Tumor necrosis factor-α-mediated threonine 435 phosphorylation of p65 nuclear factor-κB subunit in endothelial cells induces vasogenic edema and neutrophil infiltration in the rat piriform cortex following status epilepticus

<p>Abstract</p> <p>Background</p> <p>Status epilepticus (SE) induces severe vasogenic edema in the piriform cortex (PC) accompanied by neuronal and astroglial damages. To elucidate the mechanism of SE-induced vasogenic edema, we investigated the roles of tumor necrosis factor (TNF)-α in blood-brain barrier (BBB) disruption during vasogenic edema and its related events in rat epilepsy models provoked by pilocarpine-induced SE.</p> <p>Methods</p> <p>SE was induced by pilocarpine in rats that were intracerebroventricularly infused with saline-, and soluble TNF p55 receptor (sTNFp55R) prior to SE induction. Thereafter, we performed Fluoro-Jade B staining and immunohistochemical studies for TNF-α and NF-κB subunits.</p> <p>Results</p> <p>Following SE, most activated microglia showed strong TNF-α immunoreactivity. In addition, TNF p75 receptor expression was detected in endothelial cells as well as astrocytes. In addition, only p65-Thr435 phosphorylation was increased in endothelial cells accompanied by SMI-71 expression (an endothelial barrier antigen). Neutralization of TNF-α by soluble TNF p55 receptor (sTNFp55R) infusion attenuated SE-induced vasogenic edema and neuronal damages via inhibition of p65-Thr435 phosphorylation in endothelial cells. Furthermore, sTNFp55R infusion reduced SE-induced neutrophil infiltration in the PC.</p> <p>Conclusion</p> <p>These findings suggest that impairments of endothelial cell functions via TNF-α-mediated p65-Thr 485 NF-κB phosphorylation may be involved in SE-induced vasogenic edema. Subsequently, vasogenic edema results in extensive neutrophil infiltration and neuronal-astroglial loss.</p

Tissue-specific expression of the tight junction proteins claudins and occludin in the rat salivary glands

Tight junctions (TJs) are essential features of endothelial barrier membranes and of fluid-secreting epithelial cells, such as in the salivary glands. Novel integral membrane proteins have been identified as components of TJs, namely claudins and occludin. The aim of the present study was to determine the distribution of occludin and claudins in the large salivary glands of the rat. The parotid, submandibular and sublingual salivary glands were harvested from adult Sprague–Dawley rats and cryostat sections were stained using immunoperoxidase and immunofluorescence methods. Claudin-1 was expressed in endothelial cells of microvessels and in short selected segments of the duct system. Claudin-3 was expressed principally in the acinar cells and intercalated ducts, while claudin-4 was principally expressed by the striated and interlobular ducts. Claudin-5 was specific to endothelial cells of microvessels. Occludin was ubiquitously detected in the duct system. Double labelling and confocal microscopy showed some co-localization of claudin-3 with claudin-4, and minimal co-localization of occludin with claudin-4, in the striated ducts. Claudin 2 was not detected in any of the salivary glands. The results indicate specificity of the chemical composition of tight junctions in the rat salivary glands, and may reflect different physiological roles for TJs in the glandular and duct epithelial cells, and in endothelial cells of salivary gland microvessels

Expression of endothelial barrier antigen immunoreactivity in blood vessels following compression trauma in the rat spinal cord

Lu, Jianjun; Ghabriel, Mounir N.; Jones, Nigel Ronald; Blumbergs, Peter Charle

The blood-spinal cord barrier: Alteration of an endothelial cell protein rostral and caudal to cord compression

Lu, Jianjun; Ghabriel, Mounir N.; Jones, Nigel Ronald; Blumbergs, Peter Charle

Differential expression of an endothelial barrier antigen between the CNS and the PNS.

A monoclonal antibody to an antigen (EBA) expressed by neural endothelial cells (EC) was used to investigate any difference in the distribution of EBA between the CNS and PNS. Pre-embedding ultrastructural cytochemistry of rat sciatic and optic nerves was undertaken using anti-EBA, detected with a silver-enhanced gold-conjugated secondary antibody. LM immunocytochemical localisation of EBA was also performed using an HRP-conjugated secondary antibody. EC of pial and parenchymal optic nerve vessels were strongly immunopositive for EBA. Vessels of the dura were negative. At the EM level EBA was observed on the EC luminal surface. In contrast, EC of sciatic nerve were either negative or only weakly immunopositive. The molecular characteristics and function of EBA are largely unknown. Therefore the functional significance of the present findings remains to be determined

Early expression and cellular localization of proinflammatory cytokines interleukin-1[beta], interleukin-6, and tumor necrosis factor-[alpha] in human traumatic spinal cord injury

Study Design. Post-traumatic inflammatory response was studied in 11 human cases of acute spinal cord contusion injury. Objectives. To examine the inflammatory cellular response and the immunocytochemical expression and localization of interleukin-1[beta], internleukin-6, and tumor necrosis factor-[alpha]in human spinal cord after contusion injury. Summary of Background Data. The post-traumatic inflammatory response plays an important role in secondary injury mechanisms after spinal cord injury, and inter-leukin-1[beta], internleukin-6, and tumor necrosis factor-[alpha] are key inflammatory mediators. Methods. The study group comprised 11 patients with spinal cord contusion injury and 2 normal individuals. Histologic and immunocytochemical assessments were undertaken to evaluate the inflammatory cellular response and the immunoexpression of interleukin-1[beta], internleukin-6, and tumor necrosis factor-[alpha] in the injured human spinal cord. The cellular sources of interleukin-1[beta], internleukin-6, and tumor necrosis factor-[alpha] were elucidated by immunofluorescence double-labeled confocal imaging. Results. Increased immunoreactivity of interleukin-1[beta], internleukin-6, and tumor necrosis factor-[alpha]was detected in neurons 0.5 hour after injury, and in neurons and microglia 5 hours after injury, but the expression of these proinflammatory cytokines was short-lived and declined sharply to baseline by 2 days after injury. In the inflammatory cellular response, as early as 0.5 hour after spinal cord injury, activated microglia were detected, and axonal swellings and axons were surrounded by microglial processes. Numerous neutrophils appeared in the injured cord 1 day after injury, and then their number declined dramatically, whereas macrophages progressively increased after day 1. Conclusions: Endogenous cells (neurons and microglia) in the human spinal cord, not the blood-borne leukocytes, contribute to the early production of interleukin-1[beta], interleukin-6, and tumor necrosis factor-[alpha] in the post-traumatic inflammatory response, and microglia are involved the early response to traumatic axonal injury.Yang, Liqun; Blumbergs, Peter C.; Jones, Nigel R.; Manavis, Jim; Sarvestani, Ghafar T.; Ghabriel, Mounir N