Brain-wide quantitative mapping of microglia activation

SUMMARY Recent technological developments such as tissue clearing and light sheet imaging have allowed for the threedimensional visualization of the entire brain at cellular resolutionTranslucence Biosystems has advanced this technology further by developing aa proprietary Mesoscale Imaging System that allows visualization of an entire mouse brain much faster than prior techniquesbmachine learning based algorithms that identify individual cells across the entire intact mouse brain and croutines that rapidly determine cell densities in andgtbrain regions defined by the annotated Allen Brain AtlasIn the present proposal we will show the power of our technique by visualizing microglia density across the entire mouse brain as a biological marker for neuroinflammationMicroglia are the resident immune cells in the brainWhile they play important roles in healthy brain functionthey also mediate neuroinflammatory processes that have a significant impact in multiple neurodegenerative diseases such as Alzheimerandapos sParkinsonandapos sand multiple sclerosis as well as play possible roles in several neurodevelopmental and neurological disorderse gschizophreniaautism spectrum disorderchemo brainA tool for three dimensional imaging of neuroinflammation patterns across the whole brain will help advance our understanding of neuroinflammatory processes in neurological diseases and aid in the evaluation of therapeutic approachesTo visualize microgliawe will evaluate multiple strategiesincluding the CX CRGFP mouse linewhich expresses GFP in microgliaIbaimmunolabeling and other antibody markers of activated microgliaThe utility of our approach for monitoring neuroinflammation will be demonstrated in CX CRGFP mice by treating them with the inflammatory agent lipopolysaccharideLPSMice will be injected with three different LPS dosesand then microglia will be visualized and automatically counted across andgtbrain regionsWe will confirm the neuroinflammatory response to LPS by measuring protein markers of inflammationThe applicability of our technique to neurodegenerative disease will be demonstrated by studying a mouse line used as a model of Alzheimerandapos s disease that presents pronounced patterns of neuroinflammationThese experiments are designed to prove that our approach can provide reliable and detailed information describing neuroinflammation and that our results are better in terms of speedresolutionand richness of information than any other technique availableOnce the goals for Phase I are metwe will be positioned to develop our microglia activation assay into a new gold standard for precise and complete histological detection of neuroinflammationDuring phase IIwe plan todevelop machine learning tools to establish morphological criteria that differentiate resting from activated microgliacharacterize microglial signatures in various mouse models of diseases with known or suspected neuroinflammation componentsandvalidate the microglial targeting of anti inflammatory therapeutic candidates NARRATIVE Microgliathe resident immune cells of the brainprotect against injury and infectionMicroglia also play a critical role in dysfunctional neuroinflammatory processes that contribute to the development of brain diseasesWe have developed novel methods to make mouse brains transparent so we can visualize and precisely count microglia throughout the intact mouse brainIn this proposalwe will test the feasibility of measuring brain wide microglia activation using two disease models with a strong neuroinflammatory componentincluding a common transgenic mouse model that recapitulates the amyloid plaque accumulation that is a central feature of Alzheimer s Disease