2014 Pilot Projects

Description

Tauopathies affect more than 6 million people in the US and include Alzheimer’s disease, progressive supranuclear palsy, and frontotemporal dementia. In a subset of these diseases, genetic changes in MAPT, the gene that encodes the tau protein, initiate a cascade of events that leads to tau aggregation and death of neuronal populations in the brain. Some regions in the central nervous system are routinely affected in tauopathies, while other regions are spared. The cascade of events that leads to disease and that underlies cell-type specific vulnerability remains poorly understood. Due to the complexities of the MAPT gene and its expression patterns, current cell and mouse models have not resolved the mechanisms by which fully penetrant disease mutations or risk variants in MAPT disrupt the tau protein and cause disease in a cell-type specific manner. The primary objective for this pilot grant is to use two cell-fate reprogramming systems to generate human neurons and to test the feasibility of these experimental conditions to study tauopathies. Starting from the same human fibroblasts, we will i) generate neurons differentiated from induced pluripotent stem cells; and ii) use microRNAs and neural transcription factors to directly convert fibroblasts into neurons. By enriching the population of neuronal subtypes from the reprogramming conditions, we hope to understand neuronal subtype-specific vulnerability underlying tauopathies. Together, this study will use novel human cell models that will begin to define the cascade of events that lead to neurodegenerative tauopathies and will provide avenues for advancement in therapeutic intervention.

Grants and Awards

Rainwater Charitable Foundation (Karch PI)

“IPSC Modeling of AD Using Progerin”
NIH R01 AG056293 (Sally Temple PI; Karch, Co-I)
Narrative Age is the strongest risk factor for Alzheimer’s disease (AD). Yet cell and animal models of AD fail to recapitulate human aging and fail to capture key aspects of disease pathology. In this project, we will increase the level of the protein progerin, which induces cellular abnormalities associated with aging, in human induced pluripotent stem cell lines derived from patients with AD versus healthy individuals. These cells will be differentiated into brain cells that are vulnerable in AD, with the goal of defining how abnormalities associated with aging contribute to the onset and progression of AD pathology.

Publications

Christine J Huh, Bo Zhang, Matheus B Victor, Sonika Dahiya, Luis FZ Batista, Steve Horvath, Andrew S Yoo. Maintenance of age in human neurons generated by microRNA-based neuronal conversion of fibroblasts. eLife ;5:e18648, (2016).

Li Z, Del-Aguila JL, Dube U, Budde J, Morris JC, Bateman RJ, DIAN, Dougherty JD, Lee JM, Karch CM, Cruchaga C, Harari O. (2018). Genetic variants associated with Alzheimer’s disease confer different cerebral cortex cell-type population structure. Genome Medicine. Jun 8;10(1):43.

Jiang S, Wen N. Li Z, Dube U, Del Aguila J, Budde J, Martinez R, Hsu S, Fernandez MV, Cairns NJ, DIAN, IFGC, Harari O, Cruchaga C, Karch CM. (2018). Integrative system biology analyses of CRISPR-edited iPSC-derived neurons and human brains reveal deficiencies of presynaptic signaling in FTLD and PSP. Translational Psychiatry. Dec 13;8(1):265.

Wang C, Ward M, Chen R, Liu K, Tracy T, Chen X, Xie M, Sohn PD, Ludwig C, Meyer-Franke A, Karch CM, Ding S, Gan L. (2017). Scalable production of iPSC-derived human neurons to identify novel tau-lowering compounds by high-content screening. Stem Cell Reports. Oct 10;9(4):1221-1233.

Updated January 2019

Description

Our long-term goal is to discover low frequency and rare genetic coding variants (changes in a DNA sequence found in less that one percent of the general population) associated with an increased risk of developing Alzheimer’s Disease (AD).  The cumulative effect of rare variants is very significant in complex disease, as shown by our discovery of rare variants in the Phospholipase D family, member 3 (PLD3) gene  in families with AD.  Additionally, rare variants contribute to a better understanding of the pathobiology of disease.  Rare variants in the triggering receptor expressed on myeloid cells 2 (TREM2) revealed novel avenues towards the role of neuroinflamation in AD, and mutations in the amyloid-beta precursor protein (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2) genes were originally found in rare and phenotypically extreme AD cases.  We recently found that the DNAJC5 gene (DnaJ (Hsp40) homolog, subfamily C, member 5) is a Mendelian dementia-causing gene of an early-onset and rare form of dementia.  In this project, our aim is to identify rare genetic variants in DNAJC5, and to determine whether those rare variants play a role in the risk for AD.   We will do this by combining targeted-pooled-DNA next-generation sequencing in large case-control samples and analysis of Illumina Exome Chip technology, whole-exome sequencing and whole-genome-sequencing data. We will then validate the best candidate variants’s role in amyloidogenesis using in vitro assays and cell model systems.

Grants and Awards

“Effect of mutant DNACJ5/CSPα on lysosomal function in human induced pluripotent stem cell (iPSC)-derived neurons”
Children’s Discovery Institute hPSC Core Pilot Grant Program, Washington University in St. Louis (PI, Benitez).

Publications

Benitez BA, Cairns NJ, Schmidt RE, Morris JC, Norton JB, Cruchaga C, Sands MS.Clinically early-stage CSPα mutation carrier exhibits remarkable terminal stage neuronal pathology with minimal evidence of synaptic loss. Acta Neuropathol Commun; 3:73, (2015).

Benitez BA, Sands MS. Primary fibroblasts from CSPα mutation carriers recapitulate hallmarks of the adult-onset neuronal ceroid lipofuscinosis. Sci Rep (7) Article Number: 6332, (2017).

Updated January 2019

Description

Embryonic stem (ES) cell transplantation holds great promise as a potential strategy for repairfollowing spinal cord injury (SCI). Recently, we developed methods for generating populations ofpurified, genetically defined ventral spinal neurons through genetic engineering and selection;however, the functional phenotypes of these purified ES-derived neurons and their appropriateness fortransplantation have yet to be characterized. In order to devise effective circuits to bridge a SCI lesion,the network properties of ES-derived spinal neurons must be determined.

Our objective is to understand how neural circuits form in the spinal cord and how they can be rewired to promote functional recovery after spinal cord injury.  We will use a novel approach to probe what types of neurons are involved in these circuits and what kinds of cues can support their formation.  Specifically, we will use multi-electrode arrays to characterize the interactions between V2a interneurons and motor neurons as model circuits for driving rhythmic locomotor function.  This work will combine engineering, neuroscience and developmental biology approaches.  The information gained from this research can be used to guide the design of potential cell transplantation therapies with human induced pluripotent stem cells (iPSCs) for spinal cord injury.

Grants and Awards

MO Spinal Cord Injury Research Program

Publications

Gamble JR, Zhang ET, Iyer N, Sakiyama-Elbert S, Barbour DL. “In vitro assay for the detection of network connectivity in embryonic stem cell-derived cultures.” July 26, 2018. bioRxiv 377689.

Iyer, N, Gamble JR, Barbour DL, Sakiyama-Elbert S. An in vitro aggregate culture system investigating the response of embryonic stem cell derived V2a interneurons to neurotrophins and co-culture with progenitor motor neurons. J Neurosci Meth.

Updated January 2019

Description

Intraventricular hemorrhage (IVH) is the most common, severe neurological complication of preterm birth, and up to half of patients with IVH develop post-hemorrhagic hydrocephalus (PHH). PHH is typically treated with surgical implantation of a cerebrospinal fluid (CSF) shunt; however, even with successful shunting, PHH is associated with a 3-4 fold increase in the risk of cognitive and motor disabilities. Inflammatory processes triggered by IVH are believed to underlie the development of PHH and potentially contribute to the observed long-term neurological challenges.  Further, inflammation may be related to changes in the stiffness, or elastance, observed in brain tissue in the setting of PHH.  Such alterations in the mechanical properties of the brain can now be measured non-invasively with a novel magnetic resonance technique, MR elastography (MRE).  The primary objective of this project to create a new model of PHH and employ MRE to characterize the changes in brain tissue stiffness that occur during the progression of PHH.  The relationship between brain stiffness and the levels of inflammatory proteins and other candidate biomarkers in the cerebrospinal fluid will also be examined. The work produced through this study will lead to more comprehensive understanding of the diagnostic potential of MRE, the role that brain stiffness plays in PHH, and the potential for new treatments to supplement the current management approach for children with PHH.

Grants and Awards

“Therapeutic Modulation of Post-Hemorrhagic Hydrocephalus”
Hydrocephalus Association Innovator Award to James P. (Pat) McAllister II, PhD and David D. Limbrick, Jr., MD, PhD

Updated June 2017

Description

Retinal neurodegeneration encompasses a broad spectrum of diseases such as retinitis pigmentosa and age-related macular degeneration (AMD), whose end results are usually loss of viable photoreceptor (PR) neurons.  Recently, there has been a significant interest in the role of NAD+ biosynthetic processes and its dynamic regulation in the pathogenesis of retinal neurodegenerations.  The proposed research will explore the interesting connection between the role of NAD+ biosynthesis, particularly mediated by nicotinamide phosphoribosyltransferase (NAMPT), the key NAD+ biosynthetic enzyme in mammals, and the regulation of photoreceptor neuron survival and retinal degenerations.  By using genetically engineered mice, we have already obtained preliminary results suggesting the critical role of NAD+ biosynthesis in the regulation of PR energetics and survival.  We have also found that administration of nicotinamide mononucleotide (NMN), a key building block of NAD+, can ameliorate the impairment of PR function and prevent retinal neurodegeneration.  Based on these preliminary results, we hypothesize that the impairment of NAD+ biosynthesis contributes to the pathogenesis of retinal neurodegeneration and also that restoring NAD+ production in the retina by NMN administration can treat retinal neurodegenerative diseases.  A great advantage of this proposal is its direct application to a broad spectrum of neurodegenerative diseases, given the importance of NAD+ as a key co-factor in photoreceptor neurons and the ‘translational readiness’ towards clinical trials.

Updated June 2017