Jason L. Eriksen - US grants

FAS children exhibit behavioral deficits that are indicative of impaired development of neurotransmitter systems. In rodents, ethanol exposure produces a remarkable (45-65 percent) decrease of serotonin content in the raphe neurons of the fetal brainstem. This reduction is important because 5-HT is an essential trophic factor for serotonergic neurons; reductions in 5-HT impair the development of raphe neurons and the density of their projects. Maternal administration of buspirone, a 5- HT1A agonist, prevents many of the 5-HT deficits that arise from in utero ethanol exposure. This proposal will test the hypothesis that buspirone prevents the damaging effects of ethanol on developing 5-HT neurons through its stimulation of astroglial 5-TH1A receptors and subsequent release of astroglial trophic factors, notably the glial growth factor S-100beta. S-100beta plays an essential role in the development of the serotonergic system. In vivo studies have shown that disruption of S-100beta production impairs the development of the 5-HT system. The three aims of this proposal will: (1) determine whether astroglial production of S-100beta in the Midline Raphe Glial Structure is impaired by in utero ethanol exposure, and whether buspirone prevents this effect of ethanol, (2) determine whether ethanol inhibits the paracrine effects of astroglia factors that normally result in increased production of S-100beta, and whether buspirone prevents these effects of ethanol, and (3) determine whether buspirone treatment of astrocytes prevents the reduced production/secretion of astrocytic neurotrophic factors. Results from these studies will contribute to our understanding of the mechanism by which ethanol exerts its damaging effects on the 5-HT system.

DESCRIPTION (provided by applicant): Although stroke is the third leading cause of death in the Western world, clinical advances in the early diagnosis and treatment of this pathology have been relatively limited. Cerebral amyloid angiopathy (CAA) is a major cause of hemorrhagic stroke in western patient populations, associated with at least 30% percent of bleeding strokes, and affecting as many as one third of all people over the age of 75. There are currently no methods to diagnose or selectively treat cerebral amyloid angiopathy (CAA), an important cause of hemorrhagic stroke, in living patients. CAA cannot be diagnosed using any currently existing imaging technology in living patients, and only detectable by postmortem examination of brain tissue. The long-range goal of our research is to develop liposome-based nanoparticle agents for multimodal diagnostic and therapeutic applications to target this pathology by creating amyloid-binding liposomal nanoparticles with a mixture of core-encapsulated gadolinium contrast agents and therapeutic molecules. In this project, we propose to detect and treat CAA by developing a nanoparticle containing high resolution MRI imaging agents with ligands that specifically target the amyloid deposits found in CAA, and packaged with a b-sheet breaker that can selectively treat CAA pathology. The development of this nanoparticle will establish the base for a smart nanotechnology platform that allows for specific, high-resolution visualization of CAA in living patients at a resolution that far exceeds current agents with the sensitivity of SPECT, while allowing for the selective delivery of therapeutics at pathologically-affected vascular sites. We call this platform Amyloid Targeted Imaging Nanostructure (ATINS). We propose the following specific aims: (1) to characterize the role ATINS containing b-sheet breakers as aggregation inhibitors by optimizing the packaging and delivery of these nanoparticles in vivo, and (2) to demonstrate ATINS can be used as a theranostic agent that can be used for simultaneous high-resolution imaging and treatment of pre-existing CAA pathology. Success in this project will result in a versatile nanotechnology platform that will serve as proof of concept for future agents to simultaneously image and therapeutically target CAA pathology in living patients, a technology that can have an enormous impact in the area of CAA-related hemorrhagic stroke. PUBLIC HEALTH RELEVANCE: There are currently no methods to diagnose or selectively treat cerebral amyloid angiopathy (CAA), an important cause of hemorrhagic stroke, in living patients. We propose to create a therapeutic agent that can both diagnose and treat this disease by using the well-known stealth liposome as a platform nanoparticle. We propose to modify the liposome for imaging and targeting pathogenic amyloid species associated with CAA, and to package therapeutic compounds within the nanoparticle that will selectively clear the CAA pathology. The development of this multifunctional platform will provide important scientific insights into the pathological role of CAA during aging, and serve as proof of concept for future therapeutic development.

The broader impact/commercial potential of this I-Corps project is the development of a commercial antigen retrieval solution that will be used in academic, government and industrial research laboratories as well as hospitals worldwide with applications for the detection of protein and molecular biomarkers. Formaldehyde is a widely used to preserve tissue in both laboratory and clinical settings. Current tissue-based diagnostic applications for the detection of biomarkers are limited due to the requirement of formaldehyde fixation of tissue samples. Due to a loss of sensitivity associated with formaldehyde fixation, many clinically relevant biomarkers cannot be reliably studied with current technology, resulting in false-negative errors. Due to the financial cost and the effect of misdiagnosis on treatment outcomes associated with false-negative errors in clinical diagnostic testing, the development of improved antigen retrieval technology will have important societal and medical impacts. Given that there are more than 93 million diagnostic tests run worldwide that depend on antigen retrieval agents, the technology is anticipated to have substantial commercial potential in clinical settings.

This I-Corps project demonstrates how the detection of protein-epitopes in formalin-fixed paraffin-embedded tissue can be retrieved with higher sensitivity and reproducibility by using formaldehyde scavenging compounds. Current antigen retrieval reagents typically contain sodium citrate or Tris based solutions that rely primarily on heat to reverse formalin fixation from tissue samples. The proposed project expands on the current methods by using chemistry associated with formaldehyde scavenging to significantly enhance the detection of proteins in formaldehyde-fixed tissue samples. The proposed approach consists of novel compositions that contain combinations of formaldehyde scavenging compounds. Currently, we have demonstrated increased sensitivity with a series of structurally diverse compounds using a panel of blood vessel proteins as a model system. This method provides a new and more accurate method for the detection of proteins in tissue-based diagnostic assays used in clinical and research applications.