Patrick J. Cimino, Ph.D. - US grants

DESCRIPTION (provided by applicant): Activation of innate immune response in microglia is associated with the initiation or progression of several neurodegenerative diseases. Perhaps best studied in models of Alzheimer's disease (AD), innate immune activation has been shown to have both beneficial and deleterious effects on neurons. Beneficial effects are related to the clearance of nerurotoxic species of Abeta peptides, while paracrine damage to neurons results from the elaboration of a variety of toxic substances including reactive oxygen and nitrogen species. A major goal of many academic and pharmaceutical laboratories is to identify means to augment or maintain the beneficial actions of innate immune activation while suppressing paracrine neurotoxicity. Recently we demonstrated that genetic ablation of the EP2 receptor from primary mouse microglia resulted in the highly desirable dual phenotype of an increase in phagocytosis of Abeta species and complete blockade of paracrine neurotoxicity. Others have validated our findings using different methods. Taken together, these data strongly support EP2 receptor as a highly promising target for manipulating microglial innate immune response in AD and perhaps other neurodegenerative diseases. The mechanisms by which EP2-mediated signaling is related to Abeta phagocytosis and paracrine neurotoxicity are not known. Our Preliminary Data of mouse primary microglia expression identified a candidate gene that is tightly associated to EP2. We are aware of no report on the actions of this gene in any brain cells, including microglia. However, given emerging data we hypothesize that its expression and activity are mechanistically linked to EP2 signaling and that it may be a key element by which ablation of EP2 generated the highly desirable dual phenotype of enhanced Abeta phagocytosis and reduced paracrine neurotoxicity. We will test this hypothesis through the following Specific Aims: 1) Perform in vitro validation of our candidate mRNA and protein expression in wild type and EP2-/- primary mouse microglia before and after Abeta treatment. 2) Map the in vivo regional and cellular brain distribution in wild type mice and a transgenic mouse model of AD before and after following bone-marrow transplantation from either wild type or EP2-/- mice. 3) Determine the functionality of its expression in the context of the EP2-/- dual phenotype in both knockout mice and a microglial cell line using shRNA knockdown.

PROJECT SUMMARY/ABSTRACT This proposal describes a 5-year career development program in which the applicant?s ultimate goal is to become an independent physician-scientist with a focused clinical practice in neuropathology and a research laboratory dedicated to the study of diffuse gliomas. The proposed research project will capitalize on the expertise and resources available at the University of Washington/Fred Hutchinson Cancer Research Center Cancer Consortium, which has a proven track record of developing physician-scientists. Dr. Eric Holland, an expert in mouse models of glioma and cancer biology, will serve as the applicant?s research mentor. Diffuse gliomas comprise the most common and malignant primary intracranial neoplasms in adults. Furthermore, over the last several decades there has been little success in prolonging the survival of patients with diffuse glioma, and there is yet to be effective targeted therapies. One proposed mechanism for poor treatment response of diffuse glioma lies in the intra- and inter-tumoral molecular and cellular heterogeneity that make up these tumors. Over the last 3 years, the applicant has worked in Dr. Holland?s laboratory to address this molecular heterogeneity within glioma, specifically investigating the role of somatic copy number alterations (SCNAs). Through copy number profiling across adult glioma cohorts, prognostic SCNA subtypes were defined with clear differences in median survival and selection biases were found to exist in smaller cohorts, having implications on clinical trial design and applicability to the general population. Along with these human biomarker projects, studies of pre-clinical glioma mouse models have been underway to begin to elucidate genetic drivers associated with SCNAs in glioma. One such study identified HOXA5 as being a driver of chromosome 7 gain in glioma, with HOXA5 driving an aggressive glioma phenotype including mediating radioresistance in vivo. Combining the applicant?s previously published work with other preliminary data, the underlying biology of SCNA subtypes will be addressed in the current proposal, primarily through the construction of SCNA subtype glioma mouse models, which will be functionally characterized (Aim 1). Additionally, the organismal and cellular consequences of SCNA subtype-specific responses to standard therapy (Aim 2) as well as immunotherapy (Aim 3) will be characterized. Overall, the candidate?s background in human and animal investigative and diagnostic neuropathology is well-suited for this mentored research project focused on characterizing biological consequences of SCNAs in gliomas and may yield novel approaches for the treatment of this malignancy. Importantly, the proposed research also establishes a model system for studying glioma-associated SCNAs and associated driver genes in gliomagenesis, which will provide the applicant with the foundation for an independent research program.