Quantitative proteomics reveals the complex regulatory networks of LTTR-type regulators in pleiotropic functions of Aeromonas hydrophila.

LysR-type transcriptional regulators (LTTRs) are ubiquitously distributed and abundant transcriptional regulators in prokaryotes, playing pivotal roles in diverse physiological processes. Nonetheless, despite their prevalence, the intricate functionalities and physiological implications of this protein family remain incompletely elucidated. In this study, we employed a comprehensive approach to deepen our understanding of LTTRs by generating a collection of 20 LTTR gene-deletion strains in Aeromonas hydrophila, accounting for 42.6 % of the predicted total LTTR repertoire, and subjected them to meticulous assessment of their physiological phenotypes. Leveraging quantitative proteomics, we conducted a comparative analysis of protein expression variations between six representative mutants and the wild-type strain. Subsequent bioinformatics analysis unveiled the involvement of these LTTRs in modulating a wide array of biological processes, notably including two-component regulatory systems (TCSs) and intracellular central metabolism. Moreover, employing subsequent microbiological methodologies, we experimentally verified the direct involvement of at least six LTTRs in the regulation of galactose metabolism. Importantly, through ELISA and competitive ELISA assays, we demonstrated the competitive binding capabilities of these LTTRs with the promoter of the α-galactosidase gene AHA_1897 and identified that four LTTRs (XapR, YidZ, YeeY, and AHA_1805) do not engage in competitive binding with other LTTRs. Overall, our comprehensive findings not only provide fundamental insights into the regulatory mechanisms governing crucial physiological functions of bacteria through LTTR family proteins but also uncover an intricate and interactive regulatory network mediated by LTTRs.

Quantitative Proteomics Reveal the Inherent Antibiotic Resistance Mechanism against Norfloxacin Resistance in Aeromonas hydrophila.

Recently, the prevalence of Aeromonas hydrophila antibiotic-resistant strains has been reported in aquaculture, but its intrinsic antibiotic resistance mechanisms are largely unknown. In the present study, a label-free proteomics technology was used to compare the differential protein abundances in response to norfloxacin (NOR) stress in A. hydrophila. The results showed that there were 186 proteins decreasing and 220 proteins increasing abundances in response to NOR stress. Bioinformatics analysis showed that the differentially expressed proteins were enriched in several biological processes, such as sulfur metabolism and homologous recombination. Furthermore, the antibiotic sensitivity assays showed that the deletion of AHA_0904, cirA, and cysI significantly decreased the resistance against NOR, whereas ΔAHA_1239, ΔcysA, ΔcysD, and ΔcysN significantly increased the resistance against NOR. Our results provide insights into NOR resistance mechanisms and indicate that AHA_0904, cirA, AHA_1239, and sulfur metabolism may play important roles in NOR resistance in A. hydrophila.

Nrf2 plays protective role during intermittent hypoxia-induced ferroptosis in rat liver (BRL-3A) cells.

PURPOSE: Ferroptosis is reported to be involved in the chronic intermittent hypoxia (CIH)-related liver damage in vivo. Nuclear factor E2-related factor 2 (Nrf2) has an essential role in the regulation of ferroptosis. This study tested the hypothesis that intermittent hypoxia (IH) could lead to hepatocyte ferroptosis in vitro and the function of Nrf2 in IH-induced hepatocyte ferroptosis. METHODS: BRL-3A cells (rat liver cells) were exposed to normoxia or IH. The protocol of IH consisted of 32 cycles of 60-min hypoxic exposure with 30-min reoxygenation phase (nadir of 1% oxygen to peak of 20% oxygen). Ferroptosis was evaluated by cell viability, iron concentration, lipid reactive oxygen species (ROS), protein content of ferritin heavy chain (FTH1), and glutathione peroxidase 4 (GPX4). Both ferrostatin-1 (a ferroptosis inhibitor) and Nrf2 interfering RNA were applied to treat BRL-3A cells, respectively. RESULTS: IH exposure induced ferroptosis in BRL-3A cells with decreased cell viability and increased total iron content and lipid ROS levels. The protein contents of GPX4 and FTH1 in IH group were markedly lower than that in normoxic control. Ferroptosis inhibitor ferrostatin-1 alleviated IH-induced ferroptosis in BRL-3A cells. IH treatment enhanced expression of Nrf2, and Nrf2 knockdown augmented IH-induced ferroptosis in BRL-3A cells. CONCLUSIONS: The results revealed that Nrf2 played a protective role during IH-induced ferroptosis in BRL-3A cells. The finding provides a therapeutic target for obstructive sleep apnea-related liver injury.

Expression profiling and functional analysis of circular RNAs in vitro model of intermittent hypoxia-induced liver injury.

Intermittent hypoxia (IH) is a prominent feature of obstructive sleep apnea (OSA) which is increasingly recognized as a key risk factor for liver injury. Circular RNAs (circRNAs) has been suggested to act as a regulator of multiple biological processes. However, there is no study evaluating circRNAs alterations and potential role of circRNAs in OSA-related liver injury. The present study aimed to investigate circRNA expression profiles in vitro model of IH-induced liver injury, as well as potential functional characterization of the differentially expressed circRNAs (DE circRNAs). BRL-3A cells were exposed to IH or normoxia. Cell apoptosis and cell viability were evaluated using flow cytometry and cell counting kit-8, respectively. The expression profile of circRNAs was depicted by circRNA sequencing. The selected circRNAs were verified by quantitative real-time PCR (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analyses were employed to predict DE circRNAs functions. The circRNA-miRNA-mRNA regulatory network was constructed. IH treatment caused cell injury in BRL-3A cells. 98 circRNAs were identified as being dysregulated in IH-treated BRL-3A cells. Among them, 58 were up-regulated and 40 were down-regulated. Go and KEGG analyses suggested that the DE circRNAs were predominantly enriched in the biological process such as positive regulation of NF-kappaB transcription factor activity and pathways such as circadian entrainment, Wnt signaling pathway, MAPK signaling pathway, and protein export. 3 up-regulated circRNAs and 3 down-regulated circRNAs with high number of back-splicing sites were chosen for qRT-PCR validation and were consistent with the sequencing data. CircRNA1056 and circRNA805 were predicted to interact with microRNAs that might thereby regulate downstream genes. The study characterized a profile of dysregulated circRNAs in IH-induced BRL-3A cell injury. DE circRNAs may play vital roles in the pathophysiology of IH-induced liver injury. Our findings provide preliminary support for further research in mechanisms and a new theory for the pathogenesis of OSA-related liver injury.

Impact of rapid on-site evaluation combined with endobronchial ultrasound and virtual bronchoscopic navigation in diagnosing peripheral lung lesions.

BACKGROUND: To investigate the value of endobronchial ultrasound (EBUS) and virtual bronchoscopic navigation (VBN) combined with rapid on-site evaluation (ROSE) in diagnosing peripheral pulmonary lesions (PPLs). METHODS: Between January 1st 2019 to September 1st 2021, EBUS and VBN examination were performed in expected consecutive patients with PPLs who were admitted to Zhangzhou Affiliated Hospital of Fujian Medical University (Fujian, China). Finally, based on the calculation of expected diagnostic yield of R-EBUS biopsy and drop out, 198 eligible patients were randomly divided into ROSE group (100 cases) and non-ROSE group (98 cases). The diagnostic yield of brushing and biopsy, the complications, the procedure time, the diagnosis time and expense during diagnosis were analyzed. RESULTS: In the ROSE group, the positive rate of EBUS brushing and biopsy were 68%, 84%, respectively. The average procedure time and diagnosis time were 18.6 ± 6.8 min, 3.84 ± 4.28 days, respectively, and the average expense was 643.44 ± 706.56 US.$ (4093.15 ± 4494.67 yuan ¥). In the controls, the positive rate of brushing and biopsy were 44%, 74%, respectively. The average procedure time and diagnosis time were 15.4 ± 5.7 min, 6.46 ± 3.66 days, respectively. And the average expense during diagnosis was 1009.27 ± 713.89 US.$ (6420.28 ± 4541.33 yuan ¥). There was significant difference in the positive rate of EBUS brushing and biopsy, diagnosis time and expense during diagnosis between both groups. And no significant difference was observed in the complications and the procedure time. Additionally, the impact of ROSE on diagnostic yield in right upper lobe and the size of lesion ≤ 2 cm in diameter was significant. CONCLUSION: In combination with ROSE, EBUS could significantly improve the positive rate of diagnosing PPLs, shorten diagnosis time and reduce expense during diagnosis. ROSE will be of great importance in the diagnosis of PPLs and medical resource.

Association of continuous positive airway pressure with F2-isoprostanes in adults with obstructive sleep apnea: a meta-analysis.

PURPOSE: Obstructive sleep apnea (OSA) is associated with increased F2-isoprostanes, a reliable standard biomarker of oxidative stress. Treatment with continuous positive airway pressure (CPAP) is effective for all degrees of OSA. However, it remains unknown whether treatment with CPAP will decrease F2-isoprostanes. A meta-analysis was conducted to determine the effect of CPAP treatment on F2-isoprostanes among patients with OSA. METHODS: The PubMed, Embase, Web of Science, and Cochrane library were searched before September, 2018. Eight articles assessing indices of F2-isoprostanes from various body fluids were identified. Pooled standardized mean difference (SMD) and weighted mean difference (WMD) were appropriately calculated through fixed or random effects models after assessing between-study heterogeneity. RESULTS: A total of 4 studies with 108 patients were pooled for exhaled breath condensate (EBC) F2-isoprostanes; 3 studies with 93 patients were pooled for serum or plasma F2-isoprostanes; and 3 studies with 102 patients were pooled for urinary F2-isoprostanes. A significant decrease of EBC F2-isoprostanes was observed after CPAP treatment (WMD = 2.652, 95% CI = 0.168 to 5.136, z = 2.09, p = 0.036), as well as serum or plasma F2-isoprostanes and urinary F2-isoprostanes (SMD = 1.072, 95% CI = 0.276 to 1.868, z = 2.64, p = 0.008 and WMD = 85.907, 95% CI = 50.443 to 121.372, z = 4.75, p = 0.000, respectively). CONCLUSIONS: This meta-analysis suggested that CPAP therapy was associated with a significant decrease in F2-isoprostanes in patients with OSA.

Impact of continuous positive airway pressure on vascular endothelial growth factor in patients with obstructive sleep apnea: a meta-analysis.

PURPOSE: Cumulative evidence supports the clear relationship of obstructive sleep apnea (OSA) with cardiovascular disease (CVD). And, adherence to continuous positive airway pressure (CPAP) treatment alleviates the risk of CVD in subjects with OSA. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine regulated by hypoxia-inducible factor, stimulates the progression of CVD. Thus, whether treatment with CPAP can actually decrease VEGF in patients with OSA remains inconclusive. The purpose of the present study was to quantitatively evaluate the impact of CPAP therapy on VEGF levels in OSA patients. METHODS: We systematically searched Web of Science, Cochrane Library, PubMed, and Embase databases that examined the impact of CPAP on VEGF levels in OSA patients prior to May 1, 2017. Related searching terms were "sleep apnea, obstructive," "sleep disordered breathing," "continuous positive airway pressure," "positive airway pressure," and "vascular endothelial growth factor." We used standardized mean difference (SMD) to analyze the summary estimates for CPAP therapy. RESULTS: Six studies involving 392 patients were eligible for the meta-analysis. Meta-analysis of the pooled effect showed that levels of VEGF were significantly decreased in patients with OSA before and after CPAP treatment (SMD = - 0.440, 95% confidence interval (CI) = - 0.684 to - 0.196, z = 3.53, p = 0.000). Further, results demonstrated that differences in age, body mass index, apnea-hypopnea index, CPAP therapy duration, sample size, and racial differences also affected CPAP efficacy. CONCLUSIONS: Improved endothelial function measured by VEGF may be associated with CPAP therapy in OSA patients. The use of VEGF levels may be clinically important in evaluating CVD for OSA patients. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

Carbon nanobowls supported ultrafine iridium nanocrystals: An active and stable electrocatalyst for the oxygen evolution reaction in acidic media.

Highly efficient proton exchange membrane electrolyzer in acidic media is of great importance for the hydrogen production from the electrochemical water splitting. Unfortunately, the electrochemical water splitting is limited by the slow oxygen evolution reaction kinetics at anode. So far, the synthesis of active and stable electrocatalysts in acid media is still a challenging work. In the work, carbon nanobowls supported ultrafine iridium nanocrystals are synthesized by a simple complexation-reduction method with assistance of 1-hydroxyethane-1, 1-diphosphonic acid, which effectively serves as as complexant, capping agent and surfactant during the synthesis. The good dispersion and ultrafine size of Ir nanocrystals, the modified interfacial property from phosphonate with excellent hydrophilicity, as well as carbon nanobowls as advanced carbon supports contribute to their excellent electrocatalytic activity for the oxygen evolution reaction in acid media. The as-prepared carbon nanobowls supported ultrafine iridium nanocrystals present an ultra-low overpotential of 290 mV to achieve the mass activity of 1000 A g-1 and a small Tafel slope of 49.1 mV dec-1, which significantly outperform commercial Ir/C electrocatalyst. The remarkable activity and durability make carbon nanobowls supported ultrafine iridium nanocrystals as a potential candidate for the oxygen evolution reaction electrocatalyst in proton exchange membrane water electrolyzer.

Association between continuous positive airway pressure and serum aminotransferases in patients with obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) has been suggested to be a potential contributing factor for nonalcoholic fatty liver disease (NAFLD). Studies on the association between continuous positive airway pressure (CPAP) and NAFLD in OSA patients are limited and controversial. OBJECTIVES: The aim of this study was to assess the relationship between OSA and NAFLD and the effect of CPAP therapy on serum aminotransferase levels in OSA patients. METHODS: A total of 160 consecutive patients who underwent standard polysomnography were enrolled. Blood samples were obtained in the morning after sleep for biological profile measurements. Non-invasive ultrasound techniques were used to assess liver steatosis and fibrosis. Within the OSA group, serum aminotransferases were detected before and after CPAP treatment. RESULTS: Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase, and liver steatosis score increased significantly with an increase in OSA severity. Stepwise multiple regression with liver steatosis score, ALT, AST as dependent variable, respectively, apnea-hypopnea index (ß = 0.447, p = 0.020; ß = 0.266, p = 0.001; ß = 0.351, p = 0.020, respectively) significantly predicted the liver steatosis score, ALT, AST after adjustment for confounders. After 3 months of CPAP treatment, there was a significant decrease in both ALT (54.20 ± 24.34 vs. 46.52 ± 24.95, p = 0.000) and AST (31.82 ± 8.91 vs. 29.00 ± 8.34, p = 0.039). CONCLUSIONS: OSA severity was independently associated with liver steatosis and elevation of serum aminotransferases. 3 months of CPAP therapy were associated with a statistically significant improvement on liver injury in OSA patients.

Effect of continuous positive airway pressure on carotid intima-media thickness in patients with obstructive sleep apnea: A meta-analysis.

OBJECTIVE: Obstructive sleep apnea (OSA) is associated with increased carotid intima-media thickness (IMT), an early marker of atherosclerosis. Continuous positive airway pressure (CPAP) is the first-line treatment for OSA. A meta-analysis was performed to determine whether CPAP therapy could decrease carotid IMT. METHODS: The PubMed, Embase, Web of Science, and Cochrane library were searched before March, 2017. Weighted mean difference (WMD) was calculated to estimate the treatment effects of pre and post-CPAP therapy. Seven studies were examined and the meta-analysis was performed using STATA 12.0. RESULTS: There was no change of carotid IMT before and after CPAP treatment in OSA patients (WMD = 0.052, 95% confidence interval (CI) = -0.002 to 0.105, z = 1.90, p = 0.057). Meanwhile, meta-analysis of the two RCTs showed that carotid IMT was not changed in CPAP group when compared with control group (WMD = 0.002 95% CI = -0.125 to 0.129, z = 0.03, p = 0.976). Subgroup analyses indicated that carotid IMT was significantly decreased after CPAP use in more severe OSA patients (AHI≥50) (WMD = 0.073, 95% CI = 0.022 to 0.124, z = 2.80, p = 0.005) and patients with therapeutic duration ≥6 months (WMD = 0.121, 95% CI = 0.019 to 0.223, z = 2.32, p = 0.021). CONCLUSIONS: CPAP had no impact on carotid IMT in OSA patients. However, carotid IMT was significantly decreased after CPAP treatment in more severe OSA patients and patients with longer CPAP usage.

Effect of Continuous Positive Airway Pressure on Adiponectin in Patients with Obstructive Sleep Apnea: A Meta-Analysis.

OBJECTIVE: Obstructive sleep apnea (OSA) has been suggested to be associated with low levels of adiponectin. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA; however, previous studies assessing the effect of CPAP on adiponectin in patients with OSA yielded conflicting results. The present meta-analysis was performed to determine whether CPAP therapy could increase adiponectin levels. METHODS: Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before February 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum adiponectin was extracted for analysis. Standardized mean difference (SMD) was used to analyze the summary estimates for CPAP therapy. RESULTS: Eleven studies involving 240 patients were included in this meta-analysis, including ten observational studies and one randomized controlled study. The meta-analysis showed that there was no change of adiponectin levels before and after CPAP treatment in OSA patients (SMD = 0.059, 95% confidence interval (CI) = -0.250 to 0.368, z = 0.37, p = 0.710). Subgroup analyses indicated that the results were not affected by age, baseline body mass index, severity of OSA, CPAP therapy duration, sample size and racial differences. CONCLUSIONS: This meta-analysis suggested that CPAP therapy has no impact on adiponectin in OSA patients, without significant changes in body weight. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

Effect of continuous positive airway pressure on insulin growth factor-1 in patients with obstructive sleep apnea: a meta-analysis.

OBJECTIVE: Obstructive sleep apnea (OSA) has been recognized as being associated with low level of insulin growth factor-1 (IGF-1). However, the impact of OSA treatment using continuous positive airway pressure (CPAP) on IGF-1 remains controversial. We performed a meta-analysis to determine whether effective CPAP therapy could increase IGF-1 levels. DESIGN: Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before September 2014. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum IGF-1 was extracted for analysis. Standardized mean difference (SMD) was used to analyze the summary estimates for CPAP therapy. RESULTS: Six articles with 168 patients were included in this meta-analysis, including five observational studies and one randomized controlled study. The meta-analysis showed that CPAP was associated with a statistically significant increase in IGF-1 in OSA patients (SMD=-0.436, 95% confidence interval=-0.653 to -0.218, P=0.000). CONCLUSIONS: This meta-analysis suggested that CPAP therapy was associated with an increase in IGF-1 in patients with OSA. Further large-scale, well-designed interventional investigations are needed to clarify this issue.