Regulation of inflammatory transcription factors by heat shock protein 70 in primary cultured astrocytes exposed to oxygen–glucose deprivation

Inflammation is an important event in ischemic injury. These immune responses begin with the expression of pro-inflammatory genes modulating transcription factors, such as nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and signal transducers and activator of transcription-1 (STAT-1). The 70-kDa heat shock protein (Hsp70) can both induce and arrest inflammatory reactions and lead to improved neurological outcome in experimental brain injury and ischemia. Since Hsp70 are induced under heat stress, we investigated the link between Hsp70 neuroprotection and phosphorylation of inhibitor of κB (IκB), c-Jun N-terminal kinases (JNK) and p38 through co-immunoprecipitation and enzyme-linked immunosorbent assay (ELISA) assay. Transcription factors and pro-inflammatory genes were quantified by immunoblotting, electrophoretic-mobility shift assay and reverse transcription-polymerase chain reaction assays. The results showed that heat stress led to Hsp70 overexpression which rendered neuroprotection after ischemia-like injury. Overexpression Hsp70 also interrupts the phosphorylation of IκB, JNK and p38 and blunts DNA binding of their transcription factors (NF-κB, AP-1 and STAT-1), effectively downregulating the expression of pro-inflammatory genes in heat-pretreated astrocytes. Taken together, these results suggest that overexpression of Hsp70 may protect against brain ischemia via an anti-inflammatory mechanism by interrupting the phosphorylation of upstream of transcription factors

Innate Inflammatory Responses in Stroke: Mechanisms and Potential Therapeutic Targets

Stroke is a frequent cause of long-term disability and death worldwide. Ischemic stroke is more commonly encountered compared to hemorrhagic stroke, and leads to tissue death by ischemia due to occlusion of a cerebral artery. Inflammation is known to result as a result of ischemic injury, long thought to be involved in initiating the recovery and repair process. However, work over the past few decades indicates that aspects of this inflammatory response may in fact be detrimental to stroke outcome. Acutely, inflammation appears to have a detrimental effect, and anti-inflammatory treatments have been been studied as a potential therapeutic target. Chronically, reports suggest that post-ischemic inflammation is also essential for the tissue repairing and remodeling. The majority of the work in this area has centered around innate immune mechanisms, which will be the focus of this review. This review describes the different key players in neuroinflammation and their possible detrimental and protective effects in stroke. A better understanding of the roles of the different immune cells and their temporal profile of damage versus repair will help to clarify more effective modulation of inflammation post stroke. Introduction Stroke refers to conditions caused by occlusion and/or rupture of blood vessels in the brain, and is a leading cause of death and disability in the industrialized world

Effects of high dose of simvastatin on levels of dopamine and its reuptake in prefrontal cortex and striatum among SD rats

10.1016/j.neulet.2006.09.009Neuroscience Letters4083189-193NELE