ABSTRACT
BACKGROUND: Ischemic stroke is a major disease that threatens human health in ageing population. Increasing evidence has shown that neuroinflammatory mediators play crucial roles in the pathophysiology of cerebral ischemia injury. Notch signaling is recognized as the cell fate signaling but recent evidence indicates that it may be involved in the inflammatory response in activated microglia in cerebral ischemia. Previous report in our group demonstrated hypertonic saline (HS) could reduce the release of interleukin-1 beta and tumor necrosis factor-alpha in activated microglia, but the underlying molecular and cellular mechanisms have remained uncertain. This study was aimed to explore whether HS would partake in regulating production of proinflammatory mediators through Notch signaling. RESULTS: HS markedly attenuated the expression of Notch-1, NICD, RBP-JK and Hes-1 in activated microglia both in vivo and in vitro. Remarkably, HS also reduced the expression of iNOS in vivo, while the in vitro levels of inflammatory mediators Phos-NF-κB, iNOS and ROS were reduced by HS as well. CONCLUSION: Our results suggest that HS may suppress of inflammatory mediators following ischemia/hypoxic through the Notch signaling which operates synergistically with NF-κB pathway in activated microglia. Our study has provided the morphological and biochemical evidence that HS can attenuate inflammation reaction and can be neuroprotective in cerebral ischemia, thus supporting the use of hypertonic saline by clinicians in patients with an ischemia stroke.
Subject(s)
Brain Ischemia/drug therapy , Cell Hypoxia/drug effects , Microglia/drug effects , Neuroprotective Agents/pharmacology , Receptors, Notch/metabolism , Saline Solution, Hypertonic/pharmacology , Animals , Brain Ischemia/immunology , Brain Ischemia/pathology , Cell Hypoxia/physiology , Cell Line , Disease Models, Animal , Drug Evaluation, Preclinical , Male , Mice , Microglia/immunology , Microglia/pathology , Nitric Oxide Synthase Type II/metabolism , Random Allocation , Rats, Sprague-Dawley , Reperfusion Injury/drug therapy , Reperfusion Injury/immunology , Reperfusion Injury/pathology , Signal Transduction/drug effectsABSTRACT
Alzheimer's disease (AD) is the most common type of progressive neurodegenerative disorder, and is responsible for the most common form of dementia in the elderly. Inflammation occurs in the brains of patients with AD, and is critical for disease progression. In the present study, the effects of rapamycin (RAPA) on neuroinflammation lipopolysaccharide (LPS)-induced were investigated. SHSY5Y human neuroblastoma cells were treated with 20 µg/ml LPS and 0.1, 1 or 10 nmol/l RAPA, and were analyzed at various time points (6, 12 and 24 h). The mRNA expression levels of interleukin (IL) 1ß, IL6 and hypoxiainducible factor 1α (HIF1α) were determined using reverse transcriptionquantitative polymerase chain reaction. The protein expression levels of phosphorylated (p)S6, pnuclear factor κB (NFκB), pinhibitor of NFκB kinase subunit ß (IKKß) and ptau protein were measured by western blot analysis. pIKKß, pNFκB, pS6 and ptau were significantly decreased at 6, 12 and 24 h when cells were treated with ≥0.1 nmol/ml RAPA. In addition, female Sprague Dawley rats were intracranially injected with a single dose of 100 µg/kg LPS in the absence or presence of 1 mg/kg RAPA pretreatment. Brain tissues were subjected to immunohistochemical analysis 624 h later, which revealed that the expression levels of HIF1α and pS6 in rat cerebral cortex were increased following LPS injection; however, this increase was abrogated by RAPA treatment. RAPA may therefore be considered a potential therapeutic agent for the early or emergency treatment of neuroinflammation.
Subject(s)
Inflammation/etiology , Lipopolysaccharides/adverse effects , Nervous System Diseases/etiology , Sirolimus/pharmacology , Animals , Biomarkers , Cell Line, Tumor , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Cytokines/genetics , Cytokines/metabolism , Disease Models, Animal , Female , Gene Expression , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , I-kappa B Kinase/metabolism , Inflammation/drug therapy , Inflammation/metabolism , Inflammation/pathology , Inflammation Mediators/metabolism , NF-kappa B/metabolism , Nervous System Diseases/drug therapy , Nervous System Diseases/metabolism , Nervous System Diseases/pathology , Neurons/metabolism , Phosphorylation , Rats , Ribosomal Protein S6 Kinases/metabolism , tau Proteins/metabolismABSTRACT
Neuroinflammatory deregulation in the brain plays a crucial role in the pathogenesis of sepsis associated encephalopathy (SAE). Given the mounting evidence of anti-inflammatory and neuroprotective effects of the cholinergic nervous system, it is surprising that there is little information about its changes in the brain during sepsis. To elucidate the role of the cholinergic nervous system in SAE, hippocampal choline acetyltransferase, muscarinic acetylcholine receptor-1, acetylcholinesterase and acetylcholine were evaluated in LPS-induced sepsis rats. Expression of pro-inflammatory cytokines, neuronal apoptosis, and animal cognitive performance were also assessed. Furthermore, therapeutic effects of the acetylcholinesterase inhibitor Huperzine A (HupA) on the hippocampal cholinergic nervous function and neuroinflammation were evaluated. A deficiency of the cholinergic nervous function was revealed in SAE, accompanied with over-expressed pro-inflammatory cytokines, increase in neuronal apoptosis and brain cognitive impairment. HupA remarkably promoted the deficient cholinergic nervous function and attenuated the abnormal neuroinflammation in SAE, paralleled with the recovery of brain function. We suggest that the deficiency of the cholinergic nervous function and the abnormal neuroinflammation are synergistically implicated in the pathogenesis of SAE. Thus, HupA is a potential therapeutic candidate for SAE, as it improves the deficient cholinergic nervous function and exerts anti-inflammatory action.