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A genome-wide CRISPRi screen identifies homologous recombination pathway as potential target for broad-spectrum antibiotic adjuvants.

INTRODUCTION: The widespread misuse and overuse of antibiotics have driven the emergence of multidrug-resistant and pan drug-resistant bacteria, constituting a formidable global health threat. Antibiotic adjuvants that potentiate the efficacy of existing antibiotics represent a particularly promising avenue to address this challenge. METHODS: We performed a genome-wide CRISPR interference (CRISPRi) screening to identify potential targets for broad-spectrum antibiotic adjuvants, which highlighted the homologous recombination pathway as a promising candidate. To functionally validate this pathway, we employed three strategies to suppress the expression and function of recA, a key component of homologous recombination, including a CRISPRi system delivered via transconjugation, a RecX-derived peptide (RecX-20) fused to a cell-penetrating motif, and a small-molecule inhibitor cisplatin validated by surface plasmon resonance. RESULTS: Disruption of the homologous recombination pathway not only significantly increased bacterial susceptibility to multiple classes of antibiotics, including quinolones, β-lactams, aminoglycosides, and nitrofurantoin, but also reduced horizontal gene transfer of antibiotic resistance. In addition, recA deficiency resulted in a cascade of physiological disruptions, including membrane damage, efflux pump dysfunction, oxidative stress imbalance and metabolic disruption. All three recA-targeting strategies enhanced the antibacterial activity, with cisplatin exhibiting the most pronounced potentiating effect both in vitro and in vivo. CONCLUSIONS: This study reveals that the homologous recombination pathway, particularly RecA, is a viable target for the development of broad-spectrum antibiotic adjuvant. Our findings provide mechanistic insights and practical strategies to restore the effectiveness of existing antibiotics and address the growing threat of antimicrobial resistance.

Anti-Bacterial Agents

Druggable genome CRISPRi screen in hydrogels reveals regulators of cortactin-driven actin remodeling promoting glioblastoma invasion.

To identify therapeutic targets limiting glioblastoma invasion, we applied druggable genome CRISPRi screens and multiomic analysis to patient-derived glioblastoma cells in micro-dissectible biomimetic 3D hydrogels that permitted separation and analysis of core versus invasive fractions. Of 2,550 genes screened, 12 encoded druggable targets whose suppression limited invasion, of which AURKB (encoding aurora kinase B) and ACP1 (encoding low molecular weight protein tyrosine phosphatase, LMW-PTP) were validated in neurosphere assays and in vivo. Proximity labeling identified cortactin as a link between LMW-PTP and aurora B, and we observed that cortactin underwent serine phosphorylation by aurora B and tyrosine dephosphorylation by LMW-PTP. Targeting ACP1 or AURKB via CRISPRi or inhibitors in culture and in vivo shifted the cortactin phosphorylation balance in glioblastoma, reducing levels of cortactin and the actin-related protein 2/3 (Arp2/3) complex that mediates cortactin-induced actin stabilization, thereby reducing actin-cortactin-Arp2/3 colocalization and subsequent actin polymerization. AURKB or ACP1 targeting shifted actin from cytoplasm to the nucleus, reducing mesenchymal gene expression. Biophysical analysis implicated AURKB in glioblastoma cell adhesion and stiffness needed for initial migration and ACP1 in mechanical stress resistance required for later migration. These findings revealed a targetable axis balancing kinase and phosphatase activities to regulate actin polymerization during glioblastoma invasion.

Humans

CRISPRi screens identify the lncRNA, LOUP, as a multifunctional locus regulating macrophage differentiation and inflammatory signaling.

Long noncoding RNAs (lncRNAs) account for the largest portion of RNA from the transcriptome, yet most of their functions remain unknown. Here, we performed two independent high-throughput CRISPRi screens to understand the role of lncRNAs in monocyte function and differentiation. The first was a reporter-based screen to identify lncRNAs that regulate TLR4-NFkB signaling in human monocytes and the second screen identified lncRNAs involved in monocyte to macrophage differentiation. We successfully identified numerous noncoding and protein-coding genes that can positively or negatively regulate inflammation and differentiation. To understand the functional roles of lncRNAs in both processes, we chose to further study the lncRNA LOUP [lncRNA originating from upstream regulatory element of SPI1 (also known as PU.1)], as it emerged as a top hit in both screens. Not only does LOUP regulate its neighboring gene, the myeloid fate-determining factor SPI1, thereby affecting monocyte to macrophage differentiation, but knockdown of LOUP leads to a broad upregulation of NFkB-targeted genes at baseline and upon TLR4-NFkB activation. LOUP also harbors three small open reading frames capable of being translated and are responsible for LOUP's ability to negatively regulate TLR4/NFkB signaling. This work emphasizes the value of high-throughput screening to rapidly identify functional lncRNAs in the innate immune system.

RNA, Long Noncoding

CRISPRi-mediated repression of three cI repressors induces the expression of three related Neisseria gonorrhoeae bacteriophages.

The Neisseria gonorrhoeae FA1090 isolate encodes nine prophage islands (Ngoɸ1-9). Ngoɸ1-3 contain genes consistent with a Siphoviridae-dsDNA bacteriophage (phage). Saturating transposon-sequencing screens using two different N. gonorrhoeae isolates predicted that multiple prophage genes were essential, including three putative transcriptional repressors: ngo0479 (present in Ngoɸ1), ngo1116 (present in Ngoɸ2), and ngo1630 (present in Ngoɸ3). All three genes display homology to the Lambda phage cI, a regulator important for maintaining the lysogenic state and inhibiting lytic induction, but these proteins are not close paralogs. Using a Neisseria lactamica-derived Type I-C CRISPR-interference system, we show that these cI orthologs are essential, as the knockdown of each gene results in bacterial death. We determined that the repression of the three cI orthologs resulted in the significant induction of phage gene expression. Finally, we detected Siphoviridae-like phage particles released from N. gonorrhoeae following repression of ngo0479, ngo1116, or ngo1630. We hypothesize that these cI orthologs are critical for preventing phage lytic infection and cell death and allow N. gonorrhoeae to benefit from the carriage and expression of prophage genes.IMPORTANCEBacteriophage, or phage, are bacteria-infecting viruses and are the most abundant natural entities in the world. Here, we report that Neisseria gonorrhoeae's three most complete double-stranded DNA prophage islands each encode essential and related transcriptional repressors. CRISPRi-mediated repression of these transcriptional repressors leads to a significant increase in prophage gene expression and phage induction. This study marks an important initial step in studying the interaction between N. gonorrhoeae and its resident phage.

Neisseria gonorrhoeae

Genome-wide CRISPRi screen in human iNeurons identifies novel negative mTOR regulator genes associated with focal cortical dysplasia.

Focal cortical dysplasia (FCD) is a common cause of focal epilepsy that typically results from brain mosaic mutations in the mTOR cell signaling pathway. To identify new potential FCD genes, we developed an in vitro CRISPRi screen in human neurons and used FACS enrichment based on the FCD biomarker, phosphorylated S6 ribosomal protein (pS6). Using whole-genome (110,000 gRNAs) and candidate (129 gRNAs) libraries, we discovered 6 new genes in which loss of function significantly increases pS6 levels: LRRC4, EIF3A, TSN, HIP1, PIK3R3, and URI1. Further analysis of the mTOR pathway showed that only two of the genes, PIK3R3 and HIP1, caused hyperphosphorylation throughout the AKT/mTOR/S6 signaling pathway. Importantly, potential pathogenic variants in these two genes have been reported in resected brain tissue from a single FCD patient each, supporting the predictive validity of our screen. Knocking down each of the 6 genes in iNeurons made mTOR signaling resistant to the loss of neurotrophic factor signaling, specifically GDNF; even without GDNF, pS6 levels remained comparable to GDNF-stimulated controls. Thus, we have identified negative regulators of neuronal mTOR signaling in the context of lost neurotrophic factor support. Our data expand the set of genes that are likely to regulate mTOR pathway signaling in neurons, provide biological confirmation for candidate genes identified in human tissue, and suggest additional targets for investigating somatic gene variants in resected FCD tissues. The identification of novel mTOR regulators using iNeurons also highlights the importance of genetic screening in disease-related cell types.

Brain mosaicism

Mapping cell-type- and age-dependent neuronal vulnerability through genome-wide in vivo CRISPRi screens in the mouse brain.

Current brain atlases are largely descriptive, cataloging correlative molecular snapshots such as gene expression signatures yet offering limited functional insight. Here, we develop a scalable, cell-type-resolved in vivo CRISPR interference (CRISPRi) platform enabling systematic gene function profiling in the mouse brain. Through genome-wide screens across four neuronal populations at three time points spanning youth to aging, we identify neuronal essential genes missed in vitro and define a consensus set of 269 neuronal core essential genes. The data reveal cell-type-specific genetic vulnerabilities, including divergent dependencies validated for exosome component 9 (Exosc9) and osteopetrosis-associated transmembrane protein 1 (Ostm1) between excitatory and inhibitory neurons. We uncover aging-specific dependencies enriched in mitochondrial and translational pathways, aligning with transcriptional changes in the aging human brain. Finally, we establish the CRISPRinvivo data portal as a community resource for in vivo screening. Altogether, this work provides a broadly applicable platform for in vivo functional genomics and a framework for building comprehensive gene-function brain atlases.

brain aging

In vivo CRISPRi screens reveal Escherichia coli functional adaptations in the mouse gut.

Escherichia coli exhibits remarkable genetic diversity that enables it to adapt to the intestinal environment. Here we establish an in vivo CRISPR interference platform that leverages bacterial gene fitness as a high-resolution functional reporter of E. coli adaptations within mice harbouring a defined minimal microbial community (OligoMM12). The screen revealed that diet profoundly shapes the metabolic landscape of E. coli and the essential gene profile identified cross-feeding interactions. Comparison between a laboratory strain (MG1655), a uropathogenic strain (CFT073) and an adherent-invasive E. coli (AIEC LF82) identified distinct genetic requirements for intestinal colonization, highlighting divergent motility, stress response and respiration strategies. In a host inflammatory environment, we found that AIEC LF82 preferably colonized the small intestine with a mobile genetic element, Gally prophage, playing an important role in modulating fitness. These findings provide a high-resolution genetic atlas of E. coli's functional adaptation and demonstrate the utility of functional genomics to probe the gut environment itself.

Journal Article

CRISPRi screens in human iPSC-derived astrocytes elucidate regulators of distinct inflammatory reactive states.

Astrocytes become reactive in response to insults to the central nervous system by adopting context-specific cellular signatures and outputs, but a systematic understanding of the underlying molecular mechanisms is lacking. In this study, we developed CRISPR interference screening in human induced pluripotent stem cell-derived astrocytes coupled to single-cell transcriptomics to systematically interrogate cytokine-induced inflammatory astrocyte reactivity. We found that autocrine-paracrine IL-6 and interferon signaling downstream of canonical NF-κB activation drove two distinct inflammatory reactive signatures, one promoted by STAT3 and the other inhibited by STAT3. These signatures overlapped with those observed in other experimental contexts, including mouse models, and their markers were upregulated in human brains in Alzheimer's disease and hypoxic-ischemic encephalopathy. Furthermore, we validated that markers of these signatures were regulated by STAT3 in vivo using a mouse model of neuroinflammation. These results and the platform that we established have the potential to guide the development of therapeutics to selectively modulate different aspects of inflammatory astrocyte reactivity.

Humans

Regulators of interferon-responsive microglia uncovered by Genome-wide CRISPRi screening.

Microglia dynamically support brain health through the induction of specialized activation states in response to injury or disease. Activation of the interferon-responsive microglia (IRM) state has been identified across neurodevelopmental windows, age-related cognitive decline, and neurodegenerative diseases. Functionally, IRM have been linked to synaptic pruning, dead cell removal, and neuroinflammation, making this state critical to brain homeostasis. While the functional importance of this state is becoming increasingly clear, our understanding of the regulatory networks that govern IRM induction remain incomplete. To systematically identify genetic regulators of the IRM state, we conducted a genome-wide CRISPR interference screen in human iPSC-derived microglia using IFIT1 as a representative IRM marker. We identified 772 genes that modulate IRM, including canonical type I interferon signaling genes (IFNAR2, TYK2, STAT1/2, USP18) and newly described regulators. We uncovered a non-canonical role for the CCR4-NOT transcription complex subunit 10, CNOT10, in IRM activation. This work provides a comprehensive resource that can be applied to dissect the functions of interferon-responsive microglia and highlights both established and novel targets for modulating microglial interferon signaling in health and disease.

Computational biology and bioinformatics

HyperCas12a enables multiplexed CRISPRi screens.

Interactions between multiple genes or cis-regulatory elements (CREs) underlie a wide range of biological processes in both health and disease. High-throughput screens using dCas9 fused to epigenome editing domains have allowed researchers to assess the impact of activation or repression of both coding and non-coding genomic regions on a phenotype of interest, but assessment of genetic interactions between those elements has been limited to pairs. Here, we combine a hyper-efficient version of Lachnospiraceae bacterium dCas12a (dHyperLbCas12a) with RNA Polymerase II expression of long CRISPR RNA (crRNA) arrays to enable efficient highly-multiplexed epigenome editing. We demonstrate that this system is compatible with several activation and repression domains, including the P300 histone acetyltransferase domain and SIN3A interacting domain (SID). We further show that the system can be used in cultured primary immune cells and to drive differentiation of induced pluripotent stem cells. We also developed new approaches to use the dCas12a platform for simultaneous activation and repression from a single crRNA array via co-expression of multiple dCas12a orthologues. Lastly, we demonstrate that the dHyperLbCas12a effectors are highly effective for multiple modalities of high-throughput screens, namely proliferation screens and screens to dissect the independent and combinatorial contributions of CREs on gene expression. The tools and methods introduced here create new possibilities for highly multiplexed control of gene expression in a wide variety of biological systems.

Journal Article

Druggable genome CRISPRi screen in 3D hydrogels reveals regulators of cortactin-driven actin remodeling in invading glioblastoma cells.

To identify new therapeutic targets that limit glioblastoma (GBM) invasion, we applied druggable-genome CRISPR screens to patient-derived GBM cells in micro-dissectible biomimetic 3D hydrogel platforms that permit separation and independent analysis of core vs. invasive fractions. We identified 12 targets whose suppression limited invasion, of which ACP1 (LMW-PTP) and Aurora Kinase B (AURKB) were validated in neurosphere assays. Proximity labeling analysis identified cortactin as an ACP1-AURKB link, as cortactin undergoes serine phosphorylation by AURKB and tyrosine dephosphorylation by ACP1. Suppression of ACP1 or AURKB in culture and in vivo shifted the balance of cortactin phosphorylation in GBM and reduced actin polymerization and actin-cortactin co-localization. Additional biophysical analysis implicated AURKB in GBM cell adhesion and cortical stiffness, and ACP1 in resistance to mechanical stress and shape plasticity needed for 3D migration. These findings reveal a novel targetable axis that balances kinase and phosphatase activities to regulate actin polymerization during GBM invasion.

CRISPR

Exploring phage-host interactions in Burkholderia cepacia complex bacterium to reveal host factors and phage resistance genes using CRISPRi functional genomics and transcriptomics.

Complex interactions of bacteriophages with their bacterial hosts determine phage host range and infectivity. While phage defense systems and host factors have been identified in model bacteria, they remain challenging to predict in non-model bacteria. In this paper, we integrate functional genomics and transcriptomics to investigate phage-host interactions, revealing active phage resistance and host factor genes in Burkholderia cenocepacia K56-2. Burkholderia cepacia complex species are commonly found in soil and are opportunistic pathogens in immunocompromised patients. We studied infection of B. cenocepacia K56-2 with Bcep176, a temperate phage isolated from Burkholderia multivorans. A genome-wide dCas9 knockdown library targeting B. cenocepacia K56-2 was constructed, and a pooled infection experiment identified 63 novel genes or operons coding for candidate host factors or phage resistance genes. The activities of a subset of candidate host factor and resistance genes were validated via single-gene knockdowns. Transcriptomics of B. cenocepacia K56-2 during Bcep176 infection revealed that expression of genes coding for host factor and resistance candidates identified in this screen was significantly altered during infection by 4 h post-infection. Identifying which bacterial genes are involved in phage infection is important to understand the ecological niches of B. cenocepacia and its phages, and for designing phage therapies.IMPORTANCEBurkholderia cepacia complex bacteria are opportunistic pathogens inherently resistant to antibiotics, and phage therapy is a promising alternative treatment for chronically infected patients. Burkholderia bacteria are also ubiquitous in soil microbiomes. To develop improved phage therapies for pathogenic Burkholderia bacteria, or engineer phages for applications, such as microbiome editing, it's essential to know the bacterial host factors required by the phage to kill bacteria, as well as how the bacteria prevent phage infection. This work identified 65 genes involved in phage-host interactions in Burkholderia cenocepacia K56-2 and tracked their expression during infection. These findings establish a knowledge base to select and engineer phages infecting or transducing Burkholderia bacteria.

Bacteriophages

A systematic strategy for identifying causal single nucleotide polymorphisms and their target genes on Juvenile arthritis risk haplotypes.

BACKGROUND: Although genome-wide association studies (GWAS) have identified multiple regions conferring genetic risk for juvenile idiopathic arthritis (JIA), we are still faced with the task of identifying the single nucleotide polymorphisms (SNPs) on the disease haplotypes that exert the biological effects that confer risk. Until we identify the risk-driving variants, identifying the genes influenced by these variants, and therefore translating genetic information to improved clinical care, will remain an insurmountable task. We used a function-based approach for identifying causal variant candidates and the target genes on JIA risk haplotypes. METHODS: We used a massively parallel reporter assay (MPRA) in myeloid K562 cells to query the effects of 5,226 SNPs in non-coding regions on JIA risk haplotypes for their ability to alter gene expression when compared to the common allele. The assay relies on 180 bp oligonucleotide reporters ("oligos") in which the allele of interest is flanked by its cognate genomic sequence. Barcodes were added randomly by PCR to each oligo to achieve > 20 barcodes per oligo to provide a quantitative read-out of gene expression for each allele. Assays were performed in both unstimulated K562 cells and cells stimulated overnight with interferon gamma (IFNg). As proof of concept, we then used CRISPRi to demonstrate the feasibility of identifying the genes regulated by enhancers harboring expression-altering SNPs. RESULTS: We identified 553 expression-altering SNPs in unstimulated K562 cells and an additional 490 in cells stimulated with IFNg. We further filtered the SNPs to identify those plausibly situated within functional chromatin, using open chromatin and H3K27ac ChIPseq peaks in unstimulated cells and open chromatin plus H3K4me1 in stimulated cells. These procedures yielded 42 unique SNPs (total = 84) for each set. Using CRISPRi, we demonstrated that enhancers harboring MPRA-screened variants in the TRAF1 and LNPEP/ERAP2 loci regulated multiple genes, suggesting complex influences of disease-driving variants. CONCLUSION: Using MPRA and CRISPRi, JIA risk haplotypes can be queried to identify plausible candidates for disease-driving variants. Once these candidate variants are identified, target genes can be identified using CRISPRi informed by the 3D chromatin structures that encompass the risk haplotypes.

Humans

Proliferation Analyses of Conditional Knockdown Strains Using CRISPR Interference in Fission Yeast.

CRISPR interference is a method to conditionally inhibit transcription of an arbitrary target gene. This is useful to study the functions of essential genes, which are required for cellular viability. Although many conditional gene perturbation techniques are available for Schizosaccharomyces pombe, CRISPRi facilitates construction of a large number of knockdown strains because of its systematic, simple procedure. Here, we describe a method to construct and characterize knockdown strains using dCas9-mediated CRISPRi in S. pombe, including a variation of CRISPRi induction technique in a 96-well format for high-throughput studies.

Schizosaccharomyces

A massively parallel CRISPR-based screening platform for modifiers of neuronal depolarization.

Understanding the complex interplay between gene expression and neuronal activity is crucial for unraveling the molecular mechanisms underlying cognitive function and neurological disorders. Here, we developed pooled screens using CRISPR interference (CRISPRi) and the fluorescent calcium integrator CaMPARI2 to evaluate genetic modifiers of neuronal depolarization. Using this screening method, we evaluated 1343 genes for their effect on depolarization in a human iPSC-derived neuron model, revealing potential links to neurodegenerative and neurodevelopmental disorders. These genes include known regulators of neuronal excitability, such as TARPs and ion channels, as well as genes associated with autism spectrum disorder and Alzheimer's disease not previously described to affect neuronal depolarization. This CRISPRi-based screening platform offers a versatile tool to uncover molecular mechanisms controlling neuronal function in health and disease.

Humans

Interrogation of functional variants in COPD GWAS loci by massively parallel reporter assays.

RATIONALE: Genome-wide association study (GWAS) loci often contain many linked variants, making it difficult to determine which variant is functionally relevant. Massively parallel reporter assays (MPRA) allow experimental testing of candidate variants to identify those with regulatory activity. Prior chronic obstructive pulmonary disease (COPD) MPRA studies have largely focused on individual loci, whereas broader multi-locus, multi-cell-type interrogation remains limited. OBJECTIVES: We aim to identify functional variants in five COPD GWAS loci across three lung-relevant cell types. METHODS: We screened 1120 variants using MPRA in epithelial (16HBE), fibroblast (MRC5), and endothelial (HUVEC) cells followed by reporter assay validation. Public Hi-C, ChIP-seq and ATAC-seq datasets were analyzed to evaluate chromatin context near candidate variants. We further performed CRISPR interference (CRISPRi) targeting variant-containing regions and measured gene expression by RT-qPCR in primary normal human bronchial epithelial (NHBE) cells using two gRNAs per variant. Co-immunoprecipitation was performed to test interaction between selected candidate genes. MEASUREMENTS AND MAIN RESULTS: In MPRA, we identified 25 variants with allele-specific effects (∼2% of tested variants). Enrichment of H3K27Ac and open chromatin near rs35421223 was detected in 16HBE cells. CRISPRi identified two SNP-gene pairs, RUVBL1 and RAB7A regulated by rs35421223 in both the 16HBE cell line and primary NHBE cells. We detected interaction between RUVBL1 and the known COPD gene product FAM13A. CONCLUSIONS: Screening COPD loci across three cell types identified functional regulatory variants and linked them to candidate target genes for future mechanistic studies.

Journal Article

Causal circuit tracing reveals distinct computational architectures in single-cell foundation models: inhibitory dominance, biological coherence, and cross-model convergence.

MOTIVATION: Sparse autoencoders (SAEs) decompose foundation-model activations into interpretable features, but the model-internal causal interactions between those features (i.e. what ablating one feature does to the others, as distinct from the biological causal structure of the underlying cells)-and how those model-internal relationships relate to biological structure-are uncharacterized in single-cell foundation models. RESULTS: We introduce model-internal causal circuit tracing-zeroing one SAE feature at a source layer and measuring the resulting change in all downstream SAE features, for each of 120 source features-and apply it to Geneformer V2-316M and scGPT whole-human across four conditions (96&#xa0;892 ablation-derived edges, 80&#xa0;191 forward passes). On annotation-selected source features, edges share GO/KEGG/Reactome/STRING/TRRUST ontology terms at 50.9%-68.5%, a 2.9-6.2&#xd7; enrichment over a configuration-preserving permutation null (P<.002); on 20 randomly sampled source features this attenuates to 21.5%-26.3%-still 2.5-3.1&#xd7; above null-quantifying the annotation-selection contribution. Inhibitory dominance (fraction of ablation edges with d<0, i.e. source activation supports downstream target) is 65.5%-89.4%. scGPT produces larger raw per-edge effects (mean |d|=1.40 versus 1.05); after feature-share normalization, Geneformer is stronger (paired gene-pair ratio 0.64 on 33&#xa0;301 shared pairs). Cross-model consensus yields 1142 architecture-invariant domain pairs (ordered pairs of GO biological-process categories "A&#x2192;B" each connected by at least one ablation edge in both models; 10.6&#xd7; enrichment over permutation null; P<.001). Circuit edge magnitude explains <1% of the variance in marginal driver-gene coexpression on the same cells (R2=0.010, n=31&#xa0;176): the graph encodes structure beyond bivariate correlation. Against a matched-cell-type ENCODE ChIP-seq prior, circuit-predicted transcription factor (TF)&#x2192;target pairs are enriched 2.06&#xd7; (Fisher OR 5.84), markedly higher than 1.12&#xd7; against TRRUST; direct ChIP-seq-supported target pairs show 10-30&#xd7; larger CRISPRi sign-bias-corrected excess than indirect pairs. Gene-level CRISPRi validation on Replogle K562 and the noncancer RPE1 arm (and a true primary-T-cell control from Shifrut E, Carnevale J, Tobin V et&#xa0;al. Genome-wide CRISPR screens in primary human T cells reveal key regulators of immune function. Cell 2018; 175: 1958-71.e15) after sign-bias correction shows excess over baseline of +0.03 and +0.35 percentage points on K562 and RPE1, respectively (baseline already 52%-56% from sign marginals); effect-magnitude Spearman correlations &#x3c1;&#x2248;0. Bootstrap and per-cell-type stability (N&#x2208;{50,100,200}; B cell, CD4&#xa0;+ T, macrophage) give Pearson r&#x2265;0.97 on shared edges with 100% sign agreement; edge Jaccard grows monotonically with sample size. The circuit graph is therefore highly reproducible as an effect-size map, cell type specific in edge identity, consistent with coexpression encoding, and weakly but detectably enriched for ChIP-seq-supported direct regulatory edges. AVAILABILITY AND IMPLEMENTATION: https://github.com/Biodyn-AI/bio-sae-circuits (Python). Archival DOI: 10.5281/zenodo.19,633,166 (Zenodo).

Humans

A Massively Parallel CRISPR-Based Screening Platform for Modifiers of Neuronal Activity.

Understanding the complex interplay between gene expression and neuronal activity is crucial for unraveling the molecular mechanisms underlying cognitive function and neurological disorders. Here, we developed pooled screens for neuronal activity, using CRISPR interference (CRISPRi) and the fluorescent calcium integrator CaMPARI2. Using this screening method, we evaluated 1343 genes for their effect on excitability in human iPSC-derived neurons, revealing potential links to neurodegenerative and neurodevelopmental disorders. These genes include known regulators of neuronal excitability, such as TARPs and ion channels, as well as genes associated with autism spectrum disorder and Alzheimer's disease not previously described to affect neuronal excitability. This CRISPRi-based screening platform offers a versatile tool to uncover molecular mechanisms controlling neuronal activity in health and disease.

Journal Article