Biology subjects

Madden, S. L.

Publications and source records attributed to Madden, S. L..

4 recordsLinked to original sources

bioRxiv2022

High-Throughput Screening for Myelination Promoting Compounds Using Human Stem Cell-derived Oligodendrocyte Progenitor Cells Identifies Novel Targets

Promoting myelination capacity of endogenous oligodendrocyte precursor cells (OPCs) is a promising therapeutic approach for central nervous system demyelinating disorders such as Multiple Sclerosis (MS). To aid in the discovery of myelination promoting compounds, we generated an advanced, genome engineered, human pluripotent stem cell (hPSC) line that consist of three reporters (identification-and-purification tag, GFP, and secreted NanoLuc) driven by the endogenous PDGFR, PLP1 and MBP genes, respectively. Based upon this line, we established a high-throughput drug screening platform and performed a small molecule screen with 2500 bioactive molecules. In addition to a number of previously known pathways, our screening effort identified new pathways whose inhibition enhance oligodendrocyte maturation and myelination. Although further genetic and molecular validation is required, the identified inhibitors could potentially be repurposed to develop remyelination therapy for MS and other demyelinating disorders.

neuroscience↗

bioRxiv2021

Single Cell Atlas of Human Putamen Reveals Disease Specific Changes in Synucleinopathies: Parkinson's Disease and Multiple System Atrophy

Understanding disease biology at a cellular level from disease specific tissues is imperative for effective drug development for complex neurodegenerative diseases. We profiled 87,086 nuclei from putamen tissue of healthy controls, Parkinsons Disease (PD), and Multiple System Atrophy (MSA) subjects to construct a comprehensive single cell atlas. Although both PD and MSA are manifestations of -synuclein protein aggregation, we observed that both the diseases have distinct cell-type specific changes. We see a possible expansion and activation of microglia and astrocytes in PD compared to MSA and controls. Contrary to PD microglia, we found absence of upregulated unfolded protein response in MSA microglia compared to controls. Differentially expressed genes in major cell types are enriched for genes associated with PD-GWAS loci. We found altered expression of major neurodegeneration associated genes -- SNCA, MAPT, LRRK2, and APP -- at cell-type resolution. We also identified disease associated gene modules using a network biology approach. Overall, this study creates an interactive atlas from synucleinopathies and provides major cell-type specific disease insights. Link to interactive atlas will be made available at the time of publication.

genomics↗

bioRxiv2021

Single Nuclei Sequencing of Human Putamen Oligodendrocytes Reveals Altered Heterogeneity and Disease-Associated Changes in Parkinson's Disease and Multiple System Atrophy

The role of oligodendrocytes in neurodegenerative diseases remains incompletely understood and largely unexplored at the single cell level. We profiled 87,086 single nuclei from human brain putamen region for healthy control, Parkinsons Disease (PD), and Multiple System Atrophy (MSA). Oligodendrocyte lineage cells were the dominant cell-type in the putamen with oligodendrocyte subpopulations clustered by transcriptomic variation found to exhibit diverse functional enrichment patterns, and this oligodendrocyte heterogeneity was altered in a disease-specific way. Among profiled oligodendrocyte subpopulations, differences in expression of SNCA, HAPLN2, MAPT, APP, and OPALIN were observed for PD and MSA compared with healthy controls. Intriguingly, greater activation of unfolded protein response pathway gene expression was observed in PD nuclei versus MSA. Using network analysis, we then identified specific PD- and MSA-correlated gene co-expression modules enriched with disease relevant pathways; the PD-correlated module was significantly enriched for Parkinsons Disease GWAS loci (p = 0.01046). Our analysis provides a broader understanding of oligodendrocyte heterogeneity and reveals distinctive oligodendrocyte pathological alterations associated with PD and MSA which may suggest potential novel therapeutic targets and new strategies for disease modification.

genomics↗

bioRxiv2020

Network Analysis and Human Single Cell Brain Transcriptomics Reveal Novel Aspects of Alpha-Synuclein (SNCA) Biology

Alpha-synuclein (SNCA) aggregates are pathological hallmarks of synucleinopathies, neurodegenerative disorders including Parkinsons Disease (PD) and Lewy Body Dementia (LBD). Functional networks are not yet well-characterized for SNCA by CNS cell type. We investigated cell-specific differences in SNCA expression using Allen Brain Database single-nucleus RNA-seq data from human Middle Temporal Gyrus (MTG, 15,928 nuclei) and Anterior Cingulate Cortex (ACC, 7,258 nuclei). Weighted gene co-expression analysis (WGCNA) and hierarchical clustering identified a conserved SNCA co-expression module. Module genes were highly conserved (p < 10-10) and most highly expressed in excitatory neurons versus inhibitory neurons and other glial cells. SNCA co-expression module genes from ACC and MTG regions were then used to construct a protein-protein interaction (PPI) network, with SNCA empirically top hub. Genes in the SNCA PPI network were compared with genes nearest single nucleotide polymorphisms linked with PD risk in genome-wide association studies. 16 genes in our PPI network are nearest genes to PD risk loci (p < 0.0006) and 55 genes map within 100kb. Selected SNCA PPI network genes nearest PD risk loci were disrupted by CRISPR knock out gene editing for validation of network functional significance; disruption of STK39, GBA, and MBNL2 resulted in significantly elevated intracellular SNCA expression.

neuroscience↗