A Chronic Increase in Blood-Brain Barrier Permeability Facilitates Intraneuronal Deposition of Exogenous Bloodborne Amyloid-Beta1-42 Peptide in the Brain and Leads to Alzheimer's Disease-Relevant Cognitive Changes in a Mouse Model.

Background: Increased blood-brain barrier (BBB) permeability and amyloid-β (Aβ) peptides (especially Aβ1-42) (Aβ42) have been linked to Alzheimer's disease (AD) pathogenesis, but the nature of their involvement in AD-related neuropathological changes leading to cognitive changes remains poorly understood.

Objective: To test the hypothesis that chronic extravasation of bloodborne Aβ42 peptide and brain-reactive autoantibodies and their entry into the brain parenchyma via a permeable BBB contribute to AD-related pathological changes and cognitive changes in a mouse model.

Methods: The BBB was rendered chronically permeable through repeated injections of Pertussis toxin (PT), and soluble monomeric, fluorescein isothiocyanate (FITC)-labeled or unlabeled Aβ42 was injected into the tail-vein of 10-month-old male CD1 mice at designated intervals spanning ∼3 months.

A Preliminary Report: The Hippocampus and Surrounding Temporal Cortex of Patients With Schizophrenia Have Impaired Blood-Brain Barrier.

Though hippocampal volume reduction is a pathological hallmark of schizophrenia, the molecular pathway(s) responsible for this degeneration remains unknown. Recent reports have suggested the potential role of impaired blood-brain barrier (BBB) function in schizophrenia pathogenesis. However, direct evidence demonstrating an impaired BBB function is missing.

Evidence that Brain-Reactive Autoantibodies Contribute to Chronic Neuronal Internalization of Exogenous Amyloid-β1-42 and Key Cell Surface Proteins During Alzheimer's Disease Pathogenesis.

Blood-brain barrier (BBB) permeability is a recognized early feature of Alzheimer's disease (AD). In the present study, we examined consequences of increased BBB permeability on the development of AD-related pathology by tracking selected leaked plasma components and their interactions with neurons in vivo and in vitro. Histological sections of cortical regions of postmortem AD brains were immunostained to determine the distribution of amyloid-β1-42 (Aβ42), cathepsin D, IgG, GluR2/3, and alpha7 nicotinic acetylcholine receptor (α7nAChR).

Retinal pathology is associated with increased blood-retina barrier permeability in a diabetic and hypercholesterolaemic pig model: Beneficial effects of the LpPLA inhibitor Darapladib.

Using a porcine model of diabetes mellitus and hypercholesterolaemia, we previously showed that diabetes mellitus and hypercholesterolaemia is associated with a chronic increase in blood-brain barrier permeability in the cerebral cortex, leading to selective binding of immunoglobulin G and deposition of amyloid-beta peptide in pyramidal neurons. Treatment with Darapladib (GlaxoSmithKline, SB480848), an inhibitor of lipoprotein-associated phospholipase-A2, alleviated these effects. Here, investigation of the effects of chronic diabetes mellitus and hypercholesterolaemia on the pig retina revealed a corresponding increased permeability of the blood-retina barrier coupled with a leak of plasma components into the retina, alterations in retinal architecture, selective IgG binding to neurons in the ganglion cell layer, thinning of retinal layers due to cell loss and increased glial fibrillary acidic protein expression in Müller cells, all of which were curtailed by treatment with Darapladib.

Mechanical stress regulates transport in a compliant 3D model of the blood-brain barrier.

Transport of fluid and solutes is tightly controlled within the brain, where vasculature exhibits a blood-brain barrier and there is no organized lymphatic network facilitating waste transport from the interstitial space. Here, using a compliant, three-dimensional co-culture model of the blood-brain barrier, we show that mechanical stimuli exerted by blood flow mediate both the permeability of the endothelial barrier and waste transport along the basement membrane. Application of both shear stress and cyclic strain facilitates tight junction formation in the endothelial monolayer, with and without the presence of astrocyte endfeet in the surrounding matrix.

Detection of Alzheimer's disease at mild cognitive impairment and disease progression using autoantibodies as blood-based biomarkers.

Introduction: There is an urgent need to identify biomarkers that can accurately detect and diagnose Alzheimer's disease (AD). Autoantibodies are abundant and ubiquitous in human sera and have been previously demonstrated as disease-specific biomarkers capable of accurately diagnosing mild-moderate stages of AD and Parkinson's disease.

Methods: Sera from 236 subjects, including 50 mild cognitive impairment (MCI) subjects with confirmed low CSF Aβ42 levels, were screened with human protein microarrays to identify potential biomarkers for MCI.

Potential utility of autoantibodies as blood-based biomarkers for early detection and diagnosis of Parkinson's disease.

Introduction: There is a great need to identify readily accessible, blood-based biomarkers for Parkinson's disease (PD) that are useful for accurate early detection and diagnosis. This advancement would allow early patient treatment and enrollment into clinical trials, both of which would greatly facilitate the development of new therapies for PD.

Methods: Sera from a total of 398 subjects, including 103 early-stage PD subjects derived from the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) study, were screened with human protein microarrays containing 9,486 potential antigen targets to identify autoantibodies potentially useful as biomarkers for PD.

Sevoflurane and Isoflurane induce structural changes in brain vascular endothelial cells and increase blood-brain barrier permeability: Possible link to postoperative delirium and cognitive decline.

A large percentage of patients subjected to general anesthesia at 65 years and older exhibit postoperative delirium (POD). Here, we test the hypothesis that inhaled anesthetics (IAs), such as Sevoflurane and Isoflurane, act directly on brain vascular endothelial cells (BVECs) to increase blood-brain barrier (BBB) permeability, thereby contributing to POD. Rats of young (3-5 months), middle (10-12 months) and old (17-19 months) ages were anesthetized with Sevoflurane or Isoflurane for 3h.

Natural IgG autoantibodies are abundant and ubiquitous in human sera, and their number is influenced by age, gender, and disease.

The presence of self-reactive IgG autoantibodies in human sera is largely thought to represent a breakdown in central tolerance and is typically regarded as a harbinger of autoimmune pathology. In the present study, immune-response profiling of human serum from 166 individuals via human protein microarrays demonstrates that IgG autoantibodies are abundant in all human serum, usually numbering in the thousands. These IgG autoantibodies bind to human antigens from organs and tissues all over the body and their serum diversity is strongly influenced by age, gender, and the presence of specific diseases.

Diabetes and hypercholesterolemia increase blood-brain barrier permeability and brain amyloid deposition: beneficial effects of the LpPLA2 inhibitor darapladib.

Diabetes mellitus (DM) and hypercholesterolemia (HC) have emerged as major risk factors for Alzheimer's disease, highlighting the importance of vascular health to normal brain functioning. Our previous study showed that DM and HC favor the development of advanced coronary atherosclerosis in a porcine model, and that treatment with darapladib, an inhibitor of lipoprotein-associated phospholipase A2, blocks atherosclerosis progression and improves animal alertness and activity levels. In the present study, we examined the effects of DM and HC on the permeability of the blood-brain barrier (BBB) using immunoglobulin G (IgG) as a biomarker.

Plant lectin can target receptors containing sialic acid, exemplified by podoplanin, to inhibit transformed cell growth and migration.

Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets.

Neuronal PAD4 expression and protein citrullination: possible role in production of autoantibodies associated with neurodegenerative disease.

Peptidyl arginine deiminases (PADs) catalyze a post-translational protein modification reaction called citrullination, where arginine is converted to citrulline. This modification has been linked to the pathogenesis of autoimmune diseases including rheumatoid arthritis (RA). More recently, several studies have suggested that Alzheimer's disease (AD), a devastating neurodegenerative disorder, may have an autoimmune component.

Prenatal cocaine exposure increases synaptic localization of a neuronal RasGEF, GRASP-1 via hyperphosphorylation of AMPAR anchoring protein, GRIP.

Prenatal cocaine exposure causes sustained phosphorylation of the synaptic anchoring protein, glutamate receptor interacting protein (GRIP1/2), preventing synaptic targeting of the GluR2/3-containing alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors (AMPARs; J. Neurosci. 29: 6308-6319, 2009).

Brain-reactive autoantibodies prevalent in human sera increase intraneuronal amyloid-β(1-42) deposition.

Previous studies have reported immunoglobulin-positive neurons in Alzheimer's disease (AD) brains, an observation indicative of blood-brain barrier (BBB) breakdown. Recently, we demonstrated the nearly ubiquitous presence of brain-reactive autoantibodies in human sera. The significance of these observations to AD pathology is unknown.

Prenatal cocaine reduces AMPA receptor synaptic expression through hyperphosphorylation of the synaptic anchoring protein GRIP.

Prenatal cocaine exposure produces sustained neurobehavioral and brain synaptic changes closely resembling those of animals with defective AMPA receptors (AMPARs). We hypothesized that prenatal cocaine exposure attenuates AMPAR signaling by interfering with AMPAR synaptic targeting. AMPAR function is governed by receptor cycling on and off the synaptic membrane through its interaction with glutamate receptor-interacting protein (GRIP), a PDZ domain protein that is regulated by reversible phosphorylation.

Alpha7 nicotinic acetylcholine receptor expression by vascular smooth muscle cells facilitates the deposition of Abeta peptides and promotes cerebrovascular amyloid angiopathy.

Deposition of beta-amyloid (Abeta) peptides in the walls of brain blood vessels, cerebral amyloid angiopathy (CAA), is common in patients with Alzheimer's disease (AD). Previous studies have demonstrated Abeta peptide deposition among vascular smooth muscle cells (VSMCs), but the source of the Abeta and basis for its selective deposition in VSMCs are unknown. In the present study, we examined the deposition patterns of Abeta peptides, Abeta40 and Abeta42, within the cerebrovasculature of AD and control patients using single- and double-label immunohistochemistry.

Abeta peptides can enter the brain through a defective blood-brain barrier and bind selectively to neurons.

We have investigated the possibility that soluble, blood-borne amyloid beta (Abeta) peptides can cross a defective blood-brain barrier (BBB) and interact with neurons in the brain. Immunohistochemical analyses revealed extravasated plasma components, including Abeta42 in 19 of 21 AD brains, but in only 3 of 13 age-matched control brains, suggesting that a defective BBB is common in AD. To more directly test whether blood-borne Abeta peptides can cross a defective BBB, we tracked the fate of fluorescein isothiocyanate (FITC)-labeled Abeta42 and Abeta40 introduced via tail vein injection into mice with a BBB rendered permeable by treatment with pertussis toxin.

Affinity purification and comparative analysis of two distinct human uracil-DNA glycosylases.

Evidence is presented on two forms of uracil-DNA glycosylase (UDG1 and UDG2) that exist in human cells. We have developed an affinity technique to isolate uracil-DNA glycosylases from HeLa cells. This technique relies on the use of a uracil-DNA glycosylase inhibitor (Ugi) produced by the Bacillus subtilis bacteriophage, PBS2.

Intrinsic and extrinsic factors collaborate to generate driving forces for neural tube formation in the chick: a study using morphometry and computerized three-dimensional reconstruction.

The formation of the neural tube, the rudiment of the entire central nervous system, is one of the earliest morphogenetic movements. The origin of the driving forces for this process remains uncertain, but recent studies suggest the involvement of both intrinsic and extrinsic factors. In the present study, we have used morphometry, analysis of stereopair photographs of whole embryos, and computerized three-dimensional reconstruction to investigate the factors which constitute the bulk of the driving forces for neural tube formation in the developing midbrain of Hamburger and Hamilton stages 5-9 chick embryos.

Biomechanical basis of diazepam-induced neural tube defects in early chick embryos: a morphometric study.

The biomechanical basis of diazepam (Valium/Roche)-induced neural tube defects in the chick was investigated using a combination of electron microscopy and morphometry. Embryos at stage 8 (four-somite stage) of development were explanted and grown for 6 hr in nutrient medium containing 400 micrograms/ml diazepam. Nearly 80% of these embryos exhibited neural tube defects that were most pronounced in the forming midbrain region and typified by a "relaxation" or "collapse" of neural folds.

Immunoelectron microscopic localization of actin in neurites of cultured embryonic chick dorsal root ganglia: actin is a component of granular, microtubule-associated crossbridges.

Axons have been shown to contain substantial quantities of actin distributed along their length. However, the general lack of information on the structure and organizational state of this protein in axons has made it difficult to assign it a functional role. In the present study, we used electron microscopic immunocytochemistry (immunogold labeling) on neurites from cultured embryonic chick dorsal root ganglia to: (1) determine the distribution of actin in neurites: (2) identify actin-containing structures; and (3) reveal whether or not actin is associated preferentially with microtubules.

A method for preparing quick-frozen, freeze-substituted cells for transmission electron microscopy and immunocytochemistry.

A quick-freeze, freeze-substitution method is described which employs glutaraldehyde as well as osmium tetroxide (OsO4) in a 'double-fixation' protocol comparable to that used for conventional transmission electron microscopy. Cultured cells are quick-frozen in Freon 22 and freeze-substituted in an ethanolic solution of glutaraldehyde. Specimens destined for TEM are postfixed in OsO4 in acetone, embedded in Epon-Araldite, and sectioned.

Diazepam inhibits neurulation through its action on myosin-containing microfilaments in early chick embryos.

Diazepam (Valium/Roche) inhibited the morphogenesis of explanted stage 8 chick embryos in a dose-related manner. Diazepam, at concn of 400-500 micrograms/ml, preferentially inhibited closure of the neural tube. This inhibition was accompanied by a significant reduction in myosin content of the developing neuroepithelium.

Studies on the mechanisms of neurulation in the chick: possible involvement of myosin in elevation of neural folds.

The possible involvement of myosin in elevation of neural folds in the chick was studied. Indirect immunofluorescence revealed the presence of myosin in the neuroepithelium as early as the neural-plate stage and was concentrated in the apical regions of neuroepithelial cells where microfilaments are known to be organized into discrete bundles. This fluorescent pattern persisted until closure of the neural tube.