Extravasated Brain-Reactive Autoantibodies Perturb Neuronal Surface Protein Expression in Alzheimer\u27s Pathology

Background: Increased blood-brain barrier (BBB) permeability is reported in both the neuropathological and in vivo studies in both Alzheimer’s Disease (AD) and age matched cognitively normal, no cognitive impairment (NCI), subjects. Impaired BBB allows various vascular components such as immunoglobulin G (IgG) to extravasate into the brain and specifically bind to various neuronal surface proteins (NSP), also known as brain reactive autoantibodies (BrABs). This interaction is predicted to further enhance deposition of amyloid plaques. Hypothesis: Interaction between extravasated BrABs and its cognate NSPs lower the expression of that NSPs in AD patients. Methods: We selected Western blotting technique to study the expression of various brain proteins and test our hypothesis. Fresh frozen brain samples of AD and NCI subjects were acquired, and total brain protein was extracted using protocol established in Acharya lab. We also identified various NSPs to study the impact of BrABs-NSPs interactions. Additionally, we investigated the expression of amyloid plaques ((amyloid precursor protein (APP)) and apoptosis (Caspase-3) markers. Specific NSPs examined included the alpha7 nicotinic acetylcholine receptor (α7nAChR) and anti-choline acetyltransferase (ChAT). To image the membranes, fluorescent imaging was used initially, which was later switched to chemiluminescence, after much troubleshooting. Results: Most of the work done through these experiments was focused on establishing a thorough Western blot protocol that can be used to reliably perform these experiments. This involved determining the appropriate primary and secondary antibodies concentrations, loading concentrations, and testing different imaging settings to determine the most ideal image-acquisition conditions. Towards the end of the fellowship, we were successful in developing a protocol to further explore our investigation. Using this protocol, we were able to visualize bands for ChAT, α7nAChR, and caspase – 3. Conclusions: Using this protocol further Western blot experiments can be run to study and compare the expression levels of various NSP in AD and control samples for testing our hypothesi

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

Schizophrenia (SZ) is one of the most severe forms of mental illness, yet mechanisms remain unclear. A widely established brain finding in SZ is hippocampal atrophy, and a coherent explanation similarly is lacking. Epidemiological evidence suggests increased cerebrovascular and cardiovascular complications in SZ independent of lifestyle and medication, pointing to disease-specific pathology. Endothelial cell contributions to blood-brain barrier (BBB) compromise may influence neurovascular unit and peripheral vascular function, and we hypothesize that downstream functional and structural abnormalities may be explained by impaired BBB

The Brodmann Area 39/40 of the Brain in Alzheimer’s, Mild Cognitive Impairment, and No Cognitive Impairment Subjects at Advanced Age Demonstrate Comparable Levels of Blood-Brain Barrier Breach

• Alzheimer’s disease (AD) is one of the most common form of dementia • Mild cognitive impairment (MCI), specifically amnestic subtype, more likely to progress to AD • Pathogenesis Theories: o Accumulation of amyloid-beta peptides and neurofibrillary tangles containing hyperphosphorylated neuronal tau protein o Blood Brain Barrier (BBB) dysfunction is associated with AD pathogenesis • Brodmann area 39/40: regions of parietal cortex are responsible for language, spatial cognition, memory retrieval, attention, phonological processing, and emotional processing • Hypothesis: An increased BBB permeability in Brodmann area 39/40 of AD and age-matched MCI and no cognitive impairment (NCI) subject

A Preliminary Report on the Role of Lipoxin A4 in Reinstating the Blood-Brain Barrier Integrity in a Rodent Model of Acute Inflammation with Impaired Cerebrovasculature

Background: The blood-brain barrier (BBB) is responsible for maintaining brain homeostasis and ultimately proper neuronal function. Disruption of the BBB, leading to increased BBB permeability, has been reported in several neurodegenerative diseases, including Alzheimer’s disease (AD) and traumatic brain injury (TBI). Lipoxins (LXs) are a class of arachidonate-derived eicosanoids, which are a class of specialized pro-resolving lipid mediators (SPMs). SPMs are known to inhibit immune response through inhibition of cellular infiltration, downregulation of pro-inflammatory mediators and upregulation of anti-inflammatory mediators. Hence, LXs are recognized as “breaking signals” in the inflammatory process. One form of LXs, Lipoxin A4 (LXA4), has been found to decreased production of proinflammatory mediators, inhibit neutrophils chemotaxis and infiltration to the site of injury, and promote the phagocytic clearance of debris by macrophages. Therefore, LXA4 serves a critical role in resolution of inflammatory process by regulating the activation of monocytes and modulating the generation of reactive oxygen species (ROS). Hypothesis: LXA4 treatment reinstates the BBB integrity in a rodent model of acute BBB breakdown and inflammation. Methods: Nine-month-old female Sprague Dawley rats were given an intravenous (IV) injection of 15 mg/kg lipopolysaccharide (LPS) through the tail for inducing acute inflammation and BBB breach. After three hours, the rats were injected with 9 µg/kg LXA4 or Saline (Vehicle control). Four treatment groups were thus developed: LPS only, LPS/LXA4, LXA4 only, and Saline only. Animals were euthanized at 24 hours of LPS treatment and brain samples were processed for paraffin-embedded sections and immunohistochemistry. Sections comprising of hippocampus and cortical regions were selected for detection of impaired BBB as demonstrated by the extravasation of immunoglobulin G (IgG) and IBA1 (microgliosis marker). The area of the cerebral cortex and number of cortical blood vessels presenting with IgG extravasation were estimated and compared between treatment groups. Similarly, IBA1 immunoreactivity was quantified using Color Deconvolution V9 tool of Aperio ImageScope (Leica BIOSYSTEMS). Results: LXA4 treatment following LPS injection demonstrated decrease in the extent of IgG leak compared to LPS only group. Likewise, we observed significant decrease in microgliosis in LPS-LXA4 group compared to LPS only. Conclusion: These preliminary results demonstrate potential beneficial effects of LXA4 in reinstating BBB integrity and reducing neuroinflammation in rat model of acute BBB breach and inflammation

Alpha 7 Nicotinic Acetylcholine Receptor Expression in the Hippocampus of Patients with Schizophrenia

Background: Schizophrenia (SZ) is a heterogenous psychiatric condition characterized by disruptions in cognition, social activity, affect, and perception often associated with a varied combination of positive and negative symptoms. The pathophysiology behind SZ remains poorly elucidated. Earlier reports have cited the importance of the alpha 7 nicotinic acetylcholine receptors (α7nAChR) in the hippocampus and the receptor’s association with auditory sensory gating and cognitive function. Specifically, variations in the expression and functionality of α7nAChR can be linked to auditory hallucinations experienced by patients with SZ and several therapies have been researched that target α7nAChRs. However, there are very few primary research articles that directly measure α7nAChR expression in the hippocampus of patients with SZ. Earlier reports have used an indirect method of α-bungarotoxin labeling for investigating α7nAChR expression and failed to provide conclusive data. Therefore, a need was established to directly measure α7nAChR expression in the hippocampus and surrounding temporal cortex of patients with SZ. Methods: We obtained formalin-fixed paraffin-embedded postmortem brain samples from the hippocampus and surrounding temporal cortex from subjects with SZ (n=19) and age-matched controls (n=24) from the Maryland Brain Collection and NIH NeuroBioBank. We are using an immunohistochemistry (IHC) approach, and the sections were probed with anti-α7nAChR antibodies. We have scanned the slides using an Aperio Slide Scanner at 20X (Leica BIOSYSTEMS). Next, we performed a semi-quantitative image analysis utilizing Color Deconvolution V9 tool (Aperio ImageScope, Leica BIOSYSTEMS) to develop color deconvolution heat maps for IHC images. The extent of α7nAChR immunoreactivity was compared between the SZ and age-matched control groups. Hypothesis: The expression of α7nAChR in the hippocampus is perturbed in SZ compared to age-matched controls. Results: A semi-quantitative analysis of the IHC data shows an increase in α7nAChR expression in the SZ samples compared to age-matched controls. Conclusion: Our semi-quantitative data with a small sample size suggests perturbed α7nAChR expression in patients with SZ and therein, its potential role in mediating SZ-related pathophysiological and behavioral changes

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\u27s 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\u27s 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. Acquisition of learned behaviors and long-term retention were assessed via a battery of cognitive and behavioral tests and linked to neuropathological changes. RESULTS: Mice injected with both PT and Aβ42 demonstrated a preferential deficit in the capacity for long-term retention and an increased susceptibility to interference in selective attention compared to mice exposed to PT or saline only. Immunohistochemical analyses revealed increased BBB permeability and entry of bloodborne Aβ42 and immunoglobulin G (IgG) into the brain parenchyma, selective neuronal binding of IgG and neuronal accumulation of Aβ42 in animals injected with both PT and Aβ42 compared to controls. CONCLUSION: Results highlight the potential synergistic role of BBB compromise and the influx of bloodborne Aβ42 into the brain in both the initiation and progression of neuropathologic and cognitive changes associated with AD

Beyond the Stalemate of Economics versus Ethics: Corporate Social Responsibility and the Discourse of the Organizational Self

The purpose of this paper is to advance research on CSR beyond the stalemate of economic versus ethical models by providing an alternative perspective integrating existing views and allowing for more shared dialog and research in the field. It is suggested that we move beyond making a normative case for ethical models and practices of CSR by moving beyond the question of how to manage organizational self-interest toward the question of how accurate current conceptions of the organizational self seem to be. Specifically, it is proposed that CSR is not a question of how self-interested the corporation should be, but how this self is defined. Economic and ethical models of CSR are not models of opposition but exist on a continuum between egoic and post-egoic, illusory and authentic conceptions of the organizational self. This means that moving from one to the other is not a question of adopting different paradigms but rather of moving from illusion and dysfunction to authenticity and functionality, from pathology to health. Copyright Springer 2006corporate social responsibility, economic and ethical models, economic, egoic and post-egoic approaches, narratives, organizational self, psychoanalysis,