Faculty Bibliography

To test the hypothesis that developmental anomalies of the corpus callosum (CC), contribute to the pathogenesis of autism, we characterized the type, topography, and severity of CC pathology corresponding to reduced CC areas that are detected by magnetic resonance imaging in the brains of 11 individuals with autism and 11 controls. In the brains of 3 autistic subjects, partial CC agenesis resulted in complete or partial lack of interhemispheric axonal connections in CC segments III-V. In these cases, a combination of focal agenesis and uniform axonal deficit caused reduction of CC areas by 37%, of axon numbers by 62%, and of the numerical density of axons by 39%. In the CC of 8 autistic subjects without agenesis, there was an 18% deficit of the midsagittal CC area, 48.4% deficit of axon numbers, and 37% reduction of the numerical density of axons. The significantly thinner CC, reduced CC area, and uniform axonal deficit in all autistic subjects were classified as CC hypoplasia. Thus, the byproduct of partial CC agenesis and hypoplasia is reduction of axonal connections between cortical areas known to be involved in behavioral alterations observed in people with autism.

Rapidly progressive Alzheimer's disease (rpAD) is a particularly aggressive form of Alzheimer's disease, with a median survival time of 7-10 months after diagnosis. Why these patients have such a rapid progression of Alzheimer's disease is currently unknown. To further understand pathological differences between rpAD and typical sporadic Alzheimer's disease (sAD) we used localized proteomics to analyze the protein differences in amyloid plaques in rpAD and sAD. Label-free quantitative LC-MS/MS was performed on amyloid plaques microdissected from rpAD and sAD patients (n = 22 for each patient group) and protein expression differences were quantified. On average, 913 +/- 30 (mean +/- SEM) proteins were quantified in plaques from each patient and 279 of these proteins were consistently found in plaques from every patient. We found significant differences in protein composition between rpAD and sAD plaques. We found that rpAD plaques contained significantly higher levels of neuronal proteins (p = 0.0017) and significantly lower levels of astrocytic proteins (p = 1.08 x 10-6). Unexpectedly, cumulative protein differences in rpAD plaques did not suggest accelerated typical sAD. Plaques from patients with rpAD were particularly abundant in synaptic proteins, especially those involved in synaptic vesicle release, highlighting the potential importance of synaptic dysfunction in the accelerated development of plaque pathology in rpAD. Combined, our data provide new direct evidence that amyloid plaques do not all have the same protein composition and that the proteomic differences in plaques could provide important insight into the factors that contribute to plaque development. The cumulative protein differences in rpAD plaques suggest rpAD may be a novel subtype of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by the presence of parenchymal amyloid-beta (Abeta) plaques, cerebral amyloid angiopathy (CAA) and neurofibrillary tangles. Currently there are no effective treatments for AD. Immunotherapeutic approaches under development are hampered by complications related to ineffectual clearance of CAA. Genome-wide association studies have demonstrated the importance of microglia in AD pathogenesis. Microglia are the primary innate immune cells of the brain. Depending on their activation state and environment, microglia can be beneficial or detrimental. In our prior work, we showed that stimulation of innate immunity with Toll-like receptor 9 agonist, class B CpG (cytosine-phosphate-guanine) oligodeoxynucleotides (ODNs), can reduce amyloid and tau pathologies without causing toxicity in Tg2576 and 3xTg-AD mouse models. However, these transgenic mice have relatively little CAA. In the current study, we evaluated the therapeutic profile of CpG ODN in a triple transgenic mouse model, Tg-SwDI, with abundant vascular amyloid, in association with low levels of parenchymal amyloid deposits. Peripheral administration of CpG ODN, both before and after the development of CAA, negated short-term memory deficits, as assessed by object-recognition tests, and was effective at improving spatial and working memory evaluated using a radial arm maze. These findings were associated with significant reductions of CAA pathology lacking adverse effects. Together, our extensive evidence suggests that this innovative immunomodulation may be a safe approach to ameliorate all hallmarks of AD pathology, supporting the potential clinical applicability of CpG ODN. SIGNIFICANCE STATEMENT: Recent genetic studies have underscored the emerging role of microglia in Alzheimer's disease (AD) pathogenesis. Microglia lose their amyloid-beta-clearing capabilities with age and as AD progresses. Therefore, the ability to modulate microglia profiles offers a promising therapeutic avenue for reducing AD pathology. Current immunotherapeutic approaches have been limited by poor clearance of a core AD lesion, cerebral amyloid angiopathy (CAA). The present study used Tg-SwDI mice, which have extensive CAA. We found that stimulation of the innate immune system and microglia/macrophage activation via Toll-like receptor 9 using CpG (cytosine-phosphate-guanine) oligodeoxynucleotides (ODNs) leads to cognitive improvements and CAA reduction, without associated toxicity. Our data indicate that this novel concept of immunomodulation represents a safer method to reduce all aspects of AD pathology and provide essential information for potential clinical use of CpG ODN.

Experimental models of Alzheimer's disease (AD) are critical to gaining a better understanding of pathogenesis and to assess the potential of novel therapeutic approaches. The most commonly used experimental animal models are transgenic mice that overexpress human genes associated with familial AD (FAD) that result in the formation of amyloid plaques. However, AD is defined by the presence and interplay of both amyloid plaques and neurofibrillary tangle pathology. The track record of success in AD clinical trials thus far has been very poor. In part, this high failure rate has been related to the premature translation of highly successful results in animal models that mirror only limited aspects of AD pathology to humans. A greater understanding of the strengths and weakness of each of the various models and the use of more than one model to evaluate potential therapies would help enhance the success of therapy translation from preclinical studies to patients. In this review, we summarize the pathological features and limitations of the major experimental models of AD, including transgenic mice, transgenic rats, various physiological models of sporadic AD and in vitro human cell culture models.

INTRODUCTION: Alzheimer's disease (AD) is the most common cause of dementia. The search for new treatments is made more urgent given its increasing prevalence resulting from the aging of the global population. Over the past two decades, stem cell technologies have become an increasingly attractive option to both study and potentially treat neurodegenerative diseases. Several investigators reported a beneficial effect of different types of stem or progenitor cells on the pathology and cognitive function in AD models. Mouse models are among the most important research tools for AD treatment discovery. We aimed to explore the possible therapeutic potential of human umbilical cord mesenchymal stem cell xenografts in a transgenic (Tg) mouse model of AD. METHODS: APP/PS1 Tg AD model mice received human umbilical cord stem cells, directly injected into the carotid artery. To test the efficacy of the umbilical cord stem cells in this AD model, behavioral tasks (sensorimotor and cognitive tests) and immunohistochemical quantitation of the pathology was performed. RESULTS: Treatment of the APP/PS1 AD model mice, with human umbilical cord stem cells, produced a reduction of the amyloid beta burden in the cortex and the hippocampus which correlated with a reduction of the cognitive loss. CONCLUSION: Human umbilical cord mesenchymal stem cells appear to reduce AD pathology in a transgenic mouse model as documented by a reduction of the amyloid plaque burden compared to controls. This amelioration of pathology correlates with improvements on cognitive and sensorimotor tasks.

In the USA, between w250,000 e 400,000 individuals have Down syn-drome, and nearly all of them will develop Alzheimer's disease pathology starting in their 30s. By age 70, 50-70% will have dementia. There are numerous pathogenic and mechanistic links between the two disorders. Individuals with DS comprise a potential ideal population for AD clinical trials. The presence of AD pathology in DS has led to greater collaborative research toward the parallel goals of providing effective treatment for individuals with DS and AD, as well as, expediting AD drug development. Similarities and differences between DS and AD will be reviewed. Examples of immunomodulatory and other therapeutic strategies that may benefit both DS and AD will be presented. Over-dosage of the amyloid precursor protein (APP) is believed to be responsible for the high incidence of early-onset AD-like amyloidosis observed in DS patients. APP is cleaved by the sequential proteolytic activity of the B-secretase and the g-secretase complex which is responsible for the formation of amyloid b (Ab). Since activation of the g-secretase complex is the required final step for the formation of Ab, there has been a tremendous effort to develop drugs that block this complex activity as a disease-modifying therapeutic approach for lowering Ab levels. The g-secretase activating protein (GSAP) is a newly recognized protein derived from a larger precursor molecule via a caspase-3-dependent proteolytic cleavage, which by directly interacting with key components of the g-secretase complex acts as a rate-limiting step in Ab formation. Evidence suggests that GSAP is increased in post-mortem brain tissues of AD patients, and its inhibition leads to reduction of AD pathology in transgenic mouse models. Our recent evidence shows that in health control DS brains there is a significant elevation of GSAP protein and mRNA. Targeting of g-secretase as an AD therapy is problematic as it has multiple substrates including Notch. GSAP interacts with g-secretase to enhance Ab production, without affecting Notch. Pharmacological targeting of GSAP is a potentially important therapeutic approach for both DS and AD pathology

BACKGROUND: Peripheral surgical trauma may incite neuroinflammation that leads to neuronal dysfunction associated with both depression and cognitive deficits. In a previous study, we found that adult mice developed neuroinflammation and short-term working memory dysfunction in a delayed, transient manner after splenectomy that was ameliorated by the cyclooxygenase-2 inhibitor meloxicam. We tested the hypothesis that splenectomy in mice would also cause anhedonia, the diminished response to pleasure or rewarding stimuli that is a hallmark of depression, and that treatment with meloxicam would be ameliorative. METHODS: After Institutional Animal Care and Use Committee approval, Swiss-Webster mice underwent sucrose preference training before being randomized into groups on day 0, when they had either splenectomy and anesthesia or anesthesia alone. Within each group, half were randomized to receive intraperitoneal saline at 24 hours, while the other half received intraperitoneal meloxicam at 24 hours. Sucrose preference ratios were determined on days 1, 5, 9, and 14. Additional mice were randomized into groups for brain histochemistry. Specimens were stained for glial fibrillary acidic protein (GFAP), a marker of astrocytes, and CD45, a protein tyrosine phosphatase that identifies microglial activation. RESULTS: On day 5, mice receiving splenectomy and saline demonstrated diminished sucrose preference, which was not seen in mice receiving splenectomy and meloxicam. Semiquantitative analysis of histological slides taken from splenectomized mice treated with meloxicam revealed reduced microglial-based neuroinflammation and reactive astrocytosis compared to mice receiving saline. CONCLUSION: Splenectomy in mice is associated with neuroinflammation and anhedonia, as evidenced by reactive microgliosis, astrocytosis, and behavioral changes. Postsurgical treatment with meloxicam attenuates both neuroinflammation and anhedonia. These findings suggest that cyclooxygenase-2-dependent mechanisms may play a role in the development of postoperative mood disorders, possibly via modulation of peripheral effects on neuroinflammation.

Background: It is now accepted that mitochondrial dysfunction is a key early event in the progression of neuronal and vascular degeneration in Alzheimer's disease (AD) and that therapies aimed at preventing mitochondrial failure may represent promising new strategies in the pursue of a cure for this devastating disease. Carbonic anhydrases (CAs) are a family of enzymes that catalyze the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa), maintaining acid-base balance in blood and other tissues. CA isoforms are present in the mitochondria. CA inhibitors (CAIs), such as metazolamide (MTZ) and acetazolamide (ATZ) are clinically used for glaucoma, epilepsy (rarely), and high altitude sickness. Methods: We analyzed the effects of two main CAIs used in clinical settings (MTZ and ATZ) on the mechanism of mitochondrial damage and neurovascular degeneration induced by amyloid beta (Abeta), using cerebral vascular and neural cells as well as the TgSwDI (Swedish- Dutch-Iowa) transgenic mouse model of cerebral amyloidosis. Results: Both CAIs consistently prevented specific pathways of mitochondrial dysfunction induced by Abeta in cerebral microvascular endothelial, neuronal and glial cells, without affecting ATP production, pH, and Calcium flux. Increase of hydrogen peroxide, loss of mitochondrial membrane potential, release of Cytochrome C, caspase activation, and apoptotic cell death were inhibited by CAIs. ATZ was effective at concentrations lower than MTZ. Both drugs, given with diet, were able to ameliorate behavioral paradigms in relatively young TgSwDI mice. Conclusions: CAIs might represent a potentially successful strategy to prevent early mitochondrial dysfunction and neurovascular loss in AD. Further studies in animal models and clinical settings are needed to confirm our hypothesis

Objectives: MicroPET imaging has been increasingly performed on mouse models for a variety of human CNS disorders. Despite high demand, digital mouse brain atlases based on PET are still lacking. Further, most microPET systems do not provide means of mapping mouse brain with atlas. For quantitative data analysis and accurate anatomical localization, the development and evaluation of an automated atlas-based data analysis on microPET mouse brain studies is presented. Methods: MicroPET imaging studies were performed after injection of F-18 labeled Amyvid (a tracer for imaging amyloid (Aa) plaques) in isoflurane-anesthetized adult mice using Inveon PET/CT (Siemens). The list mode dynamic PET data were collected for 30-60 min and rebinned using a Fourier rebinning algorithm. A CT scan was also performed for attenuation correction and anatomical co-registration. A 3D digital magnetic resonance microscopy (MRM)-based volume of interest (VOI) atlas generated from live C57BL/6J adult mouse brain was used for brain mapping (Ma et al., 2008). Landmarks, including left and right centroids of midears and eyes (4 landmarks), were generated on atlas template and individual mouse CT images. Co-registration of atlas, CT and PET was performed using Firevoxel (FVX) (https://urldefense.proofpoint.com/v2/url?u=https- 3A__wp.nyu.edu_Firevoxel&d=DgIBAg&c=j5oPpO0eBH1iio48DtsedbOBGmuw5jHLjgvtN2r4ehE&r=KRXe NoRy5_8lkSwAJG5vjS1yT0aFSItfe494dmkdSVs&m=B4bFtJccWjUzJ- dbK1qURkxJmihDqjf87yIgZlYKTMk&s=soyp2V3_QGPs--q8qXcfkDHjv7kMngxeekpEknOQoi8&e= ) and time-activity curves (TAC) for 20 specific 3D brain regions were generated. For comparison, an expert in mouse neuroanatomy manually drew corresponding VOIs on PET-CT co-registered images derived from IRW (Inveon data analysis software without atlas). The TACs thus generated via both methods were compared. For further evaluation, the tracer uptake and kinetics in both tau and Aa transgenic mouse models were also compared. Results: Using FVX, single step co-registration of atlas, CT and PET was accomplished in seconds (by one-button pressing) and the TACs for specific ROIs of mouse brain were automatically generated after co-registration. In contrast, it took an average of 15 min to manually draw a single VOI (total 5 hours/mouse for 20 VOIs) directly on CT images using Inveon IRW without an atlas, a process that required an expert in mouse neuroanatomy. Overall, the TACs for the corresponding VOIs derived from IRW and FVX were similar in counts and shapes. Most importantly, this VOI atlas-based method can provide unbiased measures of radioactivity concentration from PET studies. The results from studies of tau vs. Aa transgenic mouse models after injection of Amyvid showed an apparent difference in the tracer uptake and kinetics (Fig. 1). Conclusions: We have demonstrated the feasibility to map mouse brain with an automated atlas-based co-registration for data analysis of microPET brain studies using FVX. This novel time-saving data analysis methodology, unachievable with current microPET imaging systems, will facilitate accurate assessment and spatial localization of brain signals in mouse model studies for a variety of human CNS disorders

Background: We have previously demonstrated that anti-beta-sheet conformational monoclonal antibodies (mAbs) recognize pathological oligomeric forms of Abeta and Tau in tissue samples of human Alzheimer's Disease (AD) brains and in AD mouse models (Goni et al 2015, Alzheimer & Dementia pp 845-6). We have now tested one of our mAbs in aged 3xTg AD animals with extensive preexisting Abeta and Tau related pathology with weekly injections of the TABP1 mAb. Methods: Two groups of 16 months old 3xTg AD animals were inoculated i.p. biweekly for three weeks and weekly thereafter for 5 weeks with either 100 mug of TABP1 in 100 muL of sterile saline or with 100 muL of vehicle alone. Radial Arm Maze behavioral analysis was performed after the treatment, followed by sacrifice and harvesting of the brains for immuno-histochemical and biochemical analyses. Results: No adverse reactions were demonstrated during the treatment. The TABP1 infused animals showed significant cognitive rescue compared to the controls. No significant differences were noted with the immunohistochemical quantitation of amyloid plaques or tau pathology; although there was a trend for reduced deposition in the infused animals. However, there was a significant decrease of the soluble and oligomeric Abeta (mainly Abeta1-42) and pathological Tau in the infused animals versus the controls. Conclusions: Anti-conformational monoclonal antibodies infused i.p. can ameliorate behavioral deficits in AD model mice. The mechanism is likely related to reductions of the levels of soluble oligomeric forms of Abeta and Tau; these species have been most closely linked to the cognitive deficits in AD patients. The results are encouraging for the further testing of humanized versions of these mAbs in clinical trials