scholarly journals Novel protective role for MAP kinase phosphatase 2 in inflammatory arthritis

RMD Open ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. e000711
Author(s):  
Juliane Schroeder ◽  
Kirsty Ross ◽  
Kathryn McIntosh ◽  
Shilan Jabber ◽  
Stuart Woods ◽  
...  
Keyword(s):  
Inflammatory Arthritis ◽  
Neutrophil Migration ◽  
Protective Role ◽  
Leukotriene B4 ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Map Kinase Phosphatase ◽  
Tnf Α ◽  
The Impact

ObjectivesWe have previously shown mitogen-activated protein kinase phosphatase 2 (MKP-2) to be a key regulator of proinflammatory cytokines in macrophages. In the study presented here, we investigated the role of MKP-2 in inflammatory arthritis with a particular focus on neutrophils.MethodsTo achieve this, we subjected MKP-2 deficient and wild type mice to collagen antibody induced arthritis, an innate model of arthritis, and determined disease pathology. To further our investigation, we depleted neutrophils in a prophylactic and therapeutic fashion. Last, we used chemotaxis assays to analyse the impact of MKP-2 deletion on neutrophil migration.ResultsMKP-2-/- mice showed a significant increase in disease pathology linked to elevated levels of proarthritic cytokines and chemokines TNF-α, IL-6 and MCP-1 in comparison to wild type controls. This phenotype is prevented or abolished after administration of neutrophil depleting antibody prior or after onset of disease, respectively. While MCP-1 levels were not affected, neutrophil depletion diminished TNF-α and reduced IL-6, thus linking these cytokines to neutrophils. In vivo imaging showed that MKP-2-/- mice had an increased influx of neutrophils into affected joints, which was higher and potentially prolonged than in wild type animals. Furthermore, using chemotaxis assays we revealed that MKP-2 deficient neutrophils migrate faster towards a Leukotriene B4 gradient. This process correlated with a reduced phosphorylation of ERK in MKP-2-/- neutrophils.ConclusionsThis is the first study to show a protective role for MKP-2 in inflammatory arthritis.

scholarly journals Production of Noncapped Genomic RNAs Is Critical to Sindbis Virus Disease and Pathogenicity

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Autumn T. LaPointe ◽  
V Douglas Landers ◽  
Claire E. Westcott ◽  
Kevin J. Sokoloski
Keyword(s):  
Sindbis Virus ◽  
Virus Disease ◽  
Severe Disease ◽  
Wild Type Virus ◽  
Wild Type ◽  
Genomic Rnas ◽  
Mortality And Morbidity ◽  
The Impact

ABSTRACT Alphaviruses are positive-sense RNA viruses that utilize a 5′ cap structure to facilitate translation of viral proteins and to protect the viral RNA genome. Nonetheless, significant quantities of viral genomic RNAs that lack a canonical 5′ cap structure are produced during alphaviral replication and packaged into viral particles. However, the role/impact of the noncapped genomic RNA (ncgRNA) during alphaviral infection in vivo has yet to be characterized. To determine the importance of the ncgRNA in vivo, the previously described D355A and N376A nsP1 mutations, which increase or decrease nsP1 capping activity, respectively, were incorporated into the neurovirulent AR86 strain of Sindbis virus to enable characterization of the impact of altered capping efficiency in a murine model of infection. Mice infected with the N376A nsP1 mutant exhibited slightly decreased rates of mortality and delayed weight loss and neurological symptoms, although levels of inflammation in the brain were similar to those of wild-type infection. Although the D355A mutation resulted in decreased antiviral gene expression and increased resistance to interferon in vitro, mice infected with the D355A mutant showed significantly reduced mortality and morbidity compared to mice infected with wild-type virus. Interestingly, expression of proinflammatory cytokines was found to be significantly decreased in mice infected with the D355A mutant, suggesting that capping efficiency and the production of ncgRNA are vital to eliciting pathogenic levels of inflammation. Collectively, these data indicate that the ncgRNA have important roles during alphaviral infection and suggest a novel mechanism by which noncapped viral RNAs aid in viral pathogenesis. IMPORTANCE Mosquito-transmitted alphaviruses have been the cause of widespread outbreaks of disease that can range from mild illness to lethal encephalitis or severe polyarthritis. There are currently no safe and effective vaccines or therapeutics with which to prevent or treat alphaviral disease, highlighting the need to better understand alphaviral pathogenesis to develop novel antiviral strategies. This report reveals production of noncapped genomic RNAs (ncgRNAs) to be a novel determinant of alphaviral virulence and offers insight into the importance of inflammation to pathogenesis. Taken together, the findings reported here suggest that the ncgRNAs contribute to alphaviral pathogenesis through the sensing of the ncgRNAs during alphaviral infection and are necessary for the development of severe disease.

TAMI-38. TUMOR-ASSOCIATED NEUTROPHILS IN GLIOBLASTOMA PROMOTE THE PERIVASCULAR GLIOMA STEM-LIKE CELL NICHE VIA OSTEOPONTIN SECRETION

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi206-vi206
Author(s):  
Angad Beniwal ◽  
Saket Jain ◽  
Sumedh Shah ◽  
Sabraj Gill ◽  
Garima Yagnik ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Leukotriene B4 ◽  
Lower Grade ◽  
Wild Type ◽  
Perivascular Niche ◽  
Neutrophil Lymphocyte Ratio ◽  
Blood Neutrophils ◽  
Poor Outcomes ◽  
Tumor Associated Neutrophils

Abstract Among clinical analyses, elevated neutrophil-lymphocyte ratio has been correlated with poor outcomes of glioblastoma patients independent of other prognostic factors. Additionally, our flow cytometric studies of primary patient samples found neutrophil percentage to be significantly higher in higher-grade glioma versus lower-grade glioma. Tumor-associated neutrophils (TANs) comprise less than 2% of the glioblastoma microenvironment. While TANs were initially considered passive bystanders due to their short-lived nature, investigation of TANs in other cancers revealed distinct pro-tumoral roles. Therefore, we transcriptomically characterized glioblastoma TANs and defined their oncologic effects. Transcriptomic analysis of patient-matched TANs versus peripheral blood neutrophils revealed that functionally quiescent circulating neutrophils infiltrate IDH1-wild type glioblastoma via leukotriene B4 chemoattraction, where tumor cells morphologically and transcriptomically activate them to become TANs. Single-cell RNA-sequencing of patient-matched TANs and peripheral blood neutrophils revealed a subset of tumor-activated neutrophils which adopt a pro-tumoral secretory phenotype, marked by activation of the IL-17 signaling pathway and high osteopontin production. Using immunofluorescence stains of primary patient glioblastoma sections, we demonstrated that activated, myeloperoxidase-positive TANs reside in the perivascular niche of glioblastoma in close proximity to glioblastoma stem-like cells (GSCs) and CD31-positive endothelial cells. Further analysis in culture demonstrated that TAN-secreted osteopontin drives the formation, self-renewal, and proliferation of GSC-containing neurospheres. These results were validated using a syngeneic stem cell-derived IDH1-wild type murine glioblastoma model in vivo. Thus, while TANs are rare in glioblastoma, their enrichment in the glioblastoma perivascular niche uniquely positions them to support the GSCs that are crucial to therapeutic resistance of GBM.

scholarly journals Bakuchiol Suppresses Inflammatory Responses Via the Downregulation of the p38 MAPK/ERK Signaling Pathway

2019 ◽  
Vol 20 (14) ◽  
pp. 3574 ◽  
Author(s):  
Hye-Sun Lim ◽  
Yu Jin Kim ◽  
Bu-Yeo Kim ◽  
Soo-Jin Jeong
Keyword(s):  
Mrna Expression ◽  
P38 Mapk ◽  
Inflammatory Responses ◽  
Mitogen Activated Protein Kinase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mice Model ◽  
Tnf Α ◽  
Cox 2

The purpose of the present study was to evaluate the effects of bakuchiol on the inflammatory response and to identify the molecular mechanism of the inflammatory effects in a lipopolysaccharide (LPS)-stimulated BV-2 mouse microglial cell line and mice model. The production of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay. The mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, and IL-6 was measured using reverse transcription–polymerase chain reaction analysis. Mitogen-activated protein kinase (MAPK) phosphorylation was determined by western blot analysis. In vitro experiments, bakuchiol significantly suppressed the production of PGE2 and IL-6 in LPS-stimulated BV-2 cells, without causing cytotoxicity. In parallel, bakuchiol significantly inhibited the LPS-stimulated expression of iNOS, COX-2, and IL-6 in BV-2 cells. However, bakuchiol had no effect on the LPS-stimulated production and mRNA expression of TNF-α or on LPS-stimulated c-Jun NH2-terminal kinase phosphorylation. In contrast, p38 MAPK and extracellular signal-regulated kinase (ERK) phosphorylation were inhibited by bakuchiol. In vivo experiments, Bakuchiol reduced microglial activation in the hippocampus and cortex tissue of LPS-injected mice. Bakuchiol significantly suppressed LPS-injected production of TNF-α and IL-6 in serum. These results indicate that the anti-neuroinflammatory effects of bakuchiol in activated microglia are mainly regulated by the inhibition of the p38 MAPK and ERK pathways. We suggest that bakuchiol may be beneficial for various neuroinflammatory diseases.

scholarly journals Noncapped Genomic RNA Are Critical for Alphaviral Infection and Pathogenicity

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 44
Author(s):  
Autumn T. LaPointe ◽  
Kevin J Sokoloski
Keyword(s):  
Growth Kinetics ◽  
Particle Production ◽  
Immune Cell ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Genomic Rnas ◽  
Viral Rnas ◽  
The Impact

Alphaviruses are positive-sense RNA arthropod-borne viruses that represent a significant threat to public health. During alphaviral replication, significant quantities of viral genomic RNAs that lack a canonical 5’ cap structure are produced and packaged into viral particles, despite the fact that the noncapped genomes cannot be translated and are essentially noninfectious. Previously, we have reported that the capping efficiency of nsP1, the alphaviral capping enzyme, of Sindbis virus (SINV) could be modulated via point mutation. It was found that increasing RNA capping efficiency led to decreased viral growth kinetics via decreased particle production, despite increased innate immune evasion, whereas decreasing capping efficiency led to wild-type growth kinetics and particle production. This led to the conclusion that the noncapped viral RNAs meaningfully contribute to the biology of alphaviral infections at the molecular level. To determine the importance of the noncapped viral RNAs in vivo, we characterized the impact of altered capping efficiency in a murine model of infection utilizing a neurovirulent strain of SINV. Mice infected with the nsP1 mutant with decreased capping exhibited wild-type rates of mortality, weight loss, and neurological symptoms. Conversely, the mice infected with the increased capping nsP1 mutant showed significantly reduced mortality and morbidity compared to mice infected with the wild-type virus. Interestingly, viral titers in the ankle, serum, and brain were equivalent between the wild-type virus and the two mutant viruses. Importantly, examination of the brain tissue revealed that mice infected with the increased capping mutant had significantly reduced immune cell infiltration and expression of proinflammatory cytokines compared to the decreased capping mutant and wild-type virus. Collectively, these data indicate that the noncapped viral RNAs have important roles during the early and late stages of alphaviral infection and suggest a novel mechanism by which noncapped viral RNA aids in viral pathogenesis.

scholarly journals RICK Promotes Inflammation and Lethality after Gram-Negative Bacterial Infection in Mice Stimulated with Lipopolysaccharide

2009 ◽  
Vol 77 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Jong-Hwan Park ◽  
Yun-Gi Kim ◽  
Gabriel Núñez
Keyword(s):  
Protein Kinase ◽  
Regulatory Protein ◽  
Mitogen Activated Protein Kinase ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Proinflammatory Response ◽  
Interacting Protein ◽  
Gram Negative ◽  
Mitogen Activated Protein

ABSTRACT RICK (receptor-interacting protein-like interacting caspase-like apoptosis regulatory protein kinase), a serine-threonine kinase, functions downstream of the pattern recognition receptors Nod1 and Nod2 to mediate NF-κB and mitogen-activated protein kinase (MAPK) activation in response to specific microbial stimuli. However, the function of RICK in the recognition and host defense of gram-negative bacteria remains poorly understood. We report here that infection of wild-type and RICK-deficient macrophages with Pseudomonas aeruginosa and Escherichia coli elicited comparable activation of NF-κB and MAPKs as well as secretion of proinflammatory cytokines. However, production of interleukin 6 (IL-6) and IL-1β induced by these gram-negative bacteria was impaired in RICK-deficient macrophages when the cells had previously been stimulated with lipopolysaccharide (LPS) or E. coli. The diminished proinflammatory response of RICK-deficient macrophages to bacteria was associated with reduced activation of NF-κB and MAPKs. Importantly, mutant mice deficient in RICK were less susceptible than wild-type mice to P. aeruginosa infection when the animals had previously been stimulated with LPS. The reduced lethality of RICK-deficient mice infected with P. aeruginosa was independent of pathogen clearance but was associated with diminished production of proinflammatory molecules in vivo. These results demonstrate that RICK contributes to the induction of proinflammatory responses and susceptibility to gram-negative bacteria after exposure to LPS, a condition that is associated with reduced Toll-like receptor signaling.

scholarly journals Impact of Resolvin E1 on Murine Neutrophil Phagocytosis in Type 2 Diabetes

2014 ◽  
Vol 83 (2) ◽  
pp. 792-801 ◽  
Author(s):  
Bruno S. Herrera ◽  
Hatice Hasturk ◽  
Alpdogan Kantarci ◽  
Marcelo O. Freire ◽  
Olivia Nguyen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Transgenic Animals ◽  
Genetically Engineered ◽  
Mitogen Activated Protein Kinase ◽  
Air Pouch ◽  
Content Type ◽  
Genetically Engineered Mice ◽  
The Impact

Diabetic complications involve inflammation-mediated microvascular and macrovascular damage, disruption of lipid metabolism, glycosylation of proteins, and abnormalities of neutrophil-mediated events. Resolution of inflamed tissues to health and homeostasis is an active process mediated by endogenous lipid agonists, including lipoxins and resolvins. This proresolution system appears to be compromised in type 2 diabetes (T2D). The goal of this study was to investigate unresolved inflammation in T2D. Wild-type (WT) and genetically engineered mice, including T2D mice (db/db), transgenic mice overexpressing the human resolvin E1 (RvE1) receptor (ERV1), and a newly bred strain ofdb/ERV1mice, were used to determine the impact of RvE1 on the phagocytosis ofPorphyromonas gingivalisin T2D. Neutrophils were isolated and incubated with fluorescein isothiocyanate-labeledP. gingivalis, and phagocytosis was measured in a fluorochrome-based assay by flow cytometry. Mitogen-activated protein kinase (MAPK) (p42 and p44) and Akt (Thr308 and Ser473) phosphorylation was analyzed by Western blotting. The mouse dorsal air pouch model was used to evaluate thein vivoimpact of RvE1. Results revealed that RvE1 increased the neutrophil phagocytosis ofP. gingivalisin WT animals but had no impact indb/dbanimals. InERV1-transgenic andERV1-transgenic diabetic mice, phagocytosis was significantly increased. RvE1 decreased Akt and MAPK phosphorylation in the transgenic animals.In vivodorsal air pouch studies revealed that RvE1 decreases neutrophil influx into the pouch and increases neutrophil phagocytosis ofP. gingivalisin the transgenic animals; cutaneous fat deposition was reduced, as was macrophage infiltration. The results suggest that RvE1 rescues impaired neutrophil phagocytosis in obese T2D mice overexpressingERV1.

scholarly journals Major Histocompatibility Complex Haplotype Determines hsp70-Dependent Protection against Measles Virus Neurovirulence

2009 ◽  
Vol 83 (11) ◽  
pp. 5544-5555 ◽  
Author(s):  
Thomas Carsillo ◽  
Mary Carsillo ◽  
Zachary Traylor ◽  
Päivi Rajala-Schultz ◽  
Phillip Popovich ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Measles Virus ◽  
Protective Role ◽  
Major Histocompatibility ◽  
Major Histocompatibility Complex Haplotype ◽  
Brain Infection ◽  
Histocompatibility Complex ◽  
The Impact

ABSTRACT In vitro studies show that hsp70 promotes gene expression for multiple viral families, although there are few reports on the in vivo significance of virus-hsp70 interaction. Previously we showed that hsp70-dependent stimulation of Edmonston measles virus (Ed MeV) transcription caused an increased cytopathic effect and mortality in transgenic hsp70-overexpressing C57BL/6 mice (H-2 b ). The response to MeV infection is influenced by the major histocompatibility complex haplotype; H-2 d mice are resistant to brain infection due to robust antiviral immune responses, whereas H-2 b mice are susceptible due to deficiencies in this response. We therefore tested the hypothesis that the outcome of MeV-hsp70 interaction may be dependent upon the host H-2 haplotype. The impact of selective neuronal hsp70 overexpression on Ed MeV brain infection was tested with congenic C57BL/10 H-2 d neonatal mice. In this context, hsp70 overexpression conferred complete protection against virus-induced mortality, compared to >30% mortality in nontransgenic mice. Selective depletion of T-cell populations showed that transgenic mice exhibit a diminished reliance on T cells for protection. Brain transcript analysis indicated enhanced innate immune activation and signaling through Toll-like receptors 2 and 4 at early times postinfection for transgenic infected mice relative to those for nontransgenic infected mice. Collectively, results suggest that hsp70 can enhance innate antiviral immunity through Toll-like receptor signaling, supporting a protective role for physiological responses that enhance tissue levels of hsp70 (e.g., fever), and that the H-2 haplotype determines the effectiveness of this response.

Impaired functional activity of alveolar macrophages from GM-CSF-deficient mice

2001 ◽  
Vol 281 (5) ◽  
pp. L1210-L1218 ◽  
Author(s):  
Robert Paine ◽  
Susan B. Morris ◽  
Hong Jin ◽  
Steven E. Wilcoxen ◽  
Susan M. Phare ◽  
...  
Keyword(s):  
Host Defense ◽  
Alveolar Macrophages ◽  
Phagocytic Activity ◽  
Wild Type ◽  
Specific Expression ◽  
Gm Csf ◽  
Functional Capabilities ◽  
Tnf Α

We hypothesized that pulmonary granulocyte-macrophage colony-stimulating factor (GM-CSF) is critically involved in determining the functional capabilities of alveolar macrophages (AM) for host defense. To test this hypothesis, cells were collected by lung lavage from GM-CSF mutant mice [GM(−/−)] and C57BL/6 wild-type mice. GM(−/−) mice yielded almost 4-fold more AM than wild-type mice. The percentage of cells positive for the β2-integrins CD11a and CD11c was reduced significantly in GM(−/−) AM compared with wild-type cells, whereas expression of CD11b was similar in the two groups. The phagocytic activity of GM(−/−) AM for FITC-labeled microspheres was impaired significantly compared with that of wild-type AM both in vitro and in vivo (after intratracheal inoculation with FITC-labeled beads). Stimulated secretion of tumor necrosis factor-α (TNF-α) and leukotrienes by AM from the GM(−/−) mice was greatly reduced compared with wild-type AM, whereas secretion of monocyte chemoattractant protein-1 was increased. Transgenic expression of GM-CSF exclusively in the lungs of GM(−/−) mice resulted in AM with normal or supranormal expression of CD11a and CD11c, phagocytic activity, and TNF-α secretion. Thus, in the absence of GM-CSF, AM functional capabilities for host defense were significantly impaired but were restored by lung-specific expression of GM-CSF.

Acute stressor exposure facilitates innate immunity more in physically active than in sedentary rats

2002 ◽  
Vol 282 (6) ◽  
pp. R1680-R1686 ◽  
Author(s):  
Monika Fleshner ◽  
Jay Campisi ◽  
Terrence Deak ◽  
Ben N. Greenwood ◽  
Jennifer A. Kintzel ◽  
...  
Keyword(s):  
Physical Activity ◽  
Innate Immunity ◽  
Acute Stress ◽  
Neutrophil Migration ◽  
Acquired Immunity ◽  
Physically Active ◽  
Inflammatory Site ◽  
Acute Stressor ◽  
The Impact

Most previous stress-immune research focused on the immunosuppressive effects of stress on acquired immunity. More recently, it has become clear that acute stressor exposure can potentiate innate, as well as suppress acquired, immunity. For example, acute stress improves recovery from bacterial inflammation, a classic in vivo measure of innate immunity. The previous work was done in sedentary organisms. Physical activity status can modulate the impact of stress on immune function. The following studies tested the hypothesis that the effect of stress on inflammation after subcutaneous challenge with bacteria ( Escherichia coli) is facilitated by physical activity. The results were that sedentary, stressed rats resolved their inflammation 1–2 days faster and have increased circulating neutrophils compared with their nonstressed, sedentary counterparts. In contrast, physically active, stressed rats resolve their inflammation 3–4 days faster and have increased circulating and inflammatory site neutrophils compared with their nonstressed counterparts. Importantly, the beneficial impact of stress on inflammation recovery and neutrophil migration was greater in the physically active, than sedentary, stressed rats. Thus physical activity status facilitates the positive effect of acute stress on innate immunity.

scholarly journals Treatment of inflammatory arthritis via targeting of tristetraprolin, a master regulator of pro-inflammatory gene expression

2016 ◽  
Vol 76 (3) ◽  
pp. 612-619 ◽  
Author(s):  
E A Ross ◽  
A J Naylor ◽  
J D O'Neil ◽  
T Crowley ◽  
M L Ridley ◽  
...  
Keyword(s):  
Inflammatory Arthritis ◽  
Inflammatory Responses ◽  
Vascular Endothelial Cells ◽  
Bone Erosion ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Critical Determinant ◽  
Anti Inflammatory

ObjectivesTristetraprolin (TTP), a negative regulator of many pro-inflammatory genes, is strongly expressed in rheumatoid synovial cells. The mitogen-activated protein kinase (MAPK) p38 pathway mediates the inactivation of TTP via phosphorylation of two serine residues. We wished to test the hypothesis that these phosphorylations contribute to the development of inflammatory arthritis, and that, conversely, joint inflammation may be inhibited by promoting the dephosphorylation and activation of TTP.MethodsThe expression of TTP and its relationship with MAPK p38 activity were examined in non-inflamed and rheumatoid arthritis (RA) synovial tissue. Experimental arthritis was induced in a genetically modified mouse strain, in which endogenous TTP cannot be phosphorylated and inactivated. In vitro and in vivo experiments were performed to test anti-inflammatory effects of compounds that activate the protein phosphatase 2A (PP2A) and promote dephosphorylation of TTP.ResultsTTP expression was significantly higher in RA than non-inflamed synovium, detected in macrophages, vascular endothelial cells and some fibroblasts and co-localised with MAPK p38 activation. Substitution of TTP phosphorylation sites conferred dramatic protection against inflammatory arthritis in mice. Two distinct PP2A agonists also reduced inflammation and prevented bone erosion. In vitro anti-inflammatory effects of PP2A agonism were mediated by TTP activation.ConclusionsThe phosphorylation state of TTP is a critical determinant of inflammatory responses, and a tractable target for novel anti-inflammatory treatments.

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