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Rogers, B. B.

Publications and source records attributed to Rogers, B. B..

6 recordsLinked to original sources

Promoter mutagenesis and a massively parallel reporter screen of the MAPT locus identifies cis-regulatory elements and genetic variation effects

Tau neurofibrillary tangles are a hallmark of several neurodegenerative diseases called tauopathies, including frontotemporal dementia and Alzheimers Disease. Ongoing clinical trials for tauopathies seek to reduce Tau in the brain through immunotherapy, antisense oligonucleotides, and siRNA. MAPT codes for Tau, therefore understanding how the MAPT gene is regulated and the effect of genetic variation at its regulatory elements is likely to have high relevance for tauopathies. We screened a [~]3 Mb region including the MAPT locus using 2 different massively parallel reporter assay (MPRA) strategies in KOLF2.1J h-NGN2 neurons and HEK293FT cells, identifying previously unannotated cis-regulatory elements (CREs). Using CRISPR interference (CRISPRi) in mixed neuron cultures, we identified a new CRE for MAPT, as well as 2 CREs for another nearby gene of interest, KANSL1. Known genetic variation from the Alzheimers Disease sequencing project was tested in a separate MPRA at the top CREs near the MAPT gene, identifying variants with altered regulatory effects including those at previously identified CREs for MAPT. Using a saturation mutagenesis screen of a 2,000 bp region encompassing the MAPT promoter, we assessed regulatory effects of each possible single nucleotide variant in this region. We identified several neuron-specific regulatory variant effects at this region, including a high confidence binding site for the transcription factors EGR2, ZBTB14, and TCLF5 at a region of high MPRA activity and genetic conservation.

genetics↗

Single Cell Multiomics Across Nine Mammals Reveals Cell Type Specific Regulatory Conservation in the Brain

Understanding the gene regulatory mechanisms underlying brain function is crucial for advancing knowledge of the genetic basis of neurologic diseases. Cis-regulatory elements (CREs) play a pivotal role in gene regulation, and their evolutionary conservation can offer valuable insights. Importantly, the function and evolution of CREs are affected not only by primary sequence, but also by the cis- and trans-regulatory context. However, comparative functional analyses across species have been limited, leaving how these regulatory landscapes evolve in the brain largely unresolved. Here, we generated single-nucleus multiomic (snRNA- and snATAC-seq) data from cortex tissue across nine mammalian species and identified candidate CREs (cCREs) in a cell type-specific manner. We developed a multidimensional framework of conservation to assess sites of shared function that integrates sequence, chromatin accessibility, and enhancer-gene associations. Using massively parallel reporter assays (MPRA) in human neural progenitor cells and neurons, we measured activity of cCREs including both conserved and human-specific regions. CRISPR interference validated conserved enhancer function, including at neurodevelopmentally important genes like FAM181B. Motif enrichment identified transcription factors distinguishing conserved versus recent cCREs. Linkage disequilibrium score regression indicated that both conserved and human-specific cCREs were enriched for neuropsychiatric GWAS risk, while neurodegenerative risk was confined to conserved elements. Our findings define functional dimensions of enhancer conservation and demonstrate how regulatory evolution shapes human brain biology and disease susceptibility.

genomics↗

KOLF2.1J iTF-Microglia: A standardized platform to studymicroglial transcriptional regulatory networks in CNS disease

Understanding transcriptional regulatory networks (TRNs) in microglia is key to uncovering mechanisms driving central nervous system (CNS) disorders. Human iPSC-derived models offer a tractable system for studying microglia, yet variability between lines has limited reproducibility. Here, we use the standardized KOLF2.1J iTF line to rapidly generate microglia-like cells (iTF-Microglia) and profile TRNs under homeostatic and inflammatory conditions. iTF-Microglia closely resemble primary brain microglia at both transcriptomic and epigenomic levels. Integrative analyses reveal microglia-enriched candidate cis-regulatory elements (cCREs) and dynamic enhancer remodeling upon differentiation and LPS+IFNG stimulation, involving key transcription factors (TFs) including NF-{kappa}B, IRF, and STAT families. TRNs active in iTF-Microglia are enriched for genetic variants linked to Alzheimers disease and other CNS disorders. These findings establish KOLF2.1J iTF-Microglia as a reproducible and genetically tractable platform for studying human microglial gene regulation and provide mechanistic insight into how TRN remodeling may contribute to CNS disease risk.

genomics↗

MAPT expression is regulated by long-range interactions with cis-regulatory elements

BackgroundTauopathies are a group of neurodegenerative diseases driven by abnormal aggregates of tau, a microtubule associated protein encoded by the MAPT gene. MAPT expression is absent in neural progenitor cells (NPCs) and increases during differentiation. This temporally dynamic expression pattern suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to differentiated cell types. Given the relevance of MAPT expression to neurodegeneration pathogenesis, identification of such elements is relevant to understanding genetic risk factors. MethodsWe performed HiC, chromatin conformation capture (Capture-C), single-nucleus multiomics (RNA-seq+ATAC-seq), bulk ATAC-seq, and ChIP-seq for H3K27Ac and CTCF in NPCs and neurons differentiated from human iPSC cultures. We nominated candidate cis-regulatory elements (cCREs) for MAPT in human NPCs, differentiated neurons, and pure cultures of inhibitory and excitatory neurons. We then assayed these cCREs using luciferase assays and CRISPR interference (CRISPRi) experiments to measure their effects on MAPT expression. Finally, we integrated cCRE annotations into an analysis of genetic variation in AD cases and controls. ResultsUsing orthogonal genomics approaches, we nominated 94 cCREs for MAPT, including the identification of cCREs specifically active in differentiated neurons. Eleven regions enhanced reporter gene transcription in luciferase assays. Using CRISPRi, 5 of the 94 regions tested were identified as necessary for MAPT expression as measured by RT-qPCR and RNA-seq. Rare and predicted damaging genetic variation in both nominated and confirmed CREs was depleted in AD cases relative to controls (OR = 0.40, p = 0.004), consistent with the hypothesis that variants that disrupt MAPT enhancer activity, and thereby reduce MAPT expression, may be protective against neurodegenerative disease. ConclusionsWe identified both proximal and distal regulatory elements for MAPT and confirmed the regulatory function for several regions, including three regions centromeric to MAPT beyond the well-described H1/H2 haplotype inversion breakpoint. This study provides compelling evidence for pursuing detailed knowledge of CREs for genes of interest to permit better understanding of disease risk.

genomics↗

Single nucleus multiomics identifies ZEB1 and MAFB as candidate regulators of Alzheimer's disease-specific cis regulatory elements.

Cell type-specific transcriptional differences between brain tissues from donors with Alzheimers disease (AD) and unaffected controls have been well-documented, but few studies have rigorously interrogated the regulatory mechanisms responsible for these alterations. We performed single nucleus multiomics (snRNA-seq+snATAC-seq) on 105,332 nuclei isolated from cortical tissues from 7 AD and 8 unaffected donors to identify candidate cis-regulatory elements (CREs) involved in AD-associated transcriptional changes. We detected 319,861 significant correlations, or links, between gene expression and cell type-specific transposase accessible regions enriched for active CREs. Among these, 40,831 were unique to AD tissues. Validation experiments confirmed the activity of many regions, including several candidate regulators of APP expression. We identified ZEB1 and MAFB as candidate transcription factors playing important roles in AD-specific gene regulation in neurons and microglia, respectively. Microglial links were globally enriched for heritability of AD risk and previously identified active regulatory regions.

genomics↗

Long-read genome sequencing for the diagnosis of neurodevelopmental disorders

PurposeExome and genome sequencing have proven to be effective tools for the diagnosis of neurodevelopmental disorders (NDDs), but large fractions of NDDs cannot be attributed to currently detectable genetic variation. This is likely, at least in part, a result of the fact that many genetic variants are difficult or impossible to detect through typical short-read sequencing approaches. MethodsHere, we describe a genomic analysis using Pacific Biosciences circular consensus sequencing (CCS) reads, which are both long (>10 kb) and accurate (>99% bp accuracy). We used CCS on six proband-parent trios with NDDs that were unexplained despite extensive testing, including genome sequencing with short reads. ResultsWe identified variants and created de novo assemblies in each trio, with global metrics indicating these data sets are more accurate and comprehensive than those provided by short-read data. In one proband, we identified a likely pathogenic (LP), de novo L1-mediated insertion in CDKL5 that results in duplication of exon 3, leading to a frameshift. In a second proband, we identified multiple large de novo structural variants, including insertion-translocations affecting DGKB and MLLT3, which we show disrupt MLLT3 transcript levels. We consider this extensive structural variation likely pathogenic. ConclusionThe breadth and quality of variant detection, coupled to finding variants of clinical and research interest in two of six probands with unexplained NDDs strongly support the value of long-read genome sequencing for understanding rare disease.

genomics↗