scholarly journals Osteopontin Expression in the Brain Triggers Localized Inflammation and Cell Death When Immune Cells Are Activated by Pertussis Toxin

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Maria Cecilia Garibaldi Marcondes ◽  
Ryan Ojakian ◽  
Nikki Bortell ◽  
Claudia Flynn ◽  
Bruno Conti ◽  
...  

Upregulation of osteopontin (OPN) is a characteristic of central nervous system pathologies. However, the role of OPN in inflammation is still controversial, since it can both prevent cell death and induce the migration of potentially damaging inflammatory cells. To understand the role of OPN in inflammation and cell survival, we expressed OPN, utilizing an adenoviral vector, in the caudoputamen of mice deficient in OPN, using beta-galactosidase- (β-gal-) expressing vector as control. The tissue pathology and the expression of proinflammatory genes were compared in both treatments. Interestingly, inflammatory infiltrate was only found when the OPN-vector was combined with a peripheral treatment with pertussis toxin (Ptx), which activated peripheral cells to express the OPN receptor CD44v6. Relative toβ-gal, OPN increased the levels of inflammatory markers, including IL13Rα1, CXCR3, and CD40L. In Ptx-treated OPN KOs, apoptotic TUNEL+ cells surrounding the OPN expression site increased, compared toβ-gal. Together, these results show that local OPN expression combined with a peripheral inflammatory stimulus, such as Ptx, may be implicated in the development of brain inflammation and induction of cell death, by driving a molecular pattern characteristic of cytotoxicity. These are characteristics of inflammatory pathologies of the CNS in which OPN upregulation is a hallmark.

Author(s):  
Sara Keränen ◽  
Santeri Suutarinen ◽  
Rahul Mallick ◽  
Johanna P. Laakkonen ◽  
Diana Guo ◽  
...  

Abstract Background Brain arteriovenous malformations (bAVM) may rupture causing disability or death. BAVM vessels are characterized by abnormally high flow that in general triggers expansive vessel remodeling mediated by cyclo-oxygenase-2 (COX2), the target of non-steroidal anti-inflammatory drugs. We investigated whether COX2 is expressed in bAVMs and whether it associates with inflammation and haemorrhage in these lesions. Methods Tissue was obtained from surgery of 139 bAVMs and 21 normal Circle of Willis samples. The samples were studied with immunohistochemistry and real-time quantitative polymerase chain reaction (RT-PCR). Clinical data was collected from patient records. Results COX2 expression was found in 78% (109/139) of the bAVMs and localized to the vessels’ lumen or medial layer in 70% (95/135) of the bAVMs. Receptors for prostaglandin E2, a COX2-derived mediator of vascular remodeling, were found in the endothelial and smooth muscle cells and perivascular inflammatory cells of bAVMs. COX2 was expressed by infiltrating inflammatory cells and correlated with the extent of inflammation (r = .231, p = .007, Spearman rank correlation). COX2 expression did not associate with haemorrhage. Conclusion COX2 is induced in bAVMs, and possibly participates in the regulation of vessel wall remodelling and ongoing inflammation. Role of COX2 signalling in the pathobiology and clinical course of bAVMs merits further studies.


2021 ◽  
Vol 22 (7) ◽  
pp. 3330
Author(s):  
Mehdi Eshraghi ◽  
Aida Adlimoghaddam ◽  
Amir Mahmoodzadeh ◽  
Farzaneh Sharifzad ◽  
Hamed Yasavoli-Sharahi ◽  
...  

Alzheimer’s disease (AD) is a debilitating neurological disorder, and currently, there is no cure for it. Several pathologic alterations have been described in the brain of AD patients, but the ultimate causative mechanisms of AD are still elusive. The classic hallmarks of AD, including am-yloid plaques (Aβ) and tau tangles (tau), are the most studied features of AD. Unfortunately, all the efforts targeting these pathologies have failed to show the desired efficacy in AD patients so far. Neuroinflammation and impaired autophagy are two other main known pathologies in AD. It has been reported that these pathologies exist in AD brain long before the emergence of any clinical manifestation of AD. Microglia are the main inflammatory cells in the brain and are considered by many researchers as the next hope for finding a viable therapeutic target in AD. Interestingly, it appears that the autophagy and mitophagy are also changed in these cells in AD. Inside the cells, autophagy and inflammation interact in a bidirectional manner. In the current review, we briefly discussed an overview on autophagy and mitophagy in AD and then provided a comprehensive discussion on the role of these pathways in microglia and their involvement in AD pathogenesis.


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.


2019 ◽  
Vol 77 (8) ◽  
pp. 1531-1550 ◽  
Author(s):  
Katarzyna Walczak ◽  
Artur Wnorowski ◽  
Waldemar A. Turski ◽  
Tomasz Plech

Abstract Kynurenic acid (KYNA) is an endogenous tryptophan metabolite exerting neuroprotective and anticonvulsant properties in the brain. However, its importance on the periphery is still not fully elucidated. KYNA is produced endogenously in various types of peripheral cells, tissues and by gastrointestinal microbiota. Furthermore, it was found in several products of daily human diet and its absorption in the digestive tract was evidenced. More recent studies were focused on the potential role of KYNA in carcinogenesis and cancer therapy; however, the results were ambiguous and the biological activity of KYNA in these processes has not been unequivocally established. This review aims to summarize the current views on the relationship between KYNA and cancer. The differences in KYNA concentration between physiological conditions and cancer, as well as KYNA production by both normal and cancer cells, will be discussed. The review also describes the effect of KYNA on cancer cell proliferation and the known potential molecular mechanisms of this activity.


2005 ◽  
Vol 25 (5) ◽  
pp. 2000-2013 ◽  
Author(s):  
Niklas Finnberg ◽  
Joshua J. Gruber ◽  
Peiwen Fei ◽  
Dorothea Rudolph ◽  
Anka Bric ◽  
...  

ABSTRACT DR5 (also called TRAIL receptor 2 and KILLER) is an apoptosis-inducing membrane receptor for tumor necrosis factor-related apoptosis-inducing ligand (also called TRAIL and Apo2 ligand). DR5 is a transcriptional target of p53, and its overexpression induces cell death in vitro. However, the in vivo biology of DR5 has remained largely unexplored. To better understand the role of DR5 in development and in adult tissues, we have created a knockout mouse lacking DR5. This mouse is viable and develops normally with the exception of having an enlarged thymus. We show that DR5 is not expressed in developing embryos but is present in the decidua and chorion early in development. DR5-null mouse embryo fibroblasts expressing E1A are resistant to treatment with TRAIL, suggesting that DR5 may be the primary proapoptotic receptor for TRAIL in the mouse. When exposed to ionizing radiation, DR5-null tissues exhibit reduced amounts of apoptosis compared to wild-type thymus, spleen, Peyer's patches, and the white matter of the brain. In the ileum, colon, and stomach, DR5 deficiency was associated with a subtle phenotype of radiation-induced cell death. These results indicate that DR5 has a limited role during embryogenesis and early stages of development but plays an organ-specific role in the response to DNA-damaging stimuli.


2010 ◽  
Vol 3 ◽  
pp. IJTR.S4321 ◽  
Author(s):  
Nicholas W.S. Davies ◽  
Gilles Guillemin ◽  
Bruce J. Brew

This review presents an up-to-date assessment of the role of the tryptophan metabolic and catabolic pathways in neurodegenerative disease and HIV-associated neurocognitive disorder. The kynurenine pathway and the effects of each of its enzymes and products are reviewed. The differential expression of the kynurenine pathway in cells within the brain, including inflammatory cells, is explored given the increasing recognition of the importance of inflammation in neurodegenerative disease. An overview of common mechanisms of neurodegeneration is presented before a review and discussion of the evidence for a pathogenetic role of the kynurenine pathway in Alzheimer's disease, HIV-associated neurocognitive disorder, Huntington's disease, motor neurone disease, and Parkinson's disease.


2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Julia A. Callender ◽  
Alexandra C. Newton

Protein kinase C (PKC) is a family of enzymes whose members transduce a large variety of cellular signals instigated by the receptor-mediated hydrolysis of membrane phospholipids. While PKC has been widely implicated in the pathology of diseases affecting all areas of physiology including cancer, diabetes, and heart disease—it was discovered, and initially characterized, in the brain. PKC plays a key role in controlling the balance between cell survival and cell death. Its loss of function is generally associated with cancer, whereas its enhanced activity is associated with neurodegeneration. This review presents an overview of signaling by diacylglycerol (DG)-dependent PKC isozymes in the brain, and focuses on the role of the Ca2+-sensitive conventional PKC isozymes in neurodegeneration.


2021 ◽  
Vol 22 (16) ◽  
pp. 8845
Author(s):  
Yang Zhou ◽  
Justine Hann ◽  
Véronique Schenten ◽  
Sébastien Plançon ◽  
Jean-Luc Bueb ◽  
...  

S100A9, a Ca2+-binding protein, is tightly associated to neutrophil pro-inflammatory functions when forming a heterodimer with its S100A8 partner. Upon secretion into the extracellular environment, these proteins behave like damage-associated molecular pattern molecules, which actively participate in the amplification of the inflammation process by recruitment and activation of pro-inflammatory cells. Intracellular functions have also been attributed to the S100A8/A9 complex, notably its ability to regulate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. However, the complete functional spectrum of S100A8/A9 at the intracellular level is far from being understood. In this context, we here investigated the possibility that the absence of intracellular S100A8/A9 is involved in cytokine secretion. To overcome the difficulty of genetically modifying neutrophils, we used murine neutrophils derived from wild-type and S100A9−/− Hoxb8 immortalized myeloid progenitors. After confirming that differentiated Hoxb8 neutrophil-like cells are a suitable model to study neutrophil functions, our data show that absence of S100A8/A9 led to a dysregulation of cytokine secretion after lipopolysaccharide (LPS) stimulation. Furthermore, we demonstrate that S100A8/A9-induced cytokine secretion was regulated by the nuclear factor kappa B (NF-κB) pathway. These results were confirmed in human differentiated HL-60 cells, in which S100A9 was inhibited by shRNAs. Finally, our results indicate that the degranulation process could be involved in the regulation of cytokine secretion by S100A8/A9.


Author(s):  
Xueyuan Yu ◽  
Jiajia Lv ◽  
Jun Wu ◽  
Yong Chen ◽  
Fei Chen ◽  
...  

Hyperactivation of NLRP3 inflammasome contributes to the neuroinflammation in autoimmune disorders, but the underlying regulating mechanism remains to be elucidated. We here demonstrate that mice lacking thymic stromal lymphopoietin receptor gene (Tslpr-/-) exhibit significant decreases in experimental autoimmune encephalitis (EAE) score, reduced CD4+ T cells infiltration, and restored expression of myelin basic protein (MBP) in the brain after induction of EAE by injection of myelin oligodendrocyte glycoprotein35-55 (MOG35-55) . TSLPR signals through Janus Kinase 2 (JAK2) to activate NLRP3. Tslpr-/- mice of EAE show decreased phosphorylation of JAK2 and expression of NLRP3 in the brain. In wild type (WT) mice after induction of EAE, inhibition of JAK2 by ruxolitinib inflammatory and CD4+ cell infiltration, decreased expression of NLRP3, and restored BMP expression in the brain. Ruxolitinib also decreased levels of IL-1β and TSLP in brain of EAE mouse when compared to that without ruxolitinib treatment. Further results with NLRP3 inhibitor MCC950 in EAE mouse of WT verified the proinflammatory role of NLRP3 by showing decreased inflammatory cells and CD4+ T cells, restored MBP expression, and declined levels of IL-1β and TSLP in the brain. In patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis we found increased level of NLRP3 and IL-1β in CSF when compared to that in control subjects. These findings highlight TSLP as a prospective target for treating JAK2-NLRP3 axis-associated autoimmune inflammatory disorders.


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