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Journal of Immunological Methods Jun 2024MHC class I pathway consists of four main steps: proteasomal cleavage in the cytosol in which precursor proteins are cleaved into smaller peptides, which are then...
MHC class I pathway consists of four main steps: proteasomal cleavage in the cytosol in which precursor proteins are cleaved into smaller peptides, which are then transported into the endoplasmic reticulum by the transporter associated with antigen processing, TAP, for further processing (trimming) from the N-terminal region by an ER resident aminopeptidases 1 (ERAP1) enzyme, to generate optimal peptides (8-10 amino acids in length) to produce a stable MHCI-peptide complex, that get transited via the Golgi apparatus to the cell surface for presentation to the cellular immune system. Several studies reported specificities related to the ERAP1 trimming process, yet there is no in silico tool for the prediction of the trimming process of the ERAP1 enzyme. In this paper, we provide and implement a prediction model for the trimming process of the ERAP1 enzyme.
PubMed: 38925438
DOI: 10.1016/j.jim.2024.113713 -
Biochemical and Biophysical Research... Jun 2024A hallmark of Alzheimer's disease (AD) is amyloid-β (Aβ) plaque deposition in the brain, causing deficits in cognitive function. Amyloid-beta oligomers (AβOs), the...
A hallmark of Alzheimer's disease (AD) is amyloid-β (Aβ) plaque deposition in the brain, causing deficits in cognitive function. Amyloid-beta oligomers (AβOs), the soluble precursor peptides producing Aβ plaques, also produce neurotoxicity and microgliosis together with glycolytic reprogramming. Recently, monocarboxylate transporter 1 (MCT1), a key glycolysis regulator, and its ancillary protein, CD147, are found to play an important role in the secretion of exosomes, 30-200 nm vesicles in size, which are considered as toxic molecule carriers in AD. However, the effect of low-concentration AβOs (1 nM) on microglia MCT1 and CD147 expression as well as 1 nM AβOs-treated microglia-derived exosomes on neuronal toxicity remain largely elusive. In this study, 1 nM AβOs induce significant axonopathy and microgliosis. Furthermore, 1 nM AβOs-treated neurons- or microglia-derived exosomes produce axonopathy through their autologous or heterologous uptake by neurons, supporting the role of exosomes as neurotoxicity mediators in AD. Interestingly, MCT1 and CD147 are enhanced in microglia by treatment with 1 nM AβOs or exosomes from 1 nM AβOs-treated- microglia or neurons, suggesting the implication of AβOs-induced enhanced MCT1 and CD147 in microglia with AD neuropathogenesis, which is consistent with the in-silico analysis of the single cell RNA sequencing data from microglia in mouse models of AD and AD patients.
PubMed: 38924962
DOI: 10.1016/j.bbrc.2024.150312 -
Science Advances Jun 2024Once considered as a "metabolic waste," lactate is now recognized as a major fuel for tricarboxylic acid (TCA) cycle. Our metabolic flux analysis reveals that skeletal...
Once considered as a "metabolic waste," lactate is now recognized as a major fuel for tricarboxylic acid (TCA) cycle. Our metabolic flux analysis reveals that skeletal muscle mainly uses lactate to fuel TCA cycle. Lactate is transported through the cell membrane via monocarboxylate transporters (MCTs) in which MCT1 is highly expressed in the muscle. We analyzed how MCT1 affects muscle functions using mice with specific deletion of MCT1 in skeletal muscle. MCT1 deletion enhances running performance, increases oxidative fibers while decreasing glycolytic fibers, and enhances flux of glucose to TCA cycle. MCT1 deficiency increases the expression of mitochondrial proteins, augments cell respiration rate, and elevates mitochondrial activity in the muscle. Mechanistically, the protein level of PGC-1α, a master regulator of mitochondrial biogenesis, is elevated upon loss of MCT1 via increases in cellular NAD level and SIRT1 activity. Collectively, these results demonstrate that MCT1-mediated lactate shuttle plays a key role in regulating muscle functions by modulating mitochondrial biogenesis and TCA flux.
Topics: Animals; Monocarboxylic Acid Transporters; Muscle, Skeletal; Symporters; Lactic Acid; Organelle Biogenesis; Mice; Citric Acid Cycle; Mitochondria; Sirtuin 1; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Mice, Knockout; Glycolysis
PubMed: 38924407
DOI: 10.1126/sciadv.adn4508 -
Diabetes, Obesity & Metabolism Jun 2024To compare the efficacy and safety of a fixed-ratio combination of insulin glargine 100 U/mL plus lixisenatide (iGlarLixi) with premixed insulin, insulin degludec plus...
The efficacy and safety of iGlarLixi versus IDegAsp in Chinese people with type 2 diabetes suboptimally controlled with oral antidiabetic drugs: The Soli-D randomized controlled trial.
AIM
To compare the efficacy and safety of a fixed-ratio combination of insulin glargine 100 U/mL plus lixisenatide (iGlarLixi) with premixed insulin, insulin degludec plus insulin aspart (IDegAsp), in Chinese people with type 2 diabetes (T2D) suboptimally controlled with oral antidiabetic drug(s) (OADs).
METHODS
In Soli-D, a 24-week, multicentre, open-label, study, insulin-naïve adults were randomized 1:1 to once-daily injections of iGlarLixi (n = 291) or IDegAsp (n = 291), with continued metformin ± sodium-glucose co-transporter-2 inhibitors. The primary endpoint was non-inferiority in HbA1c change from baseline to week 24. Key secondary endpoints included superiority in HbA1c change and body weight (BW) change at week 24. Hypoglycaemia rates were also assessed.
RESULTS
At week 24, iGlarLixi showed non-inferiority and superiority over IDegAsp in HbA1c reduction (least squares [LS] mean difference: -0.20 [95% confidence interval {CI}: -0.33, -0.07]; P < .001 for non-inferiority; [97.5% CI: -0.35, -0.05]; P = .003 for superiority). iGlarLixi decreased BW and IDegAsp increased BW from baseline to week 24, with a statistically significant LS mean difference of -1.49 kg in favour of iGlarLixi (97.5% CI: -2.32, -0.66; P < .001). Event rates (per person-year) for American Diabetes Association (ADA) Level 1, 2 or 3 hypoglycaemia were lower for iGlarLixi (1.90) versus IDegAsp (2.72) (relative risk: 0.71; 95% CI: 0.52, 0.98). No ADA Level 3 hypoglycaemia or unexpected safety findings were reported.
CONCLUSIONS
In Chinese people with T2D suboptimally controlled with OADs, once-daily iGlarLixi provided better glycaemic control with BW benefit and lower hypoglycaemia event rates versus IDegAsp.
PubMed: 38922731
DOI: 10.1111/dom.15724 -
Toxins May 2024Polyamines (PAs) are polycationic biogenic amines ubiquitously present in all life forms and are involved in molecular signaling and interaction, determining cell fate... (Review)
Review
Polyamines (PAs) are polycationic biogenic amines ubiquitously present in all life forms and are involved in molecular signaling and interaction, determining cell fate (e.g., cell proliferation, dif-ferentiation, and apoptosis). The intricate balance in the PAs' levels in the tissues will determine whether beneficial or detrimental effects will affect homeostasis. It's crucial to note that endoge-nous polyamines, like spermine and spermidine, play a pivotal role in our understanding of neu-rological disorders as they interact with membrane receptors and ion channels, modulating neuro-transmission. In spiders and wasps, monoamines (histamine, dopamine, serotonin, tryptamine) and polyamines (spermine, spermidine, acyl polyamines) comprise, with peptides and other sub-stances, the low molecular weight fraction of the venom. Acylpolyamines are venom components exclusively from spiders and a species of solitary wasp, which cause inhibition chiefly of iono-tropic glutamate receptors (AMPA, NMDA, and KA iGluRs) and nicotinic acetylcholine receptors (nAChRs). The first venom acylpolyamines ever discovered (argiopines, Joro and Nephila toxins, and philanthotoxins) have provided templates for the design and synthesis of numerous analogs. Thus far, analogs with high potency exert their effect at nanomolar concentrations, with high se-lectivity toward their ionotropic and ligand receptors. These potent and selective acylpolyamine analogs can serve biomedical purposes and pest control management. The structural modification of acylpolyamine with photolabile and fluorescent groups converted these venom toxins into use-ful molecular probes to discriminate iGluRs and nAchRs in cell populations. In various cases, the linear polyamines, like spermine and spermidine, constituting venom acyl polyamine backbones, have served as cargoes to deliver active molecules via a polyamine uptake system on diseased cells for targeted therapy. In this review, we examined examples of biogenic amines that play an essential role in neural homeostasis and cell signaling, contributing to human health and disease outcomes, which can be present in the venom of arachnids and hymenopterans. With an empha-sis on the spider and wasp venom acylpolyamines, we focused on the origin, structure, derivatiza-tion, and biomedical and biotechnological application of these pharmacologically attractive, chemically modular venom components.
Topics: Animals; Polyamines; Spider Venoms; Insecticides; Wasps; Humans; Spiders
PubMed: 38922129
DOI: 10.3390/toxins16060234 -
Insects Jun 2024The ectoparasitoid (Hymenoptera: Braconidae) exhibits a broad parasitic capability towards various lepidopteran pests, with venom serving as a crucial virulent factor...
The ectoparasitoid (Hymenoptera: Braconidae) exhibits a broad parasitic capability towards various lepidopteran pests, with venom serving as a crucial virulent factor ensuring successful parasitization and subsequent host mortality. Analyzing the constituents of its venom is essential for elucidating the mechanisms underlying efficient host killing by this parasitoid and for exploring potentially functional venom proteins. Through a transcriptomic analysis, a total of 34 venom proteins were identified within the venom of , encompassing known components such as serine protease, metalloproteinase, esterase, and serine protease inhibitors commonly present in parasitoid venoms. Unique components like paralytic protein and ion transport peptide-like were identified, possibly specific to certain parasitoids, along with novel proteins with uncharacterized functions. Spatial gene expression profiling of the identified venom proteins using transcriptomic data, corroborated by quantitative PCR validation for 13 randomly selected proteins, revealed abundant expression levels in the venom apparatus, affirming them as genuine venom components. Notably, the paralytic protein exhibited prominent expression, with the highest FPKM (fragments per kilobase of transcript per million fragments mapped) value of 24,704.87 in the venom apparatus, indicative of its significant role in successful parasitism by . The identification of these venom proteins establishes a foundation for the further exploration of bioactive agents for pest management strategies.
PubMed: 38921141
DOI: 10.3390/insects15060426 -
Analytical Chemistry Jun 2024Both controllable regulation of the conformational structure of a polypeptide and specific recognition of an amino acid are still arduous challenges. Here, a novel...
Both controllable regulation of the conformational structure of a polypeptide and specific recognition of an amino acid are still arduous challenges. Here, a novel dual-mode (electrochemical and colorimetric) biosensor was built for arginine (Arg) recognition based on a conformation switch, utilizing controllable and synergistic self-assembly of a ferrocene-grafted hexadecapeptide (PFc) with gold nanoparticles (AuNPs). Benefiting from the flexibility and unique topological structure of PFc formed nanospheres, the assembly and disassembly can undergo a conformation transition induced by Arg through controlling the distance and number of Fc detached from the gold surface, producing on-off electrical signals. Also, they can induce aggregation and dispersion of AuNPs in solution, causing a color change. The mechanism of Arg recognition with polypeptide conformation regulation was well explored by combining microstructure characterizations with molecular mechanics calculations. The electrochemical and colorimetric assays for Arg were successfully established in sensitive and selective manner, not only obtaining a very low detection limit, but also effectively eliminating the interference from other amino acids and overcoming the limitation of AuNP aggregation. Notably, the conformational change-based assay with the peptide regulated by the target will make a powerful tool for the amino acid biosensing and health diagnosis.
PubMed: 38918973
DOI: 10.1021/acs.analchem.4c01050 -
Astrobiology Jun 2024The 21st century is likely to be the first century in which large-scale short- and long-term space missions become common. Accordingly, an ever-increasing body of...
The 21st century is likely to be the first century in which large-scale short- and long-term space missions become common. Accordingly, an ever-increasing body of research is focusing on understanding the effects of current and future space expeditions on human physiology in health and disease. Yet the complex experimental environment, the small number of participants, and the high cost of space missions are among the primary factors that hinder a better understanding of the impact of space missions on human physiology. The goal of our research was to develop a cost-effective, compact, and easy-to-manipulate system to address questions related to human health and disease in space. This initiative was part of the Ramon SpaceLab program, an annual research-based learning program designed to cultivate high school students' involvement in space exploration by facilitating experiments aboard the International Space Station (ISS). In the present study, we used the nematode (), a well-suited model organism, to investigate the effect of space missions on neurodegeneration-related processes. Our study specifically focused on the level of aggregation of Huntington's disease-causing polyglutamine stretch-containing (PolyQ) proteins in muscles, the canonical system for studying neurodegeneration in this organism. We compared animals expressing PolyQ proteins grown onboard the ISS with their genetically identical siblings grown on Earth and observed a significant difference in the number of aggregates between the two populations. Currently, it is challenging to determine whether this effect stems from developmental or morphological differences between the cultures or is a result of life in space. Nevertheless, our results serve as a proof of concept and open a new avenue for utilizing to address various open questions in space studies, including the effects of space conditions on the onset and development of neurodegenerative diseases.
Topics: Caenorhabditis elegans; Animals; Space Flight; Peptides; Neurodegenerative Diseases; Humans
PubMed: 38917419
DOI: 10.1089/ast.2023.0096 -
Science Signaling Jun 2024Palmitoylation of intact or cleaved gasdermin D causes plasma membrane pore formation.
Palmitoylation of intact or cleaved gasdermin D causes plasma membrane pore formation.
Topics: Lipoylation; Humans; Cell Membrane; Intracellular Signaling Peptides and Proteins; Animals; Gasdermins; Phosphate-Binding Proteins
PubMed: 38917221
DOI: 10.1126/scisignal.adr1306 -
Science Signaling Jun 2024The stabilization of different active conformations of G protein-coupled receptors is thought to underlie the varying efficacies of biased and balanced agonists. Here,...
The stabilization of different active conformations of G protein-coupled receptors is thought to underlie the varying efficacies of biased and balanced agonists. Here, profiling the activation of signal transducers by angiotensin II type 1 receptor (ATR) agonists revealed that the extent and kinetics of β-arrestin binding exhibited substantial ligand-dependent differences, which were lost when receptor internalization was inhibited. When ATR endocytosis was prevented, even weak partial agonists of the β-arrestin pathway acted as full or near-full agonists, suggesting that receptor conformation did not exclusively determine β-arrestin recruitment. The ligand-dependent variance in β-arrestin translocation was much larger at endosomes than at the plasma membrane, showing that ligand efficacy in the β-arrestin pathway was spatiotemporally determined. Experimental investigations and mathematical modeling demonstrated how multiple factors concurrently shaped the effects of agonists on endosomal receptor-β-arrestin binding and thus determined the extent of functional selectivity. Ligand dissociation rate and G protein activity had particularly strong, internalization-dependent effects on the receptor-β-arrestin interaction. We also showed that endocytosis regulated the agonist efficacies of two other receptors with sustained β-arrestin binding: the V vasopressin receptor and a mutant β-adrenergic receptor. In the absence of endocytosis, the agonist-dependent variance in β-arrestin2 binding was markedly diminished. Our results suggest that endocytosis determines the spatiotemporal bias in GPCR signaling and can aid in the development of more efficacious, functionally selective compounds.
Topics: Endocytosis; Humans; Signal Transduction; Receptor, Angiotensin, Type 1; beta-Arrestins; HEK293 Cells; Receptors, Vasopressin; Receptors, Adrenergic, beta-2; Endosomes; Receptors, G-Protein-Coupled; Animals; Ligands; Protein Binding; Protein Transport
PubMed: 38917219
DOI: 10.1126/scisignal.adi0934