Systems Biology

Establishment of Novel DNA Methylation-Based Prostate Cancer Subtypes and a Risk-Predicting Eight-Gene Signature

Fri, 2021-03-12 06:00

Front Cell Dev Biol. 2021 Feb 23;9:639615. doi: 10.3389/fcell.2021.639615. eCollection 2021.

ABSTRACT

Prostate cancer (PCa) is the most common malignant tumor affecting males worldwide. The substantial heterogeneity in PCa presents a major challenge with respect to molecular analyses, patient stratification, and treatment. Least absolute shrinkage and selection operator was used to select eight risk-CpG sites. Using an unsupervised clustering analysis, called consensus clustering, we found that patients with PCa could be divided into two subtypes (Methylation_H and Methylation_L) based on the DNA methylation status at these CpG sites. Differences in the epigenome, genome, transcriptome, disease status, immune cell composition, and function between the identified subtypes were explored using The Cancer Genome Atlas database. This analysis clearly revealed the risk characteristics of the Methylation_H subtype. Using a weighted correlation network analysis to select risk-related genes and least absolute shrinkage and selection operator, we constructed a prediction signature for prognosis based on the subtype classification. We further validated its effectiveness using four public datasets. The two novel PCa subtypes and risk predictive signature developed in this study may be effective indicators of prognosis.

PMID:33708770 | PMC:PMC7940376 | DOI:10.3389/fcell.2021.639615

Categories: Literature Watch

Omics-Driven Biotechnology for Industrial Applications

Fri, 2021-03-12 06:00

Front Bioeng Biotechnol. 2021 Feb 23;9:613307. doi: 10.3389/fbioe.2021.613307. eCollection 2021.

ABSTRACT

Biomanufacturing is a key component of biotechnology that uses biological systems to produce bioproducts of commercial relevance, which are of great interest to the energy, material, pharmaceutical, food, and agriculture industries. Biotechnology-based approaches, such as synthetic biology and metabolic engineering are heavily reliant on "omics" driven systems biology to characterize and understand metabolic networks. Knowledge gained from systems biology experiments aid the development of synthetic biology tools and the advancement of metabolic engineering studies toward establishing robust industrial biomanufacturing platforms. In this review, we discuss recent advances in "omics" technologies, compare the pros and cons of the different "omics" technologies, and discuss the necessary requirements for carrying out multi-omics experiments. We highlight the influence of "omics" technologies on the production of biofuels and bioproducts by metabolic engineering. Finally, we discuss the application of "omics" technologies to agricultural and food biotechnology, and review the impact of "omics" on current COVID-19 research.

PMID:33708762 | PMC:PMC7940536 | DOI:10.3389/fbioe.2021.613307

Categories: Literature Watch

The Heat Shock Protein 40-Type Chaperone MASH Supports the Endoplasmic Reticulum-Associated Degradation E3 Ubiquitin Ligase MAKIBISHI1 in <em>Medicago truncatula</em>

Fri, 2021-03-12 06:00

Front Plant Sci. 2021 Feb 23;12:639625. doi: 10.3389/fpls.2021.639625. eCollection 2021.

ABSTRACT

Jasmonates (JA) are oxylipin-derived phytohormones that trigger the production of specialized metabolites that often serve in defense against biotic stresses. In Medicago truncatula, a JA-induced endoplasmic reticulum-associated degradation (ERAD)-type machinery manages the production of bioactive triterpenes and thereby secures correct plant metabolism, growth, and development. This machinery involves the conserved RING membrane-anchor (RMA)-type E3 ubiquitin ligase MAKIBISHI1 (MKB1). Here, we discovered two additional members of this protein control apparatus via a yeast-based protein-protein interaction screen and characterized their function. First, a cognate E2 ubiquitin-conjugating enzyme was identified that interacts with MKB1 to deliver activated ubiquitin and to mediate its ubiquitination activity. Second, we identified a heat shock protein 40 (HSP40) that interacts with MKB1 to support its activity and was therefore designated MKB1-supporting HSP40 (MASH). MASH expression was found to be co-regulated with that of MKB1. The presence of MASH is critical for MKB1 and ERAD functioning because the dramatic morphological, transcriptional, and metabolic phenotype of MKB1 knock-down M. truncatula hairy roots was phenocopied by silencing of MASH. Interaction was also observed between the Arabidopsis thaliana (Arabidopsis) homologs of MASH and MKB1, suggesting that MASH represents an essential and plant-specific component of this vital and conserved eukaryotic protein quality control machinery.

PMID:33708234 | PMC:PMC7940691 | DOI:10.3389/fpls.2021.639625

Categories: Literature Watch

Magnetic Field Induced Changes in the Shoot and Root Proteome of Barley (<em>Hordeum vulgare</em> L.)

Fri, 2021-03-12 06:00

Front Plant Sci. 2021 Feb 23;12:622795. doi: 10.3389/fpls.2021.622795. eCollection 2021.

ABSTRACT

The geomagnetic field (GMF) has been present since the beginning of plant evolution. Recently, some researchers have focused their efforts on employing magnetic fields (MFs) higher than GMF to improve the seed germination, growth, and harvest of agriculturally important crop plants, as the use of MFs is an inexpensive and environment-friendly technique. In this study, we have employed different treatments of MF at 7 mT (milliTesla) at different time points of exposure, including 1, 3, and 6 h. The extended exposure was followed by five consecutive days at 6 h per day in barley seeds. The results showed a positive impact of MF on growth characteristics for 5-day-old seedlings, including seed germination rate, root and shoot length, and biomass weight. Furthermore, ~5 days of delay of flowering in pre-treated plants was also observed. We used a shotgun proteomics approach to identify changes in the protein signatures of root and shoot tissues under MF effects. In total, we have identified 2,896 proteins. Thirty-eight proteins in the shoot and 15 proteins in the root showed significant changes under the MF effect. Proteins involved in primary metabolic pathways were increased in contrast to proteins with a metal ion binding function, proteins that contain iron ions in their structure, and proteins involved in electron transfer chain, which were all decreased significantly in the treated tissues. The upregulated proteins' overall biological processes included carbohydrate metabolic process, oxidation-reduction process, and cell redox homeostasis, while down-regulated processes included translation and protein refolding. In general, shoot response was more affected by MF effect than root tissue, leading to the identification of 41 shoot specific proteins. This study provides an initial insight into the proteome regulation response to MF during barley's seedling stage.

PMID:33708230 | PMC:PMC7940674 | DOI:10.3389/fpls.2021.622795

Categories: Literature Watch

Comprehensive profiling of circular RNAs with nanopore sequencing and CIRI-long

Fri, 2021-03-12 06:00

Nat Biotechnol. 2021 Mar 11. doi: 10.1038/s41587-021-00842-6. Online ahead of print.

ABSTRACT

Reconstructing the sequence of circular RNAs (circRNAs) from short RNA sequencing reads has proved challenging given the similarity of circRNAs and their corresponding linear messenger RNAs. Previous sequencing methods were unable to achieve high-throughput detection of full-length circRNAs. Here we describe a protocol for enrichment and full-length sequencing of circRNA isoforms using nanopore technology. Circular reverse transcription and size selection achieves a 20-fold higher enrichment of circRNAs from total RNA compared to previous methods. We developed an algorithm, called circRNA identifier using long-read sequencing data (CIRI-long), to reconstruct the sequence of circRNAs. The workflow was validated with simulated data and by comparison to Illumina sequencing as well as quantitative real-time RT-PCR. We used CIRI-long to analyze adult mouse brain samples and systematically profile circRNAs, including mitochondria-derived and transcriptional read-through circRNAs. We identified a new type of intronic self-ligated circRNA that exhibits special splicing and expression patterns. Our method takes advantage of nanopore long reads and enables unbiased reconstruction of full-length circRNA sequences.

PMID:33707777 | DOI:10.1038/s41587-021-00842-6

Categories: Literature Watch

Author Correction: Inherited causes of clonal haematopoiesis in 97,691 whole genomes

Fri, 2021-03-12 06:00

Nature. 2021 Mar 11. doi: 10.1038/s41586-021-03280-1. Online ahead of print.

NO ABSTRACT

PMID:33707633 | DOI:10.1038/s41586-021-03280-1

Categories: Literature Watch

Systems-wide effects of short-term feed deprivation in obese mice

Fri, 2021-03-12 06:00

Sci Rep. 2021 Mar 11;11(1):5716. doi: 10.1038/s41598-021-85020-z.

ABSTRACT

While prolonged fasting induces significant metabolic changes in humans and mice, less is known about systems-wide metabolic changes in response to short-term feed deprivation, which is used in experimental animal studies prior to metabolic challenge tests. We here performed a systems biology-based investigation of connections between gut bacterial composition and function, inflammatory and metabolic parameters in the intestine, liver, visceral adipose tissue, blood and urine in high-fat fed, obese mice that were feed deprived up to 12 h. The systems-wide analysis revealed that feed deprivation linked to enhanced intestinal butyric acid production and expression of the gene encoding the pro-thermogenic uncoupling protein UCP1 in visceral adipose tissue of obese mice. Ucp1 expression was also positively associated with Il33 expression in ileum, colon and adipose tissue as well as with the abundance of colonic Porphyromonadaceae, the latter also correlating to cecal butyric acid levels. Collectively, the data highlighted presence of a multi-tiered system of inter-tissue communication involving intestinal, immune and metabolic functions which is affected by feed deprivation in obese mice, thus pointing to careful use of short-feed deprivation in metabolic studies using obese mice.

PMID:33707503 | DOI:10.1038/s41598-021-85020-z

Categories: Literature Watch

Metabolomics of sebum reveals lipid dysregulation in Parkinson's disease

Fri, 2021-03-12 06:00

Nat Commun. 2021 Mar 11;12(1):1592. doi: 10.1038/s41467-021-21669-4.

ABSTRACT

Parkinson's disease (PD) is a progressive neurodegenerative disorder, which is characterised by degeneration of distinct neuronal populations, including dopaminergic neurons of the substantia nigra. Here, we use a metabolomics profiling approach to identify changes to lipids in PD observed in sebum, a non-invasively available biofluid. We used liquid chromatography-mass spectrometry (LC-MS) to analyse 274 samples from participants (80 drug naïve PD, 138 medicated PD and 56 well matched control subjects) and detected metabolites that could predict PD phenotype. Pathway enrichment analysis shows alterations in lipid metabolism related to the carnitine shuttle, sphingolipid metabolism, arachidonic acid metabolism and fatty acid biosynthesis. This study shows sebum can be used to identify potential biomarkers for PD.

PMID:33707447 | DOI:10.1038/s41467-021-21669-4

Categories: Literature Watch

Metabolomic analyses of COVID-19 patients unravel stage-dependent and prognostic biomarkers

Fri, 2021-03-12 06:00

Cell Death Dis. 2021 Mar 11;12(3):258. doi: 10.1038/s41419-021-03540-y.

ABSTRACT

The circulating metabolome provides a snapshot of the physiological state of the organism responding to pathogenic challenges. Here we report alterations in the plasma metabolome reflecting the clinical presentation of COVID-19 patients with mild (ambulatory) diseases, moderate disease (radiologically confirmed pneumonitis, hospitalization and oxygen therapy), and critical disease (in intensive care). This analysis revealed major disease- and stage-associated shifts in the metabolome, meaning that at least 77 metabolites including amino acids, lipids, polyamines and sugars, as well as their derivatives, were altered in critical COVID-19 patient's plasma as compared to mild COVID-19 patients. Among a uniformly moderate cohort of patients who received tocilizumab, only 10 metabolites were different among individuals with a favorable evolution as compared to those who required transfer into the intensive care unit. The elevation of one single metabolite, anthranilic acid, had a poor prognostic value, correlating with the maintenance of high interleukin-10 and -18 levels. Given that products of the kynurenine pathway including anthranilic acid have immunosuppressive properties, we speculate on the therapeutic utility to inhibit the rate-limiting enzymes of this pathway including indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase.

PMID:33707411 | DOI:10.1038/s41419-021-03540-y

Categories: Literature Watch

Correlative super-resolution fluorescence and electron cryo-microscopy based on cryo-SOFI

Fri, 2021-03-12 06:00

Methods Cell Biol. 2021;162:253-271. doi: 10.1016/bs.mcb.2020.10.021. Epub 2020 Dec 19.

ABSTRACT

The combination of super-resolution fluorescence microscopy and electron microscopy at ambient temperatures has become an established technique and a broad variety of modalities are now available to the cell biology community. In contrast, correlative cryogenic super-resolution fluorescence and electron microscopy (super-resolution cryo-CLEM) is just emerging. Aside from technical challenges, one of the major issues is the risk of devitrification of the specimen caused by the laser intensities required for super-resolution imaging. Cryo-SOFI (cryogenic super-resolution optical fluctuation imaging) allows the reconstruction of super-resolution images at particularly low laser intensities. It is fully compatible with the standard sample preparation for cryogenic electron microscopy (cryo-EM) and fairly easy to implement in any standard cryogenic fluorescence microscope.

PMID:33707015 | DOI:10.1016/bs.mcb.2020.10.021

Categories: Literature Watch

N-glycosylated GPNMB ligand-independently activates mutated EGFR signaling and promotes metastasis in NSCLC

Thu, 2021-03-11 06:00

Cancer Sci. 2021 Mar 11. doi: 10.1111/cas.14872. Online ahead of print.

ABSTRACT

Lung cancer is the leading cause of cancer related death worldwide. In spite of the identification of epidermal growth factor receptor (EGFR) driver mutations has improved the therapeutics for lung cancer, patients harboring EGFR mutations usually display shorter overall survival and a higher tendency to develop distant metastasis compared with those carrying wild-type EGFR. Nevertheless, the way to control mutated EGFR signaling remains unclear. Here, we performed membrane proteomic analysis to determine potential components that may act with EGFR mutations to promote lung cancer malignancy. The results show that the expressions of transmembrane glycoprotein non-metastatic melanoma protein B (GPNMB) is positively correlated with the status of mutated EGFR in non-small cell lung cancer (NSCLC). It is not only overexpressed but also highly glycosylated in EGFR-mutated, especially the EGFR-L858R mutated, NSCLC cells. Further examinations indicate that GPNMB could activate mutated EGFR without ligand stimulation. It could bind to the C-terminus of EGFR, facilitate its' phosphorylation at Y845, turn on the downstream STAT3 signaling, and promote cancer metastasis. Moreover, we also found that the Asn134 (N134) glycosylation of GPNMB plays a crucial role in this ligand-independent regulation. Depleting the N134-glycosylation of GPNMB could dramatically inhibit the binding of GPNMB to mutated EGFR, block its downstream signaling, and ultimately inhibit cancer metastasis in NSCLC. Clarifying the role of N-glycosylated GPNMB in regulating the ligand-independent activation of mutated EGFR may provide a new insight for developing novel therapeutics for NSCLC in the near future.

PMID:33706413 | DOI:10.1111/cas.14872

Categories: Literature Watch

A hijack mechanism of Indian SARS-CoV-2 isolates for relapsing contemporary antiviral therapeutics

Thu, 2021-03-11 06:00

Comput Biol Med. 2021 Mar 6;132:104315. doi: 10.1016/j.compbiomed.2021.104315. Online ahead of print.

ABSTRACT

Coronavirus disease (COVID-19) rapidly expands to a global pandemic and its impact on public health varies from country to country. It is caused by a new virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is imperative for relapsing current antiviral therapeutics owing to randomized genetic drift in global SARS-CoV-2 isolates. A molecular mechanism behind the emerging genomic variants is not yet understood for the prioritization of selective antivirals. The present computational study was aimed to repurpose existing antivirals for Indian SARS-CoV-2 isolates by uncovering a hijack mechanism based on structural and functional characteristics of protein variants. Forty-one protein mutations were identified in 12 Indian SARS-CoV-2 isolates by analysis of genome variations across 460 genome sequences obtained from 30 geographic sites in India. Two unique mutations such as W6152R and N5928H found in exonuclease of Surat (GBRC275b) and Gandhinagar (GBRC239) isolates. We report for the first time the impact of folding rate on stabilizing/retaining a sequence-structure-function-virulence link of emerging protein variants leading to accommodate hijack ability from current antivirals. Binding affinity analysis revealed the effect of point mutations on virus infectivity and the drug-escaping efficiency of Indian isolates. Emodin and artinemol suggested herein as repurposable antivirals for the treatment of COVID-19 patients infected with Indian isolates. Our study concludes that a protein folding rate is a key structural and evolutionary determinant to enhance the receptor-binding specificity and ensure hijack ability from the prevalent antiviral therapeutics.

PMID:33705994 | DOI:10.1016/j.compbiomed.2021.104315

Categories: Literature Watch

Updates on ion and water transport by the Malpighian tubule

Thu, 2021-03-11 06:00

Curr Opin Insect Sci. 2021 Mar 8:S2214-5745(21)00026-2. doi: 10.1016/j.cois.2021.02.018. Online ahead of print.

ABSTRACT

The Malpighian (renal) tubule is capable of transporting fluid at remarkable rates. This review will focus on recent insights into the mechanisms by which these high rates are achieved and controlled, with particular reference to the tubules of Drosophila melanogaster, in which the combination of physiology and genetics has led to particularly rapid progress. Like many vertebrate epithelia, the Drosophila tubule has specialized cell types, with active cation transport confined to a large, metabolically active principal cell; whereas the smaller intercalated stellate cell controls chloride and water shunts to achieve net fluid secretion. Recently, the genes underlying many of these processes have been identified, functionally validated and localized within the tubule. The imminent arrival of new types of post-genomic data (notably single cell sequencing) will herald an exciting era of new discovery.

PMID:33705976 | DOI:10.1016/j.cois.2021.02.018

Categories: Literature Watch

Plant synthetic biology for producing potent phyto-antimicrobials to combat antimicrobial resistance

Thu, 2021-03-11 06:00

Biotechnol Adv. 2021 Mar 8:107729. doi: 10.1016/j.biotechadv.2021.107729. Online ahead of print.

ABSTRACT

Inappropriate and injudicious use of antimicrobial drugs in human health, hygiene, agriculture, animal husbandry and food industries has contributed significantly to rapid emergence and persistence of antimicrobial resistance (AMR), one of the serious global public health threats. The crisis of AMR versus slower discovery of newer antibiotics put forth a daunting task to control these drug-resistant superbugs. Several phyto-antimicrobials have been identified in recent years with direct-killing (bactericidal) and/or drug-resistance reversal (re-sensitization of AMR phenotypes) potencies. Phyto-antimicrobials may hold the key in combating AMR owing to their abilities to target major microbial drug-resistance determinants including cell membrane, drug-efflux pumps, cell communication and biofilms. However, limited distribution, low intracellular concentrations, eco-geographical variations, beside other considerations like dynamic environments, climate change and over-exploitation of plant-resources are major blockades in full potential exploration phyto-antimicrobials. Synthetic biology (SynBio) strategies integrating metabolic engineering, RNA-interference, genome editing/engineering and/or systems biology approaches using plant chassis (as engineerable platforms) offer prospective tools for production of phyto-antimicrobials. With expanding SynBio toolkit, successful attempts towards introduction of entire gene cluster, reconstituting the metabolic pathway or transferring an entire metabolic (or synthetic) pathway into heterologous plant systems highlight the potential of this field. Through this perspective review, we are presenting herein the current situation and options for addressing AMR, emphasizing on the significance of phyto-antimicrobials in this apparently post-antibiotic era, and effective use of plant chassis for phyto-antimicrobial production at industrial scales along with major SynBio tools and useful databases. Current knowledge, recent success stories, associated challenges and prospects of translational success are also discussed.

PMID:33705914 | DOI:10.1016/j.biotechadv.2021.107729

Categories: Literature Watch

AGC kinases and MAB4/MEL proteins maintain PIN polarity by limiting lateral diffusion in plant cells

Thu, 2021-03-11 06:00

Curr Biol. 2021 Mar 5:S0960-9822(21)00269-4. doi: 10.1016/j.cub.2021.02.028. Online ahead of print.

ABSTRACT

Polar subcellular localization of the PIN exporters of the phytohormone auxin is a key determinant of directional, intercellular auxin transport and thus a central topic of both plant cell and developmental biology. Arabidopsis mutants lacking PID, a kinase that phosphorylates PINs, or the MAB4/MEL proteins of unknown molecular function display PIN polarity defects and phenocopy pin mutants, but mechanistic insights into how these factors convey PIN polarity are missing. Here, by combining protein biochemistry with quantitative live-cell imaging, we demonstrate that PINs, MAB4/MELs, and AGC kinases interact in the same complex at the plasma membrane. MAB4/MELs are recruited to the plasma membrane by the PINs and in concert with the AGC kinases maintain PIN polarity through limiting lateral diffusion-based escape of PINs from the polar domain. The PIN-MAB4/MEL-PID protein complex has self-reinforcing properties thanks to positive feedback between AGC kinase-mediated PIN phosphorylation and MAB4/MEL recruitment. We thus uncover the molecular mechanism by which AGC kinases and MAB4/MEL proteins regulate PIN localization and plant development.

PMID:33705718 | DOI:10.1016/j.cub.2021.02.028

Categories: Literature Watch

My Old World chap, this α-gal is not for you

Thu, 2021-03-11 06:00

Cell Host Microbe. 2021 Mar 10;29(3):315-317. doi: 10.1016/j.chom.2021.02.013.

ABSTRACT

30 million years ago, ancestors of Old World primates lost the ability to produce α-gal. In this issue of Cell Host & Microbe, Singh et al. (2021) show that the loss is associated with increased resistance to sepsis, but that this advantage comes alongside a cost of accelerated reproductive senescence.

PMID:33705699 | DOI:10.1016/j.chom.2021.02.013

Categories: Literature Watch

Development of a biomarker database toward performing disease classification and finding disease interrelations

Thu, 2021-03-11 06:00

Database (Oxford). 2021 Mar 11;2021:baab011. doi: 10.1093/database/baab011.

ABSTRACT

A biomarker is a measurable indicator of a disease or abnormal state of a body that plays an important role in disease diagnosis, prognosis and treatment. The biomarker has become a significant topic due to its versatile usage in the medical field and in rapid detection of the presence or severity of some diseases. The volume of biomarker data is rapidly increasing and the identified data are scattered. To provide comprehensive information, the explosively growing data need to be recorded in a single platform. There is no open-source freely available comprehensive online biomarker database. To fulfill this purpose, we have developed a human biomarker database as part of the KNApSAcK family databases which contain a vast quantity of information on the relationships between biomarkers and diseases. We have classified the diseases into 18 disease classes, mostly according to the National Center for Biotechnology Information definitions. Apart from this database development, we also have performed disease classification by separately using protein and metabolite biomarkers based on the network clustering algorithm DPClusO and hierarchical clustering. Finally, we reached a conclusion about the relationships among the disease classes. The human biomarker database can be accessed online and the inter-disease relationships may be helpful in understanding the molecular mechanisms of diseases. To our knowledge, this is one of the first approaches to classify diseases based on biomarkers. Database URL: http://www.knapsackfamily.com/Biomarker/top.php.

PMID:33705530 | DOI:10.1093/database/baab011

Categories: Literature Watch

Norovirus evolution in immunodeficient mice reveals potentiated pathogenicity via a single nucleotide change in the viral capsid

Thu, 2021-03-11 06:00

PLoS Pathog. 2021 Mar 11;17(3):e1009402. doi: 10.1371/journal.ppat.1009402. Online ahead of print.

ABSTRACT

Interferons (IFNs) are key controllers of viral replication, with intact IFN responses suppressing virus growth and spread. Using the murine norovirus (MNoV) system, we show that IFNs exert selective pressure to limit the pathogenic evolutionary potential of this enteric virus. In animals lacking type I IFN signaling, the nonlethal MNoV strain CR6 rapidly acquired enhanced virulence via conversion of a single nucleotide. This nucleotide change resulted in amino acid substitution F514I in the viral capsid, which led to >10,000-fold higher replication in systemic organs including the brain. Pathogenicity was mediated by enhanced recruitment and infection of intestinal myeloid cells and increased extraintestinal dissemination of virus. Interestingly, the trade-off for this mutation was reduced fitness in an IFN-competent host, in which CR6 bearing F514I exhibited decreased intestinal replication and shedding. In an immunodeficient context, a spontaneous amino acid change can thus convert a relatively avirulent viral strain into a lethal pathogen.

PMID:33705489 | DOI:10.1371/journal.ppat.1009402

Categories: Literature Watch

Deep learning-based molecular morphometrics for kidney biopsies

Thu, 2021-03-11 06:00

JCI Insight. 2021 Mar 11:144779. doi: 10.1172/jci.insight.144779. Online ahead of print.

ABSTRACT

Morphologic examination of tissue biopsies is essential for histopathological diagnosis. However, accurate and scalable cellular quantification in human samples remains challenging. Here, we present a deep learning-based approach for antigen-specific cellular morphometrics in human kidney biopsies, which combines indirect immunofluorescence imaging with U-Net-based architectures for image-to-image translation and dual segmentation tasks, achieving human-level accuracy. In the kidney, podocyte loss represents a hallmark of glomerular injury and can be estimated in diagnostic biopsies. Thus, we profiled over 27,000 podocytes from 110 human samples, including patients with anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN), an immune-mediated disease with aggressive glomerular damage and irreversible loss of kidney function. We identified previously unknown morphometric signatures of podocyte depletion in patients with ANCA-GN, which allowed patient classification and, in combination with routine clinical tools, showed potential for risk stratification. Our approach enables robust and scalable molecular morphometric analysis of human tissues, yielding deeper biological insights into the human kidney pathophysiology.

PMID:33705360 | DOI:10.1172/jci.insight.144779

Categories: Literature Watch

HLA class I-associated expansion of TRBV11-2 T cells in Multisystem Inflammatory Syndrome in Children

Thu, 2021-03-11 06:00

J Clin Invest. 2021 Mar 11:146614. doi: 10.1172/JCI146614. Online ahead of print.

ABSTRACT

Multisystem Inflammatory Syndrome in Children (MIS-C), a hyperinflammatory syndrome associated with SARS-CoV-2 infection, shares clinical features with toxic shock syndrome, which is triggered by bacterial superantigens. Superantigen specificity for different Vβ-chains results in Vβ-skewing, whereby T cells with specific Vβ-chains and diverse antigen specificity are overrepresented in the TCR repertoire. Here, we characterized the TCR repertoire of MIS-C patients and found a profound expansion of TCR Βeta Variable gene (TRBV)11-2, with up to 24% of clonal T cell space occupied by TRBV11-2 T cells, which correlated with MIS-C severity and serum cytokine levels. Analysis of TRBJ gene usage and CDR3 length distribution of MIS-C expanded TRBV11-2 clones revealed extensive junctional diversity. Patients with TRBV11-2 expansion showed HLA class I allele restriction to HLA-I A02, C35 and C04, indicating a novel mechanism for CDR3-independent T cell expansion. In silico modelling indicated that polyacidic residues in the Vβ chain encoded by TRBV11-2 strongly interact with the superantigen-like motif of SARS-CoV-2 spike glycoprotein, suggesting that unprocessed SARS-CoV-2 spike may directly mediate TRBV11-2 expansion. Overall, our data indicate that a CDR3-independent interaction between SARS-CoV-2 spike and TCR leads to T cell expansion and possibly activation, which may account for the clinical presentation of MIS-C.

PMID:33705359 | DOI:10.1172/JCI146614

Categories: Literature Watch

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