Michael Bienkowski - US grants

? DESCRIPTION (provided by applicant): The insular cortex is one of the least understood regions of the brain due to a complex neuroanatomy involving granular, dysgranular, and agranular subregions with distinct connectivity. While several human imaging studies have implicated insula activity in fear conditioning and post-traumatic stress disorder (PTSD), few studies have attempted to investigate the role of the insula in rodents where higher resolution anatomical and functional techniques are possible. Previous rodent studies were mostly inconclusive in using blunt lesioning strategies to dissect the functional role of the insula in fer conditioning. Now, recent advances in viral transsynaptic tracing and optogenetics allow for the identification and experimental manipulation of discrete neural circuits for behavioral analysis. The proposed research plan applies the latest monosynaptic rabies viral tracing and optogenetic methods to determining the role of the insula in the fear learning process. As part of the Mouse Connectome Project in the lab of Dr. Hong-Wei Dong at USC, anterograde/retrograde tracer coinjections into the posterior, ventral, and dorsal agranular insular cortex (AIp, AIv, AId) have revealed that each subregion sends distinct patterns of input to the amygdala subnuclei involved in fear memory. Of these three insula subregions, the AIp provides the strongest input to the lateral part of the central nucleus of the amygdala (CEAl), whose neurons are critical for fear memory acquisition. Using a monosynaptic rabies viral tracing approach in mice, Aim 1 experiments will identify the neural circuits that provide direct input to CEA- projecting AIp neurons and establish the AIp as part of a structural neural network regulating the expression and memory of fear. Building upon this anatomical foundation, Aim 2 experiments under the mentorship of Drs. Li Zhang and Michael Fanselow will investigate the functional role of AIp projections to the CEA using excitatory and inhibitory optogenetics during behavioral fear conditioning and extinction paradigms. The results of these studies have important implications for our understanding of the neural circuits mediating fear learning and identifying a novel neuroanatomical target for PTSD treatment. In pursuit of these aims, the proposed training complements my strong neuroanatomical expertise with the ability to investigate the behavioral function of anatomically-defined neural circuits. Using the most advanced viral tracing, optogenetic, and behavioral techniques, the mentorship and guidance I will receive under this training grant is important for my personal goal of becoming an independent Principal Investigator studying structure/function relationships in neural networks.

PROJECT SUMMARY/ABSTRACT Alzheimer?s disease (AD) is a progressive neurodegenerative disease that spreads across the brain from its origin in the medial temporal lobe. The hippocampus is one of the earliest and most affected brain regions in AD and hippocampal atrophy has been linked to the severity of the behavioral symptoms. Although numerous theories have been put forth, the molecular underpinnings of hippocampal neurodegeneration remain unclear. This lack of understanding has stymied AD drug development from translating animal research into human treatment. I believe that a translational cellular atlas that bridges the gap between mouse and human AD research is needed to determine which specific hippocampal cell types are affected by AD. My previous research creating the mouse Hippocampus Gene Expression Atlas (HGEA) lays a strong foundation for this effort (Bienkowski et al., Nature Neuroscience, 2018). The HGEA defines 20 distinct genetic subdivisions of the hippocampus and subiculum based on mapped gene expression patterns, delineates each region?s input/output pathways, and demonstrates how each region contributes to brain-wide networks. Overall, I found that hippocampal gene expression patterns were highly related to specific anatomical connectivity patterns. Among many new insights, I discovered that subiculum gene expression patterns revealed hidden lamina of pyramidal neurons and demonstrated how this laminar architecture underlies a columnar organization similar to the cerebral cortex. Altogether, the HGEA demonstrates the multiscale organization of the hippocampus from individual genetic cell types to neuronal networks regulating animal behavior. I established a number of resources and tools on the Mouse Connectome Project website so that other hippocampal scientists around the world could use the HGEA to guide their own research experiments. The funding of this K01 Mentored Research Scientist Career Development Award application will provide me with training and expertise I need in order to develop a human version of the HGEA as a translational resource to understand AD neurodegeneration. Building on the mouse HGEA, the proposed research uses a cutting-edge spatial transcriptomics approach in thick optically-cleared tissue sections (STARmap) to reveal multiplexed gene expression patterns, build a human HGEA that can be registered to MRI data, and investigate changes to HGEA-defined neuronal cell types caused by hippocampal neurodegeneration within an AD mouse model (5XFAD mice) and humans with AD. To guide this project and my career development, I have assembled a world-class team of supportive mentors (Drs. Arthur Toga and Berislav Zlokovic) and collaborators (Dr. Carol Miller) to provide me with new training to investigate Alzheimer?s disease in both transgenic mouse models and human post-mortem tissue. Ultimately, the funding of this K01 proposal will complete my career development toward leading a translational neuroscience laboratory studying the relationship of gene expression, connectivity, and behavior in neurological disease.

Despite enormous advances in recent years to develop neuroprosthetics to bypass damaged areas of the Central Nervous System (CNS), these devices fail to halt the progression of the underlying degenerative diseases for which they were designed. Moreover, there are no effective therapies for many of the neurodegenerative conditions that affect, for example, the eye or the brain, and the humanitarian and economic impact of blinding diseases and dementia are enormous, with underrepresented groups particularly impacted by these conditions. The goal of this project is to enable restoration of function to the CNS by therapies that promote the repair and regeneration of damaged neurons and neural networks instead of bypassing damaged areas. To achieve this goal of delaying vision loss and neural degeneration in dementia through devices this team brings together engineers, surgeons, neuroscientists and big data/imaging scientists.

This research team will devise and optimize, experimentally and computationally, the electrical stimulation waveform characteristics needed to reprogram damaged neural network morphologies; create, “first of its kind” complete mesoscale connectivity atlases of the global neural networks exposed to electric fields and field gradients; develop predictive multiscale computational models of neural activity in healthy, degenerated and electrically stimulated neural networks; and design and engineer programmable implantable electronic systems for the acute neurostimulation of the neural tissue. The utility of the tools developed in the proposed effort will be enhanced by end-users providing design input, thus facilitating fully integrated, mutually beneficial, sustained convergent collaborations that are needed to develop the therapeutic opportunities of the next generation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Abstract The 3 overarching goals of the USC Alzheimer Disease Research Center (ADRC) are to: 1) Elucidate vascular contributions to Alzheimer disease (AD), 2) catalyze basic, clinical, and translational research in AD at USC, and 3) contribute expertise in vascular disease, biomarkers, and imaging to national collaborative initiatives. The ADRC is led by 3 multiple PD/PIs: Chui, Zlokovic, and Toga and comprised of 6 required cores, the required Research Education Component (REC), and 1 optional imaging core. The Administration Core (Chui, Zlokovic, Toga) provides administrative and scientific oversight across USC ADRC, including fostering development projects and supporting ADRC-affiliated studies. The Clinical Core (Schneider, Ringman, Chui) performs standardized evaluations and diagnoses using the NACC Uniform Data Set (UDS), enrolls and follows participants in our 2 primary ADRC cohorts: Vascular Cohort Study (VCS) and Brain Research Study (BRS). The Data Management and Statistical Core (Toga and Chen) oversees the NACC UDS database, provides study- and core-specific databases and curates our large imaging data sets as a local and national resource. The Neuropathology Core (Miller and Hawes) performs standardized neuropathological examinations, stores and distributes biological tissues to research investigators. The Outreach, Recruitment, and Engagement Core (Aranda) works closely with the Clinical Core to recruit and retain the primary ADRC cohort, focusing on under- represented minority groups (especially Latinx), and the development of a participant-caregiver dyad resource database. The Biomarker Core (Zlokovic) uses state of the art methods to determine cell-and system-specific biomarkers related to the neurovascular unit, as well as to measure standard AD biomarkers. The Imaging Core (Toga and Pa) provides high field (3T and 7T) MR imaging, as well as amyloid/tau PET scans. The Research Education Component (Yassine) is dedicated to mentoring post-doctoral students committed to the study of minority issues in Alzheimer disease and related disorders. The USC Health Science Campus is located near high Latinx catchment areas. Treatable vascular-metabolic risk factors (VMRF) are particularly prevalent among the Latinx population and dovetail with the research focus of the USC ADRC.