GPR50 regulates neuronal development as a mitophagy receptor.

Neurons rely heavily on high mitochondrial metabolism to provide sufficient energy for proper development. However, it remains unclear how neurons maintain high oxidative phosphorylation (OXPHOS) during development. Mitophagy plays a pivotal role in maintaining mitochondrial quality and quantity. We herein describe that G protein-coupled receptor 50 (GPR50) is a novel mitophagy receptor, which harbors the LC3-interacting region (LIR) and is required in mitophagy under stress conditions. Although it does not localize in mitochondria under normal culturing conditions, GPR50 is recruited to the depolarized mitochondrial membrane upon mitophagy stress, which marks the mitochondrial portion and recruits the assembling autophagosomes, eventually facilitating the mitochondrial fragments to be engulfed by the autophagosomes. Mutations Δ502-505 and T532A attenuate GPR50-mediated mitophagy by disrupting the binding of GPR50 to LC3 and the mitochondrial recruitment of GPR50. Deficiency of GPR50 causes the accumulation of damaged mitochondria and disrupts OXPHOS, resulting in insufficient ATP production and excessive ROS generation, eventually impairing neuronal development. GPR50-deficient mice exhibit impaired social recognition, which is rescued by prenatal treatment with mitoQ, a mitochondrially antioxidant. The present study identifies GPR50 as a novel mitophagy receptor that is required to maintain mitochondrial OXPHOS in developing neurons.

The mechanosensitive ion channel Piezo1 contributes to podocyte cytoskeleton remodeling and development of proteinuria in lupus nephritis.

Piezo1 functions as a special transducer of mechanostress into electrochemical signals and is implicated in the pathogenesis of various diseases across different disciplines. However, whether Piezo1 contributes to the pathogenesis of lupus nephritis (LN) remains elusive. To study this, we applied an agonist and antagonist of Piezo1 to treat lupus-prone MRL/lpr mice. Additionally, a podocyte-specific Piezo1 knockout mouse model was also generated to substantiate the role of Piezo1 in podocyte injury induced by pristane, a murine model of LN. A marked upregulation of Piezo1 was found in podocytes in both human and murine LN. The Piezo1 antagonist, GsMTx4, significantly alleviated glomerulonephritis and tubulointerstitial damage, improved kidney function, decreased proteinuria, and mitigated podocyte foot process effacement in MRL/lpr mice. Moreover, podocyte-specific Piezo1 deletion showed protective effects on the progression of proteinuria and podocyte foot process effacement in the murine LN model. Mechanistically, Piezo1 expression was upregulated by inflammatory cytokines (IL-6, TNF-α and IFN-γ), soluble urokinase Plasminogen Activator Receptor and its own activation. Activation of Piezo1 elicited calcium influx, which subsequently enhanced Rac1 activity and increased active paxillin, thereby promoting cytoskeleton remodeling and decreasing podocyte motility. Thus, our work demonstrated that Piezo1 contributed to podocyte injury and proteinuria progression in LN. Hence, targeted therapy aimed at decreasing or inhibiting Piezo1 could represent a novel strategy to treat LN.

Sevoflurane inhibits the malignant behavior of nasopharyngeal carcinoma cells by regulating mitochondrial membrane potential.

This study aims to determine the effect of sevoflurane (Sev) on nasopharyngeal carcinoma (NPC) in malignant behavior and mitochondrial membrane potential (MMP). NPC cells (5-8F and CNE2) were exposed to Sev at different concentrations and then tested for proliferation by CCK-8 and colony formation assays, apoptosis by flow cytometry, and invasion and migration by Transwell assays. In addition, the Warburg effect was examined by measurements of glucose consumption, lactic acid production, and adenosine triphosphate (ATP). Mitochondrial function was evaluated by reactive oxygen species (ROS) production, oxidative stress-related indexes, and mitochondrial membrane potential. Sev suppressed 5-8F and CNE2 cell proliferation, invasion, and migration, and enhanced apoptosis. Moreover, Sev dampened the Warburg effect by reducing glucose consumption, lactic acid production, and ATP, as well as decreasing hexokinase 2 and pyruvate kinases type M2 protein expressions. Also, Sev induced ROS production and malondialdehyde content and reduced superoxide and glutathione peroxidase levels. Finally, Sev caused damage to mitochondrial homeostasis through induction of cleaved caspase-3, cleaved caspase-9, and cytochrome c protein expression and reduction of MMP. Sev inhibits the malignant behavior of NPC cells by regulating MMP.

Sirtuin 3 in renal diseases and aging: From mechanisms to potential therapies.

The longevity protein sirtuins (SIRTs) belong to a family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases. In mammals, SIRTs comprise seven members (SIRT1-7) which are localized to different subcellular compartments. As the most prominent mitochondrial deacetylases, SIRT3 is known to be regulated by various mechanisms and participate in virtually all aspects of mitochondrial homeostasis and metabolism, exerting significant impact on multiple organs. Notably, the kidneys possess an abundance of mitochondria that provide substantial energy for filtration and reabsorption. A growing body of evidence now supports the involvement of SIRT3 in several renal diseases, including acute kidney injury, chronic kidney disease, and diabetic nephropathy; notably, these diseases are all associated with aging. In this review, we summarize the emerging role of SIRT3 in renal diseases and aging, and highlights the intricate mechanisms by which SIRT3 exerts its effects. In addition, we highlight the potential therapeutic significance of modulating SIRT3 and provide valuable insights into the therapeutic role of SIRT3 in renal diseases to facilitate clinical application.

Elevated Membrane Potential as a Tetracycline Resistance Mechanism in Escherichia coli.

The metabolic environment is responsible for antibiotic resistance, which highlights the way in which the antibiotic resistance mechanism works. Here, GC-MS-based metabolomics with iTRAQ-based proteomics was used to characterize a metabolic state in tetracycline-resistant Escherichia coli K12 (E. coli-RTET) compared with tetracycline-sensitive E. coli K12. The repressed pyruvate cycle against the elevation of the proton motive force (PMF) and ATP constructed the most characteristic feature as a consequence of tetracycline resistance. To understand the role of the elevated PMF in tetracycline resistance, PMF inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and the pH gradient were used to investigate how the elevation influences bacterial viability and intracellular antibiotic concentration. A strong synergy was detected between CCCP and tetracycline to the viability, which was consistent with increasing intracellular drug and decreasing external pH. Furthermore, E. coli-RTET and E. coli-RGEN with high and low PMF concentrations were susceptible to gentamicin and tetracycline, respectively. The elevated PMF in E. coli-RTET was attributed to the activation of other metabolic pathways, except for the pyruvate cycle, including a malate-oxaloacetate-phosphoenolpyruvate-pyruvate-malate cycle. These results not only revealed a PMF-dependent mechanism for tetracycline resistance but also provided a solution to tetracycline-resistant pathogens by aminoglycosides and aminoglycoside-resistant bacteria by tetracyclines.

Feasibility of Using Intraoperative Neurophysiological Monitoring for Detecting Bone Layer of Cervical Spine Surgery.

STUDY DESIGN: Intraoperative neurophysiological monitoring (IONM) as a guide to bone layer estimation was examined during posterior cervical spine lamina grinding. OBJECTIVE: To explore the feasibility of IONM to estimate bone layer thickness. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty is a classic operation for cervical spondylosis. To increase safety and accuracy, surgery-assistant robots are currently being studied. It combines the advantages of various program awareness methods to form a feasible security strategy. In the field of spinal surgery, robots have been successfully used to help place pedicle screws. IONM is used to monitor intraoperative nerve conditions in spinal surgery. This study was designed to explore the feasibility of adding IONM to robot safety strategies. METHODS: Chinese miniature pig model was used. Electrodes were placed on the lamina, and the minimum stimulation threshold of DNEP for each lamina was measured (Intact lamina, IL). The laminae were ground to measure the DNEP threshold after incomplete grinding (Inner cortical bone preserved, ICP) and complete grinding (Inner cortical bone grinded, ICG). Subsequently, the lateral cervical mass screw canal drilling was performed, and the t-EMG threshold of the intact and perforated screw canals was measured and compared. RESULT: The threshold was significantly lower than that of the recommended threshold of DENP via percutaneous cervical laminae measurement. The DNEP threshold decreases with the process of laminae grinding. The DNEP threshold of the IL group was significantly higher than ICP and ICG group, while there was no significant difference between the ICP group and the ICG group. There was no significant relationship between the integrity of the cervical spine lateral mass screw path and t-EMG threshold. CONCLUSIONS: It is feasible to use DENP threshold to estimate lamina thickness. Cervical lateral mass screw canals by t-EMG showed no help to evaluate the integrity.

Design and characterization of Fe(II) complexes with tetradentate ligands exhibiting spin-crossover near room temperature.

Construction of spin-crossover (SCO) materials is very appealing for applications such as molecular switches and information storage. This study focuses on the design of Fe(II) complexes using N,N'-bis(2-pyridinylmethyl)-1,2-ethanediamine-based ligands with an N4 structure for SCO material development. By incorporating para-substituted benzene groups into the ligand's pyridine moiety, two polymorphs, α and ß, were obtained, both exhibiting SCO activity. Notably, the ß polymorph displayed a spin crossover temperature of 270 K, which is approaching room temperature. Structural analyses were conducted to compare the differences between the polymorphs, along with a literature review of related complexes, providing insights into the characteristics of SCO behavior.

Use of bailing capsules (cordyceps sinensis) in the treatment of chronic kidney disease: a meta-analysis and network pharmacology.

The Bailing Capsule is a commonly used traditional Chinese medicine for the treatment of chronic kidney disease (CKD). However, its therapeutic effects and pharmacological mechanisms have not been fully explored. In this study, we integrated meta-analysis and network pharmacology to provide scientific evidence for the efficacy and pharmacological mechanism of Bailing Capsule in treating CKD. We conducted searches for randomized controlled studies matching the topic in PubMed, the Cochrane Library, Embase, Web of Science, and the Wanfang Database, and screened them according to predefined inclusion and exclusion criteria. Dates from the included studies were extracted for meta-analysis, including renal function indicators, such as 24-h urinary protein (24UP), blood urea nitrogen (BUN), and serum creatinine (Scr), as well as inflammatory indicators like high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Network pharmacology was employed to extract biological information, including active drug ingredients and potential targets of the drugs and diseases, for network construction and gene enrichment. Our findings indicated that 24UP, BUN, and Scr in the treatment group containing Bailing Capsule were lower than those in the control group. In terms of inflammatory indicators, hs-CRP, IL-6, and TNF-α, the treatment group containing Bailing Capsule also exhibited lower levels than the control group. Based on network pharmacology analysis, we identified 190 common targets of Bailing Capsule and CKD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses suggested that the pharmacological mechanism of Bailing Capsule might be related to immune response, inflammatory response, vascular endothelial damage, cell proliferation, and fibrosis. This demonstrates that Bailing Capsule can exert therapeutic effects through multiple targets and pathways, providing a theoretical basis for its use.

Genetic and pharmacological targeting of XBP1 alleviates hepatic ischemia reperfusion injury by enhancing FoxO1-dependent mitophagy.

Hepatic ischemia reperfusion (I/R) injury is a common clinical complication. X-box binding protein 1 (XBP1), as a critical regulator of the endoplasmic reticulum stress, has been implicated in a variety of diseases. In this study, we aimed to investigate the effects and the underlying mechanism of XBP1 in the progression of hepatic I/R injury. Hepatocyte-specific XBP1 knockout mice, multiple viral delivery systems and specific pharmacological inhibitors were applied in vivo in a partial hepatic I/R injury mouse model and in vitro in a cell model of hypoxia-reoxygenation (H/R) injury. Mitophagy and autophagic flux were evaluated and fluorescence resonance energy transfer (FRET) as well as immunoprecipitation were performed. The results demonstrated that reperfusion for 6 h represented a critical timepoint in hepatic I/R injury and resulted in significant intracellular mitochondrial dysfunction; led to the breakdown of hepatocytes accompanied by the highest expression levels of XBP1. Hepatocyte-specific XBP1 knockout alleviated hepatic I/R injury via enhanced mitophagy, as demonstrated by the reduction in hepatocellular damage/necrosis and increased expression of mitophagy markers. Mechanistically, XBP1 interacted with FoxO1 directly and catalyzed the ubiquitination of FoxO1 for proteasomal degradation. Targeting XBP1 by genetic or pharmacological techniques potentiated the protein levels of FoxO1, further promoting the activity of the PINK1/Parkin signaling pathway, thus augmenting mitophagy and exerting hepatoprotective effects upon I/R injury. In conclusion, the inhibition of XBP1 potentiated FoxO1-mediated mitophagy in hepatic I/R injury. Specific genetic and pharmacological treatment targeting XBP1 in the perioperative 6 h prior to reperfusion exerted beneficial effects, thus providing a novel therapeutic approach.

The pro-absorptive effect of glycosylated zein-fatty acid complexes on fucoxanthin via the lipid transporter protein delivery pathway.

Growing research confirms that lipid transport proteins play a key role in the trans-intestinal epithelial transport of carotenoids. In this study, to simultaneously improve the digestive stability and intestinal absorption of fucoxanthin (FX), functionalized vectors with a capability of up-regulating the expression of FX-specific lipid transporter proteins was fabricated. The results showed that myristic acid, palmitic acid, and stearic acid effectively promoted FX-specific lipid transporter protein expression and formed stable self-assembly complexes with Millard-modified zein (MZ). The FX was sufficiently encapsulated in the MZ-fatty acid (FA) particles, forming spherical nanoparticles with a "core-shell" structure. Simulated gastrointestinal digestion showed that FA introduction significantly increased the FX bioaccessibility. In vivo results further verified that adding FAs dramatically increased the FX serum response concentration. These findings suggest that incorporating nutrients that can promote lipid transporter protein expression into delivery vehicles should be an effective strategy for improving oral carotenoid absorption.

Impact of Viscosity on Human Hepatoma Spheroids in Soft Core-Shell Microcapsules.

The extracellular environment regulates the structures and functions of cells, from the molecular to the tissue level. However, the underlying mechanisms influencing the organization and adaptation of cancer in three-dimensional (3D) environments are not yet fully understood. In this study, the influence of the viscosity of the environment is investigated on the mechanical adaptability of human hepatoma cell (HepG2) spheroids in vitro, using 3D microcapsule reactors formed with droplet-based microfluidics. To mimic the environment with different mechanical properties, HepG2 cells are encapsulated in alginate core-shell reservoirs (i.e., microcapsules) with different core viscosities tuned by incorporating carboxymethylcellulose. The significant changes in cell and spheroid distribution, proliferation, and cytoskeleton are observed and quantified. Importantly, changes in the expression and distribution of F-actin and keratin 8 indicate the relation between spheroid stiffness and viscosity of the surrounding medium. The increase of F-actin levels in the viscous medium can indicate an enhanced ability of tumor cells to traverse dense tissue. These results demonstrate the ability of cancer cells to dynamically adapt to the changes in extracellular viscosity, which is an important physical cue regulating tumor development, and thus of relevance in cancer biology.

Enriched switching in a donor-acceptor Stenhouse adduct via reversible covalent bonding.

We have utilized reversible covalent bonding to expand the accessible states of a molecular switch. Introducing a hydroxyl group onto the donor moiety of a donor-acceptor Stenhouse adduct (DASA) imparts an acidity response by forming an oxazolidine ring through intramolecular nucleophilic addition. Furthermore, we observed distinct color changes under cryogenic conditions, extending the thermal responsiveness beyond the cyclization equilibrium observed at elevated temperatures. These unique responses present promising prospects for diverse applications compared to traditional photoinduced binary isomerization.

The impact of month and season on the incidence of giant cell arteritis: an Intelligent Research in Sight (IRIS) Registry analysis.

PURPOSE: Previous investigations into the relationship between season and the incidence of giant cell arteritis (GCA) have produced conflicting results. This study aimed to explore the impact of season and new diagnoses of GCA in a more definitive sense by employing the large dataset of the Intelligent Research in Sight (IRIS) database. METHODS: The IRIS Registry was queried to identify new cases of GCA from 2013 to 2021. Statistical analyses were performed to determine the significance of the relationship between the time of year and the incidence of GCA on regional and nationwide bases via Cochran's Q statistical test. RESULTS: A total of 27,339 eyes with a new diagnosis of GCA were identified. Neither the month nor the season of the year correlated with the incidence of GCA, regardless of geographic location within the USA (p > 0.05 for each variable). CONCLUSIONS: In the USA, the incidence of GCA does not appear to vary by month or season. While this finding contradicts certain previous studies that identified a relationship, the cohort of patients identified from the IRIS Registry is much larger than that of previous investigations. Clinicians should be mindful of the possibility of GCA, regardless of the time of the year.

The essential role of arginine biosynthetic genes in lunate conidia formation, conidiation, mycelial growth, and virulence of nematophagous fungus, Esteya vermicola CBS115803.

BACKGROUND: The pinewood nematode (Bursaphelenchus xylophilus) causes severe damage to pine trees. The nematophagous fungus, Esteya vermicola, exhibits considerable promise in the biological control of Bursaphelenchus xylophilus due to its infectivity. Notably, the lunate conidia produced by E. vermicola can infect Bursaphelenchus xylophilus. In the study, we aim to investigate the genes involved in the formation of the lunate conidia of E. vermicola CBS115803. RESULTS: Esteya vermicola CBS115803 yielded 95% lunate conidia on the complete medium (CM) and 86% bacilloid conidia on the minimal medium (MM). Transcriptomic analysis of conidia from both media revealed a significant enrichment of differentially expressed genes in the pathway related to 'cellular amino acid biosynthesis and metabolism'. Functional assessment showed that the knockout of two arginine biosynthesis genes (EV232 and EV289) resulted in defects in conidia germination, mycelial growth, lunate conidia formation, and virulence of E. vermicola CBS115803 in Bursaphelenchus xylophilus. Remarkably, the addition of arginine to the MM improved mycelial growth, conidiation and lunate conidia formation in the mutants and notably increased conidia yield and the lunate conidia ratio in the wild-type E. vermicola CBS115803. CONCLUSION: This investigation confirms the essential role of two arginine biosynthesis genes in lunate conidia formation in E. vermicola CBS115803. The findings also suggest that the supplementation of arginine to the culture medium can enhance the lunate conidia yield. These insights contribute significantly to the application of E. vermicola CBS115803 in managing Bursaphelenchus xylophilus infections. © 2023 Society of Chemical Industry.

Exogenous pyruvate promotes gentamicin uptake to kill antibiotic-resistant Vibrio alginolyticus.

OBJECTIVES: Elucidating antibiotic resistance mechanisms is necessary for developing novel therapeutic strategies. The increasing incidence of antibiotic-resistant Vibrio alginolyticus infection threatens both human health and aquaculture, but the mechanism has not been fully elucidated. METHODS: Here, an isobaric tags for relative and absolute quantification (iTRAQ) functional proteomics analysis was performed on gentamicin-resistant V. alginolyticus (VA-RGEN) and a gentamicin-sensitive strain in order to characterize the global protein expression changes upon gentamicin resistance. Then, the bacterial killing assay and bacterial gentamicin pharmacokinetics were performed. RESULTS: Proteomics analysis demonstrated a global metabolic downshift in VA-RGEN, where the pyruvate cycle (the P cycle) was severely compromised. Exogenous pyruvate restored the P cycle activity, disrupting the redox state and increasing the membrane potential. It thereby potentiated gentamicin-mediated killing by approximately 3000- and 150-fold in vitro and in vivo, respectively. More importantly, bacterial gentamicin pharmacokinetics indicated that pyruvate enhanced gentamicin influx to a degree that exceeded the gentamicin expelled by the bacteria, increasing the intracellular gentamicin. CONCLUSION: Thus, our study suggests a metabolism-based approach to combating gentamicin-resistant V. algonolyticus, which paves the way for combating other types of antibiotic-resistant bacterial pathogens.

Elevated proton motive force is a tetracycline resistance mechanism that leads to the sensitivity to gentamicin in Edwardsiella tarda.

Tetracycline is a commonly used human and veterinary antibiotic that is mostly discharged into environment and thereby tetracycline-resistant bacteria are widely isolated. To combat these resistant bacteria, further understanding for tetracycline resistance mechanisms is needed. Here, GC-MS based untargeted metabolomics with biochemistry and molecular biology techniques was used to explore tetracycline resistance mechanisms of Edwardsiella tarda. Tetracycline-resistant E. tarda (LTB4-RTET ) exhibited a globally repressed metabolism against elevated proton motive force (PMF) as the most characteristic feature. The elevated PMF contributed to the resistance, which was supported by the three results: (i) viability was decreased with increasing PMF inhibitor carbonylcyanide-3-chlorophenylhydrazone; (ii) survival is related to PMF regulated by pH; (iii) LTB4-RTET were sensitive to gentamicin, an antibiotic that is dependent upon PMF to kill bacteria. Meanwhile, gentamicin-resistant E. tarda with low PMF are sensitive to tetracycline is also demonstrated. These results together indicate that the combination of tetracycline with gentamycin will effectively kill both gentamycin and tetracycline resistant bacteria. Therefore, the present study reveals a PMF-enhanced tetracycline resistance mechanism in LTB4-RTET and provides an effective approach to combat resistant bacteria.

A glucose-mediated antibiotic resistance metabolic flux from glycolysis, the pyruvate cycle, and glutamate metabolism to purine metabolism.

Introduction: Bacterial metabolic environment influences antibiotic killing efficacy. Thus, a full understanding for the metabolic resistance mechanisms is especially important to combat antibiotic-resistant bacteria. Methods: Isobaric tags for relative and absolute quantification-based proteomics approach was employed to compare proteomes between ceftazidime-resistant and -sensitive Edwarsiella tarda LTB4 (LTB4-RCAZ and LTB4-S, respectively). Results: This analysis suggested the possibility that the ceftazidime resistance mediated by depressed glucose is implemented through an inefficient metabolic flux from glycolysis, the pyruvate cycle, glutamate metabolism to purine metabolism. The inefficient flux was demonstrated by the reduced expression of genes and the decreased activity of enzymes in the four metabolic pathways. However, supplement upstream glucose and downstream guanosine separately restored ceftazidime killing, which not only supports the conclusion that the inefficient metabolic flux is responsible for the resistance, but also provides an effective approach to reverse the resistance. In addition, the present study showed that ceftazidime is bound to pts promoter in E. tarda. Discussion: Our study highlights the way in fully understanding metabolic resistance mechanisms and establishing metabolites-based metabolic reprogramming to combat antibiotic resistance.

pts promoter influences antibiotic resistance via proton motive force and ROS in Escherichia coli.

Introduction: Glucose level is related to antibiotic resistance. However, underlying mechanisms are largely unknown. Methods: Since glucose transport is performed by phosphotransferase system (PTS) in bacteria, pts promoter-deleted K12 (Δpts-P) was used as a model to investigate effect of glucose metabolism on antibiotic resistance. Gas chromatography-mass spectrometry based metabolomics was employed to identify a differential metabolome in Δpts-P compared with K12, and with glucose as controls. Results: Δpts-P exhibits the resistance to ß-lactams and aminoglycosides but not to quinolones, tetracyclines, and macrolide antibiotics. Inactivated pyruvate cycle was determined as the most characteristic feature in Δpts-P, which may influence proton motive force (PMF), reactive oxygen species (ROS), and nitric oxide (NO) that are related to antibiotic resistance. Thus, they were regarded as three ways for the following study. Glucose promoted PMF and ß-lactams-, aminoglycosides-, quinolones-mediated killing in K12, which was inhibited by carbonyl cyanide 3-chlorophenylhydrazone. Exogenous glucose did not elevated ROS in K12 and Δpts-P, but the loss of pts promoter reduced ROS by approximately 1/5, which was related to antibiotic resistance. However, NO was neither changed nor related to antibiotic resistance. Discussion: These results reveal that pts promoter regulation confers antibiotic resistance via PMF and ROS in Escherichia coli.