Bioscience Reports最新文献

Intermediate filaments are intimately involved in the mechanical behavior of cells. Unfortunately, the resolution of optical microscopy limits our understanding of their organization. Here, we combined nanoscopy, single-filament tracking, and numerical simulations to inspect the dynamical organization of vimentin intermediate filaments in live cells. We show that a higher proportion of peripheral versus perinuclear vimentin pools are constrained in their lateral motion in the seconds time window, probably due to their cross-linking to other cytoskeletal networks. In a longer time scale, active forces become evident and affect similarly both pools of filaments. Our results provide a detailed description of the dynamical organization of the vimentin network in live cells and give some cues on its response to mechanical stimuli.

The antifungal drugs of the echinocandin family show high efficacy against Aspergillus fumigatus. However, their paradoxical effect, which restores fungal growth at high drug concentrations, and the emergence of resistant strains necessitate improvements. We identified 13 fluoroquinolone compounds from a chemical library containing 10,000 compounds that potentiate the antifungal activity of caspofungin. Among them, NE-E07 significantly enhanced the efficacy of echinocandins against A. fumigatus, including resistant strains, without potentiating other antifungal families like voriconazole or amphotericin B. Specifically, NE-E07 demonstrated a unique ability to potentiate caspofungin's activity against the echinocandin-resistant strain USHM-M0051 isolated from patients. Our experiments revealed that NE-E07, in combination with caspofungin, affected ergosterol biosynthesis in a manner consistent with azole drugs. Docking tests suggest that NE-E07 has a high binding affinity with CYP51, which affects ergosterol biosynthesis similarly to azole drugs. Interestingly, known fluoroquinolones like ciprofloxacin, nalidixic acid, and norfloxacin did not show this potentiating effect, suggesting that NE-E07's unique structure is critical for its activity. Moreover, NE-E07 did not enhance echinocandin activity against Candida albicans or Cryptococcus neoformans, highlighting its specific action against A. fumigatus. In vivo studies demonstrated that co-treatment with NE-E07 and caspofungin increased the survival rate of mice infected with A. fumigatus. This significant improvement in survival underscores the potential clinical relevance of NE-E07 as a co-administered drug with echinocandins for treating fungal infections, particularly those resistant to echinocandins.

Cellular Ca2+ homeostasis is critical for normal cell physiology and is regulated by several mechanisms. Two major players in intracellular Ca2+ homeostasis in multiple tissues belong to the SLC8 (Na+/Ca2+ exchangers (NCXs); NCX1-3) and SLC24 (K+ dependent Na+/Ca2+ exchangers (NCKXs); NCKX1-5) families. It has been established that NCXs and NCKX4 are palmitoylated, and that palmitoylation promotes NCX1 inactivation. However, there is still little known about NCKXs' palmitoylation. We found that (1) NCKX3 and NCKX5, but not NCKX1, are palmitoylated, (2) Cys to Ala mutation at position 467 for NCXK3 and 325 for NCKX5 notably diminished palmitoylation and (3) reduced palmitoylation enhanced NCKX3 activity. Our findings bring novel insights into NCKX1, NCKX3 and NCKX5 palmitoylation and establish palmitoylation as an endogenous regulator of NCKX3 activity, paving the way for investigations evaluating the role of palmitoylation in NCKX3 function in health and disease.

During the COVID-19 pandemic, there has been heightened interest in the QT interval, a crucial indicator of ventricular electrical activity. Mendelian randomization (MR) is used here to investigate the genetic causation between QT interval alterations and COVID-19. Genetic proxies representing three COVID-19 phenotypes-severe, hospitalized, and COVID-19-were identified in over 1,000,000 individuals of European ancestry. Univariate two-sample MR (TSMR) and multi-exposure-adjusted multivariate MR (MVMR) were used to assess genetic causal associations between COVID-19 and QT intervals in 84,630 UK Biobank participants. The MR-robust adjusted profile score (MR-RAPS) method and radial MR frame were utilized for effective robustness and outlier variant detection, with sensitivity analyses conducted to identify horizontal pleiotropy. For every COVID-19 phenotype, univariate TSMR analysis revealed non-significant causal estimates between COVID-19 and the QT interval [COVID-19: βIVW (95% CI): -0.44 (-1.72, 0.84), P = 0.50; hospitalization: βIVW: 0.12 (-0.57, 0.80), P = 0.74; severe case: βIVW: 0.11 (-0.29, 0.51), P = 0.58]. MR-RAPS and outlier-corrected radial MR analyses further supported this null causal estimation. In confounder-adjusted MVMR analysis, this nonsignificant causality was independent of body mass index (BMI), smoking, and alcohol consumption [βBMI+Alcohol+Smoking (95% CI): -0.77 (-2.44, 0.91), P = 0.37]. Sensitivity analyses did not detect any evidence of bias from horizontal pleiotropy, abnormal data distribution, or weak instruments. These findings suggest that COVID-19 does not directly causally prolong the QT interval. Inconsistent findings in observational research may be attributed to residual confounding.

Skeletal muscle is a highly plastic tissue that can adapt relatively rapidly to a range of stimuli. In response to novel mechanical loading, e.g. unaccustomed resistance exercise, myofibers are disrupted and undergo a period of ultrastructural remodeling to regain full physiological function, normally within 7 days. The mechanisms that underpin this remodeling are believed to be a combination of cellular processes including ubiquitin-proteasome/calpain-mediated degradation, immune cell infiltration, and satellite cell proliferation/differentiation. A relatively understudied system that has the potential to be a significant contributing mechanism to repair and recovery is the autophagolysosomal system, an intracellular process that degrades damaged and redundant cellular components to provide constituent metabolites for the resynthesis of new organelles and cellular structures. This review summarizes our current understanding of the autophagolysosomal system in the context of skeletal muscle repair and recovery. In addition, we also provide hypothetical models of how this system may interact with other processes involved in skeletal muscle remodeling and provide avenues for future research to improve our understanding of autophagy in human skeletal muscle.

In this present study, we investigated the H2O2-induced oligomerization of wild-type human neuroglobin (hNgb) and of some selected variants (C46AC55A, Y44A, Y44F, Y44AC46AC55A, Y44AC46AC55A) to clarify how the process is affected by the Cys46/Cys55 disulfide bond and the distal H-bonding network and to figure out the molecular determinants of the H2O2-induced formation of amyloid-type structures and hNgb aggregates. It turns out that hydrogen peroxide exerts a two-fold effect on hNgb, inducing both heme breakdown and protein dimerization/polymerization. The enhanced resistance to the oxidizing effect of H2O2 of the disulfide-free variants indicates that both effects are strictly influenced by the heme accessibility for H2O2. Most importantly, the H2O2-induced neuroglobin dimerization/polymerization turns out to be triggered by tyrosyl radicals resulting from the oxidizing action of Compound I ([Por•Fe(IV) = O]+). Peptide mapping indicates that the H2O2-induced dimerization/polymerization of hNgb mainly involves Tyr44, which forms covalent bonds with all the other tyrosine residues, with a minor contribution from Tyr88. The presented findings contribute further important pieces of information in the quest of identifying all capabilities of hNgb and ultimately its physiological task.

Multicentre redox proteins participate in diverse metabolic processes, such as redox shuttling, multielectron catalysis, or long-distance electron conduction. The detail in which these processes can be analysed depends on the capacity of experimental methods to discriminate the multiple microstates that can be populated while the protein changes from the fully reduced to the fully oxidized state. The population of each state depends on the redox potential of the individual centres and on the magnitude of the interactions between the individual redox centres and their neighbours. It also depends on the interactions with binding sites for other ligands, such as protons, giving origin to the redox-Bohr effect. Modelling strategies that match the capacity of experimental methods to discriminate the contributions of individual centres are presented. These models provide thermodynamic and kinetic characterization of multicentre redox proteins. The current state of the art in the characterization of multicentre redox proteins is illustrated using the case of multiheme cytochromes involved in the process of extracellular electron transfer. In this new frontier of biological electron transfer, which can extend over distances that exceed the size of the individual multicentre redox proteins by orders of magnitude, current experimental data are still unable, in most cases, to provide discrimination between incoherent conduction by heme orbitals and coherent band conduction.

As a rate-limiting enzyme in the endogenous serine de novo synthesis pathway, 3-Phosphoglycerate dehydrogenase (PHGDH) has been widely concerned about its role in a variety of tumors including colon cancer and the development of inhibitors. In our previous study, we studied PHGDH in colon cancer cell lines. However, with the development of personalized therapy, we realized that in scientific research, two-dimensional cell lines lost a lot of original characteristic information during long-term culture, and the results obtained may not be enough to support the conclusion. Patient-derived tumor organoids maintain genomic stability and make up for information missing from cell lines due to monoclonal growth. Therefore, in our study, a colon cancer organoid with high PHGDH expression was selected and analyzed for transcriptomic and metabolomic changes through targeted inhibition of PHGDH. The results showed that inhibition of PHGDH significantly inhibited the proliferation of colon cancer organoids. The transcriptome, metabolome, and combined omics analysis showed that the changes in colon cancer organoids after inhibition of PHGDH were mainly involved in PRSS1 and PRSS56, steroid hormone biosynthesis, phenylalanine metabolism, ascorbate and aldarate metabolism, and tyrosine metabolism. In our study, the role of PHGDH in serine metabolism in colon cancer organoids was clarified by multi-omics analysis to provide new knowledge for an in-depth understanding of serine metabolism and PHGDH function in colon cancer.

Roughly 90% of the Polish population experiences vitamin D deficiency. The 3-epi-25(OH)D2 and 3-epi-25(OH)D3 are stereoisomers of 25(OH)D2 and 25(OH)D3, and they can inadvertently be included in measurements of 25(OH)D levels, potentially leading to its overestimating. We aimed to measure 25(OH)D2 and 25(OH)D3, their epimers 3-epi-25(OH)D2 and 3-epi-25(OH)D3, and biologically active 1,25(OH)2D3 in patients with cardiovascular disease and healthy volunteers. We enrolled 27 adult patients with cardiovascular disease (64 ± 15 years) and 35 healthy volunteers (36.37 ± 12.29 years). We used a validated ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) method to measure 25(OH)D2/3 concentrations and their epimers. Plasma concentrations of 1α,25(OH)2D3 were determined by sensitive and quantitative enzyme immunoassay following intra- and inter-day validation. Vitamin D insufficiency was observed in approximately 52% of the patients and 37% of healthy volunteers. Comparable levels of 25(OH)D3 and 25(OH)D2 were seen in both groups. The observed levels of the epimeric form 3-epi-25(OH)D3 appeared approximately 1.7 times higher in healthy volunteers, accounting for 9% misclassified according to vitamin D status. Also, patients had lower concentrations of 1,25(OH)2D3, and their 3-epi-25(OH)D2 levels were below the detection limit (2 ng/mL). In all studied subjects, 25(OH)D3 was negatively correlated with % 3-epi-25(OH)D3 (R=-0.758; P<0.001), and 3-epi-25(OH)D2 was negatively correlated with % 3-epi-25(OH)D2 (R = -0.842; P = 0.002). While the mechanism of how vitamin D epimeric forms influence diseases remains unclear, we recommend maintaining 25(OH)D3 levels above 20 ng/mL.

Candida albicans is a member of the human commensal microbiota but can also cause opportunistic infections, including life-threatening invasive candidiasis, particularly in immunocompromised patients. One of the important features of C. albicans commensalism and virulence is its ability to adapt to diverse environmental stress conditions within the host. Rap1 is a DNA-binding protein identified in yeasts, protozoa, and mammalian cells, and it plays multiple functions, including telomere regulation. Intriguingly, our previous study showed that Rap1 is also involved in cell wall integrity, biofilm formation, and virulence in C. albicans. In this work, using RNA-seq analysis and other approaches, the role of C. albicans Rap1 in oxidative stress response was further revealed. The RAP1-deletion mutant exhibited greater resistance to the superoxide generator menadione, a lower level of intracellular reactive oxygen species (ROS) upon menadione treatment, and higher expression levels of superoxide dismutase genes, all in response to oxidative stress. Moreover, the association between Rap1-mediated oxidative stress response and the mitogen-activated protein kinase (MAPK) Hog1, the transcription factor Cap1 and the TOR signalling was also determined. Together, these findings expand our understanding of the complex signalling and transcriptional mechanisms regulating stress responses in C. albicans.