Hunting polymers-transforming microbes from mangrove soils
Ontology highlight
ABSTRACT: Explore and identify the functional potential of mangrove soil microorganisms for the transformation of polymers such as lignocellulose and PET.
Project description:Background: Circulating polymers of alpha1-antitrypsin (α1AT) are chemo-attractant for neutrophils and contribute to inflammation in pulmonary, vascular and adipose tissues. Cellular factors affecting the intracellular itinerary of mutant polymerogenic α1AT remain obscure. Methods: Here, we report on an unbiased genome-wide CRISPR/Cas9 screen for regulators of trafficking of the polymerogenic α1AT-H334D variant. Single guide RNAs targeting genes whose inactivation enhanced accumulation of polymeric α1AT were enriched by iterative construction of CRISPR libraries based on genomic DNA from fixed cells selected for high polymer content by fluorescence-activated cell sorting. This approach bypassed the limitation to conventional enrichment schemes imposed by cell fixation. Results: Our screen identified 121 genes involved in polymer retention at false discovery rate < 0.1. From that set of genes, the pathway ‘cargo loading into COPII-coated vesicles’ was overrepresented with 16 significant genes, including two transmembrane cargo receptors, LMAN1 (ERGIG-53) and SURF4. LMAN1 and SURF4-disrupted cells displayed a secretion defect extended beyond α1AT monomers to polymers, whose low-level secretion was especially dependent on SURF4 and correlated with SURF4-α1AT-H334D physical interaction and with enhanced co-localisation of polymeric α1AT-H334D with the endoplasmic reticulum (ER). Conclusions: These findings suggest that ER cargo receptors co-ordinate intracellular progression of α1AT out of the ER and modulate the accumulation of polymeric α1AT not only by controlling the concentration of precursor monomers but also through a previously-unrecognised role in secretion of the polymers themselves.
2021-06-02 | GSE158574 | GEO
Project description:Metagenome assembly of PRJEB72453 data set (Explore and identify the functional potential of mangrove soil microorganisms for the transformation of polymers such as lignocellulose and PET.)
Project description:The serpinopathies are human pathologies caused by mutations that promote polymerisation and intracellular deposition of proteins of the serpin superfamily, leading to a poorly understood cell toxicity. The dementia familial encephalopathy with neuroserpin inclusion bodies (FENIB) is caused by polymerisation of the neuronal serpin neuroserpin (NS) within the endoplasmic reticulum (ER) of neurons. We have generated transgenic neural progenitor cell (NPC) cultures from mouse embryonic cerebral cortex, stably expressing the control protein GFP (green fluorescent protein), or human wild type, G392E or deltaNS. We have characterised these cells in the proliferative state and after differentiation to neurons. Our results show that G392E NS formed polymers that were mostly retained within the ER, while wild type NS was correctly secreted as a monomeric protein into the culture medium. DeltaNS was absent at steady state due to its rapid degradation, but it was easily detected upon proteasomal block. Looking at their intracellular distribution, wild type NS was found in partial co-localisation with ER and Golgi markers, while G392E NS was localised within the ER only. Furthermore, polymers of NS were detected by ELISA and immunofluorescence in neurons expressing the mutant but not the wild type protein. We used our model system to investigate which cellular pathways were activated by intracellular polymers of G392E NS by performing RNA sequencing of differentiated cells expressing G392E NS or the negative control protein GFP, and identified 747 genes with a significant upregulation (623) or downregulation (124) in G392E NS-expressing cells. We focused our attention on genes involved in the defence against oxidative stress that were up-regulated in cells expressing G392E NS. Inhibition of these defences by specific pharmacological reagents uncovered the damaging effects of NS polymers. Our results support a role for oxidative stress in the cellular toxicity underlying the neurodegenerative dementia FENIB.
Project description:This experiment investigates transcriptional changes in whole blood during the recovery phase of dextran sulfate sodium (DSS)-induced colitis in mice, with or without treatment by synthetic mucin polymers (Shear-Labile Interaction Polymers, SLIPs). DSS (2.5% w/v) was administered for four days to induce acute epithelial injury, followed by four days of recovery in which mice received either water (control) or SLIPs (6.66 mg/mL) in drinking water. Whole-blood clots were collected on day 8 and processed for RNA extraction using a modified TRIzol LS protocol adapted for frozen clots. Libraries were prepared and sequenced on an Illumina NovaSeq 6000 platform (paired-end 150 bp). Differential expression analysis compared SLIP-treated and untreated groups to identify genes involved in immune regulation, redox balance, and epithelial recovery following colitis.
Project description:This research provides a thorough ecotoxicological evaluation of natural biopolymers (BP) and naturally modified polymers (NMP). The study focuses on biopolymers such as chitosan, xanthan, alginate, and carboxymethyl cellulose (CMC), alongside NMPs like Jelucel HM 200 and Emwaxy Jel 100. Each polymer was individually tested on zebrafish embryos using a zebrafish embryo toxicity (zFET) test. Natural polymers, although prevalent in agrotechnical products, remain largely unregulated under REACH due to their natural origins. There is a critical lack of data regarding their potential impact on closed ecosystem cycles, raising concerns about environmental risks. To assess the sublethal effects of these polymers, a modified zebrafish embryo toxicity test (ZFET) was utilized, incorporating transcriptomics as an additional evaluation endpoint. This modified methodology adheres to the OECD 236 guidelines but includes specific adjustments for gene expression analysis, such as changes in the number of embryos used, test setup volume, and sample processing procedures. Zebrafish embryos were exposed for 96 hours to each polymer's filtrate at a maximum concentration of 100 mg/L. After exposure, the embryos underwent assessments for survival rates, hatching rates, and morphological malformations. The study identified differentially expressed genes (DEGs) for each polymer exposure, shedding light on the transcriptomic changes induced by both biopolymers and NMPs. The primary objective is to understand how these substances influence gene expression profiles in zebrafish embryos, aiming to identify transcriptomic biomarkers that could assist in environmental risk assessment. This research contributes valuable insights into the potential ecological impacts of natural and modified polymers, highlighting the need for further regulatory consideration.
Project description:Producing the fuels and chemicals from renewable plant biomass has been thought as a feasible way for global sustainable development. However, the economical efficiency of biorefinery remains challenges. Here a cellulolytic thermophilic fungus, Myceliophthora thermophila, was constructed into a platform through metabolic engineering, which can efficiently convert lignocellulose to important bulk chemicals for polymers, four carbon 1, 4-diacids (malic and succinic acid), directly from lignocellulose without any extra enzymes addition or complicated pretreatment, with titer of over 200 g/L on cellulose and 110 g/L on plant biomass (corncob) during fed-batch fermentation. Our study represents a milestone of consolidated bioprocessing technology (CBP) and offers a new promising system for cost-effectively production of biomass-based chemicals and potentially fuels.