Cellular Distribution of Secreted Phospholipase A2 in Lungs of IPF Patients and Its Inhibition in Bleomycin-Induced Pulmonary Fibrosis in Mice

Ergothioneine Ameliorates Liver Fibrosis by Inhibiting Glycerophospholipids Metabolism and TGF-β/Smads Signaling Pathway: Based on Metabonomics and Network Pharmacology

Ergothioneine (EGT) is a diet-derived natural sulfur-containing amino acid that exhibits strong anti-oxidant and anti-inflammation activities. Oxidative stress and chronic inflammatory injury are predominant pro-fibrogenic factors. Therefore, EGT may have therapeutic potential against liver fibrosis; however, its underlying mechanism is incompletely understood. This study aimed at investigating the protective effects of EGT on liver fibrosis based on metabonomics and network pharmacology. A mouse model of liver fibrosis was established by intraperitoneal injection with 40% CCl4 solution (2 mL/kg, twice a week) and intragastric administration with EGT (5, 10 mg/kg/d) for six weeks. Results showed that EGT improved liver function by reducing serum levels of ALT (alanine aminotransferase), AST (aspartate aminotransferase), and TBIL (total bilirubin), and alleviated liver fibrosis by reducing LN (laminin) and HyP (hydroxyproline) levels, decreasing expressions of α-SMA (α-smooth muscle actin), Col-I (collagen type I), and Col-III (collagen type III), and improving pathological changes. EGT also significantly inhibited CCl4-induced hepatic inflammation and TGF-β/Smads signaling pathway. Metabolomics identified six key metabolic pathways, such as purine metabolism, glycerophospholipid metabolism, and sphingolipid metabolism, and eight key metabolites, such as xanthine, guanine, ATP, phosphatidylcholine, and sphingosine. Network pharmacology analysis showed that IL-17, cAMP and NF-κB signaling pathways were potential key mechanisms. Integrated analysis revealed that PLA2G2A might be a potential target of EGT against liver fibrosis. EGT may inhibit the glycerophospholipid metabolism through PLA2G2A to inhibit the TGF-β/Smads signaling pathway, thereby alleviating fibrosis. The present study indicates that EGT may be considered a valid therapeutic strategy to regress liver fibrosis, and provides novel insights into the pharmacological mechanism of EGT against liver fibrosis.

Integrating Metabolomics and Network Analyses to Explore Mechanisms of Geum japonicum var. chinense Against Pulmonary Fibrosis: Involvement of Arachidonic Acid Metabolic Pathway

Pulmonary fibrosis (PF) emerges as a significant pulmonary sequelae in the convalescent phase of coronavirus disease 2019 (COVID-19), with current strategies neither specifically preventive nor therapeutic. Geum japonicum var. chinense (GJC) is used as a traditional Chinese medicine to effectively treat various respiratory conditions. However, the protective effects of GJC against PF remains unclear. In the present study, the anti-PF effect of GJC aqueous extract was studied using a PF mouse model induced by bleomycin (BLM). To characterize the metabolite changes related to PF and reveal therapeutic targets for GJC aqueous extract, we performed metabolomic and network analysis on mice lungs. Finally, key targets were then validated by Western blotting. GJC aqueous extract effectively alleviated the onset and progression of lung fibrosis in PF mice by inhibiting inflammatory responses and regulating oxidative stress levels. Integrating serum metabolomics and network analyses showed the arachidonic acid (AA) pathway to be the most important metabolic pathway of GJC aqueous extract against PF. Further validation of AA pathway protein levels showed a significant rise in the levels of ALOX5, PTGS2, CYP2C9, and PLA2G2A in PF lungs. GJC aqueous extract treatment regulated the above changes in metabolic programming. In conclusion, GJC is a promising botanical drug to delay the onset and progression of PF mice. The primary mechanism of action is associated with the comprehensive regulation of metabolites and protein expression related to the AA metabolic pathway.

Contribution of individual phospholipase A2 enzymes to the cleavage of oxidized phospholipids in human blood plasma

Phospholipids containing oxidized esterified PUFA residues (OxPLs) are increasingly recognized for multiple biological activities and causative involvement in disease pathogenesis. Pharmacokinetics of these compounds in blood plasma is essentially not studied. Human plasma contains both genuine phospholipases A2 [platelet activating factor acetyl hydrolase (PAF-AH) (also called Lp-PLA2) and secretory phospholipase A2] and multifunctional enzymes capable of removing sn-2 residues in native and oxidized PLs (lecithin-cholesterol acyltransferase, peroxiredoxin-6). The goal of this study was to compare relative activities of different PLA2 enzymes by analyzing cleavage of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylcholine (OxPAPC) and oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylethanolamine (OxPAPE) by diluted plasma in the presence of enzyme inhibitors. We have found that human plasma demonstrated high total PLA2 activity against oxidized PCs and PEs. PAF-AH/Lp-PLA2 played a dominant role in LysoPC and LysoPE production as compared to other enzymes. Molecular species of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylcholine and oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylethanolamine could be divided into three groups according to their degradation rate and sensitivity to PAF-AH/Lp-PLA2 inhibitor darapladib. Oxidatively truncated species were most rapidly metabolized in the presence of plasma; this process was strongly inhibited by darapladib. The rate of degradation of full-length OxPLs depended on the degree of oxygenation. Species containing 1 to 3 oxygen atoms were relatively stable to degradation in plasma, while OxPLs containing > 3 extra oxygens were degraded but at significantly slower rate than truncated species. In contrast to truncated species, degradation of full-length OxPLs with > 3 extra oxygens were only minimally inhibited by darapladib. These data provide further insights into the mechanisms regulating circulating levels of OxPLs and lipid mediators generated by PLA2 cleavage of OxPLs, namely oxylipins and LysoPC.

Single-cell analysis reveals the loss of FABP4-positive proliferating valvular endothelial cells relates to functional mitral regurgitation

BACKGROUND

Functional mitral regurgitation (MR) is a common form of mitral valve dysfunction that often persists even after surgical intervention, requiring reoperation in some cases. To advance our understanding of the pathogenesis of functional MR, it is crucial to characterize the cellular composition of the mitral valve leaflet and identify molecular changes in each cell subtype within the mitral valves of MR patients. Therefore, we aimed to comprehensively examine the cellular and molecular components of mitral valves in patients with MR.

METHODS

We conducted a single-cell RNA sequencing (scRNA-seq) analysis of mitral valve leaflets extracted from six patients who underwent heart transplantation. The cohort comprised three individuals with moderate-to-severe functional MR (MR group) and three non-diseased controls (NC group). Bioinformatics was applied to identify cell types, delineate cell functions, and explore cellular developmental trajectories and interactions. Key findings from the scRNA-seq analysis were validated using pathological staining to visualize key markers in the mitral valve leaflets. Additionally, in vitro experiments with human primary valvular endothelial cells were conducted to further support our results.

RESULTS

Our study revealed that valve interstitial cells are critical for adaptive valve remodelling, as they secrete extracellular matrix proteins and promote fibrosis. We discovered an abnormal decrease in a subpopulation of FABP4 (fatty acid binding protein 4)-positive proliferating valvular endothelial cells. The trajectory analysis identifies this subcluster as the origin of VECs. Immunohistochemistry on the expanded cohort showed a reduction of FABP4-positive VECs in patients with functional MR. Intervention experiments with primary cells indicated that FABP4 promotes proliferation and migration in mitral valve VECs and enhances TGFβ-induced differentiation.

CONCLUSIONS

Our study presented a comprehensive assessment of the mitral valve cellular landscape of patients with MR and sheds light on the molecular changes occurring in human mitral valves during functional MR. We found a notable reduction in the proliferating endothelial cell subpopulation of valve leaflets, and FABP4 was identified as one of their markers. Therefore, FABP4 positive VECs served as proliferating endothelial cells relates to functional mitral regurgitation. These VECs exhibited high proliferative and differentiative properties. Their reduction was associated with the occurrence of functional MR.

Analyzing how SiMiao Wan regulates ferroptosis to prevent RA-ILD using metabolomics and cyberpharmacology

BACKGROUND

Interstitial lung disease (ILD) is a common complication of rheumatoid arthritis (RA) that plays a significant role in the morbidity and mortality of individuals with this condition. In clinical settings, Si Miao Wan (SMW), a traditional Chinese medicine, is often utilized for the management of RA, as it is believed to possess properties that aid in reducing inflammation, eliminating excess moisture, and alleviating joint pain.

PURPOSE

The primary objective of this investigation was to elucidate the potential mechanism of RA-ILD prevention from the perspective of ferroptosis mediated by SMW.

METHODS

UPLC-Q-TOF/MS and network pharmacology were employed to forecast the potential targets of SMW for the early prevention of RA-ILD. Following this, HE staining, metabolomics, and RT-PCR were utilized to investigate the mechanism by which SMW prevents RA-ILD at an early stage.

RESULTS

Following six weeks of continuous administration of SMW extract at a dosage of 2.16 g/kg/day, it was observed that SMW exhibited early preventive effects against RA-ILD. Metabolomics analysis revealed seven potential biomarkers linked to the pharmacological efficacy of SMW in the early prevention of RA-ILD. Additionally, network pharmacology analysis suggested that SMW may exert its therapeutic effects on RA-ILD by modulating signaling pathways associated with lipid metabolism, atherosclerosis, TNF, and IL-17. Ultimately, through the integration of metabolomics and network pharmacology analysis, along with subsequent verification, it was determined that the early prevention of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) by Shenmai injection (SMW) is associated with the ferroptosis pathway.

CONCLUSION

This research offers preliminary insights into the potential mechanism by which traditional Chinese medicine Shen Mai Wan (SMW) may mitigate the early onset of Rheumatoid Arthritis-Interstitial Lung Disease (RA-ILD) via the process of ferroptosis. Furthermore, it establishes a theoretical framework for the development of innovative SMW-based pharmaceuticals for the management of RA-ILD. The signal proteins implicated in this process are anticipated to emerge as crucial targets for the prevention of RA-ILD.

Spatial Transcriptomics Reveals Signatures of Histopathological Changes in Muscular Sarcoidosis

Sarcoidosis is a multisystemic disease characterized by non-caseating granuloma infiltrating various organs. The form with symptomatic muscular involvement is called muscular sarcoidosis. The impact of immune cells composing the granuloma on the skeletal muscle is misunderstood. Here, we investigated the granuloma-skeletal muscle interactions through spatial transcriptomics on two patients affected by muscular sarcoidosis. Five major transcriptomic clusters corresponding to perigranuloma, granuloma, and three successive muscle tissue areas (proximal, intermediate, and distal) around the granuloma were identified. Analyses revealed upregulated pathways in the granuloma corresponding to the activation of T-lymphocytes and monocytes/macrophages cytokines, the upregulation of extracellular matrix signatures, and the induction of the TGF-β signaling in the perigranuloma. A comparison between the proximal and distal muscles to the granuloma revealed an inverse correlation between the distance to the granuloma and the upregulation of cellular response to interferon-γ/α, TNF-α, IL-1,4,6, fibroblast proliferation, epithelial to mesenchymal cell transition, and the downregulation of muscle gene expression. These data shed light on the intercommunications between granulomas and the muscle tissue and provide pathophysiological mechanisms by showing that granuloma immune cells have a direct impact on proximal muscle tissue by promoting its progressive replacement by fibrosis via the expression of pro-inflammatory and profibrosing signatures. These data could possibly explain the evolution towards a state of disability for some patients.