Chemical screening pipeline for identification of specific plant autophagy modulators

AbstractAutophagy is a major catabolic process in eukaryotes with a key role in homeostasis, programmed cell death and aging. In plants, autophagy is also known to regulate agriculturally important traits such as stress resistance, longevity, vegetative biomass and seed yield. Despite its significance, there is still a shortage of reliable tools modulating plant autophagy. Here we describe the first robust pipeline for identification of specific plant autophagy-modulating compounds. Our screening protocol comprises four phases: (i) high-throughput screening of chemical compounds in cell cultures of Nicotiana tabacum; (ii) confirmation of the identified hits in planta using Arabidopsis thaliana; (iii) further characterization of the effect using conventional molecular biology methods; (iv) verification of chemical specificity on autophagy in planta. The methods detailed here streamline identification of specific plant autophagy modulators and aid in unravelling the molecular mechanisms of plant autophagy.

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The Use of Chemical Compounds to Identify the Regulatory Mechanisms of Vertebrate Circadian Clocks

Current Drug Targets ◽

10.2174/1389450120666190926143120 ◽

2020 ◽

Vol 21 (5) ◽

pp. 425-432

Author(s):

Yoshimi Okamoto-Uchida ◽

Akari Nishimura ◽

Junko Izawa ◽

Atsuhiko Hattori ◽

Nobuo Suzuki ◽

...

Keyword(s):

Posttranslational Modifications ◽

Molecular Mechanisms ◽

Target Genes ◽

Chemical Compounds ◽

Stability Control ◽

Circadian Clocks ◽

Light Signaling ◽

Negative Feedback Loops ◽

Exact Timing

Circadian clocks are intrinsic, time-tracking processes that confer a survival advantage on an organism. Under natural conditions, they follow approximately a 24-h day, modulated by environmental time cues, such as light, to maximize an organism’s physiological efficiency. The exact timing of this rhythm is established by cell-autonomous oscillators called cellular clocks, which are controlled by transcription–translation negative feedback loops. Studies of cell-based systems and wholeanimal models have utilized a pharmacological approach in which chemical compounds are used to identify molecular mechanisms capable of establishing and maintaining cellular clocks, such as posttranslational modifications of cellular clock regulators, chromatin remodeling of cellular clock target genes’ promoters, and stability control of cellular clock components. In addition, studies with chemical compounds have contributed to the characterization of light-signaling pathways and their impact on the cellular clock. Here, the use of chemical compounds to study the molecular, cellular, and behavioral aspects of the vertebrate circadian clock system is described.

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High-throughput screening for in planta characterization of VOC biosynthetic genes by PTR-ToF-MS

Journal of Plant Research ◽

10.1007/s10265-019-01149-z ◽

2019 ◽

Vol 133 (1) ◽

pp. 123-131 ◽

Cited By ~ 2

Author(s):

Mingai Li ◽

Luca Cappellin ◽

Jia Xu ◽

Franco Biasioli ◽

Claudio Varotto

Keyword(s):

High Throughput ◽

High Throughput Screening ◽

Functional Characterization ◽

Screening Method ◽

Proton Transfer Reaction ◽

In Planta ◽

Biosynthetic Genes ◽

Voc Emission ◽

Plant Volatile

Abstract Functional characterization of plant volatile organic compound (VOC) biosynthetic genes and elucidation of the biological function of their products often involve the screening of large numbers of plants from either independent transformation events or mapping populations. The low time resolution of standard gas chromatographic methods, however, represents a major bottleneck for in planta genetic characterization of VOC biosynthetic genes. Here we present a fast and highly-sensitive method for the high-throughput characterization of VOC emission levels/patterns by coupling a Proton Transfer Reaction Time-of-Flight Mass Spectrometer to an autosampler for automation of sample measurement. With this system more than 700 samples per day can be screened, detecting for each sample hundreds of spectrometric peaks in the m/z 15–300 range. As a case study, we report the characterization of VOC emissions from 116 independent Arabidopsis thaliana lines transformed with a putative isoprene synthase gene, confirming its function also when fused to a C-terminal 3×FLAG tag. We demonstrate that the method is more reliable than conventional characterization of transgene expression for the identification of the most highly isoprene-emitting lines. The throughput of this VOC screening method exceeds that of existing alternatives, potentially allowing its application to reverse and forward genetic screenings of genes contributing to VOC emission, constituting a powerful tool for the functional characterization of VOC biosynthetic genes and elucidation of the biological functions of their products directly in planta.

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Characterization of Healthy and Tumor Oral Cell Lines of Human Origin. The preliminary stage in the assessment of relevant chemical compounds with impact on dentistry

Revista de Chimie ◽

10.37358/rc.18.10.6647 ◽

2018 ◽

Vol 69 (10) ◽

pp. 2889-2894

Author(s):

Ion Virgil Corlan ◽

Adelina Cheveresan ◽

Delia Berceanu Vaduva ◽

Cristian Nica ◽

Alin Faur ◽

...

Keyword(s):

Squamous Cell Carcinoma ◽

Cell Carcinoma ◽

Cell Lines ◽

Squamous Cell ◽

Chemical Compounds ◽

Tongue Squamous Cell Carcinoma ◽

Gingival Fibroblasts ◽

Human Origin ◽

Preliminary Stage

The present study was aimed to evaluate the confluence percentage of three oral cell lines, namely primary gingival keratinocytes (PGK), primary gingival fibroblasts (HGF) and tongue squamous cell carcinoma (SCC-4). All cells have been monitored at different passages for 21 days. Evaluation of confluence percentage reveals the fact that primary gingival keratinocytes and tongue squamous cell carcinoma at small passages requires a period of about two weeks to reach a confluence of approximately 80% while for the gingival fibroblasts a period of about three times smaller is satisfactory.

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Cannabidiol induces autophagy via ERK1/2 activation in neural cells

Scientific Reports ◽

10.1038/s41598-021-84879-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Talita A. M. Vrechi ◽

Anderson H. F. F. Leão ◽

Ingrid B. M. Morais ◽

Vanessa C. Abílio ◽

Antonio W. Zuardi ◽

...

Keyword(s):

Central Nervous System ◽

Neurodegenerative Disorders ◽

Molecular Mechanisms ◽

Cannabis Sativa ◽

Autophagic Flux ◽

Neural Cells ◽

Human Neuroblastoma ◽

Trpv1 Receptor ◽

The Central Nervous System ◽

Catabolic Process

AbstractAutophagy is a lysosomal catabolic process essential to cell homeostasis and is related to the neuroprotection of the central nervous system. Cannabidiol (CBD) is a non-psychotropic phytocannabinoid present in Cannabis sativa. Many therapeutic actions have been linked to this compound, including autophagy activation. However, the precise underlying molecular mechanisms remain unclear, and the downstream functional significance of these actions has yet to be determined. Here, we investigated CBD-evoked effects on autophagy in human neuroblastoma SH-SY5Y and murine astrocyte cell lines. We found that CBD-induced autophagy was substantially reduced in the presence of CB1, CB2 and TRPV1 receptor antagonists, AM 251, AM 630 and capsazepine, respectively. This result strongly indicates that the activation of these receptors mediates the autophagic flux. Additionally, we demonstrated that CBD activates autophagy through ERK1/2 activation and AKT suppression. Interestingly, CBD-mediated autophagy activation is dependent on the autophagy initiator ULK1, but mTORC1 independent. Thus, it is plausible that a non-canonical pathway is involved. Our findings collectively provide evidence that CBD stimulates autophagy signal transduction via crosstalk between the ERK1/2 and AKT kinases, which represent putative regulators of cell proliferation and survival. Furthermore, our study sheds light on potential therapeutic cannabinoid targets that could be developed for treating neurodegenerative disorders.

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Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18073332 ◽

2021 ◽

Vol 18 (7) ◽

pp. 3332

Author(s):

Olga V. Naidenko ◽

David Q. Andrews ◽

Alexis M. Temkin ◽

Tasha Stoiber ◽

Uloma Igara Uche ◽

...

Keyword(s):

Immune System ◽

High Throughput ◽

Environmental Protection Agency ◽

High Throughput Screening ◽

Molecular Mechanisms ◽

Specific Activity ◽

Laboratory Animals ◽

In Vitro Assays ◽

Toxicological Studies

The development of high-throughput screening methodologies may decrease the need for laboratory animals for toxicity testing. Here, we investigate the potential of assessing immunotoxicity with high-throughput screening data from the U.S. Environmental Protection Agency ToxCast program. As case studies, we analyzed the most common chemicals added to food as well as per- and polyfluoroalkyl substances (PFAS) shown to migrate to food from packaging materials or processing equipment. The antioxidant preservative tert-butylhydroquinone (TBHQ) showed activity both in ToxCast assays and in classical immunological assays, suggesting that it may affect the immune response in people. From the PFAS group, we identified eight substances that can migrate from food contact materials and have ToxCast data. In epidemiological and toxicological studies, PFAS suppress the immune system and decrease the response to vaccination. However, most PFAS show weak or no activity in immune-related ToxCast assays. This lack of concordance between toxicological and high-throughput data for common PFAS indicates the current limitations of in vitro screening for analyzing immunotoxicity. High-throughput in vitro assays show promise for providing mechanistic data relevant for immune risk assessment. In contrast, the lack of immune-specific activity in the existing high-throughput assays cannot validate the safety of a chemical for the immune system.

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Genetic mapping and transcriptomic characterization of a new fuzzless-tufted cottonseed mutant

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkaa042 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Qian-Hao Zhu ◽

Warwick Stiller ◽

Philippe Moncuquet ◽

Stuart Gordon ◽

Yuman Yuan ◽

...

Keyword(s):

Molecular Mechanisms ◽

Agronomic Traits ◽

Gene Families ◽

Mutant Phenotype ◽

Wild Type ◽

Calcium Dependent ◽

Dependent Protein ◽

Flanking Region ◽

Comparative Transcriptomic Analysis

Abstract Fiber mutants are unique and valuable resources for understanding the genetic and molecular mechanisms controlling initiation and development of cotton fibers that are extremely elongated single epidermal cells protruding from the seed coat of cottonseeds. In this study, we reported a new fuzzless-tufted cotton mutant (Gossypium hirsutum) and showed that fuzzless-tufted near-isogenic lines (NILs) had similar agronomic traits and a higher ginning efficiency compared to their recurrent parents with normal fuzzy seeds. Genetic analysis revealed that the mutant phenotype is determined by a single incomplete dominant locus, designated N5. The mutation was fine mapped to an approximately 250-kb interval containing 33 annotated genes using a combination of bulked segregant sequencing, SNP chip genotyping, and fine mapping. Comparative transcriptomic analysis using 0–6 days post-anthesis (dpa) ovules from NILs segregating for the phenotypes of fuzzless-tufted (mutant) and normal fuzzy cottonseeds (wild-type) uncovered candidate genes responsible for the mutant phenotype. It also revealed that the flanking region of the N5 locus is enriched with differentially expressed genes (DEGs) between the mutant and wild-type. Several of those DEGs are members of the gene families with demonstrated roles in cell initiation and elongation, such as calcium-dependent protein kinase and expansin. The transcriptome landscape of the mutant was significantly reprogrammed in the 6 dpa ovules and, to a less extent, in the 0 dpa ovules, but not in the 2 and 4 dpa ovules. At both 0 and 6 dpa, the reprogrammed mutant transcriptome was mainly associated with cell wall modifications and transmembrane transportation, while transcription factor activity was significantly altered in the 6 dpa mutant ovules. These results imply a similar molecular basis for initiation of lint and fuzz fibers despite certain differences.

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High-throughput computational-experimental screening protocol for the discovery of bimetallic catalysts

npj Computational Materials ◽

10.1038/s41524-021-00605-6 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Byung Chul Yeo ◽

Hyunji Nam ◽

Hyobin Nam ◽

Min-Cheol Kim ◽

Hong Woo Lee ◽

...

Keyword(s):

High Throughput ◽

Bimetallic Catalysts ◽

High Throughput Screening ◽

Direct Synthesis ◽

Catalytic Performance ◽

Platinum Group Metals ◽

Pt Catalyst ◽

Electronic Density ◽

Bimetallic Alloy ◽

Screening Protocol

AbstractTo accelerate the discovery of materials through computations and experiments, a well-established protocol closely bridging these methods is required. We introduce a high-throughput screening protocol for the discovery of bimetallic catalysts that replace palladium (Pd), where the similarities in the electronic density of states patterns were employed as a screening descriptor. Using first-principles calculations, we screened 4350 bimetallic alloy structures and proposed eight candidates expected to have catalytic performance comparable to that of Pd. Our experiments demonstrate that four bimetallic catalysts indeed exhibit catalytic properties comparable to those of Pd. Moreover, we discover a bimetallic (Ni-Pt) catalyst that has not yet been reported for H2O2 direct synthesis. In particular, Ni61Pt39 outperforms the prototypical Pd catalyst for the chemical reaction and exhibits a 9.5-fold enhancement in cost-normalized productivity. This protocol provides an opportunity for the catalyst discovery for the replacement or reduction in the use of the platinum-group metals.

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A Concerted Action of UBA5 C-Terminal Unstructured Regions Is Important for Transfer of Activated UFM1 to UFC1

International Journal of Molecular Sciences ◽

10.3390/ijms22147390 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7390

Author(s):

Nicole Wesch ◽

Frank Löhr ◽

Natalia Rogova ◽

Volker Dötsch ◽

Vladimir V. Rogov

Keyword(s):

Cellular Localization ◽

Molecular Mechanisms ◽

Biochemical Characterization ◽

Effective Interaction ◽

Regulatory Region ◽

Titration Calorimetry ◽

Enzymatic Reactions ◽

Cellular Processes ◽

Mechanism Of Interaction

Ubiquitin fold modifier 1 (UFM1) is a member of the ubiquitin-like protein family. UFM1 undergoes a cascade of enzymatic reactions including activation by UBA5 (E1), transfer to UFC1 (E2) and selective conjugation to a number of target proteins via UFL1 (E3) enzymes. Despite the importance of ufmylation in a variety of cellular processes and its role in the pathogenicity of many human diseases, the molecular mechanisms of the ufmylation cascade remains unclear. In this study we focused on the biophysical and biochemical characterization of the interaction between UBA5 and UFC1. We explored the hypothesis that the unstructured C-terminal region of UBA5 serves as a regulatory region, controlling cellular localization of the elements of the ufmylation cascade and effective interaction between them. We found that the last 20 residues in UBA5 are pivotal for binding to UFC1 and can accelerate the transfer of UFM1 to UFC1. We solved the structure of a complex of UFC1 and a peptide spanning the last 20 residues of UBA5 by NMR spectroscopy. This structure in combination with additional NMR titration and isothermal titration calorimetry experiments revealed the mechanism of interaction and confirmed the importance of the C-terminal unstructured region in UBA5 for the ufmylation cascade.

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High-resolution view of HIV-1 reverse transcriptase initiation complexes and inhibition by NNRTI drugs

Nature Communications ◽

10.1038/s41467-021-22628-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Betty Ha ◽

Kevin P. Larsen ◽

Jingji Zhang ◽

Ziao Fu ◽

Elizabeth Montabana ◽

...

Keyword(s):

Reverse Transcriptase ◽

Viral Entry ◽

Reverse Transcription ◽

Molecular Mechanisms ◽

Dissociation Kinetics ◽

Structural Mechanism ◽

Medium Resolution ◽

Kinetics Of ◽

Hiv 1

AbstractReverse transcription of the HIV-1 viral RNA genome (vRNA) is an integral step in virus replication. Upon viral entry, HIV-1 reverse transcriptase (RT) initiates from a host tRNALys3 primer bound to the vRNA genome and is the target of key antivirals, such as non-nucleoside reverse transcriptase inhibitors (NNRTIs). Initiation proceeds slowly with discrete pausing events along the vRNA template. Despite prior medium-resolution structural characterization of reverse transcriptase initiation complexes (RTICs), higher-resolution structures of the RTIC are needed to understand the molecular mechanisms that underlie initiation. Here we report cryo-EM structures of the core RTIC, RTIC–nevirapine, and RTIC–efavirenz complexes at 2.8, 3.1, and 2.9 Å, respectively. In combination with biochemical studies, these data suggest a basis for rapid dissociation kinetics of RT from the vRNA–tRNALys3 initiation complex and reveal a specific structural mechanism of nucleic acid conformational stabilization during initiation. Finally, our results show that NNRTIs inhibit the RTIC and exacerbate discrete pausing during early reverse transcription.

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