Systems Biology

Reproducibility of drug-induced effects on the contractility of an engineered heart tissue derived from human pluripotent stem cells

Thu, 2023-07-20 06:00

Front Pharmacol. 2023 Jul 4;14:1212092. doi: 10.3389/fphar.2023.1212092. eCollection 2023.

ABSTRACT

Introduction: Engineered heart tissues (EHTs) are three-dimensional culture platforms with cardiomyocytes differentiated from human pluripotent stem cells (hPSCs) and were designed for assaying cardiac contractility. For drug development applications, EHTs must have a stable function and provide reproducible results. We investigated these properties with EHTs made with different tissue casting batches and lines of differentiated hPSC-cardiomyocytes and analyzed them at different times after being fabricated. Methods: A video-optical assay was used for measuring EHT contractile outputs, and these results were compared with results from motion traction analysis of beating hPSC-cardiomyocytes cultured as monolayers in two-dimensional cultures. The reproducibility of induced contractile variations was tested using compounds with known mechanistic cardiac effects (isoproterenol, EMD-57033, omecamtiv mecarbil, verapamil, ranolazine, and mavacamten), or known to be clinically cardiotoxic (doxorubicin, sunitinib). These drug-induced variations were characterized at different electrical pacing rates and variations in intracellular calcium transients were also assessed in EHTs. Results: To ensure reproducibility in experiments, we established EHT quality control criteria based on excitation-contraction coupling and contractile sensitivity to extracellular calcium concentration. In summary, a baseline contractile force of 0.2 mN and excitation-contraction coupling of EHTs were used as quality control criteria to select suitable EHTs for analysis. Overall, drug-induced contractile responses were similar between monolayers and EHTs, where a close relationship was observed between contractile output and calcium kinetics. Contractile variations at multiple time points after adding cardiotoxic compounds were also detectable in EHTs. Discussion: Reproducibility of drug-induced effects in EHTs between experiments and relative to published work on these cellular models was generally observed. Future applications for EHTs may require additional mechanistic criteria related to drug effects and cardiac functional outputs to be measured in regard to specific contexts of use.

PMID:37469866 | PMC:PMC10352809 | DOI:10.3389/fphar.2023.1212092

Categories: Literature Watch

Epidemiology of flavescence dorée and hazelnut decline in Slovenia: geographical distribution and genetic diversity of the associated 16SrV phytoplasmas

Thu, 2023-07-20 06:00

Front Plant Sci. 2023 Jul 4;14:1217425. doi: 10.3389/fpls.2023.1217425. eCollection 2023.

ABSTRACT

Flavescence dorée (FD) phytoplasma from 16SrV-C and -D subgroups cause severe damage to grapevines throughout Europe. This phytoplasma is transmitted from grapevine to grapevine by the sap-sucking leafhopper Scaphoideus titanus. European black alder and clematis serve as perennial plant reservoirs for 16SrV-C phytoplasma strains, and their host range has recently been extended to hazelnuts. In Slovenia, hazelnut orchards are declining due to 16SrV phytoplasma infections, where large populations of the non-autochthonous leafhopper Orientus ishidae have been observed. To better characterise the phytoplasma-induced decline of hazelnut and possible transmission fluxes between these orchards and grapevine, genetic diversity of 16SrV phytoplasmas in grapevine, hazelnut and leafhoppers was monitored from 2017 to 2022. The nucleotide sequence analysis was based on the map gene. The most prevalent map genotype in grapevine in all wine-growing regions of Slovenia was M54, which accounted for 84% of the 176 grapevines tested. Besides M54, other epidemic genotypes with lower frequency were M38 (6%), M51 (3%), M50 (2%) and M122 (1%). M38, M50 and M122 were also detected in infected cultivated hazelnuts and in specimens of O. ishidae leafhopper caught in declining hazelnut orchards. It suggests that this polyphagous vector could be responsible for phytoplasma infection in hazelnut orchards and possibly for some phytoplasma exchanges between hazelnuts and grapevine. We hereby describe new genotypes: M158 in grapevine as well as four never reported genotypes M159 to M162 in hazelnut. Of these four genotypes in hazelnut, one (M160) was also detected in O. ishidae. Analysis of additional genes of the new genotypes allowed us to assign them to the VmpA-III cluster, which corresponds to the 16SrV-C strains previously shown to be compatible with S. titanus transmission.

PMID:37469777 | PMC:PMC10352807 | DOI:10.3389/fpls.2023.1217425

Categories: Literature Watch

Differential fibril morphologies and thermostability determine functional roles of <em>Staphylococcus aureus</em> PSMα1 and PSMα3

Thu, 2023-07-20 06:00

Front Mol Biosci. 2023 Jul 4;10:1184785. doi: 10.3389/fmolb.2023.1184785. eCollection 2023.

ABSTRACT

Phenol-soluble modulins (PSMs) are virulent peptides secreted by staphylococci that undergo self-assembly into amyloid fibrils. This study focuses on Staphylococcus aureus PSMα1 and PSMα3, which share homologous sequences but exhibit distinct amyloid fibril structures. Upon subjecting PSMα1 to an 80°C heat shock, it fibrillates into cross-β structures, resulting in the loss of cytotoxic activity. Conversely, PSMα3 cross-α fibrils undergo reversible disaggregation upon heat shock, leading to the recovery of cytotoxicity. The differential thermostability probably arises from the presence of hydrogen bonds along the β-strands within the β-sheets of the cross-β fibrils. We propose that the breakdown of PSMα3 fibrils into soluble species, potentially co-aggregating with membrane lipids, is crucial for its toxic process and enables the reversible modulation of its biological activity under stress conditions. In contrast, the formation of robust and irreversible cross-β fibrils by PSMα1 corresponds to its role in biofilm stability. These findings emphasize how the unique fibril morphologies and thermostability of PSMα1 and PSMα3 shape their functional roles in various environments of S. aureus.

PMID:37469708 | PMC:PMC10353841 | DOI:10.3389/fmolb.2023.1184785

Categories: Literature Watch

CRISPR/Cas9 as a therapeutic tool for triple negative breast cancer: from bench to clinics

Thu, 2023-07-20 06:00

Front Mol Biosci. 2023 Jul 4;10:1214489. doi: 10.3389/fmolb.2023.1214489. eCollection 2023.

ABSTRACT

Clustered regularly interspaced short palindromic repeats (CRISPR) is a third-generation genome editing method that has revolutionized the world with its high throughput results. It has been used in the treatment of various biological diseases and infections. Various bacteria and other prokaryotes such as archaea also have CRISPR/Cas9 systems to guard themselves against bacteriophage. Reportedly, CRISPR/Cas9-based strategy may inhibit the growth and development of triple-negative breast cancer (TNBC) via targeting the potentially altered resistance genes, transcription, and epigenetic regulation. These therapeutic activities could help with the complex issues such as drug resistance which is observed even in TNBC. Currently, various methods have been utilized for the delivery of CRISPR/Cas9 into the targeted cell such as physical (microinjection, electroporation, and hydrodynamic mode), viral (adeno-associated virus and lentivirus), and non-viral (liposomes and lipid nano-particles). Although different models have been developed to investigate the molecular causes of TNBC, but the lack of sensitive and targeted delivery methods for in-vivo genome editing tools limits their clinical application. Therefore, based on the available evidences, this review comprehensively highlighted the advancement, challenges limitations, and prospects of CRISPR/Cas9 for the treatment of TNBC. We also underscored how integrating artificial intelligence and machine learning could improve CRISPR/Cas9 strategies in TNBC therapy.

PMID:37469704 | PMC:PMC10352522 | DOI:10.3389/fmolb.2023.1214489

Categories: Literature Watch

Ascites-derived CDCP1+ extracellular vesicles subcluster as a novel biomarker and therapeutic target for ovarian cancer

Thu, 2023-07-20 06:00

Front Oncol. 2023 Jul 3;13:1142755. doi: 10.3389/fonc.2023.1142755. eCollection 2023.

ABSTRACT

INTRODUCTION: Ovarian cancer (OVCA) is one of the most prevalent malignant tumors of the female reproductive system, and its diagnosis is typically accompanied by the production of ascites. Although liquid biopsy has been widely implemented recently, the diagnosis or prognosis of OVCA based on liquid biopsy remains the primary emphasis.

METHODS: In this study, using proximity barcoding assay, a technique for analyzing the surface proteins on single extracellular vesicles (EVs). For validation, serum and ascites samples from patients with epithelial ovarian cancer (EOC) were collected, and their levels of CDCP1 was determined by enzyme-linked immunosorbent assay. Tissue chips were prepared to analyze the relationship between different expression levels of CDCP1 and the prognosis of ovarian cancer patients.

RESULTS: We discovered that the CUB domain-containing protein 1+ (CDCP1+) EVs subcluster was higher in the ascites of OVCA patients compared to benign ascites. At the same time, the level of CDCP1 was considerably elevated in the ascites of OVCA patients. The overall survival and disease-free survival of the group with high CDCP1 expression in EOC were significantly lower than those of the group with low expression. In addition, the receiver operating characteristic curve demonstrates that EVs-derived CDCP1 was a biomarker of early response in OVCA ascites.

DISCUSSION: Our findings identified a CDCP1+ EVs subcluster in the ascites of OVCA patients as a possible biomarker for EOC prevention.

PMID:37469398 | PMC:PMC10352483 | DOI:10.3389/fonc.2023.1142755

Categories: Literature Watch

The Oxysterol Receptor EBI2 Links Innate and Adaptive Immunity to Limit IFN Response and Systemic Lupus Erythematosus

Thu, 2023-07-20 06:00

Adv Sci (Weinh). 2023 Jul 19:e2207108. doi: 10.1002/advs.202207108. Online ahead of print.

ABSTRACT

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with abnormal activation of the immune system. Recent attention is increasing about how aberrant lipid and cholesterol metabolism is linked together with type I interferon (IFN-I) signaling in the regulation of the pathogenesis of SLE. Here, a metabonomic analysis is performed and increased plasma concentrations of oxysterols, especially 7α, 25-dihydroxycholesterol (7α, 25-OHC), are identified in SLE patients. The authors find that 7α, 25-OHC binding to its receptor Epstein-Barr virus-induced gene 2 (EBI2) in macrophages can suppress STAT activation and the production of IFN-β, chemokines, and cytokines. Importantly, monocytes/macrophages from SLE patients and mice show significantly reduced EBI2 expression, which can be triggered by IFN-γ produced in activated T cells. Previous findings suggest that EBI2 enhances immune cell migration. Opposite to this effect, the authors demonstrate that EBI2-deficient macrophages produce higher levels of chemokines and cytokines, which recruits and activates myeloid cells,T and B lymphocytes to exacerbate tetramethylpentadecane-induced SLE. Together, via sensing the oxysterol 7α, 25-OHC, EBI2 in macrophages can modulate innate and adaptive immune responses, which may be used as a potential diagnostic marker and therapeutic target for SLE.

PMID:37469011 | DOI:10.1002/advs.202207108

Categories: Literature Watch

Cell-level reference maps for the human body take shape

Wed, 2023-07-19 06:00

Nature. 2023 Jul;619(7970):467-468. doi: 10.1038/d41586-023-01817-0.

NO ABSTRACT

PMID:37468591 | DOI:10.1038/d41586-023-01817-0

Categories: Literature Watch

Identifying Stress-Exacerbated Thermal-Injury Induced microRNAs

Wed, 2023-07-19 06:00

J Pain. 2023 Jul 17:S1526-5900(23)00479-0. doi: 10.1016/j.jpain.2023.07.013. Online ahead of print.

ABSTRACT

Using a model of Combat and Operational Stress Reaction (COSR), our lab recently showed that exposure to an unpredictable combat stress (UPCS) procedure prior to a thermal injury increases pain sensitivity in male rats. Additionally, our lab has recently shown that circulating extracellular vesicle-microRNAs (EV-miRNAs), which normally function to suppress inflammation, were down regulated in a male rat model of neuropathic pain. In this current study, male and female rats exposed to UPCS followed by thermal injury, were evaluated for changes in circulating EV-miRNAs. Adult female and male Sprague Dawley rats were exposed to an UPCS procedure for either 2 or 4 weeks. Groups consisted of the following: non-stress (NS), stress (S), NS + thermal injury (TI), and S+TI. Mechanical sensitivity was measured and plasma collected at baseline, throughout the UPCS exposure, and post thermal-injury. EV-miRNA isolation was performed, followed by small RNA sequencing and subsequent data analysis. UPCS exposure alone resulted in mechanical allodynia in both males and female rats at specific time points. Thermal-injury induction occurring at peak UPCS resulted in increased mechanical allodynia in the injured hind paw compared to thermal-injury alone. Differential expression of the EV-miRNAs was observed between the NS and S groups as well as between NS+TI and S+TI groups. Consistent differences in EV-miRNAs are detectable in both COSR as well as during the development of mechanical sensitivity and potentially serve as key regulators, biomarkers, and targets in the treatment of COSR and thermal-injury induced mechanical sensitivity. PERSPECTIVE: This article presents the effects of unpredictable combat stress and thermal injury on extracellular vesicle contained microRNAs in an animal model. These same mechanisms may exist in clinical patients and could be future prognostic and diagnostic biomarkers.

PMID:37468024 | DOI:10.1016/j.jpain.2023.07.013

Categories: Literature Watch

A proteomics analysis of 5xFAD mouse brain regions reveals the lysosome-associated protein Arl8b as a candidate biomarker for Alzheimer's disease

Wed, 2023-07-19 06:00

Genome Med. 2023 Jul 20;15(1):50. doi: 10.1186/s13073-023-01206-2.

ABSTRACT

BACKGROUND: Alzheimer's disease (AD) is characterized by the intra- and extracellular accumulation of amyloid-β (Aβ) peptides. How Aβ aggregates perturb the proteome in brains of patients and AD transgenic mouse models, remains largely unclear. State-of-the-art mass spectrometry (MS) methods can comprehensively detect proteomic alterations, providing relevant insights unobtainable with transcriptomics investigations. Analyses of the relationship between progressive Aβ aggregation and protein abundance changes in brains of 5xFAD transgenic mice have not been reported previously.

METHODS: We quantified progressive Aβ aggregation in hippocampus and cortex of 5xFAD mice and controls with immunohistochemistry and membrane filter assays. Protein changes in different mouse tissues were analyzed by MS-based proteomics using label-free quantification; resulting MS data were processed using an established pipeline. Results were contrasted with existing proteomic data sets from postmortem AD patient brains. Finally, abundance changes in the candidate marker Arl8b were validated in cerebrospinal fluid (CSF) from AD patients and controls using ELISAs.

RESULTS: Experiments revealed faster accumulation of Aβ42 peptides in hippocampus than in cortex of 5xFAD mice, with more protein abundance changes in hippocampus, indicating that Aβ42 aggregate deposition is associated with brain region-specific proteome perturbations. Generating time-resolved data sets, we defined Aβ aggregate-correlated and anticorrelated proteome changes, a fraction of which was conserved in postmortem AD patient brain tissue, suggesting that proteome changes in 5xFAD mice mimic disease-relevant changes in human AD. We detected a positive correlation between Aβ42 aggregate deposition in the hippocampus of 5xFAD mice and the abundance of the lysosome-associated small GTPase Arl8b, which accumulated together with axonal lysosomal membranes in close proximity of extracellular Aβ plaques in 5xFAD brains. Abnormal aggregation of Arl8b was observed in human AD brain tissue. Arl8b protein levels were significantly increased in CSF of AD patients.

CONCLUSIONS: We report a comprehensive biochemical and proteomic investigation of hippocampal and cortical brain tissue derived from 5xFAD transgenic mice, providing a valuable resource to the neuroscientific community. We identified Arl8b, with significant abundance changes in 5xFAD and AD patient brains. Arl8b might enable the measurement of progressive lysosome accumulation in AD patients and have clinical utility as a candidate biomarker.

PMID:37468900 | DOI:10.1186/s13073-023-01206-2

Categories: Literature Watch

Leveraging pre-trained language models for mining microbiome-disease relationships

Wed, 2023-07-19 06:00

BMC Bioinformatics. 2023 Jul 19;24(1):290. doi: 10.1186/s12859-023-05411-z.

ABSTRACT

BACKGROUND: The growing recognition of the microbiome's impact on human health and well-being has prompted extensive research into discovering the links between microbiome dysbiosis and disease (healthy) states. However, this valuable information is scattered in unstructured form within biomedical literature. The structured extraction and qualification of microbe-disease interactions are important. In parallel, recent advancements in deep-learning-based natural language processing algorithms have revolutionized language-related tasks such as ours. This study aims to leverage state-of-the-art deep-learning language models to extract microbe-disease relationships from biomedical literature.

RESULTS: In this study, we first evaluate multiple pre-trained large language models within a zero-shot or few-shot learning context. In this setting, the models performed poorly out of the box, emphasizing the need for domain-specific fine-tuning of these language models. Subsequently, we fine-tune multiple language models (specifically, GPT-3, BioGPT, BioMedLM, BERT, BioMegatron, PubMedBERT, BioClinicalBERT, and BioLinkBERT) using labeled training data and evaluate their performance. Our experimental results demonstrate the state-of-the-art performance of these fine-tuned models ( specifically GPT-3, BioMedLM, and BioLinkBERT), achieving an average F1 score, precision, and recall of over [Formula: see text] compared to the previous best of 0.74.

CONCLUSION: Overall, this study establishes that pre-trained language models excel as transfer learners when fine-tuned with domain and problem-specific data, enabling them to achieve state-of-the-art results even with limited training data for extracting microbiome-disease interactions from scientific publications.

PMID:37468830 | DOI:10.1186/s12859-023-05411-z

Categories: Literature Watch

Targeting an allosteric site in dynamin-related protein 1 to inhibit Fis1-mediated mitochondrial dysfunction

Wed, 2023-07-19 06:00

Nat Commun. 2023 Jul 19;14(1):4356. doi: 10.1038/s41467-023-40043-0.

ABSTRACT

The large cytosolic GTPase, dynamin-related protein 1 (Drp1), mediates both physiological and pathological mitochondrial fission. Cell stress triggers Drp1 binding to mitochondrial Fis1 and subsequently, mitochondrial fragmentation, ROS production, metabolic collapse, and cell death. Because Drp1 also mediates physiological fission by binding to mitochondrial Mff, therapeutics that inhibit pathological fission should spare physiological mitochondrial fission. P110, a peptide inhibitor of Drp1-Fis1 interaction, reduces pathology in numerous models of neurodegeneration, ischemia, and sepsis without blocking the physiological functions of Drp1. Since peptides have pharmacokinetic limitations, we set out to identify small molecules that mimic P110's benefit. We map the P110-binding site to a switch I-adjacent grove (SWAG) on Drp1. Screening for SWAG-binding small molecules identifies SC9, which mimics P110's benefits in cells and a mouse model of endotoxemia. We suggest that the SWAG-binding small molecules discovered in this study may reduce the burden of Drp1-mediated pathologies and potentially pathologies associated with other members of the GTPase family.

PMID:37468472 | DOI:10.1038/s41467-023-40043-0

Categories: Literature Watch

Molecular and Dual-Isotopic Profiling of the Microbial Controls on Nitrogen Leaching in Agricultural Soils under Managed Aquifer Recharge

Wed, 2023-07-19 06:00

Environ Sci Technol. 2023 Jul 19. doi: 10.1021/acs.est.3c01356. Online ahead of print.

ABSTRACT

Nitrate (NO3-) leaching is a serious health and ecological concern in global agroecosystems, particularly those under the application of agricultural-managed aquifer recharge (Ag-MAR); however, there is an absence of information on microbial controls affecting NO3- leaching outcomes. We combine natural dual isotopes of NO3- (15N/14N and 18O/16O) with metagenomics, quantitative polymerase chain reaction (PCR), and a threshold indicator taxa analysis (TITAN) to investigate the activities, taxon profiles, and environmental controls of soil microbiome associated with NO3- leaching at different depths from Californian vineyards under Ag-MAR application. The isotopic signatures demonstrated a significant priming effect (P < 0.01) of Ag-MAR on denitrification activities in the topsoil (0-10 cm), with a 12-25-fold increase of 15N-NO3- and 18O-NO3- after the first 24 h of flooding, followed by a sharp decrease in the enrichment of both isotopes with ∼80% decline in denitrification activities thereafter. In contrast, deeper soils (60-100 cm) showed minimal or no denitrification activities over the course of Ag-MAR application, thus resulting in 10-20-fold of residual NO3- being leached. Metagenomic profiling and laboratory microcosm demonstrated that both nitrifying and denitrifying groups, responsible for controlling NO3- leaching, decreased in abundance and potential activity rates with soil depth. TITAN suggested that Nitrosocosmicus and Bradyrhizobium, as the major nitrifier and denitrifier, had the highest and lowest tipping points with regard to the NO3- changes (P < 0.05), respectively. Overall, our study provides new insight into specific depth limitations of microbial controls on soil NO3- leaching in agroecosystems.

PMID:37467434 | DOI:10.1021/acs.est.3c01356

Categories: Literature Watch

Targeting the Siglec-sialic acid axis promotes antitumor immune responses in preclinical models of glioblastoma

Wed, 2023-07-19 06:00

Sci Transl Med. 2023 Jul 19;15(705):eadf5302. doi: 10.1126/scitranslmed.adf5302. Epub 2023 Jul 19.

ABSTRACT

Glioblastoma (GBM) is the most aggressive form of primary brain tumor, for which effective therapies are urgently needed. Cancer cells are capable of evading clearance by phagocytes such as microglia- and monocyte-derived cells through engaging tolerogenic programs. Here, we found that high expression of sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) correlates with reduced survival in patients with GBM. Using microglia- and monocyte-derived cell-specific knockouts of Siglec-E, the murine functional homolog of Siglec-9, together with single-cell RNA sequencing, we demonstrated that Siglec-E inhibits phagocytosis by these cells, thereby promoting immune evasion. Loss of Siglec-E on monocyte-derived cells further enhanced antigen cross-presentation and production of pro-inflammatory cytokines, which resulted in more efficient T cell priming. This bridging of innate and adaptive responses delayed tumor growth and resulted in prolonged survival in murine models of GBM. Furthermore, we showed the combinatorial activity of Siglec-E blockade and other immunotherapies demonstrating the potential for targeting Siglec-9 as a treatment for patients with GBM.

PMID:37467314 | DOI:10.1126/scitranslmed.adf5302

Categories: Literature Watch

Single Nanovesicles Tracking Reveals Their Heterogeneous Extracellular Adsorptions

Wed, 2023-07-19 06:00

Small. 2023 Jul 19:e2301888. doi: 10.1002/smll.202301888. Online ahead of print.

ABSTRACT

The vigorous nanomedicine offers significant possibilities for effective therapeutics of various diseases, and nanovesicles (NVs) represented by artificial liposomes and natural exosomes and cytomembranes especially show great potential. However, their complex interactions with cells, particularly the heterogeneous extracellular adsorptions, are difficult to analyze spatiotemporally due to the transient dynamics. In this study, by single NVs tracking, the extracellular NVs adsorptions are directly observed and their heterogeneous characteristics are revealed. Briefly, plenty of NVs adsorbed on HCT116 cells are tracked and classified, and it is discovered that they exhibit various diffusion properties from different extracellular regions: stable adsorptions on the rear surface and restricted adsorptions on the front protrusion. After the hydrolysis of hyaluronic acid in the extracellular matrix by hyaluronidase, the restricted adsorptions are further weakened and manifested as dissociative adsorptions, which demonstrated reduced total NVs adsorptions from a single-cell and single-particle perspective. Compared with traditional static analysis, the spatiotemporal tracking and heterogeneous results not only reveal the extracellular NVs-cell interactions but also inspire a wide variety of nanomedicine and their nano-investigations.

PMID:37467296 | DOI:10.1002/smll.202301888

Categories: Literature Watch

Transposons are important contributors to gene expression variability under selection in rice populations

Wed, 2023-07-19 06:00

Elife. 2023 Jul 19;12:RP86324. doi: 10.7554/eLife.86324.

ABSTRACT

Transposable elements (TEs) are an important source of genome variability. Here, we analyze their contribution to gene expression variability in rice by performing a TE insertion polymorphism expression quantitative trait locus mapping using expression data from 208 varieties from the Oryza sativa ssp. indica and O. sativa ssp. japonica subspecies. Our data show that TE insertions are associated with changes of expression of many genes known to be targets of rice domestication and breeding. An important fraction of these insertions were already present in the rice wild ancestors, and have been differentially selected in indica and japonica rice populations. Taken together, our results show that small changes of expression in signal transduction genes induced by TE insertions accompany the domestication and adaptation of rice populations.

PMID:37467142 | DOI:10.7554/eLife.86324

Categories: Literature Watch

First report of grapevine Flavescence dorée phytoplasma in the Czech Republic

Wed, 2023-07-19 06:00

Plant Dis. 2023 Jul 19. doi: 10.1094/PDIS-02-23-0315-PDN. Online ahead of print.

ABSTRACT

Viticulture is a traditional branch of agriculture in the Czech Republic. Grapevines (Vitis vinifera L.) are cultivated on more than 18,000 hectares in the wine-growing regions of Bohemia and South Moravia. South Moravia alone accounts for more than 90 % of the total wine-growing area in the country. Grapevine yellows are a complex of diseases associated with the phytoplasma presence. Phytoplasmas of at least five different groups can cause similar symptoms in grapevines, and they can be distinguished only on a molecular basis (EPPO 2016). One of them, the grapevine Flavescence dorée phytoplasma (GFDP), which belongs to the 16SrV group, is listed in Annex II, Part B, of the Commission Implementing Regulation (EU) 2019/2072 of 28 November 2019 as a Union quarantine pest known to occur in the Union territory. Official surveys for GFDP in the Czech Republic have been carried out since 2007. In 2016, the first occurrence of Scaphoideus titanus Ball, 1932, the main vector of GFDP, was reported in the South Moravian Region (EPPO Reporting Service 2016). This is a matter of concern because it indicates that there is a risk of disease dissemination to other geographical locations. In September 2021, a total of 250 samples of V. vinifera (preferentially focused on symptomatic plants) and four samples of the wild plant host Clematis vitalba L. were collected from 50 vineyards in South Moravia. Total DNA was extracted using High Pure PCR Template Preparation Kit (Roche, Basel, Switzerland). For phytoplasma screening, a real-time PCR test for generic detection of phytoplasmas was used (Christensen et al. 2004). Samples evaluated as positive were further tested by PCR using phytoplasma universal P1 and P7 primers (Deng and Hiruki 1991; Schneider et al. 1995), followed by nested PCR using the 16SrV group-specific primers fB1 and rULWS1 (Smart et al. 1996). For identification of 16SrV phytoplasma, sequence analysis of the secY-map genetic locus was performed. Two sets of primers were used: FD9f5/MAPr1 primers for the first PCR and FD9f6/MAPr2 for the nested PCR (Arnaud et al. 2007) with PCRBIO TaqMix (PCR Biosystems, London, UK). The nested PCR products were purified and sequenced (Eurofins Genomics, Ebersberg, Germany). The sequences were compared with sequences from the GenBank database. Phytoplasma of the 16SrV group was detected in three samples: V. vinifera cv. Gewürztraminer with symptoms of leaf reddening with no rolling and no other typical symptoms; C. vitalba L. with leaf curling (Fig. 1A); symptomless C. vitalba. The obtained sequences of the secY-map locus of all three 16SrV-positive samples were identical to the sequence of GFDP, isolate Vv-SI257 (Acc. No. FN811141), detected in grapevine in Tuscany (Italy), which belongs to 16SrV group. The sequence of the V. vinifera cv. Gewürztraminer isolate was submitted to GenBank under Acc. No. OQ185203. This isolate belongs to the Map-FD3 cluster (Fig. 1B), and the genotype identified is M51 (corresponding to FD-C), which has already been found in C. vitalba and outbreaks of Flavescence dorée in grapevines in some other European countries (Malembic-Maher et al. 2020). Based on the abovementioned results, this is the first report of the GFDP in the Czech Republic.

PMID:37467129 | DOI:10.1094/PDIS-02-23-0315-PDN

Categories: Literature Watch

Plasticity of the binding pocket in peptide transporters underpins promiscuous substrate recognition

Wed, 2023-07-19 06:00

Cell Rep. 2023 Jul 18;42(8):112831. doi: 10.1016/j.celrep.2023.112831. Online ahead of print.

ABSTRACT

Proton-dependent oligopeptide transporters (POTs) are promiscuous transporters of the major facilitator superfamily that constitute the main route of entry for a wide range of dietary peptides and orally administrated peptidomimetic drugs. Given their clinical and pathophysiological relevance, several POT homologs have been studied extensively at the structural and molecular level. However, the molecular basis of recognition and transport of diverse peptide substrates has remained elusive. We present 14 X-ray structures of the bacterial POT DtpB in complex with chemically diverse di- and tripeptides, providing novel insights into the plasticity of the conserved central binding cavity. We analyzed binding affinities for more than 80 peptides and monitored uptake by a fluorescence-based transport assay. To probe whether all 8400 natural di- and tripeptides can bind to DtpB, we employed state-of-the-art molecular docking and machine learning and conclude that peptides with compact hydrophobic residues are the best DtpB binders.

PMID:37467108 | DOI:10.1016/j.celrep.2023.112831

Categories: Literature Watch

DeepTraSynergy: Drug Combinations using Multi-modal Deep Learning with Transformers

Wed, 2023-07-19 06:00

Bioinformatics. 2023 Jul 19:btad438. doi: 10.1093/bioinformatics/btad438. Online ahead of print.

ABSTRACT

MOTIVATION: Screening bioactive compounds in cancer cell lines receive more attention. Multidisciplinary drugs or drug combinations have a more effective role in treatments and selectively inhibit the growth of cancer cells.

RESULTS: Hence, we propose a new deep learning-based approach for drug combination synergy prediction called DeepTraSynergy. Our proposed approach utilizes multi-modal input including drug-target interaction, protein-protein interaction, and cell-target interaction to predict drug combination synergy. To learn the feature representation of drugs, we have utilized transformers. It is worth noting that our approach is a multi-task approach that predicts three outputs including the drug-target interaction, its toxic effect, and drug combination synergy. In our approach, drug combination synergy is the main task and the two other ones are the auxiliary tasks that help the approach to learn a better model. In the proposed approach three loss functions are defined: synergy loss, toxic loss, and drug-protein interaction loss. The last two loss functions are designed as auxiliary losses to help learn a better solution. DeepTraSynergy outperforms the classic and state-of-the-art models in predicting synergistic drug combinations on the two latest drug combination datasets. The DeepTraSynergy algorithm achieves accuracy values of 0.7715 and 0.8052 (an improvement over other approaches) on the DrugCombDB and Oncology-Screen datasets, respectively. Also, we evaluate the contribution of each component of DeepTraSynergy to show its effectiveness in the proposed method. The introduction of the relation between proteins (PPI networks) and drug-protein interaction significantly improves the prediction of synergistic drug combinations.

AVAILABILITY: The source code and data are available at https://github.com/fatemeh-rafiei/DeepTraSynergy.

PMID:37467066 | DOI:10.1093/bioinformatics/btad438

Categories: Literature Watch

Illuminate the Functions of Dark Proteins Using the Reactome-IDG Web Portal

Wed, 2023-07-19 06:00

Curr Protoc. 2023 Jul;3(7):e845. doi: 10.1002/cpz1.845.

ABSTRACT

Understudied or dark proteins have the potential to shed light on as-yet undiscovered molecular mechanisms that underlie phenotypes and suggest innovative therapeutic approaches for many diseases. The Reactome-IDG (Illuminating the Druggable Genome) project aims to place dark proteins in the context of manually curated, highly reliable pathways in Reactome, the most comprehensive, open-source biological pathway knowledgebase, facilitating the understanding functions and predicting therapeutic potentials of dark proteins. The Reactome-IDG web portal, deployed at https://idg.reactome.org, provides a simple, interactive web page for users to search pathways that may functionally interact with dark proteins, enabling the prediction of functions of dark proteins in the context of Reactome pathways. Enhanced visualization features implemented at the portal allow users to investigate the functional contexts for dark proteins based on tissue-specific gene or protein expression, drug-target interactions, or protein or gene pairwise relationships in the original Reactome's systems biology graph notation (SBGN) diagrams or the new simplified functional interaction (FI) network view of pathways. The protocols in this chapter describe step-by-step procedures to use the web portal to learn biological functions of dark proteins in the context of Reactome pathways. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Search for interacting pathways of a protein Support Protocol: Interacting pathway results for an annotated protein Alternate Protocol: Use individual pairwise relationships to predict interacting pathways of a protein Basic Protocol 2: Using the IDG pathway browser to study interacting pathways Basic Protocol 3: Overlaying tissue-specific expression data Basic Protocol 4: Overlaying protein/gene pairwise relationships in the pathway context Basic Protocol 5: Visualizing drug/target interactions.

PMID:37467006 | DOI:10.1002/cpz1.845

Categories: Literature Watch

Integrating analog and digital modes of gene expression at <em>Arabidopsis FLC</em>

Wed, 2023-07-19 06:00

Elife. 2023 Jul 19;12:e79743. doi: 10.7554/eLife.79743.

ABSTRACT

Quantitative gene regulation at the cell population level can be achieved by two fundamentally different modes of regulation at individual gene copies. A 'digital' mode involves binary ON/OFF expression states, with population-level variation arising from the proportion of gene copies in each state, while an 'analog' mode involves graded expression levels at each gene copy. At the Arabidopsis floral repressor FLOWERING LOCUS C (FLC), 'digital' Polycomb silencing is known to facilitate quantitative epigenetic memory in response to cold. However, whether FLC regulation before cold involves analog or digital modes is unknown. Using quantitative fluorescent imaging of FLC mRNA and protein, together with mathematical modeling, we find that FLC expression before cold is regulated by both analog and digital modes. We observe a temporal separation between the two modes, with analog preceding digital. The analog mode can maintain intermediate expression levels at individual FLC gene copies, before subsequent digital silencing, consistent with the copies switching OFF stochastically and heritably without cold. This switch leads to a slow reduction in FLC expression at the cell population level. These data present a new paradigm for gradual repression, elucidating how analog transcriptional and digital epigenetic memory pathways can be integrated.

PMID:37466633 | DOI:10.7554/eLife.79743

Categories: Literature Watch

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