Research Interests

 

 Laboratory Personnel

 

·               AnnMarie Armenti - Research Support Specialist

·         Judianne Davis - Senior Research Support Specialist

·         Michael Hoos - MCB Doctoral Graduate Student

·         Mei-Chen Liao - MCB Doctoral Graduate Student

·         Mary Lou Previti - Research Support Specialist

·         Feng Xu - Senior Research Associate

 

 

Research

 

The research in my laboratory has largely focused on pathogenic mechanisms in cerebral amyloid angiopathy (CAA), a pathological condition that is characterized by accumulation of amyloid ß-protein (Aß) in and along brain blood vessels and capillaries. CAA is prevalent in Alzheimer's disease and several related neurodegenerative disorders and is a significant cause of hemorrhagic stroke. We have generated transgenic mice, known as Tg-SwDI, that specifically develop CAA in the cerebral microvasculature and showed that this condition promotes a robust localized neuroinflammatory response that leads to behavioral deficits. These Tg-SwDI transgenic mice provide a useful model to study cerebrovascular amyloid-mediated cognitive impairment, an emerging component of dementia in Alzheimer's disease and related disorders, and provide a translational system to evaluate potential therapies to treat this deleterious condition.

 

   

 

 

brain capillary from the Tg-SwDI transgenic mice showing numerous amyloid ß-protein deposits.   

 

The Aß peptide is proteolytically derived from a much larger protein known as the amyloid ß-protein precursor (AßPP). Although its role as the precursor to Aß is most studied little is known of physiological functions of AßPP. Through the course of our investigations we have shown that AßPP is potent serine proteinase inhibitor with strong activity towards several key pro-thrombotic enzymes of the coagulation cascade. To this end, we have an active research program studying the activities of AßPP that regulate cerebral thrombosis during events of cerebral vascular injury including stroke and hemorrhage.

 

  
  
 

 

Atomic force microscopy imaging shows that Aß peptide normally assembles into fibril

structures (left panel) and that this process is inhibited when MBP is present (right panel).

 

 

The pathologic accumulation of Aß peptide in brain that occurs in Alzheimer's disease and related disorders is believed to largely result from deficient clearance of the peptide from the central nervous system. In another project in my laboratory we have been characterizing novel enzymes that degrade Aß peptides and novel factors that regulate Aß assembly and deposition in the brain. Both of these processes affect Aß clearance from the central nervous system and play a role in its pathological accumulation. One factor that we identified that strongly inhibits Aß assembly is myelin basic protein (MBP), a protein that normally surrounds nerve cells and maintains their normal function. This work is leading to the development of novel approaches to reduce the assembly and deposition of Aß in brain, a key pathological component of Alzheimer's disease and related disorders.

 

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Transgenic mice that were developed to produce elevated amounts of AßPP show much larger hemorrhages (left) compared to mice that produce normal amounts of AßPP (right) due to AßPP blocking the activities of enzymes that promote clotting and prevent bleeding.

 

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