scholarly journals A Fatal Alliance between Microglia, Inflammasomes, and Central Pain

2020 ◽  
Vol 21 (11) ◽  
pp. 3764 ◽  
Author(s):  
Stefanie Hoffmann ◽  
Cordian Beyer
Keyword(s):  
Depressive Disorders ◽  
Inflammatory Responses ◽  
Ion Homeostasis ◽  
Short Review ◽  
Brain Parenchyma ◽  
Inflammasome Activation ◽  
Central Pain ◽  
Brain Response ◽  
Inflammatory Reactions ◽  
Major Depressive Disorders

Microglia are the resident immune cells in the CNS, which survey the brain parenchyma for pathogens, initiate inflammatory responses, secrete inflammatory mediators, and phagocyte debris. Besides, they play a role in the regulation of brain ion homeostasis and in pruning synaptic contacts and thereby modulating neural networks. More recent work shows that microglia are embedded in brain response related to stress phenomena, the development of major depressive disorders, and pain-associated neural processing. The microglia phenotype varies between activated-toxic-neuroinflammatory to non-activated-protective-tissue remodeling, depending on the challenges and regulatory signals. Increased inflammatory reactions result from brain damage, such as stroke, encephalitis, as well as chronic dysfunctions, including stress and pain. The dimension of damage/toxic stimuli defines the amplitude of inflammation, ranging from an on-off event to low but continuous simmering to uncontrollable. Pain, either acute or chronic, involves inflammasome activation at the point of origin, the different relay stations, and the sensory and processing cortical areas. This short review aimed at identifying a sinister role of the microglia-inflammasome platform for the development and perpetuation of acute and chronic central pain and its association with changes in CNS physiology.

scholarly journals ROS-Mediated NLRP3 Inflammasome Activation in Brain, Heart, Kidney, and Testis Ischemia/Reperfusion Injury

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Letteria Minutoli ◽  
Domenico Puzzolo ◽  
Mariagrazia Rinaldi ◽  
Natasha Irrera ◽  
Herbert Marini ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Current Knowledge ◽  
Ischemia Reperfusion ◽  
Ion Homeostasis ◽  
Inflammasome Activation ◽  
Mortality And Morbidity ◽  
Arterial Blood ◽  
Nlrp3 Inflammasome Activation

Ischemia and reperfusion (I/R) causes a reduction in arterial blood supply to tissues, followed by the restoration of perfusion and consequent reoxygenation. The reestablishment of blood flow triggers further damage to the ischemic tissue through reactive oxygen species (ROS) accumulation, interference with cellular ion homeostasis, and inflammatory responses to cell death. In normal conditions, ROS mediate important beneficial responses. When their production is prolonged or elevated, harmful events are observed with peculiar cellular changes. In particular, during I/R, ROS stimulate tissue inflammation and induce NLRP3 inflammasome activation. The mechanisms underlying the activation of NLRP3 are several and not completely elucidated. It was recently shown that NLRP3 might sense directly the presence of ROS produced by normal or malfunctioning mitochondria or indirectly by other activators of NLRP3. Aim of the present review is to describe the current knowledge on the role of NLRP3 in some organs (brain, heart, kidney, and testis) after I/R injury, with particular regard to the role played by ROS in its activation. Furthermore, as no specific therapy for the prevention or treatment of the high mortality and morbidity associated with I/R is available, the state of the art of the development of novel therapeutic approaches is illustrated.

scholarly journals Brain Disorders and Chemical Pollutants: A Gap Junction Link?

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Marc Mesnil ◽  
Norah Defamie ◽  
Christian Naus ◽  
Denis Sarrouilhe
Keyword(s):  
Autism Spectrum Disorders ◽  
Gap Junctions ◽  
Depressive Disorders ◽  
Autism Spectrum ◽  
Brain Parenchyma ◽  
Brain Disorders ◽  
Major Depressive Disorders ◽  
Spectrum Disorders ◽  
Attention Deficit Hyperactivity Disorders ◽  
Gap Junctional

The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson’s disease, Alzheimer’s disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson’s and Alzheimer’s diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.

scholarly journals SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pan Pan ◽  
Miaomiao Shen ◽  
Zhenyang Yu ◽  
Weiwei Ge ◽  
Keli Chen ◽  
...  
Keyword(s):  
Lung Injury ◽  
Nlrp3 Inflammasome ◽  
Cultured Cells ◽  
Inflammatory Responses ◽  
Specific Inhibitor ◽  
Inflammasome Activation ◽  
N Protein ◽  
Distinct Mechanism ◽  
Nlrp3 Inflammasome Activation ◽  
Proinflammatory Responses

AbstractExcessive inflammatory responses induced upon SARS-CoV-2 infection are associated with severe symptoms of COVID-19. Inflammasomes activated in response to SARS-CoV-2 infection are also associated with COVID-19 severity. Here, we show a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation. N protein facilitates maturation of proinflammatory cytokines and induces proinflammatory responses in cultured cells and mice. Mechanistically, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates NLRP3 inflammasome assembly. More importantly, N protein aggravates lung injury, accelerates death in sepsis and acute inflammation mouse models, and promotes IL-1β and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production are blocked by MCC950 (a specific inhibitor of NLRP3) and Ac-YVAD-cmk (an inhibitor of caspase-1). Therefore, this study reveals a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses.

scholarly journals Flavonoids: Nutraceuticals for Rheumatic Diseases via Targeting of Inflammasome Activation

2021 ◽  
Vol 22 (2) ◽  
pp. 488
Author(s):  
Young-Su Yi
Keyword(s):  
Rheumatic Diseases ◽  
Fruits And Vegetables ◽  
Inflammatory Responses ◽  
Protein Complexes ◽  
Cellular Damage ◽  
Inflammatory Rheumatic Diseases ◽  
Inflammasome Activation ◽  
Central Feature ◽  
Inflammatory Protein ◽  
Anti Inflammatory

Inflammation, an innate immune response that prevents cellular damage caused by pathogens, consists of two successive mechanisms, namely priming and triggering. While priming is an inflammation-preparation step, triggering is an inflammation-activation step, and the central feature of triggering is the activation of inflammasomes and intracellular inflammatory protein complexes. Flavonoids are natural phenolic compounds predominantly present in plants, fruits, and vegetables and are known to possess strong anti-inflammatory activities. The anti-inflammatory activity of flavonoids has long been demonstrated, with the main focus on the priming mechanisms, while increasing numbers of recent studies have redirected the research focus on the triggering step, and studies have reported that flavonoids inhibit inflammatory responses and diseases by targeting inflammasome activation. Rheumatic diseases are systemic inflammatory and autoimmune diseases that primarily affect joints and connective tissues, and they are associated with numerous deleterious effects. Here, we discuss the emerging literature on the ameliorative role of flavonoids targeting inflammasome activation in inflammatory rheumatic diseases.

scholarly journals The Role of HPA Axis and Allopregnanolone on the Neurobiology of Major Depressive Disorders and PTSD

2021 ◽  
Vol 22 (11) ◽  
pp. 5495
Author(s):  
Felipe Borges Almeida ◽  
Graziano Pinna ◽  
Helena Maria Tannhauser Barros
Keyword(s):  
Hpa Axis ◽  
Depressive Disorders ◽  
Post Traumatic Stress ◽  
Major Depressive ◽  
Physiological Adaptations ◽  
Suppression Test ◽  
Post Traumatic ◽  
Major Depressive Disorders ◽  
Cortisol Release

Under stressful conditions, the hypothalamic-pituitary-adrenal (HPA) axis acts to promote transitory physiological adaptations that are often resolved after the stressful stimulus is no longer present. In addition to corticosteroids (e.g., cortisol), the neurosteroid allopregnanolone (3α,5α-tetrahydroprogesterone, 3α-hydroxy-5α-pregnan-20-one) participates in negative feedback mechanisms that restore homeostasis. Chronic, repeated exposure to stress impairs the responsivity of the HPA axis and dampens allopregnanolone levels, participating in the etiopathology of psychiatric disorders, such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD). MDD and PTSD patients present abnormalities in the HPA axis regulation, such as altered cortisol levels or failure to suppress cortisol release in the dexamethasone suppression test. Herein, we review the neurophysiological role of allopregnanolone both as a potent and positive GABAergic neuromodulator but also in its capacity of inhibiting the HPA axis. The allopregnanolone function in the mechanisms that recapitulate stress-induced pathophysiology, including MDD and PTSD, and its potential as both a treatment target and as a biomarker for these disorders is discussed.

scholarly journals Development of a Nomogram for Predicting Depression in the Elderly Using Patient Health Questionnaire-9 among a Nationwide Sample of Korean Elderly

2021 ◽  
Vol 11 (7) ◽  
pp. 645
Author(s):  
Haewon Byeon
Keyword(s):  
Depressive Disorders ◽  
The Elderly ◽  
Subjective Health ◽  
Moderate Intensity ◽  
Subjective Health Status ◽  
Major Depressive ◽  
Moderate Intensity Physical Activity ◽  
Patient Health ◽  
Intensity Physical Activity ◽  
Major Depressive Disorders

This cross-sectional study developed a nomogram that could allow medical professionals in the primary care setting to easily and visually confirm high-risk groups of depression. This study analyzed 4011 elderly people (≥60 years old) who completed a health survey, blood pressure, physical measurement, blood test, and a standardized depression screening test. A major depressive disorder was measured using the Korean version of the Patient Health Questionnaire (PHQ-9). This study built a model for predicting major depressive disorders using logistic regression analysis to understand the relationship of each variable with major depressive disorders. In the result, the prevalence of depression measured by PHQ-9 was 6.8%. The results of multiple logistic regression analysis revealed that the major depressive disorder of the elderly living alone was significantly (p < 0.05) related to monthly mean household income, the mean frequency of having breakfast per week for the past year, moderate-intensity physical activity, subjective level of stress awareness, and subjective health status. The results of this study implied that it would be necessary to continuously monitor these complex risk factors such as household income, skipping breakfast, moderate-intensity physical activity, subjective stress, and subjective health status to prevent depression among older adults living in the community.

scholarly journals Role of MDA5 in regulating CXCL10 expression induced by TLR3 signaling in human rheumatoid fibroblast-like synoviocytes

2021 ◽  
Author(s):  
Tatsuro Saruga ◽  
Tadaatsu Imaizumi ◽  
Shogo Kawaguchi ◽  
Kazuhiko Seya ◽  
Tomoh Matsumiya ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Neutralizing Antibody ◽  
Poly I:C ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Inflammatory Reactions ◽  
Polyinosinic:Polycytidylic Acid ◽  
Tlr3 Signaling ◽  
Fibroblast Like Synoviocytes

AbstractC-X-C motif chemokine 10 (CXCL10) is an inflammatory chemokine and a key molecule in the pathogenesis of rheumatoid arthritis (RA). Melanoma differentiation-associated gene 5 (MDA5) is an RNA helicase that plays a role in innate immune and inflammatory reactions. The details of the regulatory mechanisms of CXCL10 production and the precise role of MDA5 in RA synovitis have not been fully elucidated. The aim of this study was to examine the role of MDA5 in regulating CXCL10 expression in cultured human rheumatoid fibroblast-like synoviocytes (RFLS). RFLS was stimulated with Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA mimetic. Expression of interferon beta (IFN-β), MDA5, and CXCL10 was measured by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assay. A neutralizing antibody of IFN-β and siRNA-mediated MDA5 knockdown were used to determine the role of these molecules in regulating CXCL10 expression downstream of TLR3 signaling in RFLS. Poly I:C induced IFN-β, MDA5, and CXCL10 expression in a concentration- and time-dependent manner. IFN-β neutralizing antibody suppressed the expression of MDA5 and CXCL10, and knockdown of MDA5 decreased a part of CXCL10 expression (p < 0.001). The TLR3/IFN-β/CXCL10 axis may play a crucial role in the inflammatory responses in RA synovium, and MDA5 may be partially involved in this axis.

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