Selective blood-brain barrier permeabilization of brain metastases by a type 1 receptor-selective tumor necrosis factor mutein.

Background: Metastasis to the brain is a major challenge with poor prognosis. The blood-brain barrier (BBB) is a significant impediment to effective treatment, being intact during the early stages of tumor development and heterogeneously permeable at later stages. Intravenous injection of tumor necrosis factor (TNF) selectively induces BBB permeabilization at sites of brain micrometastasis, in a TNF type 1 receptor (TNFR1)-dependent manner.

The contribution of the acute phase response to the pathogenesis of relapse in chronic-relapsing experimental autoimmune encephalitis models of multiple sclerosis.

Background: Increased relapse rates in multiple sclerosis (MS) as a consequence of peripheral immune system activation, owing to infection for example, have been widely reported, but the mechanism remains unclear. Acute brain injury models can be exacerbated by augmenting the hepatic acute phase response (APR). Here, we explored the contribution of the hepatic APR to relapse in two rodent models of MS.

Covalent assembly of nanoparticles as a peptidase-degradable platform for molecular MRI.

Ligand-conjugated microparticles of iron oxide (MPIO) have the potential to provide high sensitivity contrast for molecular magnetic resonance imaging (MRI). However, the accumulation and persistence of non-biodegradable micron-sized particles in liver and spleen precludes their clinical use and limits the translational potential of MPIO-based contrast agents. Here we show that ligand-targeted MPIO derived from multiple iron oxide nanoparticles may be coupled covalently through peptide linkers that are designed to be cleaved by intracellular macrophage proteases.

The effect of B-cell depletion in the Theiler's model of multiple sclerosis.

B cell depletion (BCD) is being considered as a treatment for multiple sclerosis (MS), but there are many uncertainties surrounding the use of this therapy, such as its potential effect in individuals with concurrent viral infections. We sought to discover what effect BCD, induced by an anti-CD20 monoclonal antibody, would have on Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD). Mice were injected with the anti-CD20 monoclonal antibody 5D2, 14 days before or 14 days after infection with TMEV.

Viral pre-challenge increases central nervous system inflammation after intracranial interleukin-1β injection.

Introduction: Systemic inflammation has been shown to significantly worsen the outcome of neurological disease. However, after acute injuries to the brain both pre- and post-conditioning with bacterial endotoxin has been shown to reduce leukocyte recruitment to the CNS. Here, we sought to determine whether viral pre-challenge would have an effect on the outcome of acute CNS inflammation that was distinct from endotoxin.

Anti-IL-17A treatment reduces clinical score and VCAM-1 expression detected by in vivo magnetic resonance imaging in chronic relapsing EAE ABH mice.

IL-17 is argued to play an important role in the multiple sclerosis-like disease experimental autoimmune encephalitis (EAE). We investigated the therapeutic effects of anti-IL-17A in a chronic relapsing EAE ABH mouse model using conventional scoring, quantitative behavioral outcomes, and a novel vascular cell adhesion molecule 1 (VCAM-1)-targeted magnetic resonance imaging (MRI) contrast agent [anti-VCAM-microparticles of iron oxide (MPIO)] to identify conventionally undetectable neuropathology. Mice were administered prophylactic or treatment regimens of anti-IL-17A or IgG and two injections of anti-VCAM-MPIO before undergoing T2*-weighted three-dimensional and gadolinium-diethylenetriamine pentaacetic acid T1-weighted MRI.

VCAM-1-targeted magnetic resonance imaging reveals subclinical disease in a mouse model of multiple sclerosis.

Diagnosis of multiple sclerosis (MS) currently requires lesion identification by gadolinium (Gd)-enhanced or T(2)-weighted magnetic resonance imaging (MRI). However, these methods only identify late-stage pathology associated with blood-brain barrier breakdown. There is a growing belief that more widespread, but currently undetectable, pathology is present in the MS brain.

Sickness behaviour is induced by a peripheral CXC-chemokine also expressed in multiple sclerosis and EAE.

Non-CNS chemokine production may contribute to previously unrecognised components of Multiple Sclerosis (MS) pathology. Here we show that IL-8, a neutrophil chemoattractant, is significantly increased in serum from individuals with MS, and that the rodent homolog of IL-8 (CXCL1) is expressed in the liver in experimental autoimmune encephalomyelitis (EAE), a rodent model of MS. The hepatic expression of CXCL1 in EAE is accompanied by neutrophil recruitment to the liver, and we show that this recruitment is a feature of post mortem liver tissue from MS patients, which is a previously unrecognised phenomenon.

Comparison of MRI signatures in pattern I and II multiple sclerosis models.

The majority of individuals with multiple sclerosis (MS) exhibit T-cell- and macrophage-dominated lesions (patterns I and II; as opposed to III and IV). These lesions, in turn, may be distinguished on the basis of whether or not there are immunoglobulin and complement depositions at the sites of active myelin destruction; such depositions are found exclusively in pattern II lesions. The main aim of this study was to determine whether pattern I and pattern II MS lesions exhibit distinct MRI signatures.

Systemic inflammatory response reactivates immune-mediated lesions in rat brain.

The potential association between microbial infection and reactivation of a multiple sclerosis (MS) lesion is an important issue that remains unresolved, primarily because of the absence of suitable animal models and imaging techniques. Here, we have evaluated this question in an empirical manner using immunohistochemistry and magnetic resonance imaging (MRI), before and after the induction of a systemic inflammatory response in two distinct models of MS. In a pattern-II-type focal myelin oligodendrocyte glycoprotein-experimental autoimmune encephalomyelitis model, systemic endotoxin injection caused an increase in regional cerebral blood volume (rCBV) around the lesion site after 6 h, together with a reduction in the magnetization transfer ratio of the lesioned corpus callosum.

Glyconanoparticles allow pre-symptomatic in vivo imaging of brain disease.

Initial recruitment of leukocytes in inflammation associated with diseases such as multiple sclerosis (MS), ischemic stroke, and HIV-related dementia, takes place across intact, but activated brain endothelium. It is therefore undetectable to symptom-based diagnoses and cannot be observed by conventional imaging techniques, which rely on increased permeability of the blood-brain barrier (BBB) in later stages of disease. Specific visualization of the early-activated cerebral endothelium would provide a powerful tool for the presymptomatic diagnosis of brain disease and evaluation of new therapies.

Liver Kupffer cells control the magnitude of the inflammatory response in the injured brain and spinal cord.

The CNS inflammatory response is regulated by hepatic chemokine synthesis, which promotes leukocytosis and facilitates leukocyte recruitment to the site of injury. To understand the role of the individual cell populations in the liver during the hepatic response to acute brain injury, we selectively depleted Kupffer cells (KC), using clodronate-filled liposomes, and assessed the inflammatory response following a microinjection of IL-1beta into the rat brain or after a compression injury in the spinal cord. We show by immunohistochemistry that KC depletion reduces neutrophil infiltration into the IL-1beta-injected brain by 70% and by 50% into the contusion-injured spinal cord.

Hepatic nuclear factor kappa B regulates neutrophil recruitment to the injured brain.

Acute brain injury is associated with induction of hepatic chemokine expression, which is an essential element in the subsequent recruitment of leukocytes to the damaged brain. To further understand the significance of the hepatic inflammatory response, we focused on nuclear factor (NF)-kappa B, a pivotal regulator of inflammation. Nondestructive real-time whole-body imaging was undertaken in the 3XNF-kappa B-luciferase mouse to monitor NF-kappa B activation.

A contrast agent recognizing activated platelets reveals murine cerebral malaria pathology undetectable by conventional MRI.

Human and murine cerebral malaria are associated with elevated levels of cytokines in the brain and adherence of platelets to the microvasculature. Here we demonstrated that the accumulation of platelets in the brain microvasculature can be detected with MRI, using what we believe to be a novel contrast agent, at a time when the pathology is undetectable by conventional MRI. Ligand-induced binding sites (LIBS) on activated platelet glycoprotein IIb/IIIa receptors were detected in the brains of malaria-infected mice 6 days after inoculation with Plasmodium berghei using microparticles of iron oxide (MPIOs) conjugated to a single-chain antibody specific for the LIBS (LIBS-MPIO).

Immunomodulatory effects of etanercept in a model of brain injury act through attenuation of the acute-phase response.

TNF-alpha has proved to be a successful target in the treatment of many peripheral inflammatory diseases, but the same interventions worsen immune-mediated CNS disease. However, anti-TNF-alpha strategies may offer promise as therapy for non-immune CNS injury. In this study, we have microinjected IL-1beta or lipopolysaccharide (LPS) into the rat brain as a simple model of brain injury and have systemically administered the TNF-alpha antagonist etanercept to discover whether hepatic TNF-alpha, produced as part of the acute-phase response to CNS injury, modulates the inflammatory response in the brain.

Overexpression of IL-1beta by adenoviral-mediated gene transfer in the rat brain causes a prolonged hepatic chemokine response, axonal injury and the suppression of spontaneous behaviour.

Acute brain injury induces early and transient hepatic expression of chemokines, which amplify the injury response and give rise to movement of leukocytes into the blood and subsequently the brain and liver. Here, we sought to determine whether an ongoing injury stimulus within the brain would continue to drive the hepatic chemokine response and how it impacts on behaviour and CNS integrity. We generated chronic IL-1beta expression in rat brain by adenoviral-mediated gene transfer, which resulted in chronic leukocyte recruitment, axonal injury and prolonged depression of spontaneous behaviour.

Expanding the diversity of chemical protein modification allows post-translational mimicry.

One of the most important current scientific paradoxes is the economy with which nature uses genes. In all higher animals studied, we have found many fewer genes than we would have previously expected. The functional outputs of the eventual products of genes seem to be far more complex than the more restricted blueprint.

Post-conditioning with lipopolysaccharide reduces the inflammatory infiltrate to the injured brain and spinal cord: a potential neuroprotective treatment.

Systemic infection often accompanies or precedes acute brain injury, but it remains unclear how the systemic response contributes to outcome. To examine this problem we have microinjected recombinant interleukin-1beta (IL-1beta), a cytokine associated with acute brain injury, into the rat brain parenchyma and either preceded or followed this challenge with the intravenous injection of lipopolysaccharide (LPS), which mimics systemic inflammatory response syndrome. The microinjection of IL-1beta alone into the brain parenchyma gives rise to leukocyte mobilization in the blood, and to the delayed recruitment of neutrophils and monocytes to the brain with no evidence of blood-brain barrier breakdown or overt neuronal cell death.

Central nervous system injury triggers hepatic CC and CXC chemokine expression that is associated with leukocyte mobilization and recruitment to both the central nervous system and the liver.

The administration of interleukin-1beta to the brain induces hepatic CXC chemokine synthesis, which increases neutrophil levels in the blood, liver, and brain. We now show that such hepatic response is not restricted to the CXC chemokines. CCL-2, a CC chemokine, was released by the liver in response to a tumor necrosis factor (TNF)-alpha challenge to the brain and boosted monocyte levels.

Differential regulation of type I and type II interleukin-1 receptors in focal brain inflammation.

Most pathologies of the brain have an inflammatory component, associated with the release of cytokines such as interleukin-1beta (IL-1beta) from resident and infiltrating cells. The IL-1 type I receptor (IL-1RI) initiates a signalling cascade but the type II receptor (IL-1RII) acts as a decoy receptor. Here we have investigated the expression of IL-1beta, IL-1RI and IL-1RII in distinct inflammatory lesions in the rat brain.

The murine Cyp1a1 gene is expressed in a restricted spatial and temporal pattern during embryonic development.

In adult mice the cytochrome P450 Cyp1a1 gene is not constitutively expressed but is highly inducible by foreign compounds acting through the aryl hydrocarbon (Ah) receptor. However, the expression profile of the Cyp1a1 gene in the developing embryo is not well under-stood. Using established transgenic mouse lines where 8.

Study of cytokine induced neuropathology by high resolution proton NMR spectroscopy of rat urine.

Multiple sclerosis is a major cause of non-traumatic neurological disability. The identification of markers that differentiate disease progression is critical to effective therapy. A combination of NMR spectroscopic metabolic profiling of urine and statistical pattern recognition was used to detect focal inflammatory central nervous system (CNS) lesions induced by microinjection of a replication-deficient recombinant adenovirus expressing TNF-alpha or IL1-beta cDNA into the brains of Wistar rats.

Reduction of excitotoxicity and associated leukocyte recruitment by a broad-spectrum matrix metalloproteinase inhibitor.

An important step in the cascade leading to neuronal cell death is degradation of laminin and other components of the brain extracellular matrix by microglia-derived proteases. Excitotoxic cell death of murine hippocampal neurones in vivo can be prevented by inhibitors of tissue plasminogen activator (tPA) or by inhibitors of plasmin. Plasmin is a potent activator of the matrix metalloproteinases (MMPs), which are made by resident and recruited leukocytes following CNS injury.

Hdm2 recruits a hypoxia-sensitive corepressor to negatively regulate p53-dependent transcription.

The transcription factor p53 lies at the center of a protein network that controls cell cycle progression and commitment to apoptosis. p53 is inactive in proliferating cells, largely because of negative regulation by the Hdm2/Mdm2 oncoprotein, with which it physically associates. Release from this negative regulation is sufficient to activate p53 and can be triggered in cells by multiple stimuli through diverse pathways.

CINC-1 is an acute-phase protein induced by focal brain injury causing leukocyte mobilization and liver injury.

Following injury or infection, the liver releases acute-phase proteins (APP). After a severe focal injury, this systemic response can be excessive and may lead to multiorgan dysfunction (MODS). CINC-1 is a neutrophil chemoattractant, and we have now established that it also functions as an early APP after injury to the brain or to peripheral tissues.