocytes in neurodegenerative diseases is essential for developing effective therapies. In this review, we discuss the roles of inflammatory response in neurodegenerative diseases, focusing on the contributions of microglia and astrocytes and their relationship. In addition, we discuss biomarkers to measure neuroinflammation and studies on therapeutic drugs that can modulate neuroinflammation.


2009 ◽  
Vol 23 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Chiara Gabbi ◽  
Margaret Warner ◽  
Jan-Åke Gustafsson

Abstract Liver X receptors, LXRα and LXRβ, are nuclear receptors belonging to the large family of transcription factors. After activation by oxysterols, LXRs play a central role in the control of lipid and carbohydrate metabolism as well as inflammation. The role of LXRα has been extensively studied, particularly in the liver and macrophages. In the liver it prevents cholesterol accumulation by increasing bile acid synthesis and secretion into the bile through ATP-binding cassette G5/G8 transporters, whereas in macrophages it increases cholesterol reverse transport. The function of LXRβ is still under investigation with most of the current knowledge coming from the study of phenotypes of LXRβ−/− mice. With these mice new emerging roles for LXRβ have been demonstrated in the pathogenesis of diseases such as amyotrophic lateral sclerosis and chronic pancreatitis. The present review will focus on the abnormalities described so far in LXRβ−/− mice and the insight gained into the possible roles of LXRβ in human diseases.


2009 ◽  
Vol 9 ◽  
pp. 970-981 ◽  
Author(s):  
Julio Cesar García-Rodríguez ◽  
Iliana Sosa Teste

Intranasal delivery provides a practical, noninvasive method of bypassing the blood-brain barrier (BBB) in order to deliver therapeutic agents to the brain. This method allows drugs that do not cross the BBB to be delivered to the central nervous system in a few minutes. With this technology, it will be possible to eliminate systemic administration and its potential side effects. Using the intranasal delivery system, researchers have demonstrated neuroprotective effects in different animal models of stroke using erythropoietin (EPO) as a neuroprotector or other different types of EPO without erythropoiesis-stimulating activity. These new molecules retain their ability to protect neural tissue against injury and they include Asialoerythropoietin (asialoEPO) carbamylated EPO (CEPO), and rHu-EPO with low sialic acid content (Neuro-EPO). Contrary to the other EPO variants, Neuro-EPO is not chemically modified, making it biologically similar to endogenous EPO, with the advantage of less adverse reactions when this molecule is applied chronically. This constitutes a potential benefit of Neuro-EPO over other variants of EPO for the chronic treatment of neurodegenerative illnesses. Nasal administration of EPO is a potential, novel, neurotherapeutic approach. However, it will be necessary to initiate clinical trials in stroke patients using intranasal delivery in order to obtain the clinical evidence of its neuroprotectant capacity in the treatment of patients with acute stroke and other neurodegenerative disorders. This new therapeutic approach could revolutionize the treatment of neurodegenerative disorders in the 21stcentury.


2019 ◽  
Vol 20 (15) ◽  
pp. 3685 ◽  
Author(s):  
Roberta Cascella ◽  
Giulia Fani ◽  
Alessandra Bigi ◽  
Fabrizio Chiti ◽  
Cristina Cecchi

Frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) are progressive and fatal neurodegenerative disorders showing mislocalization and cytosolic accumulation of TDP-43 inclusions in the central nervous system. The decrease in the efficiency of the clearance systems in aging, as well as the presence of genetic mutations of proteins associated with cellular proteostasis in the familial forms of TDP-43 proteinopathies, suggest that a failure of these protein degradation systems is a key factor in the aetiology of TDP-43 associated disorders. Here we show that the internalization of human pre-formed TDP-43 aggregates in the murine neuroblastoma N2a cells promptly resulted in their ubiquitination and hyperphosphorylation by endogenous machineries, mimicking the post-translational modifications observed in patients. Moreover, our data identify mitochondria as the main responsible sites for the alteration of calcium homeostasis induced by TDP-43 aggregates, which, in turn, stimulates an increase in reactive oxygen species and, finally, caspase activation. The inhibition of TDP-43 proteostasis in the presence of selective inhibitors against the proteasome and macroautophagy systems revealed that these two systems are both severely involved in TDP-43 accumulation and have a strong influence on each other in neurodegenerative disorders associated with TDP-43.


2004 ◽  
Vol 33 (3) ◽  
pp. 609-622 ◽  
Author(s):  
Knut R Steffensen ◽  
Soek Ying Neo ◽  
Thomas M Stulnig ◽  
Vinsensius B Vega ◽  
Safia S Rahman ◽  
...  

The liver X receptors α and β (LXRα and LXRβ ) are members of the nuclear receptor superfamily of proteins which are highly expressed in metabolically active tissues. They regulate gene expression of critical genes involved in cholesterol catabolism and transport, lipid and triglyceride biosynthesis and carbohydrate metabolism in response to distinct oxysterols and intermediates in the cholesterol metabolic pathway. The biological roles of the LXRs in tissues other than liver, intestine and adipose tissue are poorly elucidated. In this study we used global gene-expression profiling analysis to detect differences in expression patterns in several tissues from mice fed an LXR agonist or vehicle. Our results show that LXR plays an important role in the kidney, lung, adrenals, brain, testis and heart where several putative LXR target genes were found. The effects of the LXRs were further analysed in adrenals where treatment with an LXR agonist induced expression of adrenocorticotrophic hormone receptor, suppressed expression of uncoupling protein (UCP)-1 and UCP-3 as well as several glycolytic enzymes and led to increased serum corticosterone levels. These results indicate novel biological roles of the LXR including regulation of energy metabolism, glycolysis and steroidogenesis in the adrenals via alteration of expression profiles of putative target genes.


Author(s):  
Ramneek Kaur ◽  
Harleen Kaur ◽  
Rashi Rajput ◽  
Sachin Kumar ◽  
Rachana R. ◽  
...  

Neurodegenerative disorders (NDs) are a diverse group of disorders characterized by selective and progressive loss of neural systems that cause dysfunction of the central nervous system (CNS). The examples of NDs include Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Huntington's disease (HD). The aggregated proteins block or disrupt the normal proteosomal turnover, autophagy, and become abnormally modified with time, generating toxicity via pathways thereby resulting in neurodegeneration and neuron death. The chapter highlights the understanding in the areas of AD, PD, HD as illustrative of major research so as to define the key factors and events in the improvement of NDs. It defines the physiological functioning of neural transmission (presynaptic, postsynaptic activity) at neural signaling pathway, then the dynamics of neuronal dysfunctioning and its molecular mechanism. Further, it also discusses the progression from synaptic dysfunction to transmission failure followed by NDs.


2021 ◽  
Vol 10 (20) ◽  
pp. 4640
Author(s):  
Katarzyna Stopińska ◽  
Maria Radziwoń-Zaleska ◽  
Izabela Domitrz

The central nervous system (CNS) is closely related to the gastrointestinal tract, mainly through regulating its function and homeostasis. Simultaneously, the gut flora affects the CNS and plays an essential role in the pathogenesis of neurologic and neuropsychological disorders such as Parkinson’s and Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis or autism spectrum disorder. The population of gut microorganisms contains more than one billion bacteria. The most common are six phyla: Proteobacteria, Actinomyces, Verucomicrobia, Fusobacteria, and dominant Bacteroides with Firmicutes. The microbiota–gut–brain axis is a bidirectional nervous, endocrine, and immune communication between these two organs. They are connected through a variety of pathways, including the vagus nerve, the immune system, microbial metabolites such as short-chain fatty acids (SCFAs), the enteric nervous system, and hormones. Age, diet, antibiotics influence the balance of gut microorganisms and probably lead to the development of neurodegenerative disorders. In this article, a review is presented and discussed, with a specific focus on the changes of gut microbiota, gut–brain axis, related disorders, and the factors that influence gut imbalance.


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