Phosphatidylethanolamine Induces an Antifibrotic Phenotype in Normal Human Lung Fibroblasts and Ameliorates Bleomycin-Induced Lung Fibrosis in Mice

Stratification according to autoantibody status in systemic sclerosis reveals distinct molecular signatures

OBJECTIVES

Systemic sclerosis (SSc) is a heterogeneous disease, complicating its management. Its complexity and the insufficiency of clinical manifestations alone to delineate homogeneous patient groups further challenge this task. However, autoantibodies could serve as relevant markers for the pathophysiological mechanisms driving the disease. Identifying specific immunological mechanisms based on patients' serological statuses might facilitate a deeper understanding of the diversity of the disease.

METHODS

A cohort of 206 patients with SSc enrolled in the PRECISESADS cross-sectional study was examined. Patients were stratified based on their anti-centromere (ACA) and anti-SCL70 (SCL70) antibody statuses. Comprehensive omics analyses including transcriptomic, flow cytometric, cytokine and metabolomic data were analysed to characterise the differences between these patient groups.

RESULTS

Patients with SCL70 antibodies showed severe clinical features such as diffuse cutaneous sclerosis and pulmonary fibrosis and were biologically distinguished by unique transcriptomic profiles. They exhibit a pro-inflammatory and fibrotic signature associated with impaired tissue remodelling and increased carnitine metabolism. Conversely, ACA-positive patients exhibited an immunomodulation and tissue homeostasis signature and increased phospholipid metabolism.

CONCLUSIONS

Patients with SSc display varying biological profiles based on their serological status. The findings highlight the potential utility of serological status as a discriminating factor in disease severity and suggest its relevance in tailoring treatment strategies and future research directions.

Investigating the effects of dexamethasone on pulmonary surfactant lipids based on lipidomics studies

Dexamethasone, a glucocorticoid commonly used in pediatric patients, has potent anti-inflammatory and immunosuppressive properties. However, it is associated with side effects such as reduced lung function and decreased immunity. Pulmonary surfactant lipids are closely linked to lung disease and play a role in reducing surface tension, immune response and antiviral activity. The dysregulation of lipid metabolism is closely associated with lung disease. Hence, untargeted lipidomics may be instrumental in elucidating the effects of dexamethasone on pulmonary surfactant lipids. We obtained surfactant lipid samples from the bronchoalveolar lavage fluid of young mice injected subcutaneously with dexamethasone and conducted a comprehensive lipidomic analysis, comparing them with a control group. We observed a decrease in lipids, such as phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine, and an increase in ceramide, fatty acid, diacylglycerol and monoglyceride, which may impact lung health. This study revealed the influence of dexamethasone on pulmonary surfactant lipids, offering new insights into adverse reactions in clinical settings.

Fagopyrum Dibotrys Rhizoma regulates pulmonary lipid metabolic homeostasis and the ERK-cPLA2 pathway to alleviate asthma in mice

BACKGROUND

Asthma is a complex disease with mechanisms involving multiple factors, and there is still a lack of highly effective and low-side-effect drugs. Traditional Chinese medicine Fagopyrum Dibotrys Rhizoma (FDR) has been applied for the treatment of acute and chronic bronchitis as well as bronchial asthma due to its favorable pharmacological activity. However, the exact mechanism of FDR remains unclear.

OBJECTIVE

A mouse model of asthma was created using OVA and HDM. To investigate the mechanism of FDR in asthma treatment, a combination of network pharmacology, lipidomics, and molecular biology approaches was employed.

METHODS

To evaluate the therapeutic effects of FDR on asthma, we established two distinct models of asthma in C57BL/6 J mice using OVA and HDM, respectively. We then employed LC-MS to analyze the major chemical constituents in FDR. Next, the network pharmacology approach was used to predict the potential targets and mechanisms of FDR in asthma treatment. Additionally, lipidomics analysis of mouse serum was conducted using LC-MS. Finally, the impact of FDR on the ERK -cPLA2 signaling pathway was investigated through Western Blotting assay.

RESULTS

FDR treatment has been shown to improve histomorphological changes, lung function and inflammation in models of OVA and HDM-induced asthma. Using UPLC/LTQ-Orbitrap-MS, we were able to identify 12 potential active components. Network pharmacology analysis revealed that FDR shares 75 targets with asthma. Further analysis using GO and KEGG pathways demonstrated the involvement of key pathways such as PI3K-Akt, TNF, and MAPK. Additionally, lipidomics analysis of the serum from OVA and HDM induced asthma mice showed disturbances in lipid metabolism, which were effectively ameliorated by FDR treatment. Mechanistically, FDR inhibits ERK1/2-cPLA2, leading to a reduction in lysophospholipids and restoration of lipid balance, thereby aiding in the treatment of asthma.

CONCLUSION

FDR has been shown to improve lipid metabolism disorder in the serum of asthmatic mice, thereby potentially serving as a treatment for asthma. This can be achieved by regulating the activation levels of ERK1/2 and p38MAPK. Consequently, the production of lysophosphatide is reduced, thereby alleviating the disorder of lipid metabolism and achieving the desired therapeutic effect in asthma treatment.

The novel molecular mechanism of pulmonary fibrosis: insight into lipid metabolism from reanalysis of single-cell RNA-seq databases

Pulmonary fibrosis (PF) is a severe pulmonary disease with limited available therapeutic choices. Recent evidence increasingly points to abnormal lipid metabolism as a critical factor in PF pathogenesis. Our latest research identifies the dysregulation of low-density lipoprotein (LDL) is a new risk factor for PF, contributing to alveolar epithelial and endothelial cell damage, and fibroblast activation. In this study, we first integrative summarize the published literature about lipid metabolite changes found in PF, including phospholipids, glycolipids, steroids, fatty acids, triglycerides, and lipoproteins. We then reanalyze two single-cell RNA-sequencing (scRNA-seq) datasets of PF, and the corresponding lipid metabolomic genes responsible for these lipids' biosynthesis, catabolism, transport, and modification processes are uncovered. Intriguingly, we found that macrophage is the most active cell type in lipid metabolism, with almost all lipid metabolic genes being altered in macrophages of PF. In type 2 alveolar epithelial cells, lipid metabolic differentially expressed genes (DEGs) are primarily associated with the cytidine diphosphate diacylglycerol pathway, cholesterol metabolism, and triglyceride synthesis. Endothelial cells are partly responsible for sphingomyelin, phosphatidylcholine, and phosphatidylethanolamines reprogramming as their metabolic genes are dysregulated in PF. Fibroblasts may contribute to abnormal cholesterol, phosphatidylcholine, and phosphatidylethanolamine metabolism in PF. Therefore, the reprogrammed lipid profiles in PF may be attributed to the aberrant expression of lipid metabolic genes in different cell types. Taken together, these insights underscore the potential of targeting lipid metabolism in developing innovative therapeutic strategies, potentially leading to extended overall survival in individuals affected by PF.

Organic synthesis of 1,2-dipalmitoyl-rac-glycero-3-phosphatidylethanolamine and its effect on the induction of apoptosis in normal human lung fibroblasts

BACKGROUND /OBJECTIVE

The phospholipid 1,2-dipalmitoyl-rac-glycero-3-phosphatidylethanolamine (PE) comprises two fatty acid chains: glycerol, phosphate, and ethanolamine. PE participates in critical cellular processes such as apoptosis and autophagy, which places it as a target for designing new therapeutic alternatives in diseases such as pulmonary fibrosis. Therefore, this study aimed obtain PE through a six-step organic synthesis pathway and determine its biological effect on apoptosis induction in normal human lung fibroblasts (NHLF).

METHODOLOGY

The first step of the organic synthesis route began with protected glycerol that was benzylated at sn-3; later, it was deprotected to react with palmitic acid at sn-1, sn-2. To remove the benzyl group, hydrogenation was performed with palladium on carbon (Pd/C); subsequently, the molecule was phosphorylated in sn-3 with phosphorus oxychloride and triethylamine, and the intermediate was hydrolyzed in an acid medium to obtain the final compound. After PE synthesis, apoptosis assessment was performed: apoptosis was induced using exposure to annexin V-FITC/propidium iodide-ECD (PI) and quantified using flow cytometry. The experiments were performed in three NHLF cell lines with different concentrations of PE 10, 100 and 1000 µg/mL for 24 and 48 h.

RESULTS

The PE obtained by organic synthesis presented a melting point of 190-192 °C, a purity of 95%, and a global yield of 8%. The evaluation of apoptosis with flow cytometry showed that at 24 h, exposure to PE 10, 100, and 1000 µg/mL induces early apoptosis in 19.42%- 25.54%, while late apoptosis was only significant P < 0.05 in cells challenged with 100 µg/mL PE. At 48 h, NHLF exposed to PE 10, 100, and 1000 µg/mL showed decreasing early apoptosis: 28.69-32.16%, 12.59-18.84%, and 10.91-12.61%, respectively. The rest of the NHLF exposed to PE showed late apoptosis: 12.03-16-42%, 11.04-15.94%, and 49.23-51.28%. Statistical analysis showed a significance P < 0.05 compared to the control.

CONCLUSION

The organic synthesis route of PE allows obtaining rac-1,2-O-Dipalmitoyl-glycero-3-phosphoethanolamine (1), which showed an apoptotic effect on NHLF.

An Analysis of Targeted Serum Lipidomics in Patients with Pneumoconiosis - China, 2022

Introduction

Pneumoconiosis emerges as the most critical and prevalent occupational disease in China at present, according to research. Studies indicate that pneumoconiosis may indeed impact the body's phospholipid metabolism.

Methods

In this study, serum samples were taken from 46 paired participants, which included patients with pneumoconiosis and dust-exposed workers. We employed ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology in targeted lipidomics to investigate serum target phospholipids. Initially, a pilot study was conducted with a selection of 24 pneumoconiosis patients and 24 dust-exposed workers, using both univariate and multivariate statistical analyses to preliminarily identify significant differences in phospholipids. Subsequent to this, the remaining subjects were engaged in a validation study, wherein receiver operating characteristic (ROC) analysis was performed to further substantiate the screening potency of potential lipid biomarkers for pneumoconiosis.

Results

The pilot study revealed significantly reduced serum levels of 16∶0 lysophosphatidylcholines (Lyso PC), 18∶0-18∶1 phosphatidylglycerol (PG), 18∶0-18∶1 phosphatidylethanolamine (PE), 18∶0 PE, and 18∶1 lysophosphatidylethanolamine（Lyso PE) in the case group in comparison to the control group. Additionally, 18∶0 PE, 18∶0-18∶1 PE, and 18∶1 Lyso PE emerged as significant phospholipids with superior diagnostic values [area under the curve (AUC)>0.7]. A diagnostic model was established, built on 16∶0 PC and 18∶0 PE (AUC>0.8). In the ROC analyses of validation studies, the 18∶0-18∶1 PE and this diagnostic model demonstrated excellent screening efficiency (AUC>0.7).

Discussion

A significant divergence in phospholipid metabolism has been observed between pneumoconiosis patients and dust-exposed workers. The 18∶0-18∶1 PE present in serum could potentially function as a lipid biomarker for pneumoconiosis. Additionally, diagnostic models were developed relying on 16∶0 PC and 18∶0 PE, proving to have superior screening efficiency.

Metabolomic Signatures Associated with Radiation-Induced Lung Injury by Correlating Lung Tissue to Plasma in a Rat Model

The lung has raised significant concerns because of its radiosensitivity. Radiation-induced lung injury (RILI) has a serious impact on the quality of patients' lives and limits the effect of radiotherapy on chest tumors. In clinical practice, effective drug intervention for RILI remains to be fully elucidated. Therefore, an in-depth understanding of the biological characteristics is essential to reveal the mechanisms underlying the complex biological processes and discover novel therapeutic targets in RILI. In this study, Wistar rats received 0, 10, 20 or 35 Gy whole-thorax irradiation (WTI). Lung and plasma samples were collected within 5 days post-irradiation. Then, these samples were processed using liquid chromatography-mass spectrometry (LC-MS). A panel of potential plasma metabolic markers was selected by correlation analysis between the lung tissue and plasma metabolic features, followed by the evaluation of radiation injury levels within 5 days following whole-thorax irradiation (WTI). In addition, the multiple metabolic dysregulations primarily involved amino acids, bile acids and lipid and fatty acid β-oxidation-related metabolites, implying disturbances in the urea cycle, intestinal flora metabolism and mitochondrial dysfunction. In particular, the accumulation of long-chain acylcarnitines (ACs) was observed as early as 2 d post-WTI by dynamic plasma metabolic data analysis. Our findings indicate that plasma metabolic markers have the potential for RILI assessment. These results reveal metabolic characteristics following WTI and provide new insights into therapeutic interventions for RILI.

Metabolic fingerprinting of systemic sclerosis: a systematic review

Introduction: Systemic sclerosis (SSc) is a chronic autoimmune disease, marked by an unpredictable course, high morbidity, and increased mortality risk that occurs especially in the diffuse and rapidly progressive forms of the disease, characterized by fibrosis of the skin and internal organs and endothelial dysfunction. Recent studies suggest that the identification of altered metabolic pathways may play a key role in understanding the pathophysiology of the disease. Therefore, metabolomics might be pivotal in a better understanding of these pathogenic mechanisms. Methods: Through a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA), searches were done in the PubMed, EMBASE, Web of Science, and Scopus databases from 2000 to September 2022. Three researchers independently reviewed the literature and extracted the data based on predefined inclusion and exclusion criteria. Results: Of the screened studies, 26 fulfilled the inclusion criteria. A total of 151 metabolites were differentially distributed between SSc patients and healthy controls (HC). The main deregulated metabolites were those derived from amino acids, specifically homocysteine (Hcy), proline, alpha-N-phenylacetyl-L-glutamine, glutamine, asymmetric dimethylarginine (ADMA), citrulline and ornithine, kynurenine (Kyn), and tryptophan (Trp), as well as acylcarnitines associated with long-chain fatty acids and tricarboxylic acids such as citrate and succinate. Additionally, differences in metabolic profiling between SSc subtypes were identified. The diffuse cutaneous systemic sclerosis (dcSSc) subtype showed upregulated amino acid-related pathways involved in fibrosis, endothelial dysfunction, and gut dysbiosis. Lastly, potential biomarkers were evaluated for the diagnosis of SSc, the identification of the dcSSc subtype, pulmonary arterial hypertension, and interstitial lung disease. These potential biomarkers are within amino acids, nucleotides, carboxylic acids, and carbohydrate metabolism. Discussion: The altered metabolite mechanisms identified in this study mostly point to perturbations in amino acid-related pathways, fatty acid beta-oxidation, and in the tricarboxylic acid cycle, possibly associated with inflammation, vascular damage, fibrosis, and gut dysbiosis. Further studies in targeted metabolomics are required to evaluate potential biomarkers for diagnosis, prognosis, and treatment response.

Molecular Impact of Conventional and Electronic Cigarettes on Pulmonary Surfactant

The alveolar epithelium is covered by a non-cellular layer consisting of an aqueous hypophase topped by pulmonary surfactant, a lipo-protein mixture with surface-active properties. Exposure to cigarette smoke (CS) affects lung physiology and is linked to the development of several diseases. The macroscopic effects of CS are determined by several types of cell and molecular dysfunction, which, among other consequences, lead to surfactant alterations. The purpose of this review is to summarize the published studies aimed at uncovering the effects of CS on both the lipid and protein constituents of surfactant, discussing the molecular mechanisms involved in surfactant homeostasis that are altered by CS. Although surfactant homeostasis has been the topic of several studies and some molecular pathways can be deduced from an analysis of the literature, it remains evident that many aspects of the mechanisms of action of CS on surfactant homeostasis deserve further investigation.

Multi-omic assessment shows dysregulation of pulmonary and systemic immunity to e-cigarette exposure

Electronic cigarette (Ecig) use has become more common, gaining increasing acceptance as a safer alternative to tobacco smoking. However, the 2019 outbreak of Ecig and Vaping-Associated Lung Injury (EVALI) alerted the community to the potential for incorporation of deleterious ingredients such as vitamin E acetate into products without adequate safety testing. Understanding Ecig induced molecular changes in the lung and systemically can provide a path to safety assessment and protect consumers from unsafe formulations. While vitamin E acetate has been largely removed from commercial and illicit products, many Ecig products contain additives that remain largely uncharacterized. In this study, we determined the lung-specific effects as well as systemic immune effects in response to exposure to a common Ecig base, propylene glycol and vegetable glycerin (PGVG), with and without a 1% addition of phytol, a diterpene alcohol that has been found in commercial products. We exposed animals to PGVG with and without phytol and assessed metabolite, lipid, and transcriptional markers in the lung. We found both lung-specific as well as systemic effects in immune parameters, metabolites, and lipids. Phytol drove modest changes in lung function and increased splenic CD4 T cell populations. We also conducted multi-omic data integration to better understand early complex pulmonary responses, highlighting a central enhancement of acetylcholine responses and downregulation of palmitic acid connected with conventional flow cytometric assessments of lung, systemic inflammation, and pulmonary function. Our results demonstrate that Ecig exposure not only leads to changes in pulmonary function but also affects systemic immune and metabolic parameters.

The Role of Pulmonary Surfactant Phospholipids in Fibrotic Lung Diseases

Diffuse parenchymal lung diseases (DPLD) or Interstitial lung diseases (ILD) are a heterogeneous group of lung conditions with common characteristics that can progress to fibrosis. Within this group of pneumonias, idiopathic pulmonary fibrosis (IPF) is considered the most common. This disease has no known cause, is devastating and has no cure. Chronic lesion of alveolar type II (ATII) cells represents a key mechanism for the development of IPF. ATII cells are specialized in the biosynthesis and secretion of pulmonary surfactant (PS), a lipid-protein complex that reduces surface tension and minimizes breathing effort. Some differences in PS composition have been reported between patients with idiopathic pulmonary disease and healthy individuals, especially regarding some specific proteins in the PS; however, few reports have been conducted on the lipid components. This review focuses on the mechanisms by which phospholipids (PLs) could be involved in the development of the fibroproliferative response.

Histamine activates an intracellular Ca2+ signal in normal human lung fibroblast WI-38 cells

Histamine is an inflammatory mediator that can be released from mast cells to induce airway remodeling and cause persistent airflow limitation in asthma. In addition to stimulating airway smooth muscle cell constriction and hyperplasia, histamine promotes pulmonary remodeling by inducing fibroblast proliferation, contraction, and migration. It has long been known that histamine receptor 1 (H1R) mediates the effects of histamine on human pulmonary fibroblasts through an increase in intracellular Ca2+ concentration ([Ca2+]i), but the underlying signaling mechanisms are still unknown. Herein, we exploited single-cell Ca2+ imaging to assess the signal transduction pathways whereby histamine generates intracellular Ca2+ signals in the human fetal lung fibroblast cell line, WI-38. WI-38 fibroblasts were loaded with the Ca2+-sensitive fluorophore, FURA-2/AM, and challenged with histamine in the absence and presence of specific pharmacological inhibitors to dissect the Ca2+ release/entry pathways responsible for the onset of the Ca2+ response. Histamine elicited complex intracellular Ca2+ signatures in WI-38 fibroblasts throughout a concentration range spanning between 1 µM and 1 mM. In accord, the Ca2+ response to histamine adopted four main temporal patterns, which were, respectively, termed peak, peak-oscillations, peak-plateau-oscillations, and peak-plateau. Histamine-evoked intracellular Ca2+ signals were abolished by pyrilamine, which selectively blocks H1R, and significantly reduced by ranitidine, which selectively inhibits H2R. Conversely, the pharmacological blockade of H3R and H4R did not affect the complex increase in [Ca2+]i evoked by histamine in WI-38 fibroblasts. In agreement with these findings, histamine-induced intracellular Ca2+ signals were initiated by intracellular Ca2+ release from the endoplasmic reticulum through inositol-1,4,5-trisphosphate (InsP3) receptors (InsP3R) and sustained by store-operated Ca2+ channels (SOCs). Conversely, L-type voltage-operated Ca2+ channels did not support histamine-induced extracellular Ca2+ entry. A preliminary transcriptomic analysis confirmed that WI-38 human lung fibroblasts express all the three InsP3R isoforms as well as STIM2 and Orai3, which represent the molecular components of SOCs. The pharmacological blockade of InsP3 and SOC, therefore, could represent an alternative strategy to prevent the pernicious effects of histamine on lung fibroblasts in asthmatic patients.

Mechanisms exploration of Terrestrosin D on pulmonary fibrosis based on plasma metabolomics and network pharmacology

Terrestrosin D (TED) is the active ingredient of Tribulus terrestris L., which is used in traditional Chinese medicine (TCM) formulations and has a wide range of pharmacological activities. A previous study showed that TED alleviated bleomycin (BLM)-induced pulmonary fibrosis (PF) in mice. However, the mechanisms underlying the therapeutic effect of TED are still unclear and need further investigation. In this study, we evaluated the effect of TED in a mice of BLM-induced PF in terms of histopathological and biochemical indices. UHPLC-MS-based plasma metabolomics combined with network pharmacology was used to explore the pathological basis of PF and the mechanism of action of TED. Histological and biochemical analyses showed that TED mitigated inflammatory injury in the lungs, especially at the dosage of 20 mg/kg. Furthermore, BLM changed the plasma metabolite profile in the mice, which was reversed by TED via regulation of amino acid and lipid metabolism. Subsequently, a biomarkers-targets-disease network was constructed, tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β1 were identified as the putative therapeutic targets of TED. Both factors were quantitatively analyzed by enzyme-linked immunosorbent assay (ELISA). Taken together, the combination of UHPLC-MS-based metabolomics and network pharmacology can unveil the mechanisms of diseases and drug action.

Changes in Plasma Phospholipid Metabolism Are Associated with Clinical Manifestations of Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease with fibrosis of the skin and/or internal organs, causing a decrease in quality of life and survival. There is no causative therapy, and the pathophysiology of the SSc remains unclear. Studies showed that lipid metabolism was relevant for autoimmune diseases, but little is known about the role of lipids in SSc. In the present study, we sought to explore the phospholipid profile of SSc by using the lipidomics approach. We also aimed to analyze lipidomics results for different clinical manifestations of SSc. Experiments were performed using high-performance liquid chromatography coupled to mass spectrometry for the lipidomic profiling of plasma samples from patients with SSc. Our study showed, for the first time, significant changes in the level of phospholipids such as plasmalogens and sphingomyelins from the plasma of SSc patients as compared to controls. Phosphatidylcholine plasmalogens species and sphingomyelins were significantly increased in SSc patients as compared to controls. Our results also demonstrated a significant association of changes in the metabolism of phospholipids (phosphatidylcholine and phosphatidylethanolamine plasmalogens species and sphingomyelins) with different clinical manifestations of SSc. Further lipidomic studies might lead to the detection of lipids as new biomarkers or therapeutic targets of SSc.

Hypoxia in Cancer and Fibrosis: Part of the Problem and Part of the Solution

Adaptive responses to hypoxia are involved in the progression of lung cancer and pulmonary fibrosis. However, it has not been pointed out that hypoxia may be the link between these diseases. As tumors or scars expand, a lack of oxygen results in the activation of the hypoxia response, promoting cell survival even during chronic conditions. The role of hypoxia-inducible factors (HIFs) as master regulators of this adaptation is crucial in both lung cancer and idiopathic pulmonary fibrosis, which have shown the active transcriptional signature of this pathway. Emerging evidence suggests that interconnected feedback loops such as metabolic changes, fibroblast differentiation or extracellular matrix remodeling contribute to HIF overactivation, making it an irreversible phenomenon. This review will focus on the role of HIF signaling and its possible overlapping in order to identify new opportunities in therapy and regeneration.

Calcium Regulation on the Atrial Regional Difference of Collagen Production Activity in Atrial Fibrogenesis

Background: Atrial fibrosis plays an important role in the genesis of heart failure and atrial fibrillation. The left atrium (LA) exhibits a higher level of fibrosis than the right atrium (RA) in heart failure and atrial arrhythmia. However, the mechanism for the high fibrogenic potential of the LA fibroblasts remains unclear. Calcium (Ca²⁺) signaling contributes to the pro-fibrotic activities of fibroblasts. This study investigated whether differences in Ca²⁺ homeostasis contribute to differential fibrogenesis in LA and RA fibroblasts. Methods: Ca²⁺ imaging, a patch clamp assay and Western blotting were performed in isolated rat LA and RA fibroblasts. Results: The LA fibroblasts exhibited a higher Ca²⁺ entry and gadolinium-sensitive current compared with the RA fibroblasts. The LA fibroblasts exhibited greater pro-collagen type I, type III, phosphorylated Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), phosphorylated phospholipase C (PLC), stromal interaction molecule 1 (STIM1) and transient receptor potential canonical (TRPC) 3 protein expression compared with RA fibroblasts. In the presence of 1 mmol/L ethylene glycol tetra-acetic acid (EGTA, Ca²⁺ chelator), the LA fibroblasts had similar pro-collagen type I, type III and phosphorylated CaMKII expression compared with RA fibroblasts. Moreover, in the presence of KN93 (a CaMKII inhibitor, 10 μmol/L), the LA fibroblasts had similar pro-collagen type I and type III compared with RA fibroblasts. Conclusion: The discrepancy of phosphorylated PLC signaling and gadolinium-sensitive Ca²⁺ channels in LA and RA fibroblasts induces different levels of Ca²⁺ influx, phosphorylated CaMKII expression and collagen production.

Development of an optimized and scalable method for isolation of umbilical cord blood-derived small extracellular vesicles for future clinical use

Extracellular vesicles (EV) are a promising therapeutic tool in regenerative medicine. These particles were shown to accelerate wound healing, through delivery of regenerative mediators, such as microRNAs. Herein we describe an optimized and upscalable process for the isolation of EV smaller than 200 nm (sEV), secreted by umbilical cord blood mononuclear cells (UCB-MNC) under ischemic conditions and propose quality control thresholds for the isolated vesicles, based on the thorough characterization of their protein, lipid and RNA content. Ultrafiltration and size exclusion chromatography (UF/SEC) optimized methodology proved superior to traditional ultracentrifugation (UC), regarding production time, standardization, scalability, and vesicle yield. Using UF/SEC, we were able to recover approximately 400 times more sEV per mL of media than with UC, and upscaling this process further increases EV yield by about 3-fold. UF/SEC-isolated sEV display many of the sEV/exosomes classical markers and are enriched in molecules with anti-inflammatory and regenerative capacity, such as hemopexin and miR-150. Accordingly, treatment with sEV promotes angiogenesis and extracellular matrix remodeling, in vitro. In vivo, UCB-MNC-sEV significantly accelerate skin regeneration in a mouse model of delayed wound healing. The proposed isolation protocol constitutes a significant improvement compared to UC, the gold-standard in the field. Isolated sEV maintain their regenerative properties, whereas downstream contaminants are minimized. The use of UF/SEC allows for the standardization and upscalability required for mass production of sEV to be used in a clinical setting.

Impact of the gut microbiota on heat stroke rat mediated by Xuebijing metabolism

The goal of the present study was to evaluate the fecal microbiome and serum metabolites in Xuebijing (XBJ)-injected rats after heat stroke using 16S rRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS) metabolomics. Eighteen rats were divided into the control group (CON), heat stroke group (HS), and XBJ group. The 16S rRNA gene sequencing results revealed that the abundance of Bacteroidetes was overrepresented in the XBJ group compared to the HS group, while Actinobacteria was underrepresented. Metabolomic profiling showed that the pyrimidine metabolism pathway, pentose phosphate pathway, and glycerophospholipid metabolism pathway were upregulated in the XBJ group compared to the HS group. Taken together, these results demonstrated that heat stroke not only altered the gut microbiome community structure of rats but also greatly affected metabolic functions, leading to gut microbiome toxicity.

Metabolic changes induced by TGF-β1 via reduced expression of phosphatidylserine decarboxylase during myofibroblast transition

Metabolic alteration is increasingly recognized as an important pathogenic process that underlies fibrosis across many organ types, and metabolically targeted therapies could become important strategies for reducing fibrosis. In present study, target enzymes that are involved in changes in phospholipid metabolism during fibroblast-to-myofibroblast transition induced by transforming growth factor beta 1 (TGF-β1) were examined. Different amounts of phospholipids were found in the 2 groups. In response to TGF-β1 stimulation, 17 lipids decreased and 17 increased. The latter included the phospholipids phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE). Furthermore, among the rate-limiting enzymes that regulate these phospholipids, phosphatidylserine decarboxylase (PISD), which controls conversion of PS to PE and is localized in mitochondria, decreased in response to TGF-β1. Knockdown of PISD alone without TGF-β1 stimulation increased expression of α-smooth muscle actin mRNA and production of total collagen. Taken together, these results indicate that PISD is involved in the mechanism of fibrogenesis by regulating phospholipid metabolism.

Lipid Mediators Regulate Pulmonary Fibrosis: Potential Mechanisms and Signaling Pathways

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease of unknown etiology characterized by distorted distal lung architecture, inflammation, and fibrosis. The molecular mechanisms involved in the pathophysiology of IPF are incompletely defined. Several lung cell types including alveolar epithelial cells, fibroblasts, monocyte-derived macrophages, and endothelial cells have been implicated in the development and progression of fibrosis. Regardless of the cell types involved, changes in gene expression, disrupted glycolysis, and mitochondrial oxidation, dysregulated protein folding, and altered phospholipid and sphingolipid metabolism result in activation of myofibroblast, deposition of extracellular matrix proteins, remodeling of lung architecture and fibrosis. Lipid mediators derived from phospholipids, sphingolipids, and polyunsaturated fatty acids play an important role in the pathogenesis of pulmonary fibrosis and have been described to exhibit pro- and anti-fibrotic effects in IPF and in preclinical animal models of lung fibrosis. This review describes the current understanding of the role and signaling pathways of prostanoids, lysophospholipids, and sphingolipids and their metabolizing enzymes in the development of lung fibrosis. Further, several of the lipid mediators and enzymes involved in their metabolism are therapeutic targets for drug development to treat IPF.

Lipids - two sides of the same coin in lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive extracellular matrix deposition in the lung parenchyma leading to the destruction of lung structure, respiratory failure and premature death. Recent studies revealed that the pathogenesis of IPF is associated with alterations in the synthesis and the activity of lipids, lipid regulating proteins and cell membrane lipid transporters and receptors in different lung cells. Furthermore, deregulated lipid metabolism was found to contribute to the profibrotic phenotypes of lung fibroblasts and alveolar epithelial cells. Consequently, several pharmacological agents, targeting lipids, lipid mediators, and lipoprotein receptors, was successfully tested in the animal models of lung fibrosis and entered early phase clinical trials. In this review, we highlight new therapeutic options to counteract disturbed lipid hemostasis in the maladaptive lung remodeling.