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Results for “high-content screening”

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At least 19 recordsLinked to original sources

PubMed1999

Quantification of G-Protein Coupled Receptor Internatilization Using G-Protein Coupled Receptor-Green Fluorescent Protein Conjugates with the ArrayScantrade mark High-Content Screening System.

Many G-protein coupled receptors (GPCRs) undergo ligand-dependent homologous desensitization and internalization. Desensitization, defined as a decrease in the responsiveness to ligand, is accompanied by receptor aggregation on the cell surface and internalization via clathrin-coated pits to an intracellular endosomal compartment. In this study, we have taken advantage of the trafficking properties of GPCRs to develop a useful screening method for the identification of receptor mimetics. A series of studies were undertaken to evaluate the expression, functionality, and ligand-dependent trafficking of GPCR-green fluorescent protein (GFP) fusion conjugates stably transfected into HEK 293 cells. These GPCR-GFP expressing cells were then utilized in the validation of the ArrayScantrade mark (Cellomicstrade mark, Pittsburgh, PA), a microtiter plate imaging system that permits cellular and subcellular quantitation of fluorescence in whole cells. These studies demonstrated our ability to measure the internalization of a parathyroid hormone (PTH) receptor-GFP conjugate after ligand treatment by spatially resolving internalized receptors. Internalization was time- and dose-dependent and appeared to be selective for PTH. Similar results were obtained for a beta(2)-adrenergic receptor (beta(2) AR)-GFP conjugate stably expressed in HEK 293 cells. The internalized GFP-labeled receptors were visualized as numerous punctate ³spots² within the cell interior. An algorithm has been developed that identifies and collects information about these spots, allowing quantification of the internalization process. Variables such as the receptor-GFP expression level, plating density, cell number per field, number of fields scanned per well, spot size, and spot intensity were evaluated during the development of this assay. The method represents a valuable tool to screen for receptor mimetics and antagonists of receptor internalization in whole cells rapidly.

Journal Article↗

PubMed2000

Cell-based, high-content screen for receptor internalization, recycling and intracellular trafficking.

A variety of physiologically important receptors are internalized and then recycled back to the plasma membrane by the endocytic recycling compartment. These include the transferrin receptor and many G-protein coupled receptors (GPCRs). The internalization of GPCRs is a result of agonist stimulation. A cell-based fluorescent imaging assay is described that detects and quantifies the presence of fluorescently labeled receptors and macromolecules in the recycling compartment. This High Content Screening application is conducted on the ArrayScan II System that includes fluorescent reagents, imaging instrumentation and the informatics tools necessary to screen for compounds that affect receptor internalization, recycling and GPCR activation. We demonstrate the Receptor Internalization and Trafficking application by quantifying (i) the internalization and recycling of the transferrin receptor using a fluorescently labeled ligand and (ii) the internalization of a physiologically functional model GPCR, a GFP-parathyroid hormone receptor chimera. These assays give high signal-to-noise ratios, broad dynamic ranges between stimulated and unstimulated conditions and low variability across different screening runs. Thus, the Receptor Internalization and Trafficking application, in conjunction with the ArrayScan II System, forms the basis of a robust, information-rich and automated screen for GPCR activation.

Animals↗

PubMed1999

Green fluorescent protein (GFP): applications in cell-based assays for drug discovery.

Green fluorescent protein (GFP) is a powerful tool for cell-based assays owing to the intrinsic fluorescence of this protein that allows real-time analysis of molecular events in living cells. A number of GFP variants have been developed with optimal properties for both high-throughput screening and high-content screening. The author discusses advances in basic GFP technology, including the discovery of fluorescent proteins from divergent bioluminescent species, as well as the development of various GFP biosensors suited to the drug discovery process.

Journal Article↗

PubMed2026

High-Content CRISPR Screening: Methods and Applications.

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screening has become a central technology in functional genomics, enabling genome-scale interrogation via pooled perturbations. Early CRISPR screens employed survival or simple phenotypic readouts to identify essential genes and drug resistance mechanisms. However, as biological questions have shifted toward understanding regulatory networks, cellular heterogeneity, and context-dependent gene functions, there has been increasing demand for screening strategies capable of capturing complex cellular phenotypes beyond cell fitness. Recent advances in single-cell sequencing, high-content imaging, and spatial transcriptomics have expanded the resolution of CRISPR screening by enabling multidimensional phenotypic characterization following genetic perturbation. By integrating pooled perturbations with diverse readouts, these approaches systematically map targeted gene edits to transcriptional states, cellular phenotypes, and microenvironmental contexts. Meanwhile, innovations in library design, delivery, and computational pipelines have further improved the robustness and interpretability of high-content screening platforms. This review synthesizes the methodological evolution of CRISPR screening, emphasizing advances in perturbation strategies, delivery systems, and multimodal readouts. Representative applications spanning oncology, immunotherapy, developmental biology, neurobiology, and infectious diseases are delineated to demonstrate refined gene network annotations. Additionally, existing technical bottlenecks, such as scalability, cost constraints, and in vivo limitations, are critically assessed. Finally, future directions are proposed to facilitate the development of precise medicine.

CRISPR screening↗

PubMed1998

Fluorescent-protein biosensors: new tools for drug discovery.

Recent improvements in target discovery and high-throughput screening have increased the pressure at key points along the drug-discovery pipeline. High-content screening was developed to ease the bottlenecks formed at the target-validation and lead-optimization points, and a new generation of reagents that report on specific molecular processes in living cells (fluorescent-protein biosensors) have been important in its development. Creative designs of fluorescent-protein biosensors have emerged and been used to measure the molecular dynamics of macromolecules, metabolites and ions. Recent applications of fluorescent-protein biosensors to biological problems have provided a foundation for their use in biotechnology.

Biosensing Techniques↗

PubMed2025

CROPseq-multi: a universal solution for multiplexed perturbation in high-content pooled CRISPR screens.

Forward genetic screens seek to dissect complex biological systems by systematically perturbing genetic elements and observing the resulting phenotypes. While standard screening methodologies introduce individual perturbations, multiplexing perturbations improves the performance of single-target screens and enables combinatorial screens for the study of genetic interactions. Current tools for multiplexing perturbations are limited by technical challenges and do not offer compatibility across diverse screening methodologies, including enrichment, single-cell sequencing, and optical pooled screens. Here, we report the development of CROPseq-multi (CSM), a CROPseq1-inspired lentiviral system to multiplex Streptococcus pyogenes (Sp) Cas9-based perturbations with versatile readout compatibility and high performance for both perturbation and barcode identification. CSM has equivalent per-guide activity to CROPseq and low lentiviral recombination frequencies. Dual-guide CSM libraries are constructed in a single, facile molecular cloning step that facilitates the use of unique molecular identifiers. CSM is compatible with enrichment screening methodologies, single-cell RNA-sequencing readouts, and optical pooled screens. For optical pooled screens, an optimized and multiplexed in situ detection protocol improves barcode counts 10-fold (for mRNA detection), enables detection of recombination events, and reduces the number of sequencing cycles required for decoding by 3-fold relative to CROPseq. CROPseq-multi-v2 (CSMv2) adds compatibility for detection methods based on T7 RNA polymerase in vitro transcription2-5. CSM provides a single system for CRISPR screens that is compatible with individual and combinatorial perturbations, diverse SpCas9-based perturbation technologies, and multiple high-content, single-cell phenotypic readouts.

CRISPR Cas9↗

PubMed2025

A Reporter Platform to Study Therapy-Induced Senescence in Live Cancer Cells.

Senescence is a durable state of cell cycle arrest that can be induced by various stressors, including DNA damage caused by chemotherapeutic agents or ionizing radiation. In the context of cancer, therapy-induced senescence (TIS) plays a dual role: while it effectively halts tumor cell proliferation, TIS also carries the risk of promoting tumor relapse through the senescence-associated secretory phenotype (SASP). Beyond its direct impact on tumor cells, cancer therapies leading to TIS often induce short- and long-term side effects that significantly affect the quality of life for patients. However, the lack of universal biomarkers for TIS hinders a comprehensive understanding of its characteristics and its role in cancer therapies. A lamin-based senescence reporter platform is developed to reliably detect and sort live senescent cancer cells. This versatile tool supports live-cell imaging, enabling real-time tracking of senescence induction and escape to investigate heterogeneity in treatment response. Additionally, it allows high-content screening and marker integration, for example incorporating IL6 as SASP marker. It is therefore a valuable tool for fundamental research addressing new questions in the field of TIS as well as for drug discovery, including the development of novel senolytics.

Humans↗

PubMed2026

Endogenous tagging of the TBXT (Brachyury) gene with 2A-EGFP in BJNhem19 human embryonic stem cells using CRISPR-Cas9 genome editing.

Brachyury (TBXT) is a T-box transcription factor essential for directing human embryonic stem cells (hESCs) toward mesodermal lineage specification. Here, we report the generation of a Brachyury/TBXT-2A-EGFP knock-in reporter line in the BJNhem19 hESC line using CRISPR/Cas9-mediated homology-directed repair. Accurate integration of the reporter cassette was confirmed by DNA sequencing and validated by the comparison of EGFP expression to endogenous TBXT gene expression following directed mesodermal differentiation. This reporter line provides a tractable fluorescence-based platform for real-time monitoring of mesodermal commitment, which will help in high-content screening of differentiation protocols.

Journal Article↗

PubMed2026

PLCG2 downregulation impairs synaptic function and increases Alzheimer's disease hallmarks in neuronal cultures.

We developed a high-content screening to investigate how Alzheimer's disease (AD) genetic risk factors may affect synaptic mechanisms in rat primary neuronal cultures. Of the target genes identified, we found that Plcg2 downregulation in mouse dentate gyrus neurons consistently disrupted dendritic morphology and synaptic function. In human neuronal cultures (hNCs), PLCG2 downregulation also impaired synaptic function and increased amyloid-β (Aβ) levels and Tau phosphorylation. Very rare PLCG2 loss-of-function (LoF) variants were associated with a tenfold increased AD risk. PLCG2 LoF carriers show low mRNA/protein PLCG2/PLCγ2 levels and the R953* LoF mutation compromised synaptic function and increased AD hallmarks in hNCs. Single-nucleus RNA sequencing analyses confirmed that the downregulation of PLCG2 impacted pathways related to synaptic and neuronal functions, potentially through neurexins in neurons. In conclusion, PLCγ2 downregulation could increase AD risk by impairing synaptic functions and by increasing Aβ levels and Tau phosphorylation in neurons.

Alzheimer Disease↗

PubMed2026

Integrative chemical genetics platform identifies condensate modulators linked to neurological disorders.

Dysregulation of biomolecular condensates is implicated across multiple neurological disorders. However, approaches to systematically identify their modulators remain limited. Here, we expand the utility of MLF2 as a versatile condensate biomarker and develop CondenScreen, an integrated high-content screening and bioinformatics pipeline enabling identification of condensate modulators across chemical and genetic space. Screening 1760 bioactive compounds in a cellular DYT1 dystonia model, we validate the platform for condensate-targeted drug discovery, identifying drugs that prevent the accumulation of the MLF2 reporter into nuclear envelope condensates. In parallel, a genome-wide CRISPR/Cas9 screen correlates nuclear condensate abundance with genes implicated in microcephaly and over eight additional neurodevelopmental disorders. Machine learning and confocal imaging resolve distinct condensate phenotypes, with RNF26 deletion provoking nuclear envelope condensates that phenocopy hallmarks of torsin deficiency. Our study provides a scalable platform for identifying modulators of condensates and establishes a correlative connection between nuclear condensate accumulation and genes implicated in neurodevelopmental disorders.

Humans↗

PubMed1991

Factors influencing determination of high-level aminoglycoside resistance in Enterococcus faecalis.

The ability of seven methods to detect high-level gentamicin (58 strains) and streptomycin resistance (56 strains) among 107 Enterococcus faecalis isolates was investigated at the University of Chicago Medical Center and the University of Nebraska Medical Center. Methods included a standard agar screen plate, high-content disk diffusion, Remel (Lenexa, Kans.) EF Synergy Quad plates, standard microdilution panels prepared in house, Pasco MIC Gram-Positive panels (Difco Laboratories, Detroit, Mich.), MicroScan MIC Type 5 dry panels (Baxter Healthcare Corp., MicroScan Div., West Sacramento, Calif.), and Vitek GPS-TA cards (Vitek Systems Inc., Hazelwood, Mo.). Results indicating false resistance were not obtained by any method, and there was 100% agreement between the results of the disk diffusion and standard agar screen methods. Prolonging incubation from 24 to 48 h increased resistance detection for both agar and microdilution screens. EF Synergy Quad plates inoculated with micropipettes detected 100% of the streptomycin- and gentamicin-resistant isolates. Resistance detection for streptomycin and gentamicin, respectively, was 93 and 96% by standard microdilution, 93 and 98% by Pasco panels, 88 and 89% by MicroScan panels, and 88 and 91% by Vitek GPS-TA cards. False susceptibility occurred more frequently with streptomycin-resistant isolates than it did with gentamicin-resistant strains and appeared to be strain related in some instances. The use of an increased inoculum size enhanced resistance detection with these strains, but it complicated interpretation of results and led to the selection of streptomycin-resistant mutants. Until results of further studies delineate optimum test conditions, a delay in the final interpretation of agar and microdilution screen results until 48 h for isolates showing no or light growth at 24 h may help to minimize the occurrence of false susceptibility reporting.

Anti-Bacterial Agents↗

PubMed2026

Field-isolate recombinant tick-borne encephalitis viruses define reporter-stability guidelines for antiviral testing in flaviviruses.

As arthropod-borne viruses continue to threaten populations globally, there is a pressing need for experimental systems that enable rapid antiviral discovery. Reverse-genetics platforms producing recombinant reporter orthoflaviviruses have been developed to address this gap. Here, we present two new recombinant tick-borne encephalitis viruses (TBEVrec) generated on a European-subtype Haselmühl Tiho1 isolate backbone. A reporter gene, either eGFP or Nluc, was inserted in the capsid-coding region of the genome downstream of the capsid RNA regulatory signal and separated from the complete viral polyprotein by a 2A self-cleaving peptide. TBEVrec was better rescued using the circular polymerase extension reaction (CPER) than with the infectious subgenomic amplicon (ISA) method. TBEVrec replicated efficiently in relevant human cell lines, with comparable replication to wild-type TBEV in a neuronal cell line and moderately reduced titers and RNA levels in immune-derived cell lines. Using either eGFP or Nluc, we illustrate how TBEVrec enabled high-content RNAi screening, highlighting Nucleolin and PRKD1 as potential TBEV host factors, and drug testing on a benchtop plate reader. Nanopore sequencing of the eGFP insert revealed that the reporter is excised without affecting flanking regions. Comparative analysis of eGFP and Nluc further shows that this instability is time- and cell type-dependent, and that Nluc is comparatively more stable. From these observations, we outline safeguards and design principles that are broadly applicable both to the rescue of existing constructs and to the design of future recombinant reporter virus platforms.

CPER↗

PubMed2025

Panduratin A Induces Autophagy Through AMPK Activation Independent of mTOR Inhibition and Restricts Mycobacterium tuberculosis in Host Macrophages.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a major global health burden, especially with the increasing prevalence of drug-resistant strains. There is an urgent need for new therapeutics that act via alternative mechanisms. Autophagy, a vital cell-autonomous defense process, allows macrophages to degrade intracellular pathogens such as Mtb and has gained attention as a potential target for host-directed therapy. In this study, we conducted a high-content imaging screen of herb-derived compounds to identify autophagy inducers in RAW264.7 macrophages. Panduratin A (NPA), a natural compound from Boesenbergia rotunda, was found to potently induce autophagy. NPA promoted autophagic vacuole formation in a dose-dependent fashion at low micromolar levels. Its autophagy-inducing effect was validated using RFP-GFP-LC3 dual fluorescence assays and immunoblotting in the presence of bafilomycin A1. Further mechanistic analysis revealed that NPA activates autophagy through AMPK activation, independent of mTOR inhibition. Importantly, NPA significantly promoted intracellular Mtb clearance and increased colocalization of Mtb with autophagosomes and lysosomes, in a manner dependent on Beclin-1. These findings highlight NPA as a potent enhancer of macrophage antimicrobial responses via autophagy, supporting its potential as a candidate for host-directed adjunctive therapy against TB.

Autophagy↗

PubMed2025

Monitoring Influenza A Virus Entry Using Quantitative Fluorescence Microscopy.

Influenza A virus (IAV) is a major threat to global human health and is a topic of intense research. With the continuous problem of seasonal influenza and the threat of potential pandemics due to frequent emergence of new viral strains, development of new, broad-spectrum antivirals is an urgent priority. In antiviral development against influenza, the process of host cell entry of IAV is of particular interest as inhibiting the virus at the entry step should stop infection early on, blocking the downstream infection processes including viral replication and transcription. Therefore, a detailed understanding of the IAV entry processes is essential to illuminate virus-assisting host factors that can serve as potentially valuable targets for therapeutic interventions. To accelerate the identification of novel antivirals or host-directed targets that play essential role in IAV entry, quantitative assays that can be used to monitor the virus at sequential entry steps would be important for performing high-content genetic or inhibitor screens. In this chapter, we describe how IAV entry can be monitored at the sequential entry steps, spanning from the initial attachment of the virus particle to the cell surface to the transmission of the viral genome to the nucleus, by fluorescence microscopy. Further, we provide the methods to quantify the images acquired with high-content microscope for each of the major IAV entry steps. The fluorescence microscopy-based IAV entry assays and the image quantification methods described here can be used to boost our understanding of the virus-host cell interactions and can lead to the discovery of novel host-directed prophylactic or therapeutic interventions.

Humans↗

PubMed2025

Genome-wide CRISPR screens identify critical targets to enhance CAR-NK cell antitumor potency.

Adoptive cell therapy using engineered natural killer (NK) cells is a promising approach for cancer treatment, with targeted gene editing offering the potential to further enhance their therapeutic efficacy. However, the spectrum of actionable genetic targets to overcome tumor and microenvironment-mediated immunosuppression remains largely unexplored. We performed multiple genome-wide CRISPR screens in primary human NK cells and identified critical checkpoints regulating resistance to immunosuppressive pressures. Ablation of MED12, ARIH2, and CCNC significantly improved NK cell antitumor activity against multiple treatment-refractory human cancers in vitro and in vivo. CRISPR editing augmented both innate and CAR-mediated NK cell function, associated with enhanced metabolic fitness, increased secretion of proinflammatory cytokines, and expansion of cytotoxic NK cell subsets. Through high-content genome-wide CRISPR screening in NK cells, this study reveals critical regulators of NK cell function and provides a valuable resource for engineering next-generation NK cell therapies with improved efficacy against cancer.

Humans↗

PubMed1995

Detection of aminoglycoside-penicillin synergy against Enterococcus faecium using high-content aminoglycoside disks.

Thirty-seven Enterococcus faecium strains were screened for high-level aminoglycoside resistance with an agar diffusion test using high-content aminoglycoside disks (300 micrograms of streptomycin and 120 micrograms of gentamicin, tobramycin, kanamycin or amikacin). The inhibition zones obtained were correlated with results of time-kill penicillin-aminoglycoside synergy studies. An 11 mm breakpoint differentiated strains susceptible or resistant to the synergy of streptomycin plus penicillin. Irrespective of the inhibition zones obtained with tobramycin and kanamycin disks, Enterococcus faecium strains never showed synergy with penicillin in combination with these aminoglycosides. Penicillin-amikacin synergy cannot be predicted by the amikacin disks. Nevertheless, even though kanamycin disks do not predict penicillin-kanamycin synergy, they can be used to predict penicillin-amikacin synergy. In summary, high-content streptomycin, gentamicin and kanamycin disks can be used to predict the susceptibility of Enterococcus faecium strains to the synergistic combination of penicillin plus one of the aminoglycosides (streptomycin, gentamicin or amikacin, respectively).

Aminoglycosides↗

PubMed1998

Prevalence of high level aminoglycoside and vancomycin resistance among enterococci in Turkey.

Enterococcus spp. have become the third most common cause of nosocomial infections. High-level aminoglycoside resistance (HLAR), an important clinical concern, has been associated with some species of enterococci. The synergistic effect obtained by the combination of aminoglycosides with penicillin or vancomycin disappears in strains that show high-level resistance (HLR) to the aminoglycosides. We evaluated the agar dilution and high content disk diffusion tests for the detection of HLAR for 60 isolated enterococci. In our study 4 strains of Enterococcus faecalis (6.6%) and 8 strains of Enterococcus faecium (13.3%), totally 20% were found to be highly resistant to gentamicin; 2 strains of E. faecalis (13.3%), 8 strains of E. faecium (3.3%), totally 16.6% showed HLR to streptomycin by agar dilution method and the same rates were found by high-content disk diffusion method. 2 strains of E. faecalis (3.3%), 4 strains of E. faecium (6.6%), totally 10% showed vancomycin resistance by agar dilution method. The ratio for beta lactamase activity was found to be 26.6% for E. faecalis and 3.3% for E. faecium. Our results demonstrate that high-content disk diffusion test should be performed by using both gentamicin and streptomycin in routine screening of HLAR among enterococci and the determination of beta lactamase activity at the same time is also useful for detecting resistance to a beta lactam agent.

Anti-Bacterial Agents↗

PubMed1995

Molecular characterization and multilaboratory evaluation of Enterococcus faecalis ATCC 51299 for quality control of screening tests for vancomycin and high-level aminoglycoside resistance in enterococci.

Studies were conducted to validate the use of Enterococcus faecalis ATCC 51299 (which is vancomycin resistant and resistant to high levels of gentamicin and streptomycin) and E. faecalis ATCC 29212 (which is susceptible to vancomycin and against which gentamicin or streptomycin and cell wall-active agents have synergistic kill activity) as controls in an agar screening test for vancomycin resistance and high-level streptomycin and gentamicin resistance and a broth microdilution screening test for high-level streptomycin and gentamicin resistance. Both organisms performed as expected in these tests and will serve as appropriate controls. However, E. faecalis ATCC 29212 was occasionally noted to produce light growth on the vancomycin screening plate with certain lots of agar. Quality control ranges for disk diffusion tests with disks with large amounts of streptomycin (300 micrograms) and gentamicin (120 micrograms) were established for E. faecalis ATCC 29212; zone limits are 16 to 22 mm for gentamicin and 14 to 19 mm for streptomycin. No zones for inhibition were seen when E. faecalis ATCC 51299 was tested with these high-content disks.

Aminoglycosides↗