Publications by authors named "Sheena Li"

Article Synopsis
  • Diffuse large B-cell lymphoma (DLBCL) relapses in about 40% of patients after initial treatment, with mutations in STAT6 linked to these relapses and indicating a role in resistance to therapy.
  • Research shows that STAT6 mutations help DLBCL cells survive by reprogramming their surrounding environment and enhancing cell signaling, particularly after IL-4 stimulation.
  • The study identifies the increased expression of survival-related genes, including CCL17, which recruits helper T-cells to the tumor area, suggesting that STAT6 mutations change both the behavior of the cancer cells and the immune landscape in DLBCL.
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Purpose: Exome and genome sequencing have rapidly transitioned from research methods to widely used clinical tests for diagnosing rare genetic diseases. We sought to synthesize the topics covered and appraise the development processes of clinical guidance documents generated by genetics professional organizations.

Methods: We conducted a scoping review of guidance documents published since 2010, systematically identified in peer-reviewed and gray literature, using established methods and reporting guidelines.

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Rising drug resistance among pathogenic fungi, paired with a limited antifungal arsenal, poses an increasing threat to human health. To identify antifungal compounds, we screened the RIKEN natural product depository against representative isolates of four major human fungal pathogens. This screen identified NPD6433, a triazenyl indole with broad-spectrum activity against all screening strains, as well as the filamentous mold Aspergillus fumigatus.

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Biological networks constructed from varied data can be used to map cellular function, but each data type has limitations. Network integration promises to address these limitations by combining and automatically weighting input information to obtain a more accurate and comprehensive representation of the underlying biology. We developed a deep learning-based network integration algorithm that incorporates a graph convolutional network framework.

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Fungal infections cause more than 1.5 million deaths annually. With an increase in immune-deficient susceptible populations and the emergence of antifungal drug resistance, there is an urgent need for novel strategies to combat these life-threatening infections.

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Article Synopsis
  • - Morphological profiling is an approach that helps identify the cellular targets of chemical compounds by comparing their impact on yeast cell shapes to those of genetically altered (gene-deleted) cells.
  • - A new high-throughput platform was created to efficiently assess yeast morphology using drug-sensitive strains and advanced imaging techniques, allowing for faster and more reliable predictions of compound targets.
  • - Using this platform, researchers investigated a new compound called poacidiene, discovering it impacts the DNA damage response and shows promise as an antifungal agent against plant pathogens.
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The limited number of available effective agents necessitates the development of new antifungals. We report that jervine, a jerveratrum-type steroidal alkaloid isolated from Veratrum californicum, has antifungal activity. Phenotypic comparisons of cell wall mutants, K1 killer toxin susceptibility testing, and quantification of cell wall components revealed that β-1,6-glucan biosynthesis was significantly inhibited by jervine.

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The pathogen Mycobacterium tuberculosis (Mtb) evades the innate immune system by interfering with autophagy and phagosomal maturation in macrophages, and, as a result, small molecule stimulation of autophagy represents a host-directed therapeutics (HDTs) approach for treatment of tuberculosis (TB). Here we show the marine natural product clionamines activate autophagy and inhibit Mtb survival in macrophages. A yeast chemical-genetics approach identified Pik1 as target protein of the clionamines.

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A common strategy for identifying molecules likely to possess a desired biological activity is to search large databases of compounds for high structural similarity to a query molecule that demonstrates this activity, under the assumption that structural similarity is predictive of similar biological activity. However, efforts to systematically benchmark the diverse array of available molecular fingerprints and similarity coefficients have been limited by a lack of large-scale datasets that reflect biological similarities of compounds. To elucidate the relative performance of these alternatives, we systematically benchmarked 11 different molecular fingerprint encodings, each combined with 13 different similarity coefficients, using a large set of chemical-genetic interaction data from the yeast as a systematic proxy for biological activity.

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Momilactone B is a natural product with dual biological activities, including antimicrobial and allelopathic properties, and plays a major role in plant chemical defense against competitive plants and pathogens. The pharmacological effects of momilactone B on mammalian cells have also been reported. However, little is known about the molecular and cellular mechanisms underlying its broad bioactivity.

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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Article Synopsis
  • The antifungal drug options available today are limited, leading to a search for alternative treatments like Decyl gallate (G14), which shows broad-spectrum antifungal activity and fewer side effects.
  • A genetic analysis revealed that G14 targets key processes in fungi, such as N-glycosylation and the unfolded protein response (UPR), which affect fungal cell wall integrity.
  • G14's effectiveness was demonstrated through reduced fungal viability and ability to adhere to human lung cells, suggesting it could play a role in managing inflammation during fungal infections.
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Chemical genomics has been applied extensively to evaluate small molecules that modulate biological processes in Saccharomyces cerevisiae. Here, we use yeast as a surrogate system for studying compounds that are active against metazoan targets. Large-scale chemical-genetic profiling of thousands of synthetic and natural compounds from the Chinese National Compound Library identified those with high-confidence bioprocess target predictions.

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The construction of genome-wide mutant collections has enabled high-throughput, high-dimensional quantitative characterization of gene and chemical function, particularly via genetic and chemical-genetic interaction experiments. As the throughput of such experiments increases with improvements in sequencing technology and sample multiplexing, appropriate tools must be developed to handle the large volume of data produced. Here, we describe how to apply our approach to high-throughput, fitness-based profiling of pooled mutant yeast collections using the BEAN-counter software pipeline (Barcoded Experiment Analysis for Next-generation sequencing) for analysis.

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Chemical-genetic interactions-observed when the treatment of mutant cells with chemical compounds reveals unexpected phenotypes-contain rich functional information linking compounds to their cellular modes of action. To systematically identify these interactions, an array of mutants is challenged with a compound and monitored for fitness defects, generating a chemical-genetic interaction profile that provides a quantitative, unbiased description of the cellular function(s) perturbed by the compound. Genetic interactions, obtained from genome-wide double-mutant screens, provide a key for interpreting the functional information contained in chemical-genetic interaction profiles.

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Summary: Chemical-genomic approaches that map interactions between small molecules and genetic perturbations offer a promising strategy for functional annotation of uncharacterized bioactive compounds. We recently developed a new high-throughput platform for mapping chemical-genetic (CG) interactions in yeast that can be scaled to screen large compound collections, and we applied this system to generate CG interaction profiles for more than 13 000 compounds. When integrated with the existing global yeast genetic interaction network, CG interaction profiles can enable mode-of-action prediction for previously uncharacterized compounds as well as discover unexpected secondary effects for known drugs.

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Chemical-genetic approaches offer the potential for unbiased functional annotation of chemical libraries. Mutations can alter the response of cells in the presence of a compound, revealing chemical-genetic interactions that can elucidate a compound's mode of action. We developed a highly parallel, unbiased yeast chemical-genetic screening system involving three key components.

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Article Synopsis
  • The researchers created a global genetic interaction network for yeast, generating over 23 million double mutants to identify around 550,000 negative and 350,000 positive genetic interactions.
  • The network highlights essential genes as key connectors and allows for the assembly of a hierarchical model that represents various aspects of cell function, including protein complexes and biological processes.
  • Negative interactions link related genes and core biological processes, while positive interactions reflect broader regulatory connections, ultimately forming a functional wiring diagram of the cell.
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Article Synopsis
  • Imidazolium ionic liquids (IILs) are promising in producing fermentable sugars but are toxic to yeast, necessitating engineered strains that can tolerate these compounds.
  • Researchers identified that IILs interfere with mitochondria, as their effects resemble those of a mitochondrial disruptor, with specific gene deletions increasing sensitivity to IILs.
  • The study highlights the potential of using chemical genomics to engineer yeast strains (like the ptk2∆ S. cerevisiae) that can thrive in the presence of IILs, enhancing biorefinery processes.
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Background: Microbial conversion of lignocellulosic feedstocks into biofuels remains an attractive means to produce sustainable energy. It is essential to produce lignocellulosic hydrolysates in a consistent manner in order to study microbial performance in different feedstock hydrolysates. Because of the potential to introduce microbial contamination from the untreated biomass or at various points during the process, it can be difficult to control sterility during hydrolysate production.

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Article Synopsis
  • A new antifungal compound called poacic acid was discovered in grass waste, showing promise as a treatment against resistant fungi.
  • Poacic acid disrupts fungal cell walls, leading to cell lysis, and works well alongside existing antifungal medications like caspofungin and fluconazole.
  • This finding suggests that byproducts from biofuel production, like lignocellulosic hydrolysates, could be valuable sources for developing effective bioactive compounds.
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Chemical genomics is an unbiased, whole-cell approach to characterizing novel compounds to determine mode of action and cellular target. Our version of this technique is built upon barcoded deletion mutants of Saccharomyces cerevisiae and has been adapted to a high-throughput methodology using next-generation sequencing. Here we describe the steps to generate a chemical genomic profile from a compound of interest, and how to use this information to predict molecular mechanism and targets of bioactive compounds.

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Vacuolar proton-translocating ATPases (V-ATPases) are highly conserved, ATP-driven proton pumps regulated by reversible dissociation of its cytosolic, peripheral V1 domain from the integral membrane V(o) domain. Multiple stresses induce changes in V1-V(o) assembly, but the signaling mechanisms behind these changes are not understood. Here we show that certain stress-responsive changes in V-ATPase activity and assembly require the signaling lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2).

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