RBPs (RNA binding proteins) play critical roles in the cell by regulating mRNA transport, splicing, editing, and stability. The RBP SRSF3 (serine/arginine-rich splicing factor 3) is essential for ...blastocyst formation and for proper liver development and function. However, its role in the heart has not been explored.
To investigate the role of SRSF3 in cardiac function.
Cardiac SRSF3 expression was high at mid gestation and decreased during late embryonic development. Mice lacking SRSF3 in the embryonic heart showed impaired cardiomyocyte proliferation and died in utero. In the adult heart, SRSF3 expression was reduced after myocardial infarction, suggesting a possible role in cardiac homeostasis. To determine the role of this RBP in the adult heart, we used an inducible, cardiomyocyte-specific SRSF3 knockout mouse model. After SRSF3 depletion in cardiomyocytes, mice developed severe systolic dysfunction that resulted in death within 8 days. RNA-Seq analysis revealed downregulation of mRNAs encoding sarcomeric and calcium handling proteins. Cardiomyocyte-specific SRSF3 knockout mice also showed evidence of alternative splicing of mTOR (mammalian target of rapamycin) mRNA, generating a shorter protein isoform lacking catalytic activity. This was associated with decreased phosphorylation of 4E-BP1 (eIF4E-binding protein 1), a protein that binds to eIF4E (eukaryotic translation initiation factor 4E) and prevents mRNA decapping. Consequently, we found increased decapping of mRNAs encoding proteins involved in cardiac contraction. Decapping was partially reversed by mTOR activation.
We show that cardiomyocyte-specific loss of SRSF3 expression results in decapping of critical mRNAs involved in cardiac contraction. The molecular mechanism underlying this effect likely involves the generation of a short mTOR isoform by alternative splicing, resulting in reduced 4E-BP1 phosphorylation. The identification of mRNA decapping as a mechanism of systolic heart failure may open the way to the development of urgently needed therapeutic tools.
Mining activities in general, and quarrying processes in particular, generate huge amounts of tailings with a considerable presence of fine particles and with a variable composition of minerals, ...which could limit the direct application of those wastes. Under the paradigm of a circular economy, more effort has to be made to find adequate applications for those secondary raw materials. In this study, a process was proposed and tests were performed to valorise fine particle product as a raw material for the building and construction industry. Samples were taken from wastes in several aggregate production plants, being characterized and processed to remove the clayey components to obtain the cleanest quartz fraction. Then, different characterization and validation tests were carried out to analyse the application of these products as raw materials in the building and construction industry (cement and ceramics). Results showed that with no complex technologies, the tailings can be considered as a mineral raw material in different applications.
This work evaluates different dendrimer-silica supports for the immobilization of enzymes by multipoint covalent binding. Thermolysin was immobilized on two dendrimers (PAMAM and carbosilane) with ...two different generations (zero (G0) and first (G1)). Results were compared with a control, a silica support functionalized with a monofunctional molecule. Dendrimers increased the number of available sites to bind the enzyme. Despite the enzyme was immobilized on all supports, G0 dendrimers immobilized a 30% more enzyme than G1. Thermolysin immobilized on G0 dendrimer supports showed the highest activity and could be employed in three consecutive hydrolysis cycles. Optimal immobilization time was 1 h while optimal protein loading was 25 mg enzyme/100 mg support. Enzyme activity was promoted when using 5 mg of immobilized enzyme at 750 rpm, 60 °C, and 2 h of hydrolysis. Under these conditions, the activity of thermolysin increased up to the 78% of the free enzyme activity. Kinetics of the hydrolysis reaction using the immobilized thermolysin was also studied and compared with the obtained using the free thermolysin. The addition of ZnCl2 and NaCl during the immobilization procedure increased thermolysin activity in the second (22% more) and in the third (14% more) hydrolysis clycles.
•Thermolysin has been successfully immobilized on dendrimer-silica supports.•Zero generation PAMAM and carbosilane dendrimers showed the highest immobilization.•Immobilized thermolysin was reutilized for different digestion cycles.•Enzyme immobilization in presence of salts improved thermolysin activity.•Supports activated by dendrimers promoted the immobilization and activity of enzyme.
A nonaqueous capillary electrophoresis method with electrospray-mass spectrometric detection was developed to study the glycerophospholipid fraction in olive fruit and olive oil samples. In olive ...fruits, where the information available about the phospholipid fraction was very scarce, results obtained in this work allowed us to complete and improve this knowledge. The glycerophospholipid fraction of the olive fruit samples analyzed was composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), lysophosphatidylethanolamine (lyso-PE), phosphatidylinositol (PI), phosphatidic acid (PA), lysophosphatidic acid (lyso-PA), and phosphatidylglycerol (PG). Differences in the relative abundance of the glycerophospholipid classes determined were observed as a function of the botanical and geographical origin of the olive fruits analyzed. Interestingly, the olive stone and pulp analyzed also showed different glycerophospholipid compositions. For olive oil, five glycerophospholipids (lyso-PA, PC, PE, lyso-PE, and PG) were detected. Finally, identification of the main molecular species in the different glycerophospholipid classes for the olive fruit samples analyzed was accomplished by tandem mass spectrometric experiments and information from the literature.
Embryonic stem cells (ESC) have the potential to generate all the cell lineages that form the body. However, the molecular mechanisms underlying ESC differentiation and especially the role of ...alternative splicing in this process remain poorly understood. Here, we show that the alternative splicing regulator MBNL1 promotes generation of the atypical calcineurin Aβ variant CnAβ1 in mouse ESCs (mESC). CnAβ1 has a unique C-terminal domain that drives its localization mainly to the Golgi apparatus by interacting with Cog8. CnAβ1 regulates the intracellular localization and activation of the mTORC2 complex. CnAβ1 knockdown results in delocalization of mTORC2 from the membrane to the cytoplasm, inactivation of the AKT/GSK3β/β-catenin signaling pathway, and defective mesoderm specification. In summary, here we unveil the structural basis for the mechanism of action of CnAβ1 and its role in the differentiation of mESCs to the mesodermal lineage.
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•CnAβ1 is mainly localized at the Golgi apparatus through its C-terminal domain•CnAβ1 is needed for mTORC2 localization and activation at the cellular membranes•CnAβ1 is necessary for activation of the AKT/GSK3β/β-catenin signaling pathway•CnAβ1 regulates differentiation of mouse embryonic stem cells to mesoderm
Gómez-Salinero et al. show that the calcineurin splicing variant CnAβ1 is enriched in mouse embryonic stem cells and regulates their differentiation to mesoderm. CnAβ1's unique C-terminal domain drives its localization to the Golgi apparatus and is necessary for its interaction with mTOR and activation of the AKT/GSK3β/β-catenin pathway.
The feasibility of using carbosilane dendronized gold nanoparticles (GNPs) for protein sample preparation was evaluated. Three different dendrons with three different generations (1G, 2G, and 3G) ...were employed to modify the GNPs, viz. sulfonate terminated (STC-GNPs), carboxylate terminated (CTC-GNPs), and trimethylammonium terminated (ATC-GNPs) dendrons. The synthesis of the CTC-GNP is described. The other dendronized GNPs were synthesized using previously described routes. Bovine serum albumin, lysozyme, and myoglobin were employed to study the potential of GNPs to interact with proteins. The interaction between the GNPs and the proteins was evaluated using fluorescence spectroscopy and polyacrylamide gel electrophoresis. The CTC-GNPs and STC-GNPs under acidic and neutral conditions, respectively, promoted the establishment of electrostatic interactions with positively charged proteins. Proteins from 10 to 75 kDa molecular weights interacted with GNPs at protein: nanoparticle ratios of 1:0.25. The GNPs were applied to the extraction of proteins from a peach seed. In the authors’ perception, the method is a clean alternative to established extraction methods based on the use of organic or polluting chemicals.
Graphical abstract
Schematic representation of the interaction of peach seeds proteins and carbosilane dendron coated gold nanoparticles, and the electrophoretic profiles of extracted proteins.
Solid electrolytes are the core components for many next generation lithium battery concepts such as all-solid-state batteries (ASSB) or batteries based on metallic lithium anodes protected by a ...ceramic or composite passivation layer. Therefore, the search for new solid state Li-ion conductors with superior properties and improved electrochemical stabilities remains of high interest. In this work, the synthesis of a new class of silicon-containing, sulfide-based lithium-ion conductors is reported. Very good conductivities of up to ∼2.0–3.0·10−3 S/cm could be achieved for compositions such as Li22SiP2S18, among the highest for silicon sulfide containing materials. Based on the recorded powder XRD diffraction patterns and simulations it could be confirmed that they constitute novel members of the argyrodite family of sulfide lithium-ion conductors. The cubic high-temperature modification of such argyrodites with high lithium-ion conductivity can therefore be stabilized by implementation of silicon into the lattice, while additional doping with halogen atoms is not necessary.
•Novel sulfidic argyrodite-type lithium-ion superconductors were synthesized.•High-temperature modification can be stabilized by partial substitution of P by Si.•No further halogen-doping is required.•Improved stability against carbonate-based electrolytes was observed.
Ventricular remodelling following myocardial infarction progressively leads to loss of contractile capacity and heart failure. Although calcineurin promotes maladaptive cardiac hypertrophy, we ...recently showed that the calcineurin splicing variant, CnAβ1, has beneficial effects on the infarcted heart. However, whether this variant limits necrosis or improves remodelling is still unknown, precluding translation to the clinical arena. Here, we explored the effects and therapeutic potential of CnAβ1 overexpression post-infarction.
Double transgenic mice with inducible cardiomyocyte-specific overexpression of CnAβ1 underwent left coronary artery ligation followed by reperfusion. Echocardiographic analysis showed depressed cardiac function in all infarcted mice 3 days post-infarction. Induction of CnAβ1 overexpression 1 week after infarction improved function and reduced ventricular dilatation. CnAβ1-overexpressing mice showed shorter, thicker scars, and reduced infarct expansion, accompanied by reduced myocardial remodelling. CnAβ1 induced vascular endothelial growth factor (VEGF) expression in cardiomyocytes, which resulted in increased infarct vascularization. This paracrine angiogenic effect of CnAβ1 was mediated by activation of the Akt/mammalian target of rapamycin pathway and VEGF.
Our results indicate that CnAβ1 exerts beneficial effects on the infarcted heart by promoting infarct vascularization and preventing infarct expansion. These findings emphasize the translational potential of CnAβ1 for gene-based therapies.
Metabolic profiling provides an unbiased view of the physiological status of an organism as a "function" of the metabolic composition of a measured sample. Here, we propose a simple LC-MS based ...workflow for metabolic profiling of volume-restricted samples, namely individual 20 μm-thick histological sections of a mouse kidney. The main idea of this workflow is to re-use the material after an RPLC-MS run, namely using the volume remaining in the vial after injection, and then introducing a phase changing step to enable HILIC-MS analysis. To test the applicability of the workflow and its ability to extract valuable biological information, we applied it to an animal model of polycystic kidney disease (PKD).
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