scholarly journals Neuroinflammation in Sepsis: Molecular Pathways of Microglia Activation

2021 ◽  
Vol 14 (5) ◽  
pp. 416
Author(s):  
Carolina Araújo Moraes ◽  
Camila Zaverucha-do-Valle ◽  
Renaud Fleurance ◽  
Tarek Sharshar ◽  
Fernando Augusto Bozza ◽  
...  

Frequently underestimated, encephalopathy or delirium are common neurological manifestations associated with sepsis. Brain dysfunction occurs in up to 80% of cases and is directly associated with increased mortality and long-term neurocognitive consequences. Although the central nervous system (CNS) has been classically viewed as an immune-privileged system, neuroinflammation is emerging as a central mechanism of brain dysfunction in sepsis. Microglial cells are major players in this setting. Here, we aimed to discuss the current knowledge on how the brain is affected by peripheral immune activation in sepsis and the role of microglia in these processes. This review focused on the molecular pathways of microglial activity in sepsis, its regulatory mechanisms, and their interaction with other CNS cells, especially with neuronal cells and circuits.

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2353
Author(s):  
Maja Potokar ◽  
Jernej Jorgačevski

Plectin, a high-molecular-mass cytolinker, is abundantly expressed in the central nervous system (CNS). Currently, a limited amount of data about plectin in the CNS prevents us from seeing the complete picture of how plectin affects the functioning of the CNS as a whole. Yet, by analogy to its role in other tissues, it is anticipated that, in the CNS, plectin also functions as the key cytoskeleton interlinking molecule. Thus, it is likely involved in signalling processes, thereby affecting numerous fundamental functions in the brain and spinal cord. Versatile direct and indirect interactions of plectin with cytoskeletal filaments and enzymes in the cells of the CNS in normal physiological and in pathologic conditions remain to be fully addressed. Several pathologies of the CNS related to plectin have been discovered in patients with plectinopathies. However, in view of plectin as an integrator of a cohesive mesh of cellular proteins, it is important that the role of plectin is also considered in other CNS pathologies. This review summarizes the current knowledge of plectin in the CNS, focusing on plectin isoforms that have been detected in the CNS, along with its expression profile and distribution alongside diverse cytoskeleton filaments in CNS cell types. Considering that the bidirectional communication between neurons and glial cells, especially astrocytes, is crucial for proper functioning of the CNS, we place particular emphasis on the known roles of plectin in neurons, and we propose possible roles of plectin in astrocytes.


2017 ◽  
Vol 23 (6) ◽  
pp. 587-604 ◽  
Author(s):  
Julien Gibon ◽  
Philip A. Barker

Neurotrophins have been intensively studied and have multiple roles in the brain. Neurotrophins are first synthetized as proneurotrophins and then cleaved intracellularly and extracellularly. Increasing evidences demonstrate that proneurotrophins and mature neurotrophins exerts opposing role in the central nervous system. In the present review, we explore the role of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4) and their respective proform in cellular processes related to learning and memory. We focused on their roles in synaptic activity and plasticity in the brain with an emphasis on long-term potentiation, long-term depression, and basal synaptic transmission in the hippocampus and the temporal lobe area. We also discuss new findings on the role of the Val66Met polymorphism on the BDNF propeptide on synaptic activity.


Psychiatry ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 125-134
Author(s):  
E. F. Vasilyeva ◽  
O. S. Brusov

Background: at present, the important role of the monocyte-macrophage link of immunity in the pathogenesis of mental diseases has been determined. In the first and second parts of our review, the cellular and molecular mechanisms of activation of monocytes/macrophages, which secreting proinflammatory CD16 receptors, cytokines, chemokines and receptors to them, in the development of systemic immune inflammation in the pathogenesis of somatic diseases and mental disorders, including schizophrenia, bipolar affective disorder (BAD) and depression were analyzed. The association of high levels of proinflammatory activity of monocytes/macrophages in patients with mental disorders with somatic comorbidity, including immune system diseases, is shown. It is known that proinflammatory monocytes of peripheral blood, as a result of violation of the integrity of the hematoencephalic barrier can migrate to the central nervous system and activate the resident brain cells — microglia, causing its activation. Activation of microglia can lead to the development of neuroinammation and neurodegenerative processes in the brain and, as a result, to cognitive disorders. The aim of review: to analyze the results of the main scientific studies concerning the role of cellular and molecular mechanisms of peripheral blood monocytes interaction with microglial cells and platelets in the development of neuroinflammation in the pathogenesis of mental disorders, including Alzheimer’s disease (AD). Material and methods: keywords “mental disorders, AD, proinflammatory monocytes, microglia, neuroinflammation, cytokines, chemokines, cell adhesion molecules, platelets, microvesicles” were used to search for articles of domestic and foreign authors published over the past 30 years in the databases PubMed, eLibrary, Science Direct and EMBASE. Conclusion: this review analyzes the results of studies which show that monocytes/macrophages and microglia have similar gene expression profiles in schizophrenia, BAD, depression, and AD and also perform similar functions: phagocytosis and inflammatory responses. Monocytes recruited to the central nervous system stimulate the increased production of proinflammatory cytokines IL-1, IL-6, tumor necrosis factor alpha (TNF-α), chemokines, for example, MCP-1 (Monocyte chemotactic protein-1) by microglial cells. This promotes the recruitment of microglial cells to the sites of neuronal damage, and also enhances the formation of the brain protein beta-amyloid (Aβ). The results of modern studies are presented, indicating that platelets are involved in systemic inflammatory reactions, where they interact with monocytes to form monocyte-platelet aggregates (MTA), which induce the activation of monocytes with a pro inflammatory phenotype. In the last decade, it has been established that activated platelets and other cells of the immune system, including monocytes, detached microvesicles (MV) from the membrane. It has been shown that MV are involved as messengers in the transport of biologically active lipids, cytokines, complement, and other molecules that can cause exacerbation of systemic inflammatory reactions. The presented review allows us to expand our knowledge about the cellular and molecular aspects of the interaction of monocytes/macrophages with microglial cells and platelets in the development of neuroinflammation and cognitive decline in the pathogenesis of mental diseases and in AD, and also helps in the search for specific biomarkers of the clinical severity of mental disorder in patients and the prospects for their response to treatment.


Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2340
Author(s):  
Hannah E. Henson ◽  
Michael R. Taylor

The spliceosome consists of accessory proteins and small nuclear ribonucleoproteins (snRNPs) that remove introns from RNA. As splicing defects are associated with degenerative conditions, a better understanding of spliceosome formation and function is essential. We provide insight into the role of a spliceosome protein U4/U6.U5 tri-snRNP-associated protein 1, or Squamous cell carcinoma antigen recognized by T-cells (Sart1). Sart1 recruits the U4.U6/U5 tri-snRNP complex to nuclear RNA. The complex then associates with U1 and U2 snRNPs to form the spliceosome. A forward genetic screen identifying defects in choroid plexus development and whole-exome sequencing (WES) identified a point mutation in exon 12 of sart1 in Danio rerio (zebrafish). This mutation caused an up-regulation of sart1. Using RNA-Seq analysis, we identified additional upregulated genes, including those involved in apoptosis. We also observed increased activated caspase 3 in the brain and eye and down-regulation of vision-related genes. Although splicing occurs in numerous cells types, sart1 expression in zebrafish was restricted to the brain. By identifying sart1 expression in the brain and cell death within the central nervous system (CNS), we provide additional insights into the role of sart1 in specific tissues. We also characterized sart1’s involvement in cell death and vision-related pathways.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ilse Bollaerts ◽  
Jessie Van houcke ◽  
Lien Andries ◽  
Lies De Groef ◽  
Lieve Moons

Damage to the central nervous system (CNS) is one of the leading causes of morbidity and mortality in elderly, as repair after lesions or neurodegenerative disease usually fails because of the limited capacity of CNS regeneration. The causes underlying this limited regenerative potential are multifactorial, but one critical aspect is neuroinflammation. Although classically considered as harmful, it is now becoming increasingly clear that inflammation can also promote regeneration, if the appropriate context is provided. Here, we review the current knowledge on how acute inflammation is intertwined with axonal regeneration, an important component of CNS repair. After optic nerve or spinal cord injury, inflammatory stimulation and/or modification greatly improve the regenerative outcome in rodents. Moreover, the hypothesis of a beneficial role of inflammation is further supported by evidence from adult zebrafish, which possess the remarkable capability to repair CNS lesions and even restore functionality. Lastly, we shed light on the impact of aging processes on the regenerative capacity in the CNS of mammals and zebrafish. As aging not only affects the CNS, but also the immune system, the regeneration potential is expected to further decline in aged individuals, an element that should definitely be considered in the search for novel therapeutic strategies.


2010 ◽  
Vol 391 (4) ◽  
Author(s):  
Shigetaka Yoshida

Abstract Klk8 is a tryptic serine protease with limited substrate specificity. Klk8 mRNA is expressed in many developing organs, whereas its expression is confined to limited regions, including the hippocampus, in adults. In the hippocampus, Klk8 is involved in activity-dependent synaptic changes such as long-term potentiation, which was found to be suppressed in Klk8 knockout (KO) mice. Oligodendrocytes only expressed Klk8 mRNA after injury to the central nervous system. The epidermis of the skin is one of the tissues that exhibits a high level of KLK8 expression. Klk8 might be involved in desquamation through the degradation of adhesive molecules that connect layers of the epidermis. Klk8 might thus be involved in tissue development and rearrangement.


2021 ◽  
Vol 17 (2) ◽  
pp. 6-15
Author(s):  
L.A. Dziak ◽  
O.S. Tsurkalenko ◽  
K.V. Chekha ◽  
V.M. Suk

Coronavirus infection is a systemic pathology resulting in impairment of the nervous system. The involvement of the central nervous system in COVID-19 is diverse by clinical manifestations and main mechanisms. The mechanisms of interrelations between SARS-CoV-2 and the nervous system include a direct virus-induced lesion of the central nervous system, inflammatory-mediated impairment, thrombus burden, and impairment caused by hypoxia and homeostasis. Due to the multi-factor mechanisms (viral, immune, hypoxic, hypercoagulation), the SARS-CoV-2 infection can cause a wide range of neurological disorders involving both the central and peripheral nervous system and end organs. Dizziness, headache, altered level of consciousness, acute cerebrovascular diseases, hypogeusia, hyposmia, peripheral neuropathies, sleep disorders, delirium, neuralgia, myalgia are the most common signs. The structural and functional changes in various organs and systems and many neurological symptoms are determined to persist after COVID-19. Regardless of the numerous clinical reports about the neurological and psychiatric symptoms of COVID-19 as before it is difficult to determine if they are associated with the direct or indirect impact of viral infection or they are secondary to hypoxia, sepsis, cytokine reaction, and multiple organ failure. Penetrated the brain, COVID-19 can impact the other organs and systems and the body in general. Given the mechanisms of impairment, the survivors after COVID-19 with the infection penetrated the brain are more susceptible to more serious diseases such as Parkinson’s disease, cognitive decline, multiple sclerosis, and other autoimmune diseases. Given the multi-factor pathogenesis of COVID-19 resulting in long-term persistence of the clinical symptoms due to impaired neuroplasticity and neurogenesis followed by cholinergic deficiency, the usage of Neuroxon® 1000 mg a day with twice-day dosing for 30 days. Also, a long-term follow-up and control over the COVID-19 patients are recommended for the prophylaxis, timely determination, and correction of long-term complications.


Author(s):  
Benjamin M. Greenberg ◽  
Allen Desena

Acute disseminated encephalomyelitis (ADEM) is a rare inflammatory disorder of the central nervous system (CNS) that can be fatal or lead to long-term disability. Various triggers have been identified in children and adults, which presumably cause an autoimmune response targeting myelin. The resulting inflammation causes demyelination and edema of the brain, spinal cord, and optic nerves. Depending on which portion of the CNS is affected, patients will experience a variety of symptoms including weakness, numbness, ataxia, encephalopathy, and seizures. Treatment is currently focused on reducing the amount of inflammation and supportive care.


Author(s):  
Sahib S. Khalsa ◽  
Justin S. Feinstein

A regulatory battle for control ensues in the central nervous system following a mismatch between the current physiological state of an organism as mapped in viscerosensory brain regions and the predicted body state as computed in visceromotor control regions. The discrepancy between the predicted and current body state (i.e. the “somatic error”) signals a need for corrective action, motivating changes in both cognition and behavior. This chapter argues that anxiety disorders are fundamentally driven by somatic errors that fail to be adaptively regulated, leaving the organism in a state of dissonance where the predicted body state is perpetually out of line with the current body state. Repeated failures to quell somatic error can result in long-term changes to interoceptive circuitry within the brain. This chapter explores the neuropsychiatric sequelae that can emerge following chronic allostatic dysregulation of somatic errors and discusses novel therapies that might help to correct this dysregulation.


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