Systems Biology
Microbiome Metadata Standards: Report of the National Microbiome Data Collaborative's Workshop and Follow-On Activities
mSystems. 2021 Feb 23;6(1):e01194-20. doi: 10.1128/mSystems.01194-20.
ABSTRACT
Microbiome samples are inherently defined by the environment in which they are found. Therefore, data that provide context and enable interpretation of measurements produced from biological samples, often referred to as metadata, are critical. Important contributions have been made in the development of community-driven metadata standards; however, these standards have not been uniformly embraced by the microbiome research community. To understand how these standards are being adopted, or the barriers to adoption, across research domains, institutions, and funding agencies, the National Microbiome Data Collaborative (NMDC) hosted a workshop in October 2019. This report provides a summary of discussions that took place throughout the workshop, as well as outcomes of the working groups initiated at the workshop.
PMID:33622857 | DOI:10.1128/mSystems.01194-20
Intracellular pathways for lignin catabolism in white-rot fungi
Proc Natl Acad Sci U S A. 2021 Mar 2;118(9):e2017381118. doi: 10.1073/pnas.2017381118.
ABSTRACT
Lignin is a biopolymer found in plant cell walls that accounts for 30% of the organic carbon in the biosphere. White-rot fungi (WRF) are considered the most efficient organisms at degrading lignin in nature. While lignin depolymerization by WRF has been extensively studied, the possibility that WRF are able to utilize lignin as a carbon source is still a matter of controversy. Here, we employ 13C-isotope labeling, systems biology approaches, and in vitro enzyme assays to demonstrate that two WRF, Trametes versicolor and Gelatoporia subvermispora, funnel carbon from lignin-derived aromatic compounds into central carbon metabolism via intracellular catabolic pathways. These results provide insights into global carbon cycling in soil ecosystems and furthermore establish a foundation for employing WRF in simultaneous lignin depolymerization and bioconversion to bioproducts-a key step toward enabling a sustainable bioeconomy.
PMID:33622792 | DOI:10.1073/pnas.2017381118
Subcellular Architecture of the <em>xyl</em> Gene Expression Flow of the TOL Catabolic Plasmid of Pseudomonas putida mt-2
mBio. 2021 Feb 23;12(1):e03685-20. doi: 10.1128/mBio.03685-20.
ABSTRACT
Despite intensive research on the biochemical and regulatory features of the archetypal catabolic TOL system borne by pWW0 of Pseudomonas putida strain mt-2, the physical arrangement and tridimensional logic of the xyl gene expression flow remains unknown. In this work, the spatial distribution of specific xyl mRNAs with respect to the host nucleoid, the TOL plasmid, and the ribosomal pool has been investigated. In situ hybridization of target transcripts with fluorescent oligonucleotide probes revealed that xyl mRNAs cluster in discrete foci, adjacent but clearly separated from the TOL plasmid and the cell nucleoid. Also, they colocalize with ribosome-rich domains of the intracellular milieu. This arrangement was maintained even when the xyl genes were artificially relocated to different chromosomal locations. The same held true when genes were expressed through a heterologous T7 polymerase-based system, which likewise led to mRNA foci outside the DNA. In contrast, rifampin treatment, known to ease crowding, blurred the confinement of xyl transcripts. This suggested that xyl mRNAs exit from their initiation sites to move to ribosome-rich points for translation-rather than being translated coupled to transcription. Moreover, the results suggest the distinct subcellular motion of xyl mRNAs results from both innate properties of the sequences and the physical forces that keep the ribosomal pool away from the nucleoid in P. putida This scenario is discussed within the background of current knowledge on the three-dimensional organization of the gene expression flow in other bacteria and the environmental lifestyle of this soil microorganism.IMPORTANCE The transfer of information between DNA, RNA, and proteins in a bacterium is often compared to the decoding of a piece of software in a computer. However, the tridimensional layout and the relational logic of the cognate biological hardware, i.e., the nucleoid, the RNA polymerase, and the ribosomes, are habitually taken for granted. In this work, we inspected the localization and fate of the transcripts that stem from the archetypal biodegradative plasmid pWW0 of soil bacterium Pseudomonas putida strain KT2440 through the nonhomogeneous milieu of the bacterial cytoplasm. The results expose that-similarly to computers-the material components that enable the expression flow are well separated physically and they decipher the sequences through a distinct tridimensional arrangement with no indication of transcription/translation coupling. We argue that the resulting subcellular architecture enters an extra regulatory layer that obeys a species-specific positional code and accompanies the environmental lifestyle of this bacterium.
PMID:33622725 | DOI:10.1128/mBio.03685-20
Discovery of novel community-relevant small proteins in a simplified human intestinal microbiome
Microbiome. 2021 Feb 23;9(1):55. doi: 10.1186/s40168-020-00981-z.
ABSTRACT
BACKGROUND: The intestinal microbiota plays a crucial role in protecting the host from pathogenic microbes, modulating immunity and regulating metabolic processes. We studied the simplified human intestinal microbiota (SIHUMIx) consisting of eight bacterial species with a particular focus on the discovery of novel small proteins with less than 100 amino acids (= sProteins), some of which may contribute to shape the simplified human intestinal microbiota. Although sProteins carry out a wide range of important functions, they are still often missed in genome annotations, and little is known about their structure and function in individual microbes and especially in microbial communities.
RESULTS: We created a multi-species integrated proteogenomics search database (iPtgxDB) to enable a comprehensive identification of novel sProteins. Six of the eight SIHUMIx species, for which no complete genomes were available, were sequenced and de novo assembled. Several proteomics approaches including two earlier optimized sProtein enrichment strategies were applied to specifically increase the chances for novel sProtein discovery. The search of tandem mass spectrometry (MS/MS) data against the multi-species iPtgxDB enabled the identification of 31 novel sProteins, of which the expression of 30 was supported by metatranscriptomics data. Using synthetic peptides, we were able to validate the expression of 25 novel sProteins. The comparison of sProtein expression in each single strain versus a multi-species community cultivation showed that six of these sProteins were only identified in the SIHUMIx community indicating a potentially important role of sProteins in the organization of microbial communities. Two of these novel sProteins have a potential antimicrobial function. Metabolic modelling revealed that a third sProtein is located in a genomic region encoding several enzymes relevant for the community metabolism within SIHUMIx.
CONCLUSIONS: We outline an integrated experimental and bioinformatics workflow for the discovery of novel sProteins in a simplified intestinal model system that can be generically applied to other microbial communities. The further analysis of novel sProteins uniquely expressed in the SIHUMIx multi-species community is expected to enable new insights into the role of sProteins on the functionality of bacterial communities such as those of the human intestinal tract. Video abstract.
PMID:33622394 | DOI:10.1186/s40168-020-00981-z
Extracellular vesicles from HTLV-1 infected cells modulate target cells and viral spread
Retrovirology. 2021 Feb 23;18(1):6. doi: 10.1186/s12977-021-00550-8.
ABSTRACT
BACKGROUND: The Human T-cell Lymphotropic Virus Type-1 (HTLV-1) is a blood-borne pathogen and etiological agent of Adult T-cell Leukemia/Lymphoma (ATLL) and HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). HTLV-1 has currently infected up to 10 million globally with highly endemic areas in Japan, Africa, the Caribbean and South America. We have previously shown that Extracellular Vesicles (EVs) enhance HTLV-1 transmission by promoting cell-cell contact.
RESULTS: Here, we separated EVs into subpopulations using differential ultracentrifugation (DUC) at speeds of 2 k (2000×g), 10 k (10,000×g), and 100 k (100,000×g) from infected cell supernatants. Proteomic analysis revealed that EVs contain the highest viral/host protein abundance in the 2 k subpopulation (2 k > 10 k > 100 k). The 2 k and 10 k populations contained viral proteins (i.e., p19 and Tax), and autophagy proteins (i.e., LC3 and p62) suggesting presence of autophagosomes as well as core histones. Interestingly, the use of 2 k EVs in an angiogenesis assay (mesenchymal stem cells + endothelial cells) caused deterioration of vascular-like-tubules. Cells commonly associated with the neurovascular unit (i.e., astrocytes, neurons, and macrophages) in the blood-brain barrier (BBB) showed that HTLV-1 EVs may induce expression of cytokines involved in migration (i.e., IL-8; 100 k > 2 k > 10 k) from astrocytes and monocyte-derived macrophages (i.e., IL-8; 2 k > 10 k). Finally, we found that EVs were able to promote cell-cell contact and viral transmission in monocytic cell-derived dendritic cell. The EVs from both 2 k and 10 k increased HTLV-1 spread in a humanized mouse model, as evidenced by an increase in proviral DNA and RNA in the Blood, Lymph Node, and Spleen.
CONCLUSIONS: Altogether, these data suggest that various EV subpopulations induce cytokine expression, tissue damage, and viral spread.
PMID:33622348 | DOI:10.1186/s12977-021-00550-8
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Homology-directed repair protects the replicating genome from metabolic assaults
Dev Cell. 2021 Feb 22;56(4):461-477.e7. doi: 10.1016/j.devcel.2021.01.011.
ABSTRACT
Homology-directed repair (HDR) safeguards DNA integrity under various forms of stress, but how HDR protects replicating genomes under extensive metabolic alterations remains unclear. Here, we report that besides stalling replication forks, inhibition of ribonucleotide reductase (RNR) triggers metabolic imbalance manifested by the accumulation of increased reactive oxygen species (ROS) in cell nuclei. This leads to a redox-sensitive activation of the ATM kinase followed by phosphorylation of the MRE11 nuclease, which in HDR-deficient settings degrades stalled replication forks. Intriguingly, nascent DNA degradation by the ROS-ATM-MRE11 cascade is also triggered by hypoxia, which elevates signaling-competent ROS and attenuates functional HDR without arresting replication forks. Under these conditions, MRE11 degrades daughter-strand DNA gaps, which accumulate behind active replisomes and attract error-prone DNA polymerases to escalate mutation rates. Thus, HDR safeguards replicating genomes against metabolic assaults by restraining mutagenic repair at aberrantly processed nascent DNA. These findings have implications for cancer evolution and tumor therapy.
PMID:33621493 | DOI:10.1016/j.devcel.2021.01.011
Reconstructing the Lineage Histories and Differentiation Trajectories of Individual Cancer Cells in Myeloproliferative Neoplasms
Cell Stem Cell. 2021 Feb 18:S1934-5909(21)00051-5. doi: 10.1016/j.stem.2021.02.001. Online ahead of print.
ABSTRACT
Some cancers originate from a single mutation event in a single cell. Blood cancers known as myeloproliferative neoplasms (MPNs) are thought to originate when a driver mutation is acquired by a hematopoietic stem cell (HSC). However, when the mutation first occurs in individuals and how it affects the behavior of HSCs in their native context is not known. Here we quantified the effect of the JAK2-V617F mutation on the self-renewal and differentiation dynamics of HSCs in treatment-naive individuals with MPNs and reconstructed lineage histories of individual HSCs using somatic mutation patterns. We found that JAK2-V617F mutations occurred in a single HSC several decades before MPN diagnosis-at age 9 ± 2 years in a 34-year-old individual and at age 19 ± 3 years in a 63-year-old individual-and found that mutant HSCs have a selective advantage in both individuals. These results highlight the potential of harnessing somatic mutations to reconstruct cancer lineages.
PMID:33621486 | DOI:10.1016/j.stem.2021.02.001
Circulating SARS-CoV-2 spike N439K variants maintain fitness while evading antibody-mediated immunity
Cell. 2021 Jan 28:S0092-8674(21)00080-5. doi: 10.1016/j.cell.2021.01.037. Online ahead of print.
ABSTRACT
SARS-CoV-2 can mutate and evade immunity, with consequences for efficacy of emerging vaccines and antibody therapeutics. Here, we demonstrate that the immunodominant SARS-CoV-2 spike (S) receptor binding motif (RBM) is a highly variable region of S and provide epidemiological, clinical, and molecular characterization of a prevalent, sentinel RBM mutation, N439K. We demonstrate N439K S protein has enhanced binding affinity to the hACE2 receptor, and N439K viruses have similar in vitro replication fitness and cause infections with similar clinical outcomes as compared to wild type. We show the N439K mutation confers resistance against several neutralizing monoclonal antibodies, including one authorized for emergency use by the US Food and Drug Administration (FDA), and reduces the activity of some polyclonal sera from persons recovered from infection. Immune evasion mutations that maintain virulence and fitness such as N439K can emerge within SARS-CoV-2 S, highlighting the need for ongoing molecular surveillance to guide development and usage of vaccines and therapeutics.
PMID:33621484 | DOI:10.1016/j.cell.2021.01.037
Lettuce (Lactuca sativa) productivity influenced by microbial inocula under nitrogen-limited conditions in aquaponics
PLoS One. 2021 Feb 23;16(2):e0247534. doi: 10.1371/journal.pone.0247534. eCollection 2021.
ABSTRACT
The demand for food will outpace productivity of conventional agriculture due to projected growth of the human population, concomitant with shrinkage of arable land, increasing scarcity of freshwater, and a rapidly changing climate. While aquaponics has potential to sustainably supplement food production with minimal environmental impact, there is a need to better characterize the complex interplay between the various components (fish, plant, microbiome) of these systems to optimize scale up and productivity. Here, we investigated how the commonly-implemented practice of continued microbial community transfer from pre-existing systems might promote or impede productivity of aquaponics. Specifically, we monitored plant growth phenotypes, water chemistry, and microbiome composition of rhizospheres, biofilters, and fish feces over 61-days of lettuce (Lactuca sativa var. crispa) growth in nitrogen-limited aquaponic systems inoculated with bacteria that were either commercially sourced or originating from a pre-existing aquaponic system. Lettuce above- and below-ground growth were significantly reduced across replicates treated with a pre-existing aquaponic system inoculum when compared to replicates treated with a commercial inoculum. Reduced productivity was associated with enrichment in specific bacterial genera in plant roots, including Pseudomonas, following inoculum transfer from pre-existing systems. Increased productivity was associated with enrichment of nitrogen-fixing Rahnella in roots of plants treated with the commercial inoculum. Thus, we show that inoculation from a pre-existing system, rather than from a commercial inoculum, is associated with lower yields. Further work will be necessary to test the putative mechanisms involved.
PMID:33621265 | DOI:10.1371/journal.pone.0247534
Reproducibility in systems biology modelling
Mol Syst Biol. 2021 Feb;17(2):e9982. doi: 10.15252/msb.20209982.
ABSTRACT
Reproducibility of scientific results is a key element of science and credibility. The lack of reproducibility across many scientific fields has emerged as an important concern. In this piece, we assess mathematical model reproducibility and propose a scorecard for improving reproducibility in this field.
PMID:33620773 | DOI:10.15252/msb.20209982
Depressed β-adrenergic inotropic responsiveness and intracellular calcium handling abnormalities in Duchenne Muscular Dystrophy patients' induced pluripotent stem cell-derived cardiomyocytes
J Cell Mol Med. 2021 Feb 22. doi: 10.1111/jcmm.16341. Online ahead of print.
ABSTRACT
Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, is an X-linked disease affecting male and rarely adult heterozygous females, resulting in death by the late 20s to early 30s. Previous studies reported depressed left ventricular function in DMD patients which may result from deranged intracellular Ca2+ -handling. To decipher the mechanism(s) underlying the depressed LV function, we tested the hypothesis that iPSC-CMs generated from DMD patients feature blunted positive inotropic response to β-adrenergic stimulation. To test the hypothesis, [Ca2+ ]i transients and contractions were recorded from healthy and DMD-CMs. While in healthy CMs (HC) isoproterenol caused a prominent positive inotropic effect, DMD-CMs displayed a blunted inotropic response. Next, we tested the functionality of the sarcoplasmic reticulum (SR) by measuring caffeine-induced Ca2+ release. In contrast to HC, DMD-CMs exhibited reduced caffeine-induced Ca2+ signal amplitude and recovery time. In support of the depleted SR Ca2+ stores hypothesis, in DMD-CMs the negative inotropic effects of ryanodine and cyclopiazonic acid were smaller than in HC. RNA-seq analyses demonstrated that in DMD CMs the RNA-expression levels of specific subunits of the L-type calcium channel, the β1-adrenergic receptor (ADRβ1) and adenylate cyclase were down-regulated by 3.5-, 2.8- and 3-fold, respectively, which collectively contribute to the depressed β-adrenergic responsiveness.
PMID:33619882 | DOI:10.1111/jcmm.16341
The human tRNA taurine modification enzyme GTPBP3 is an active GTPase linked to mitochondrial diseases
Nucleic Acids Res. 2021 Feb 22:gkab104. doi: 10.1093/nar/gkab104. Online ahead of print.
ABSTRACT
GTPBP3 and MTO1 cooperatively catalyze 5-taurinomethyluridine (τm5U) biosynthesis at the 34th wobble position of mitochondrial tRNAs. Mutations in tRNAs, GTPBP3 or MTO1, causing τm5U hypomodification, lead to various diseases. However, efficient in vitro reconstitution and mechanistic study of τm5U modification have been challenging, in part due to the lack of pure and active enzymes. A previous study reported that purified human GTPBP3 (hGTPBP3) is inactive in GTP hydrolysis. Here, we identified the mature form of hGTPBP3 and showed that hGTPBP3 is an active GTPase in vitro that is critical for tRNA modification in vivo. Unexpectedly, the isolated G domain and a mutant with the N-terminal domain truncated catalyzed GTP hydrolysis to only a limited extent, exhibiting high Km values compared with that of the mature enzyme. We further described several important pathogenic mutations of hGTPBP3, associated with alterations in hGTPBP3 localization, structure and/or function in vitro and in vivo. Moreover, we discovered a novel cytoplasm-localized isoform of hGTPBP3, indicating an unknown potential noncanonical function of hGTPBP3. Together, our findings established, for the first time, the GTP hydrolysis mechanism of hGTPBP3 and laid a solid foundation for clarifying the τm5U modification mechanism and etiology of τm5U deficiency-related diseases.
PMID:33619562 | DOI:10.1093/nar/gkab104
Four-pronged negative feedback of DSB machinery in meiotic DNA-break control in mice
Nucleic Acids Res. 2021 Feb 22:gkab082. doi: 10.1093/nar/gkab082. Online ahead of print.
ABSTRACT
In most taxa, halving of chromosome numbers during meiosis requires that homologous chromosomes (homologues) pair and form crossovers. Crossovers emerge from the recombination-mediated repair of programmed DNA double-strand breaks (DSBs). DSBs are generated by SPO11, whose activity requires auxiliary protein complexes, called pre-DSB recombinosomes. To elucidate the spatiotemporal control of the DSB machinery, we focused on an essential SPO11 auxiliary protein, IHO1, which serves as the main anchor for pre-DSB recombinosomes on chromosome cores, called axes. We discovered that DSBs restrict the DSB machinery by at least four distinct pathways in mice. Firstly, by activating the DNA damage response (DDR) kinase ATM, DSBs restrict pre-DSB recombinosome numbers without affecting IHO1. Secondly, in their vicinity, DSBs trigger IHO1 depletion mainly by another DDR kinase, ATR. Thirdly, DSBs enable homologue synapsis, which promotes the depletion of IHO1 and pre-DSB recombinosomes from synapsed axes. Finally, DSBs and three DDR kinases, ATM, ATR and PRKDC, enable stage-specific depletion of IHO1 from all axes. We hypothesize that these four negative feedback pathways protect genome integrity by ensuring that DSBs form without excess, are well-distributed, and are restricted to genomic locations and prophase stages where DSBs are functional for promoting homologue pairing and crossover formation.
PMID:33619545 | DOI:10.1093/nar/gkab082
A unique subset of glycolytic tumour-propagating cells drives squamous cell carcinoma
Nat Metab. 2021 Feb;3(2):182-195. doi: 10.1038/s42255-021-00350-6. Epub 2021 Feb 22.
ABSTRACT
Head and neck squamous cell carcinoma (SCC) remains among the most aggressive human cancers. Tumour progression and aggressiveness in SCC are largely driven by tumour-propagating cells (TPCs). Aerobic glycolysis, also known as the Warburg effect, is a characteristic of many cancers; however, whether this adaptation is functionally important in SCC, and at which stage, remains poorly understood. Here, we show that the NAD+-dependent histone deacetylase sirtuin 6 is a robust tumour suppressor in SCC, acting as a modulator of glycolysis in these tumours. Remarkably, rather than a late adaptation, we find enhanced glycolysis specifically in TPCs. More importantly, using single-cell RNA sequencing of TPCs, we identify a subset of TPCs with higher glycolysis and enhanced pentose phosphate pathway and glutathione metabolism, characteristics that are strongly associated with a better antioxidant response. Together, our studies uncover enhanced glycolysis as a main driver in SCC, and, more importantly, identify a subset of TPCs as the cell of origin for the Warburg effect, defining metabolism as a key feature of intra-tumour heterogeneity.
PMID:33619381 | DOI:10.1038/s42255-021-00350-6
Gut microbiome pattern reflects healthy ageing and predicts survival in humans
Nat Metab. 2021 Feb;3(2):274-286. doi: 10.1038/s42255-021-00348-0. Epub 2021 Feb 18.
ABSTRACT
The gut microbiome has important effects on human health, yet its importance in human ageing remains unclear. In the present study, we demonstrate that, starting in mid-to-late adulthood, gut microbiomes become increasingly unique to individuals with age. We leverage three independent cohorts comprising over 9,000 individuals and find that compositional uniqueness is strongly associated with microbially produced amino acid derivatives circulating in the bloodstream. In older age (over ~80 years), healthy individuals show continued microbial drift towards a unique compositional state, whereas this drift is absent in less healthy individuals. The identified microbiome pattern of healthy ageing is characterized by a depletion of core genera found across most humans, primarily Bacteroides. Retaining a high Bacteroides dominance into older age, or having a low gut microbiome uniqueness measure, predicts decreased survival in a 4-year follow-up. Our analysis identifies increasing compositional uniqueness of the gut microbiome as a component of healthy ageing, which is characterized by distinct microbial metabolic outputs in the blood.
PMID:33619379 | DOI:10.1038/s42255-021-00348-0
Shape deformation analysis reveals the temporal dynamics of cell-type-specific homeostatic and pathogenic responses to mutant huntingtin
Elife. 2021 Feb 23;10:e64984. doi: 10.7554/eLife.64984.
ABSTRACT
Loss of cellular homeostasis has been implicated in the etiology of several neurodegenerative diseases (NDs). However, the molecular mechanisms that underlie this loss remain poorly understood on a systems level in each case. Here, using a novel computational approach to integrate dimensional RNA-seq and in vivo neuron survival data, we map the temporal dynamics of homeostatic and pathogenic responses in four striatal cell types of Huntington's disease (HD) model mice. This map shows that most pathogenic responses are mitigated and most homeostatic responses are decreased over time, suggesting that neuronal death in HD is primarily driven by the loss of homeostatic responses. Moreover, different cell types may lose similar homeostatic processes, for example, endosome biogenesis and mitochondrial quality control in Drd1-expressing neurons and astrocytes. HD relevance is validated by human stem cell, genome-wide association study, and post-mortem brain data. These findings provide a new paradigm and framework for therapeutic discovery in HD and other NDs.
PMID:33618800 | DOI:10.7554/eLife.64984
L-plastin Ser5 phosphorylation is modulated by the PI3K/SGK pathway and promotes breast cancer cell invasiveness
Cell Commun Signal. 2021 Feb 22;19(1):22. doi: 10.1186/s12964-021-00710-5.
ABSTRACT
BACKGROUND: Metastasis is the predominant cause for cancer morbidity and mortality accounting for approximatively 90% of cancer deaths. The actin-bundling protein L-plastin has been proposed as a metastatic marker and phosphorylation on its residue Ser5 is known to increase its actin-bundling activity. We recently showed that activation of the ERK/MAPK signalling pathway leads to L-plastin Ser5 phosphorylation and that the downstream kinases RSK1 and RSK2 are able to directly phosphorylate Ser5. Here we investigate the involvement of the PI3K pathway in L-plastin Ser5 phosphorylation and the functional effect of this phosphorylation event in breast cancer cells.
METHODS: To unravel the signal transduction network upstream of L-plastin Ser5 phosphorylation, we performed computational modelling based on immunoblot analysis data, followed by experimental validation through inhibition/overexpression studies and in vitro kinase assays. To assess the functional impact of L-plastin expression/Ser5 phosphorylation in breast cancer cells, we either silenced L-plastin in cell lines initially expressing endogenous L-plastin or neoexpressed L-plastin wild type and phosphovariants in cell lines devoid of endogenous L-plastin. The established cell lines were used for cell biology experiments and confocal microscopy analysis.
RESULTS: Our modelling approach revealed that, in addition to the ERK/MAPK pathway and depending on the cellular context, the PI3K pathway contributes to L-plastin Ser5 phosphorylation through its downstream kinase SGK3. The results of the transwell invasion/migration assays showed that shRNA-mediated knockdown of L-plastin in BT-20 or HCC38 cells significantly reduced cell invasion, whereas stable expression of the phosphomimetic L-plastin Ser5Glu variant led to increased migration and invasion of BT-549 and MDA-MB-231 cells. Finally, confocal image analysis combined with zymography experiments and gelatin degradation assays provided evidence that L-plastin Ser5 phosphorylation promotes L-plastin recruitment to invadopodia, MMP-9 activity and concomitant extracellular matrix degradation.
CONCLUSION: Altogether, our results demonstrate that L-plastin Ser5 phosphorylation increases breast cancer cell invasiveness. Being a downstream molecule of both ERK/MAPK and PI3K/SGK pathways, L-plastin is proposed here as a potential target for therapeutic approaches that are aimed at blocking dysregulated signalling outcome of both pathways and, thus, at impairing cancer cell invasion and metastasis formation. Video abstract.
PMID:33618712 | DOI:10.1186/s12964-021-00710-5
Sinus bradycardia in paediatric athletes.
Sinus bradycardia in paediatric athletes.
Eur J Prev Cardiol. 2020 Jun 10;:
Authors: Diaz-Gonzalez L, Bruña V, Valenzuela PL, Velásquez-Rodriguez J, Boraita A, Lucia A, Martinez-Sellés M
PMID: 33611538 [PubMed - as supplied by publisher]
Physical activity, sports and risk of atrial fibrillation: umbrella review of meta-analyses.
Physical activity, sports and risk of atrial fibrillation: umbrella review of meta-analyses.
Eur J Prev Cardiol. 2020 May 16;:
Authors: Valenzuela PL, Santos-Lozano A, Morales JS, López-Ortiz S, Pinto-Fraga J, Castillo-García A, Martín-Hernández J, Villacastín JP, Boraita A, Lucia A
PMID: 33611432 [PubMed - as supplied by publisher]