Bioscience Reports最新文献

UDP-glucose pyrophosphorylases (UGPases) catalyze the conversion of UTP and glucose-1-phosphate (Glc1P) to UDP-glucose and pyrophosphate, playing crucial roles in cell metabolism. The UGPases are related to the biosynthesis of glycans in various organisms and linked to bacterial survival, plant programmed cell death, and even human cancers. Eleven UGPases from the bacterium Escherichia coli; fungi Saccharomyces cerevisiae (ScUGP) and Aspergillus niger (AnUGP); plants Hordeum vulgare (barley) (HvUGP), Arabidopsis thaliana (AtUGP), Solanum tuberosum (potato) (StUGP), Manihot esculenta (cassava) (MeUGP), Ipomoea batatas (sweet potato) (IbUGP), and Zea mays (maize) (ZmUGP); and animals Drosophila melanogaster (fruit fly) (DmUGP) and Homo sapiens (human) (HsUGP) were expressed in E. coli and assayed. MeUGP and StUGP have the highest and second-highest specific activities, respectively. The second-order rate constant kcat/KM values of 11 UGPases are ranked from high to low in the following order: MeUGP > StUGP > ZmUGP > IbUGP > AtUGP > AnUGP > HvUGP > HsUGP > DmUGP > ScUGP > EcUGP. EcUGP, ScUGP, AnUGP, HvUGP, AtUGP, DmUGP, and HsUGP show a temperature optimum of 37℃. MeUGP, IbUGP, and ZmUGP showed a temperature optimum of 50℃. Overall, recombinant UGPases were not thermally stable. Ten UGPases were rapidly inactivated at 60℃ except for IbUGP. The recombinant UGPases use Glc1P with high activities. UGPases exhibit variations in NTP utilization efficiency. The results improve the knowledge of the characteristics of UGPase from various organisms and provide the potential to use MeUGP or StUGP as the engineering target of cell factories.

The tumor suppressor PALB2 is a key player in the homologous recombination (HR) pathway, functionally connecting BRCA proteins at the DNA damage site. PALB2 forms homodimers via its coiled-coil domain, and during HR, it forms a heterodimeric complex with BRCA1 using the same domain. However, the structural details of the human PALB2 coiled-coil domain are unknown. Several missense variants have been reported in the coiled-coil domain. The structure-function relationship of these variants is poorly understood, posing a challenge to genetic counseling. In this study, we present the solution structure of the human PALB2 coiled-coil domain, which forms an antiparallel homodimer. We then use this structure to investigate the impact of a few well-characterized missense mutations on the fold and interactions of the PALB2 coiled-coil domain. Our findings reveal a strong correlation between the structural impact of mutations and their efficiency in homologous recombination, suggesting that our approach can be applied to study other genetic variations in PALB2. These findings hold promise for improving genetic counseling and advancing cancer research.

Cells respond to a variety of internal and external stimuli by regulating the activities of different signalling cascades and cellular processes, often via chemical modifications of biological macromolecules that modulate their overall levels, biochemical activities or biophysical interactions. One such modification, termed ADP-ribosylation (ADPr), is emerging as an important player in the interferon (IFN) response, but the molecular targets and functions of ADP-ribosyltransferases within this core component of innate immunity still remains unclear. We and others have recently identified that stimulation of IFN signalling cascades promotes the formation of a novel cytosolic structure in human cells that is enriched in ADP-ribosyl modifications. Here, we propose to name these structures 'interferon-induced cytosolic ADPr bodies' (ICABs) and discuss their known components and potential functions. We also review methods to detect ICABs (and cellular ADPr in general) using a range of recently developed reagents. This lays the foundation for future studies aimed at elucidating the molecular functions of ICABs and ADPr in innate immune responses, which is a central unanswered question in the field.

Ginger (Zingiber officinale) exerts an antidiabetic effect by restoring pancreatic β-cells. The present study aimed to investigate the mechanism by which ginger extract induces the regeneration of functional β-cells in diabetic rats. Sprague-Dawley rats (n=27) were divided into three groups: normal rats given double distilled water (ddH2O) (NC, n=11), diabetic rats (injected with 60 mg/kg streptozotocin) given ddH2O (DC, n=8), and diabetic rats treated with aqueous ginger extract (DG, n=8). The effect of ginger extract intake on the differential expression of neurogenin-3 (Neurog3), V-maf musculoaponeurotic fibrosarcoma oncogene homolog B (Mafb), insulin 2 (Ins2), and glucagon (Gcg) was assessed using quantitative real-time PCR after one and eight weeks of treatment. The pancreatic insulin source was determined using immunohistochemical analysis. After one week, ginger treatment significantly up-regulated the expression of both Neurog3 and Mafb in the DG rats compared with the DC rats. However, after eight weeks, the mRNA levels of these genes dropped significantly in parallel with the up-regulation of Ins2 and Gcg expression, resulting in increased serum insulin levels, weight, and lowered fasting blood glucose levels. Immunohistochemical analysis revealed a restored β-cell mass and islet architecture in the DG group. Ginger extract exerts an antidiabetic effect by acting on pancreatic progenitors and α-cells to restore β-cell mass in streptozotocininduced diabetic rats. These findings suggest that ginger extract could be a potential stimulator of β-cell neogenesis, which provides an alternative to meet the increasing demand for exogenous insulin in patients with diabetes.

Approximately one in every 800 children is born with the severe aneuploid condition of Down syndrome (DS), a trisomy of chromosome 21. Low blood pressure (hypotension) is a common condition associated with DS and can have a significant impact on exercise tolerance and quality of life. Little is known about the factors driving this hypotensive phenotype, therefore therapeutic interventions are limited. Carbonyl reductase 1 (CBR1) is an enzyme contributing to the metabolism of prostaglandins, glucocorticoids, reactive oxygen species and neurotransmitters, encoded by a gene (CBR1) positioned on chromosome 21 with the potential to affect blood pressure. Utilising telemetric blood pressure measurement of genetically modified mice, we tested the hypothesis that CBR1 influences blood pressure and that its overexpression contributes to hypotension in DS by evaluating possible contributing mechanisms in vitro. In a mouse model of DS (Ts65Dn), which exhibits hypotension, CBR1 activity was increased and pharmacological inhibition of CBR1 ed to increased blood pressure. Mice heterozygous null for Cbr1 had reduced CBR1 enzyme activity and elevated blood pressure. Further experiments indicate that the underlying mechanisms include alterations in both sympathetic tone and prostaglandin metabolism. We conclude that CBR1 activity contributes to blood pressure homeostasis and inhibition of CBR1 may present a novel therapeutic opportunity to correct symptomatic hypotension in DS.

Sepsis-induced cardiac dysfunction is one of the most common complications of sepsis. It is also a major cause of death in pediatric intensive care units. The underlying mechanism of sepsis-induced cardiac dysfunction remains elusive. Cold-inducible RNA-binding protein (CIRP) is a damage-associated molecular pattern that is up-regulated during sepsis. Hydrogen sulfide (H2S) has been shown to play a protective role in sepsis-induced cardiac dysfunction in adult animals. The present study aimed to determine whether H2S ameliorates the cardiac function in infant rats by inhibiting CIRP-mediated sepsis-induced cardiac dysfunction. Rat pups aged 17-18 days were subjected to cecal ligation and puncture (CLP) to induce sepsis. Six hours after CLP, hemodynamic results demonstrated that there was a significant decrease in +dP/dtmax, -dP/dtmax, left ventricular ejection fraction, and left ventricular shortening fraction, indicating cardiac dysfunction. The plasma levels of myocardial injury markers such as creatine kinase-myocardial band and cardiac troponin I were significantly increased at 6 h after CLP. The inhibition of CIRP with C23 improved the cardiac function of the rats with CLP-induced sepsis, accompanied by a significant decrease in endoplasmic reticulum stress (ERS) activation. Moreover, treatment with sodium 4-phenylbutyrate (an inhibitor of ERS) ameliorated myocardial injury and dysfunction, accompanied by a significant decrease in ERS activation. Sodium hydrosulfide, a H2S donor, ameliorated CLP-induced cardiac dysfunction and decreased CIRP levels and ERS. In contrast, the inhibition of endogenous H2S production by propargylglycine (a cystathionine-γ-lyase inhibitor) aggravated CLP-induced cardiac dysfunction and increased CIRP levels. In conclusion, the present study demonstrated that H2S exerted cardioprotective effects by inhibiting the CIRP/ERS pathway in infant rats with sepsis. These findings might indicate a novel target in the treatment of sepsis in infants.

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.