Increased susceptibility to Klebsiella pneumonia and mortality in GSNOR-deficient mice

The identification of metabolism-related subtypes and potential treatments for idiopathic pulmonary fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is caused by aberrant repair because of alveolar epithelial injury and can only be effectively treated with several compounds. Several metabolism-related biomolecular processes were found to be involved in IPF. We aimed to identify IPF subtypes based on metabolism-related pathways and explore potential drugs for each subtype. Methods: Gene profiles and clinical information were obtained from the Gene Expression Omnibus (GEO) database (GSE70867 and GSE93606). The enrichment scores for 41 metabolism-related pathways, immune cells, and immune pathways were calculated using the Gene Set Variation Analysis (GSVA) package. The ConsensusClusterPlus package was used to cluster samples. Novel modules and hub genes were identified using weighted correlation network analysis (WGCNA). Receiver operating characteristic (ROC) and calibration curves were plotted, and decision curve analysis (DCA) were performed to evaluate the model in the training and validation cohorts. A connectivity map was used as a drug probe. Results: Two subtypes with significant differences in prognosis were identified based on the metabolism-related pathways. Subtype C1 had a poor prognosis, low metabolic levels, and a unique immune signature. CDS2, LCLAT1, GPD1L, AGPAT1, ALDH3A1, LAP3, ADH5, AHCYL2, and MDH1 were used to distinguish between the two subtypes. Finally, subtype-specific drugs, which can potentially treat IPF, were identified. Conclusion: The aberrant activation of metabolism-related pathways contributes to differential prognoses in patients with IPF. Collectively, our findings provide novel mechanistic insights into subtyping IPF based on the metabolism-related pathway and potential treatments, which would help clinicians provide subtype-specific individualized therapeutic management to patients.

Roles and current applications of S-nitrosoglutathione in anti-infective biomaterials

Bacterial infections can compromise the physical and biological functionalities of humans and pose a huge economical and psychological burden on infected patients. Nitric oxide (NO) is a broad-spectrum antimicrobial agent, whose mechanism of action is not affected by bacterial resistance. S-nitrosoglutathione (GSNO), an endogenous donor and carrier of NO, has gained increasing attention because of its potent antibacterial activity and efficient biocompatibility. Significant breakthroughs have been made in the application of GSNO in biomaterials. This review is based on the existing evidence that comprehensively summarizes the progress of antimicrobial GSNO applications focusing on their anti-infective performance, underlying antibacterial mechanisms, and application in anti-infective biomaterials. We provide an accurate overview of the roles and applications of GSNO in antibacterial biomaterials and shed new light on the avenues for future studies.

Correlation Between Nasal and Laryngeal Lesions of Rhinoscleroma in Patients of Upper Egypt

INTRODUCTION

Rhinoscleroma (RS) is a chronic granulomatous disease of URT caused by Klebsiella Rinoescleromatis. RS is considered endemic in Egypt. The nasal mucosa represents the primary region of occurrence. The disease can potentially spread to involve the larynx and trachea causing dysphonia, stridor, and airway obstruction.

OBJECTIVES

To describe various nasal and laryngeal presentations of RS in our endemic area, to correlate between these findings and to alert physicians to suspect RS in any case of unexplained nasal or laryngeal lesion.

METHODS

The study included 100 patients admitted in our otorhinolaryngolgy department (Minia University, Minia, Egypt). Patients presented with various manifestations of Rhino-pharyngo-laryngo scleroma. Diagnosis based on clinical, bacteriological, and pathological examination.

RESULTS

Patients had typical nasal stages of RS, however; only 12 % of patients had the typical described laryngeal presentations (ie, subglottic narrowing and subglottic membrane). Other patients presented with atypical laryngeal presentations (eg, unhealthy vocal folds, ventricular fold hypertrophy, and suproglottic sticky greenish discharge). There was significant correlation between nasal stages and laryngeal lesions.

CONCLUSION

RS can present with atypical laryngeal presentations in endemic areas which should be kept in mind to avoid misdiagnosis. Possible laryngeal lesions of RS can be predicted from observing associated nasal lesions.

Chemoproteomics-based target profiling of sinomenine reveals multiple protein regulators of inflammation

Although sinomenine (SIN) has been used to treat several inflammation-related diseases in the clinic for decades, the detailed anti-inflammatory mechanism remains elusive. Here, we present a chemoproteomic study that supports a polypharmacological mode of action for SIN to inhibit inflammation. Notably, functional validation revealed multiple new protein regulators whose knockdown could significantly affect inflammation.

S-nitrosoglutathione reductase maintains mitochondrial homeostasis by promoting clearance of damaged mitochondria in porcine preimplantation embryos

OBJECTIVES

S-nitrosoglutathione reductase (GSNOR), a protein denitrosylase, protects the mitochondria from mitochondrial nitrosative stress. Mammalian preimplantation embryos are mitochondria-rich, but the effects of GSNOR on mitochondrial function in preimplantation embryos are not well-studied. In the present study, we investigate whether GSNOR plays a role in mitochondrial regulation during porcine preimplantation embryo development.

MATERIALS AND METHODS

GSNOR dsRNA was employed to knock down the expression of GSNOR, and Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME), a pan-NOS inhibitor, was used to prevent protein S-nitrosylation. Mitochondrial amount and function in embryo development were assessed by performing immunofluorescence staining, Western blot, fluorescent probe and real-time reverse transcription PCR.

RESULTS

GSNOR knock-down significantly impaired blastocyst formation and quality and markedly induced the increase in protein S-nitrosylation. Notably, GSNOR knock-down-induced overproduction of S-nitrosylation caused mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondria-derived reactive oxygen species (ROS) increase and ATP deficiency. Interestingly, GSNOR knock-down-induced total mitochondrial amount increase, but the ratio of active mitochondria reduction, suggesting that the damaged mitochondria were accumulated and mitochondrial clearance was inhibited. In addition, damaged mitochondria produced more ROS, and caused DNA damage and apoptosis. Importantly, supplementation with L-NAME reverses the increase in S-nitrosylation, accumulation of damaged mitochondria, and oxidative stress-induced cell death. Interestingly, autophagy was downregulated after GSNOR knock-down, but reversed by L-NAME treatment. Thus, GSNOR maintains mitochondrial homeostasis by promoting autophagy and the clearing of damaged mitochondria in porcine preimplantation embryos.

Taraxacum officinale extract ameliorates dextran sodium sulphate-induced colitis by regulating fatty acid degradation and microbial dysbiosis

Numerous data show that taraxacum officinale extract (TOE) exerts protective effects on inflammatory diseases. However, the underlying mechanisms by which TOE affects dextran sulphate sodium (DSS)-induced colitis remain unclear. After DSS-induced colitis were treated with different concentrations of TOE for 8 days, the bodyweight, disease activity index (DAI), colon lengths and pathological scoring were assessed, and histopathological examination was confirmed by HE staining. Furthermore, a transcriptome sequencing was performed by using the colon tissues between TOE and DSS groups, and the differentially expressed genes were conducted for the Kyoto Encyclopaedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA) and were validated by qRT-PCR and immunohistochemistry analysis. In addition, a 16S rDNA sequencing was carried out to distinguish the differential gut microbiota by using the mouse faecal samples between TOE and DSS groups. We found that TOE attenuated the clinical symptoms, lowered the inflammatory scoring and inhibited the secretion of proinflammatory factors TNF-α, IL-1β and IL-6 in DSS-induced colitis. KEGG and GSEA analysis demonstrated that fatty acid degradation and cytokine-receptor signalling were predominantly enriched in TOE-treated colitis as compared with the DSS group. Further investigations revealed that TOE increased the expression levels of Adh5, Aldh3a2 and Acox3, but decreased those of CCL20, CCR6 and CXCL1/5 in DSS-induced colitis, where TOE also induced the enrichment of S24-7 and adlercreutzia, but decreased the amount of anaerostipes, enterococcus, enterobacteriaceae and peptostreptococcaceae. In conclusion, TOE ameliorated DSS-induced colitis by regulating fatty acid degradation and microbial dysbiosis.

S-nitrosation of protein phosphatase 1 mediates alcohol-induced ciliary dysfunction

Alcohol use disorder (AUD) is a strong risk factor for development and mortality of pneumonia. Mucociliary clearance, a key innate defense against pneumonia, is perturbed by alcohol use. Specifically, ciliated airway cells lose the ability to increase ciliary beat frequency (CBF) to β-agonist stimulation after prolonged alcohol exposure. We previously found that alcohol activates protein phosphatase 1 (PP1) through a redox mechanism to cause ciliary dysfunction. Therefore, we hypothesized that PP1 activity is enhanced by alcohol exposure through an S-nitrosothiol-dependent mechanism resulting in desensitization of CBF stimulation. Bronchoalveolar S-nitrosothiol (SNO) content and tracheal PP1 activity was increased in wild-type (WT) mice drinking alcohol for 6-weeks compared to control mice. In contrast, alcohol drinking did not increase SNO content or PP1 activity in nitric oxide synthase 3-deficient mice. S-nitrosoglutathione induced PP1-dependent CBF desensitization in mouse tracheal rings, cultured cells and isolated cilia. In vitro expression of mutant PP1 (cysteine 155 to alanine) in primary human airway epithelial cells prevented CBF desensitization after prolonged alcohol exposure compared to cells expressing WT PP1. Thus, redox modulation in the airways by alcohol is an important ciliary regulatory mechanism. Pharmacologic strategies to reduce S-nitrosation may enhance mucociliary clearance and reduce pneumonia prevalence, mortality and morbidity with AUD.

The role of S-nitrosoglutathione reductase (GSNOR) in human disease and therapy

S-nitrosoglutathione reductase (GSNOR), or ADH5, is an enzyme in the alcohol dehydrogenase (ADH) family. It is unique when compared to other ADH enzymes in that primary short-chain alcohols are not its principle substrate. GSNOR metabolizes S-nitrosoglutathione (GSNO), S-hydroxymethylglutathione (the spontaneous adduct of formaldehyde and glutathione), and some alcohols. GSNOR modulates reactive nitric oxide (•NO) availability in the cell by catalyzing the breakdown of GSNO, and indirectly regulates S-nitrosothiols (RSNOs) through GSNO-mediated protein S-nitrosation. The dysregulation of GSNOR can significantly alter cellular homeostasis, leading to disease. GSNOR plays an important regulatory role in smooth muscle relaxation, immune function, inflammation, neuronal development and cancer progression, among many other processes. In recent years, the therapeutic inhibition of GSNOR has been investigated to treat asthma, cystic fibrosis and interstitial lung disease (ILD). The direct action of •NO on cellular pathways, as well as the important regulatory role of protein S-nitrosation, is closely tied to GSNOR regulation and defines this enzyme as an important therapeutic target.

Rhinoscleroma with Pharyngolaryngeal Involvement Caused by Klebsiella ozaenae

Rhinoscleroma is a chronic, slowly progressive granulomatous bacterial infection that is endemic to the tropical world, namely, Central America and Africa. It is occasionally seen in the United States of America (USA). It predominately affects the nasal mucosa but can also involve the rest of the upper respiratory tract. The well-known causative agent for rhinoscleroma is the bacterium Klebsiella rhinoscleromatis, a subspecies of Klebsiella pneumoniae. However, Klebsiella ozaenae can also, albeit very rarely, cause rhinoscleroma. The diagnosis is confirmed by histopathology examination that shows the characteristic Mikulicz cells, considered pathognomonic for this infection. We report a patient with histologically proven rhinoscleroma with pharyngolaryngeal involvement in whom cultures yielded Klebsiella ozaenae. To the best of our knowledge, only two cases of rhinoscleroma due to Klebsiella ozaenae have been reported in the literature to date. Our case illustrates the importance of recognizing this infection in a nonendemic setting such as the USA. A lack of awareness and a delay in the diagnosis of this disease can lead to complications including upper airway obstruction, physical deformity, and, rarely, sepsis. In addition, it must be remembered that the treatment of rhinoscleroma is challenging and requires a prolonged course of antibiotics to achieve a definite cure and avoid relapses.

Flavone inhibits nitric oxide synthase (NOS) activity, nitric oxide production and protein S-nitrosylation in breast cancer cells

As the core structure of flavonoids, flavone has been proved to possess anticancer effects. Flavone's growth inhibitory functions are related to NO. NO is synthesized by nitric oxide synthase (NOS), and generally increased in a variety of cancer cells. NO regulates multiple cellular responses by S-nitrosylation. In this study, we explored flavone-induced regulations on nitric oxide (NO)-related cellular processes in breast cancer cells. Our results showed that, flavone suppresses breast cancer cell proliferation and induces apoptosis. Flavone restrains NO synthesis by does-dependent inhibiting NOS enzymatic activity. The decrease of NO generation was detected by fluorescence microscopy and flow cytometry. Flavone-induced inhibitory effect on NOS activity is dependent on intact cell structure. For the NO-induced protein modification, flavone treatment significantly down-regulated protein S-nitrosylation, which was detected by "Biotin-switch" method. The present study provides a novel, NO-related mechanism for the anticancer function of flavone.