Systems Biology

Superoxide dismutase A (SodA) is a c-di-GMP effector protein governing oxidative stress tolerance in Stenotrophomonas maltophilia

Fri, 2023-11-03 06:00

Microbiol Res. 2023 Oct 22;278:127535. doi: 10.1016/j.micres.2023.127535. Online ahead of print.

ABSTRACT

C-di-GMP is a bacterial second messenger implicated in the regulation of many key functions including antibiotic tolerance and biofilm formation. Our understanding of how c-di-GMP exerts its action via receptors to modulate different biological functions is still limited. Here we used a c-di-GMP affinity pull-down assay coupled to LC-MS/MS to identify c-di-GMP-binding proteins in the opportunistic pathogen Stenotrophomonas maltophilia. This analysis identified Smlt3238 (SodA), a protein of the superoxide dismutase family, as a c-di-GMP-binding protein. Microscale thermophoresis showed that purified SodA protein bound c-di-GMP with an estimated dissociation constant (Kd) value of 141.5 μM. Using various in vivo and in vitro experiments, we demonstrated that c-di-GMP modulates the enzyme activity of SodA directly. Circular dichroism experiments revealed that SodA protein gradually altered its basic structure with increasing levels of c-di-GMP. Phenotypic experiments conducted in the presence of a range of intracellular c-di-GMP levels showed that SodA function is modulated by c-di-GMP. The findings thus identify a novel c-di-GMP binding protein that governs oxidative stress tolerance in S. maltophilia.

PMID:37922698 | DOI:10.1016/j.micres.2023.127535

Categories: Literature Watch

Stress and Epilepsy: Towards Understanding of Neurobiological Mechanisms for Better Management

Fri, 2023-11-03 06:00

eNeuro. 2023 Nov 3;10(11):ENEURO.0200-23.2023. doi: 10.1523/ENEURO.0200-23.2023. Print 2023 Nov.

ABSTRACT

Stress has been identified as a major contributor to human disease and is postulated to play a substantial role in epileptogenesis. In a significant proportion of individuals with epilepsy, sensitivity to stressful events contributes to dynamic symptomatic burden, notably seizure occurrence and frequency, and presence and severity of psychiatric comorbidities [anxiety, depression, posttraumatic stress disorder (PTSD)]. Here, we review this complex relationship between stress and epilepsy using clinical data and highlight key neurobiological mechanisms including the hypothalamic-pituitary-adrenal (HPA) axis dysfunction, altered neuroplasticity within limbic system structures, and alterations in neurochemical pathways such as brain-derived neurotrophic factor (BNDF) linking epilepsy and stress. We discuss current clinical management approaches of stress that help optimize seizure control and prevention, as well as psychiatric comorbidities associated with epilepsy. We propose that various shared mechanisms of stress and epilepsy present multiple avenues for the development of new symptomatic and preventative treatments, including disease modifying therapies aimed at reducing epileptogenesis. This would require close collaborations between clinicians and basic scientists to integrate data across multiple scales, from genetics to systems biology, from clinical observations to fundamental mechanistic insights. In future, advances in machine learning approaches and neuromodulation strategies will enable personalized and targeted interventions to manage and ultimately treat stress-related epileptogenesis.

PMID:37923391 | DOI:10.1523/ENEURO.0200-23.2023

Categories: Literature Watch

Phenotypic heterogeneity associated with KIF21A: Two new cases and review of the literature

Fri, 2023-11-03 06:00

Am J Med Genet A. 2023 Nov 3. doi: 10.1002/ajmg.a.63455. Online ahead of print.

ABSTRACT

Our understanding of genetic and phenotypic heterogeneity associated with the clinical spectrum of rare diseases continues to expand. Thorough phenotypic descriptions and model organism functional studies are valuable tools in dissecting the biology of the disease process. Kinesin genes are well known to be associated with specific disease phenotypes and a subset of kinesin genes, including KIF21A, have been associated with more than one disease. Here we report two patients with KIF21A variants identified by exome sequencing; one with biallelic variants, supporting a novel KIF21A related syndrome with recessive inheritance and the second report of this condition, and another with a heterozygous de novo variant allele representing a phenotypic expansion of the condition described to date. We provide detailed phenotypic information on both families, including a novel neuropathology finding of neuroaxonal dystrophy associated with biallelic variants in KIF21A. Additionally, we studied the dominant variant in Saccharomyces cerevisiae to assess variant pathogenicity and found that this variant appears to impair protein function. KIF21A associated disease has mounting evidence for phenotypic heterogeneity; further patients and study of an allelic series are required to define the phenotypic spectrum and further explore the molecular etiology for each of these conditions.

PMID:37921537 | DOI:10.1002/ajmg.a.63455

Categories: Literature Watch

Critical assessment of methods of protein structure prediction (CASP)-Round XV

Fri, 2023-11-03 06:00

Proteins. 2023 Nov 2. doi: 10.1002/prot.26617. Online ahead of print.

ABSTRACT

Computing protein structure from amino acid sequence information has been a long-standing grand challenge. Critical assessment of structure prediction (CASP) conducts community experiments aimed at advancing solutions to this and related problems. Experiments are conducted every 2 years. The 2020 experiment (CASP14) saw major progress, with the second generation of deep learning methods delivering accuracy comparable with experiment for many single proteins. There is an expectation that these methods will have much wider application in computational structural biology. Here we summarize results from the most recent experiment, CASP15, in 2022, with an emphasis on new deep learning-driven progress. Other papers in this special issue of proteins provide more detailed analysis. For single protein structures, the AlphaFold2 deep learning method is still superior to other approaches, but there are two points of note. First, although AlphaFold2 was the core of all the most successful methods, there was a wide variety of implementation and combination with other methods. Second, using the standard AlphaFold2 protocol and default parameters only produces the highest quality result for about two thirds of the targets, and more extensive sampling is required for the others. The major advance in this CASP is the enormous increase in the accuracy of computed protein complexes, achieved by the use of deep learning methods, although overall these do not fully match the performance for single proteins. Here too, AlphaFold2 based method perform best, and again more extensive sampling than the defaults is often required. Also of note are the encouraging early results on the use of deep learning to compute ensembles of macromolecular structures. Critically for the usability of computed structures, for both single proteins and protein complexes, deep learning derived estimates of both local and global accuracy are of high quality, however the estimates in interface regions are slightly less reliable. CASP15 also included computation of RNA structures for the first time. Here, the classical approaches produced better agreement with experiment than the new deep learning ones, and accuracy is limited. Also, for the first time, CASP included the computation of protein-ligand complexes, an area of special interest for drug design. Here too, classical methods were still superior to deep learning ones. Many new approaches were discussed at the CASP conference, and it is clear methods will continue to advance.

PMID:37920879 | DOI:10.1002/prot.26617

Categories: Literature Watch

Network-based drug repurposing for HPV-associated cervical cancer

Fri, 2023-11-03 06:00

Comput Struct Biotechnol J. 2023 Oct 19;21:5186-5200. doi: 10.1016/j.csbj.2023.10.038. eCollection 2023.

ABSTRACT

In women, cervical cancer (CC) is the fourth most common cancer around the world with average cases of 604,000 and 342,000 deaths per year. Approximately 50% of high-grade CC are attributed to human papillomavirus (HPV) types 16 and 18. Chances of CC in HPV-positive patients are 6 times more than HPV-negative patients which demands timely and effective treatment. Repurposing of drugs is considered a viable approach to drug discovery which makes use of existing drugs, thus potentially reducing the time and costs associated with de-novo drug discovery. In this study, we present an integrative drug repurposing framework based on a systems biology-enabled network medicine platform. First, we built an HPV-induced CC protein interaction network named HPV2C following the CC signatures defined by the omics dataset, obtained from GEO database. Second, the drug target interaction (DTI) data obtained from DrugBank, and related databases was used to model the DTI network followed by drug target network proximity analysis of HPV-host associated key targets and DTIs in the human protein interactome. This analysis identified 142 potential anti-HPV repurposable drugs to target HPV induced CC pathways. Third, as per the literature survey 51 of the predicted drugs are already used for CC and 33 of the remaining drugs have anti-viral activity. Gene set enrichment analysis of potential drugs in drug-gene signatures and in HPV-induced CC-specific transcriptomic data in human cell lines additionally validated the predictions. Finally, 13 drug combinations were found using a network based on overlapping exposure. To summarize, the study provides effective network-based technique to quickly identify suitable repurposable drugs and drug combinations that target HPV-associated CC.

PMID:37920815 | PMC:PMC10618120 | DOI:10.1016/j.csbj.2023.10.038

Categories: Literature Watch

Biotic countermeasures that rescue <em>Nannochloropsis gaditana</em> from a <em>Bacillus safensis</em> infection

Fri, 2023-11-03 06:00

Front Microbiol. 2023 Oct 18;14:1271836. doi: 10.3389/fmicb.2023.1271836. eCollection 2023.

ABSTRACT

The natural assemblage of a symbiotic bacterial microbiome (bacteriome) with microalgae in marine ecosystems is now being investigated as a means to increase algal productivity for industry. When algae are grown in open pond settings, biological contamination causes an estimated 30% loss of the algal crop. Therefore, new crop protection strategies that do not disrupt the native algal bacteriome are needed to produce reliable, high-yield algal biomass. Bacteriophages offer an unexplored solution to treat bacterial pathogenicity in algal cultures because they can eliminate a single species without affecting the bacteriome. To address this, we identified a highly virulent pathogen of the microalga Nannochloropsis gaditana, the bacterium Bacillus safensis, and demonstrated rescue of the microalgae from the pathogen using phage. 16S rRNA amplicon sequencing showed that phage treatment did not alter the composition of the bacteriome. It is widely suspected that the algal bacteriome could play a protective role against bacterial pathogens. To test this, we compared the susceptibility of a bacteriome-attenuated N. gaditana culture challenged with B. safensis to a N. gaditana culture carrying a growth-promoting bacteriome. We showed that the loss of the bacteriome increased the susceptibility of N. gaditana to the pathogen. Transplanting the microalgal bacteriome to the bacteriome-attenuated culture reconstituted the protective effect of the bacteriome. Finally, the success of phage treatment was dependent on the presence of beneficial bacteriome. This study introduces two synergistic countermeasures against bacterial pathogenicity in algal cultures and a tractable model for studying interactions between microalgae, phages, pathogens, and the algae microbiome.

PMID:37920264 | PMC:PMC10618357 | DOI:10.3389/fmicb.2023.1271836

Categories: Literature Watch

A community resource to mass explore the wheat grain proteome and its application to the late-maturity alpha-amylase (LMA) problem

Fri, 2023-11-03 06:00

Gigascience. 2022 Dec 28;12:giad084. doi: 10.1093/gigascience/giad084.

ABSTRACT

BACKGROUND: Late-maturity alpha-amylase (LMA) is a wheat genetic defect causing the synthesis of high isoelectric point alpha-amylase following a temperature shock during mid-grain development or prolonged cold throughout grain development, both leading to starch degradation. While the physiology is well understood, the biochemical mechanisms involved in grain LMA response remain unclear. We have applied high-throughput proteomics to 4,061 wheat flours displaying a range of LMA activities. Using an array of statistical analyses to select LMA-responsive biomarkers, we have mined them using a suite of tools applicable to wheat proteins.

RESULTS: We observed that LMA-affected grains activated their primary metabolisms such as glycolysis and gluconeogenesis; TCA cycle, along with DNA- and RNA- binding mechanisms; and protein translation. This logically transitioned to protein folding activities driven by chaperones and protein disulfide isomerase, as well as protein assembly via dimerisation and complexing. The secondary metabolism was also mobilized with the upregulation of phytohormones and chemical and defence responses. LMA further invoked cellular structures, including ribosomes, microtubules, and chromatin. Finally, and unsurprisingly, LMA expression greatly impacted grain storage proteins, as well as starch and other carbohydrates, with the upregulation of alpha-gliadins and starch metabolism, whereas LMW glutenin, stachyose, sucrose, UDP-galactose, and UDP-glucose were downregulated.

CONCLUSIONS: To our knowledge, this is not only the first proteomics study tackling the wheat LMA issue but also the largest plant-based proteomics study published to date. Logistics, technicalities, requirements, and bottlenecks of such an ambitious large-scale high-throughput proteomics experiment along with the challenges associated with big data analyses are discussed.

PMID:37919977 | DOI:10.1093/gigascience/giad084

Categories: Literature Watch

Transcription factor HSFA7b controls thermomemory at the shoot apical meristem by regulating ethylene biosynthesis and signaling in Arabidopsis

Fri, 2023-11-03 06:00

Plant Commun. 2023 Nov 1:100743. doi: 10.1016/j.xplc.2023.100743. Online ahead of print.

ABSTRACT

The shoot apical meristem (SAM) is responsible for overall shoot growth by generating all above-ground structures. Recent research identified that the SAM displays an autonomous heat stress (HS) memory of a previous non-lethal HS event. Considering the importance of the SAM for plant growth it is essential to unlock how its thermomemory is mechanistically controlled. Here, we report that HEAT SHOCK TRANSCRIPTION FACTOR A7b (HSFA7b) plays a crucial role in this process in Arabidopsis, since the absence of functional HSFA7b results in the temporal suppression of the SAM activity after thermopriming. We found that HSFA7b directly regulates ethylene response at the SAM by binding to the promoter of the key ethylene signaling gene ETHYLENE-INSENSITIVE 3 to establish thermotolerance. Moreover, we demonstrated that HSFA7b regulates the expression of ETHYLENE OVERPRODUCER 1 (ETO1) and ETO1-LIKE 1, both of which encode ethylene biosynthesis repressors, thereby ensuring ethylene homeostasis at the SAM. Taken together, these results indicate a crucial and tissue-specific role of HSFA7b in thermomemory at the Arabidopsis SAM.

PMID:37919897 | DOI:10.1016/j.xplc.2023.100743

Categories: Literature Watch

p38 MAPK signaling in chronic obstructive pulmonary disease pathogenesis and inhibitor therapeutics

Fri, 2023-11-03 06:00

Cell Commun Signal. 2023 Nov 2;21(1):314. doi: 10.1186/s12964-023-01337-4.

ABSTRACT

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar remodeling. Although the abnormalities are primarily prompted by chronic exposure to inhaled irritants, maladjusted and self-reinforcing immune responses are significant contributors to the development and progression of the disease. The p38 isoforms are regarded as pivotal hub proteins that regulate immune and inflammatory responses in both healthy and disease states. As a result, their inhibition has been the subject of numerous recent studies exploring their therapeutic potential in COPD.

MAIN BODY: We performed a systematic search based on the PRISMA guidelines to find relevant studies about P38 signaling in COPD patients. We searched the PubMed and Google Scholar databases and used "P38" AND "COPD" Mesh Terms. We applied the following inclusion criteria: (1) human, animal, ex vivo and in vitro studies; (2) original research articles; (3) published in English; and (4) focused on P38 signaling in COPD pathogenesis, progression, or treatment. We screened the titles and abstracts of the retrieved studies and assessed the full texts of the eligible studies for quality and relevance. We extracted the following data from each study: authors, year, country, sample size, study design, cell type, intervention, outcome, and main findings. We classified the studies according to the role of different cells and treatments in P38 signaling in COPD.

CONCLUSION: While targeting p38 MAPK has demonstrated some therapeutic potential in COPD, its efficacy is limited. Nevertheless, combining p38 MAPK inhibitors with other anti-inflammatory steroids appears to be a promising treatment choice. Clinical trials testing various p38 MAPK inhibitors have produced mixed results, with some showing improvement in lung function and reduction in exacerbations in COPD patients. Despite these mixed results, research on p38 MAPK inhibitors is still a major area of study to develop new and more effective therapies for COPD. As our understanding of COPD evolves, we may gain a better understanding of how to utilize p38 MAPK inhibitors to treat this disease. Video Abstract.

PMID:37919729 | DOI:10.1186/s12964-023-01337-4

Categories: Literature Watch

Single-haplotype comparative genomics provides insights into lineage-specific structural variation during cat evolution

Fri, 2023-11-03 06:00

Nat Genet. 2023 Nov 2. doi: 10.1038/s41588-023-01548-y. Online ahead of print.

ABSTRACT

The role of structurally dynamic genomic regions in speciation is poorly understood due to challenges inherent in diploid genome assembly. Here we reconstructed the evolutionary dynamics of structural variation in five cat species by phasing the genomes of three interspecies F1 hybrids to generate near-gapless single-haplotype assemblies. We discerned that cat genomes have a paucity of segmental duplications relative to great apes, explaining their remarkable karyotypic stability. X chromosomes were hotspots of structural variation, including enrichment with inversions in a large recombination desert with characteristics of a supergene. The X-linked macrosatellite DXZ4 evolves more rapidly than 99.5% of the genome clarifying its role in felid hybrid incompatibility. Resolved sensory gene repertoires revealed functional copy number changes associated with ecomorphological adaptations, sociality and domestication. This study highlights the value of gapless genomes to reveal structural mechanisms underpinning karyotypic evolution, reproductive isolation and ecological niche adaptation.

PMID:37919451 | DOI:10.1038/s41588-023-01548-y

Categories: Literature Watch

scDiffCom: a tool for differential analysis of cell-cell interactions provides a mouse atlas of aging changes in intercellular communication

Fri, 2023-11-03 06:00

Nat Aging. 2023 Nov 2. doi: 10.1038/s43587-023-00514-x. Online ahead of print.

ABSTRACT

Dysregulation of intercellular communication is a hallmark of aging. To better quantify and explore changes in intercellular communication, we present scDiffCom and scAgeCom. scDiffCom is an R package, relying on approximately 5,000 curated ligand-receptor interactions, that performs differential intercellular communication analysis between two conditions from single-cell transcriptomics data. Built upon scDiffCom, scAgeCom is an atlas of age-related cell-cell communication changes covering 23 mouse tissues from 58 single-cell RNA sequencing datasets from Tabula Muris Senis and the Calico murine aging cell atlas. It offers a comprehensive resource of tissue-specific and sex-specific aging dysregulations and highlights age-related intercellular communication changes widespread across the whole body, such as the upregulation of immune system processes and inflammation, the downregulation of developmental processes, angiogenesis and extracellular matrix organization and the deregulation of lipid metabolism. Our analysis emphasizes the relevance of the specific ligands, receptors and cell types regulating these processes. The atlas is available online ( https://scagecom.org ).

PMID:37919434 | DOI:10.1038/s43587-023-00514-x

Categories: Literature Watch

KMD clustering: robust general-purpose clustering of biological data

Fri, 2023-11-03 06:00

Commun Biol. 2023 Nov 2;6(1):1110. doi: 10.1038/s42003-023-05480-z.

ABSTRACT

The noisy and high-dimensional nature of biological data has spawned advanced clustering algorithms that are tailored for specific biological datatypes. However, the performance of such methods varies greatly between datasets and they require post hoc tuning of cryptic hyperparameters. We present k minimal distance (KMD) clustering, a general-purpose method based on a generalization of single and average linkage hierarchical clustering. We introduce a generalized silhouette-like function to eliminate the cryptic hyperparameter k, and use sampling to enable application to million-object datasets. Rigorous comparisons to general and specialized clustering methods on simulated, mass cytometry and scRNA-seq datasets show consistent high performance of KMD clustering across all datasets.

PMID:37919399 | DOI:10.1038/s42003-023-05480-z

Categories: Literature Watch

Cross species systems biology discovers glial DDR2, STOM, and KANK2 as therapeutic targets in progressive supranuclear palsy

Fri, 2023-11-03 06:00

Nat Commun. 2023 Nov 2;14(1):6801. doi: 10.1038/s41467-023-42626-3.

ABSTRACT

Progressive supranuclear palsy (PSP) is a neurodegenerative parkinsonian disorder characterized by cell-type-specific tau lesions in neurons and glia. Prior work uncovered transcriptome changes in human PSP brains, although their cell-specificity is unknown. Further, systematic data integration and experimental validation platforms to prioritize brain transcriptional perturbations as therapeutic targets in PSP are currently lacking. In this study, we combine bulk tissue (n = 408) and single nucleus RNAseq (n = 34) data from PSP and control brains with transcriptome data from a mouse tauopathy and experimental validations in Drosophila tau models for systematic discovery of high-confidence expression changes in PSP with therapeutic potential. We discover, replicate, and annotate thousands of differentially expressed genes in PSP, many of which reside in glia-enriched co-expression modules and cells. We prioritize DDR2, STOM, and KANK2 as promising therapeutic targets in PSP with striking cross-species validations. We share our findings and data via our interactive application tool PSP RNAseq Atlas ( https://rtools.mayo.edu/PSP_RNAseq_Atlas/ ). Our findings reveal robust glial transcriptome changes in PSP, provide a cross-species systems biology approach, and a tool for therapeutic target discoveries in PSP with potential application in other neurodegenerative diseases.

PMID:37919278 | DOI:10.1038/s41467-023-42626-3

Categories: Literature Watch

In situ quantification of osmotic pressure within living embryonic tissues

Fri, 2023-11-03 06:00

Nat Commun. 2023 Nov 2;14(1):7023. doi: 10.1038/s41467-023-42024-9.

ABSTRACT

Mechanics is known to play a fundamental role in many cellular and developmental processes. Beyond active forces and material properties, osmotic pressure is believed to control essential cell and tissue characteristics. However, it remains very challenging to perform in situ and in vivo measurements of osmotic pressure. Here we introduce double emulsion droplet sensors that enable local measurements of osmotic pressure intra- and extra-cellularly within 3D multicellular systems, including living tissues. After generating and calibrating the sensors, we measure the osmotic pressure in blastomeres of early zebrafish embryos as well as in the interstitial fluid between the cells of the blastula by monitoring the size of droplets previously inserted in the embryo. Our results show a balance between intracellular and interstitial osmotic pressures, with values of approximately 0.7 MPa, but a large pressure imbalance between the inside and outside of the embryo. The ability to measure osmotic pressure in 3D multicellular systems, including developing embryos and organoids, will help improve our understanding of its role in fundamental biological processes.

PMID:37919265 | DOI:10.1038/s41467-023-42024-9

Categories: Literature Watch

Role of ALS-associated OPTN-K489E mutation in neuronal cell-death regulation

Thu, 2023-11-02 06:00

Mol Cell Neurosci. 2023 Oct 31:103904. doi: 10.1016/j.mcn.2023.103904. Online ahead of print.

ABSTRACT

Optineurin (OPTN) gene is a marker of amyotrophic lateral sclerosis (ALS). However, the role of optineurin protein (OPTN) in ALS pathology is unclear, even though it is known to regulate autophagy, apoptosis, and other survival-death cellular processes. Genetic analysis of Indian ALS patients by our group ascertained a novel mutation K489E in the OPTN gene. To identify the molecular mechanism associated with OPTN and its mutation, we developed an in-vitro cell model using SH-SY5Y cells harbouring OPTN and OPTN-K489E mutation along with its control vector. Since we observed a significant decrease in cell viability in the mutant, we measured the expressions of genes and proteins mediating apoptosis, necroptosis, and autophagy, to establish the role of OPTN in cell death regulation. Our results show that OPTN-K489E mutation changes the relative gene expressions of miRNA-9, REST, CoREST and BDNF, and causes apoptosis. We also observed an up-regulation in the expressions of necroptosis mediated genes RIPK1, RIPK3, and MLKL and autophagy mediated genes TBK1, P62, and LC3II. The results of FACS analyses revealed that this mutation promotes apoptotic and necroptotic processes confirming the pathogenicity of OPTN-K489E.

PMID:37918554 | DOI:10.1016/j.mcn.2023.103904

Categories: Literature Watch

The proteomic landscape of synaptic diversity across brain regions and cell types

Thu, 2023-11-02 06:00

Cell. 2023 Oct 26:S0092-8674(23)01082-6. doi: 10.1016/j.cell.2023.09.028. Online ahead of print.

ABSTRACT

Neurons build synaptic contacts using different protein combinations that define the specificity, function, and plasticity potential of synapses; however, the diversity of synaptic proteomes remains largely unexplored. We prepared synaptosomes from 7 different transgenic mouse lines with fluorescently labeled presynaptic terminals. Combining microdissection of 5 different brain regions with fluorescent-activated synaptosome sorting (FASS), we isolated and analyzed the proteomes of 18 different synapse types. We discovered ∼1,800 unique synapse-type-enriched proteins and allocated thousands of proteins to different types of synapses (https://syndive.org/). We identify shared synaptic protein modules and highlight the proteomic hotspots for synapse specialization. We reveal unique and common features of the striatal dopaminergic proteome and discover the proteome signatures that relate to the functional properties of different interneuron classes. This study provides a molecular systems-biology analysis of synapses and a framework to integrate proteomic information for synapse subtypes of interest with cellular or circuit-level experiments.

PMID:37918396 | DOI:10.1016/j.cell.2023.09.028

Categories: Literature Watch

Discovery of highly neutralizing human antibodies targeting Pseudomonas aeruginosa

Thu, 2023-11-02 06:00

Cell. 2023 Oct 27:S0092-8674(23)01084-X. doi: 10.1016/j.cell.2023.10.002. Online ahead of print.

ABSTRACT

Drug-resistant Pseudomonas aeruginosa (PA) poses an emerging threat to human health with urgent need for alternative therapeutic approaches. Here, we deciphered the B cell and antibody response to the virulence-associated type III secretion system (T3SS) in a cohort of patients chronically infected with PA. Single-cell analytics revealed a diverse B cell receptor repertoire directed against the T3SS needle-tip protein PcrV, enabling the production of monoclonal antibodies (mAbs) abrogating T3SS-mediated cytotoxicity. Mechanistic studies involving cryoelectron microscopy identified a surface-exposed C-terminal PcrV epitope as the target of highly neutralizing mAbs with broad activity against drug-resistant PA isolates. These anti-PcrV mAbs were as effective as treatment with conventional antibiotics in vivo. Our study reveals that chronically infected patients represent a source of neutralizing antibodies, which can be exploited as therapeutics against PA.

PMID:37918395 | DOI:10.1016/j.cell.2023.10.002

Categories: Literature Watch

Short term decreases in salinity, combined with the right choice of species, can allow for a more nutritious sea lettuce lipid profile

Thu, 2023-11-02 06:00

Food Chem. 2023 Oct 27;437(Pt 1):137865. doi: 10.1016/j.foodchem.2023.137865. Online ahead of print.

ABSTRACT

The sea lettuce Ulva spp is becoming an increasingly important macroalgae for aquaculture. Sea lettuce can be grown on- and off-shore, displays high growth rates, and its biomass possesses attractive nutritional benefits. Among those are their fatty acids (FA) and lipid profiles, rich in omega 3 Polyunsaturated Fatty Acids (PUFAs) as well as bioactive lipids. In order to tailor those properties for food applications, we explored the use of a short-term (seven days) low salinity treatment to modulate the lipid profile of two species of Ulva. We found large quantitative differences between species, and while a low-salinity treatment negatively affected growth, Ulva australis' lipid profile was positively impacted. Total FA particularly ɷ-3 PUFAs, increased three-fold, as well as most polar lipid species including known bioactive compounds. This study highlights profound differences between species and describes a simple method to increase the nutritional properties of Ulva biomass for food applications.

PMID:37918163 | DOI:10.1016/j.foodchem.2023.137865

Categories: Literature Watch

IFNγ-mediated IL-33 production is dependent on the aryl hydrocarbon receptor in human bronchial epithelial cells

Thu, 2023-11-02 06:00

Cytokine. 2023 Oct 31;172:156414. doi: 10.1016/j.cyto.2023.156414. Online ahead of print.

ABSTRACT

IL-33 is an alarmin produced by stromal cells and is known to promote airway inflammation. IL-33 is a critical mediator of steroid-unresponsiveness in severe asthma. We have previously shown that IFNγ, a cytokine known to be elevated in airway inflammation and severe asthma, enhances the abundance of IL-33 in bronchial epithelial cells. Previous studies have shown that environmental insults such as particulate matter results in activation of the aryl hydrocarbon receptor (AhR) and IL-33 production. However, the role of AhR in cytokine-mediated IL-33 production is unknown. In this study, we demonstrate that the knockdown of AhR results in significant decrease in IFNγ-mediated IL-33 production and phosphorylation of STAT1 (Y701), in human bronchial epithelial cells. The findings of this report suggest that AhR may be an essential component in IFNγ-mediated IL-33 production in the lungs.

PMID:37918052 | DOI:10.1016/j.cyto.2023.156414

Categories: Literature Watch

Finding a good balance: two distinct chromatin factors fine-tune stress response in Arabidopsis seedlings

Thu, 2023-11-02 06:00

New Phytol. 2023 Nov 2. doi: 10.1111/nph.19357. Online ahead of print.

NO ABSTRACT

PMID:37919230 | DOI:10.1111/nph.19357

Categories: Literature Watch

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