Uridine alleviates LPS-induced ARDS and improves insulin sensitivity by decreasing oxidative stress and inflammatory processes

Production of pyrimidine nucleosides in microbial systems via metabolic engineering: Theoretical analysis research and prospects

Pyrimidine nucleosides, as intermediate materials of significant commercial value, find extensive applications in the pharmaceutical industry. However, the current production of pyrimidine nucleosides largely relies on chemical synthesis, creating environmental problems that do not align with sustainable development goals. Recent progress in systemic metabolic engineering and synthetic biology has enabled the synthesis of natural products like pyrimidine nucleosides through microbial fermentation, offering a more sustainable alternative. Nevertheless, the intricate and tightly regulated biosynthetic pathways involved in the microbial production of pyrimidine nucleosides pose a formidable challenge. This study focuses on metabolic engineering and synthetic biology strategies aimed at enhancing pyrimidine nucleoside production. These strategies include gene modification, transcriptional regulation, metabolic flux analysis, cofactor balance optimization, and transporter engineering. Finally, this research highlights the challenges involved in the further development of pyrimidine nucleoside-producing strains and offers potential solutions in order to provide theoretical guidance for future research endeavors in this field.

The Triglycerides and Glucose Index Is an Independent Risk Factor for Acute Respiratory Distress Syndrome in Patients with COVID-19

Introduction: Although it has been observed that the triglycerides and glucose (TyG) index, a biomarker of insulin resistance, is associated with severity and morbidity by COVID-19, evidence is still scarce. Therefore, the objective of this study was to determine whether the TyG index is associated with both the degree of severity and mortality by acute respiratory distress syndrome (ARDS) in patients with COVID-19. Methods: Men and women aged 20 years or more with diagnosis of COVID-19 were included in a case-control study. Exclusion criteria were pregnancy, cancer, autoimmune diseases, autoimmune treatment, and incomplete data. Patients with severe COVID-19 ARDS were allocated into the case group, and those with mild or moderate COVID-19 ARDS in the control group. COVID-19 was defined by a positive reverse transcriptase-polymerase chain reaction test for SARS-CoV-2, and ARDS was defined according to the Berlin criteria. Results: A total of 206 patients were included and allocated into the case (n = 103) and control (n = 103) groups. The logistic regression analysis adjusted by age, sex, and body mass index showed that the TyG index is significantly associated with moderate [odds ratio (OR) = 6.0; 95% confidence interval (CI): 1.1-30.6] and severe (OR = 9.5; 95% CI: 2.4-37.5) COVID-19 ARDS, and death (OR = 10.1; 95% CI: 2.2-46.5). Conclusion: The results of our study show a significant and independent association of the TyG index with ARDS and mortality in patients with COVID-19.

Putative causal relations among gut flora, serums metabolites and arrhythmia: a Mendelian randomization study

BACKGROUND

The pathogenesis of cardiac arrhythmias is multifaceted, encompassing genetic, environmental, hemodynamic, and various causative factors. Emerging evidence underscores a plausible connection between gut flora, serum metabolites, and specific types of arrhythmias. Recognizing the role of host genetics in shaping the microbiota, we employed two-sample Mendelian randomization analyses to investigate potential causal associations between gut flora, serum metabolites, and distinct arrhythmias.

METHODS

Mendelian randomization methods were deployed to ascertain causal relationships between 211 gut flora, 575 serum metabolites, and various types of arrhythmias. To ensure the reliability of the findings, five complementary Mendelian randomization methods, including inverse variance weighting methods, were employed. The robustness of the results was scrutinized through a battery of sensitivity analyses, incorporating the Cochran Q test, leave-one-out test, and MR-Egger intercept analysis.

RESULTS

Eighteen gut flora and twenty-six serum metabolites demonstrated associations with the risk of developing atrial fibrillation. Moreover, ten gut flora and fifty-two serum metabolites were linked to the risk of developing supraventricular tachycardia, while eight gut flora and twenty-five serum metabolites were associated with the risk of developing tachycardia. Additionally, six gut flora and twenty-one serum metabolites exhibited associations with the risk of developing bradycardia.

CONCLUSION

This study revealed the potential causal relationship that may exist between gut flora, serum metabolites and different cardiac arrhythmias and highlights the need for further exploration. This study provides new perspectives to enhance diagnostic and therapeutic strategies in the field of cardiac arrhythmias.

Engineered Extracellular Vesicles Derived from Dermal Fibroblasts Attenuate Inflammation in a Murine Model of Acute Lung Injury

Acute respiratory distress syndrome (ARDS) represents a significant burden to the healthcare system, with ≈200 000 cases diagnosed annually in the USA. ARDS patients suffer from severe refractory hypoxemia, alveolar-capillary barrier dysfunction, impaired surfactant function, and abnormal upregulation of inflammatory pathways that lead to intensive care unit admission, prolonged hospitalization, and increased disability-adjusted life years. Currently, there is no cure or FDA-approved therapy for ARDS. This work describes the implementation of engineered extracellular vesicle (eEV)-based nanocarriers for targeted nonviral delivery of anti-inflammatory payloads to the inflamed/injured lung. The results show the ability of surfactant protein A (SPA)-functionalized IL-4- and IL-10-loaded eEVs to promote intrapulmonary retention and reduce inflammation, both in vitro and in vivo. Significant attenuation is observed in tissue damage, proinflammatory cytokine secretion, macrophage activation, influx of protein-rich fluid, and neutrophil infiltration into the alveolar space as early as 6 h post-eEVs treatment. Additionally, metabolomics analyses show that eEV treatment causes significant changes in the metabolic profile of inflamed lungs, driving the secretion of key anti-inflammatory metabolites. Altogether, these results establish the potential of eEVs derived from dermal fibroblasts to reduce inflammation, tissue damage, and the prevalence/progression of injury during ARDS via nonviral delivery of anti-inflammatory genes/transcripts.

Uridine Alleviates Sepsis-Induced Acute Lung Injury by Inhibiting Ferroptosis of Macrophage

Uridine metabolism is extensively reported to be involved in combating oxidative stress. Redox-imbalance-mediated ferroptosis plays a pivotal role in sepsis-induced acute lung injury (ALI). This study aims to explore the role of uridine metabolism in sepsis-induced ALI and the regulatory mechanism of uridine in ferroptosis. The Gene Expression Omnibus (GEO) datasets including lung tissues in lipopolysaccharides (LPS) -induced ALI model or human blood sample of sepsis were collected. In vivo and vitro, LPS was injected into mice or administered to THP-1 cells to generate sepsis or inflammatory models. We identified that uridine phosphorylase 1 (UPP1) was upregulated in lung tissues and septic blood samples and uridine significantly alleviated lung injury, inflammation, tissue iron level and lipid peroxidation. Nonetheless, the expression of ferroptosis biomarkers, including SLC7A11, GPX4 and HO-1, were upregulated, while lipid synthesis gene (ACSL4) expression was greatly restricted by uridine supplementation. Moreover, pretreatment of ferroptosis inducer (Erastin or Era) weakened while inhibitor (Ferrostatin-1 or Fer-1) strengthened the protective effects of uridine. Mechanistically, uridine inhibited macrophage ferroptosis by activating Nrf2 signaling pathway. In conclusion, uridine metabolism dysregulation is a novel accelerator for sepsis-induced ALI and uridine supplementation may offer a potential avenue for ameliorating sepsis-induced ALI by suppressing ferroptosis.