Dose-dependent activation of microglial cells by Toll-like receptor agonists alone and in combination

2005 ◽  
Vol 159 (1-2) ◽  
pp. 87-96 ◽  
Author(s):  
Sandra Ebert ◽  
Joachim Gerber ◽  
Steffi Bader ◽  
Frank Mühlhauser ◽  
Katrin Brechtel ◽  
...  
2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Catharina Diesselberg ◽  
Sandra Ribes ◽  
Jana Seele ◽  
Annika Kaufmann ◽  
Sandra Redlich ◽  
...  

Author(s):  
Jaedeok Kwon ◽  
Christos Arsenis ◽  
Maria Suessmilch ◽  
Alison McColl ◽  
Jonathan Cavanagh ◽  
...  

AbstractMicroglial activation is believed to play a role in many psychiatric and neurodegenerative diseases. Based largely on evidence from other cell types, it is widely thought that MAP kinase (ERK, JNK and p38) signalling pathways contribute strongly to microglial activation following immune stimuli acting on toll-like receptor (TLR) 3 or TLR4. We report here that exposure of SimA9 mouse microglial cell line to immune mimetics stimulating TLR4 (lipopolysaccharide—LPS) or TLR7/8 (resiquimod/R848), results in marked MAP kinase activation, followed by induction of nitric oxide synthase, and various cytokines/chemokines. However, in contrast to TLR4 or TLR7/8 stimulation, very few effects of TLR3 stimulation by poly-inosine/cytidine (polyI:C) were detected. Induction of chemokines/cytokines at the mRNA level by LPS and resiquimod were, in general, only marginally affected by MAP kinase inhibition, and expression of TNF, Ccl2 and Ccl5 mRNAs, along with nitrite production, were enhanced by p38 inhibition in a stimulus-specific manner. Selective JNK inhibition enhanced Ccl2 and Ccl5 release. Many distinct responses to stimulation of TLR4 and TLR7 were observed, with JNK mediating TNF protein induction by the latter but not the former, and suppressing Ccl5 release by the former but not the latter. These data reveal complex modulation by MAP kinases of microglial responses to immune challenge, including a dampening of some responses. They demonstrate that abnormal levels of JNK or p38 signalling in microglial cells will perturb their profile of cytokine and chemokine release, potentially contributing to abnormal inflammatory patterns in CNS disease states.


1997 ◽  
Vol 28 ◽  
pp. S89
Author(s):  
Masahiro Sakanaka ◽  
Hiroko Fujita ◽  
Junya Tanaka ◽  
Seiji Matsuda ◽  
Nobuji Maeda

2015 ◽  
Vol 18;4 (4;18) ◽  
pp. E615-E628
Author(s):  
Lei Chen

Background: Chronic pancreatitis (CP) is a long-standing inflammation of the exocrine pancreas, which typically results in severe and constant abdominal pain. Previous studies on the mechanisms underlying CP-induced pain have primarily focused on the peripheral nociceptive system. A role for a central mechanism in the mediation or modulation of abdominal pain is largely unknown. Tanshinone IIA (TSN IIA), an active component of the traditional Chinese medicine Danshen, exhibits anti-inflammatory properties via downregulation of the expression of high-mobility group protein B1 (HMGB1), a late proinflammatory cytokine. HMGB1 binds and activates toll-like receptor 4 (TLR4) to induce spinal astrocyte activation and proinflammatory cytokine release in neuropathic pain. Objective: In this study, we investigated the effect of TSN IIA on pain responses in rats with trinitrobenzene sulfonic acid (TNBS)-induced CP. The roles of central mechanisms in the mediation or modulation of CP were also investigated. Study Design: A randomized, double-blind, placebo-controlled animal trial. Methods: CP was induced in rats by intrapancreatic infusion of trinitrobenzene sulfonic acid (TNBS). Pancreatic histopathological changes were characterized with semi-quantitative scores. The abdomen nociceptive behaviors were assessed with von Frey filaments. The effects of intraperitoneally administered TSN IIA on CP-induced mechanical allodynia were tested. The spinal protein expression of HMGB1 was determined by western blot. The spinal mRNA and protein expression of proinflammatory cytokines IL-1β, TNF-α, and IL-6 were determined by RT-PCR and western blot, respectively. The spinal expression of the HMGB1 receptor TRL4 and the astrocyte activation marker glial fibrillary acidic protein (GFAP) were determined by western blot or immunohistological staining after intraperitoneal injection of TSN IIA or intrathecal administration of a neutralizing anti-HMGB1 antibody. Results: TNBS infusion resulted in pancreatic histopathological changes of chronic pancreatitis and mechanical allodynia in rats. TSN IIA significantly attenuated TNBS-induced mechanical allodynia in a dose-dependent manner. TNBS significantly increased the spinal expression of HMGB1 and proinflammatory cytokines IL-1β, TNF-α, and IL-6. These TNBS-induced changes were significantly inhibited by TSN IIA in a dose-dependent manner. Furthermore, TSN IIA, but not the neutralizing anti-HMGB1 antibody, significantly inhibited TNBS-induced spinal TLR4 and GFAP expression. Limitations: In addition to TLR4, HMGB1 can also bind to toll-like receptor-2 (TLR2) and the receptor for advanced glycation end products (RAGE). Additional studies are warranted to ascertain whether HMGB1 contributes to CP-induced pain through activation of these receptors. Conclusions: Our results suggest that spinal HMGB1 contributes to the development of CPinduced pain and can potentially be a therapeutic target. TSN IIA attenuates CP-induced pain via downregulation of spinal HMGB1 and TRL4 expression. Therefore, TSN IIA may be a potential anti-nociceptive drug for the treatment of CP-induced pain. Key words: Chronic pancreatitis, HMGB1, proinflammatory cytokine, Tanshinone IIA, spinal cord, astrocyte, TLR4


2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Bethany Crouse ◽  
Shannon Miller ◽  
Christine Robinson ◽  
Valeria Gradinati ◽  
Linda Hicks ◽  
...  

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