Exosomal secreted SCIMP regulates communication between macrophages and neutrophils in pneumonia

Plasma-derived extracellular vesicles prime alveolar macrophages for autophagy and ferroptosis in sepsis-induced acute lung injury

Sepsis-induced acute respiratory distress syndrome (ARDS) is a severe complication of sepsis and the leading cause of mortality. Although the role of alveolar macrophages (AMs) in stabilizing pulmonary homeostasis is well established, the effects of circulating extracellular vesicles (EVs) on AMs remain largely unknown. In this study, an investigation was conducted to map the miRNA and protein expression profiles of EVs derived from septic plasma. Notably, EV-based panels (miR-122-5p, miR-125b-5p, miR-223-3p, OLFM4, and LCN2) have been found to be associated with the severity or prognosis of sepsis, with promising AUC values. Moreover, the levels of LCN2, miR-122-5p, and miR-223-3p were identified as independent predictors of septic ARDS. The in vitro coculture results revealed that the effects of LPS-EVs from the plasma of sepsis-induced acute lung injury (ALI), which carry pro-inflammatory EVs, were partly mediated by miR-223-3p, as evidenced by the promotion of inflammation, autophagy and ferroptosis in AMs. Mechanistically, the upregulation of miR-223-3p in LPS-EVs triggers autophagy and ferroptosis in AMs by activating Hippo signaling via the targeting of MEF2C. In vivo, the inhibition of miR-223-3p effectively mitigated LPS-EV-induced inflammation and AM death in the lungs, as well as histological lesions. Overall, miR-223-3p in LPS-EVs contributes to sepsis-induced ALI by priming AMs for autophagy and ferroptosis through the MEF2C/Hippo signaling pathway. These findings suggest a novel mechanism of plasma-AM interaction in sepsis-induced ALI, offering a plausible strategy for assessing septic progression and treating lung injury.

Gene Regulation of Neutrophils Mediated Liver and Lung Injury through NETosis in Acute Pancreatitis

Acute pancreatitis (AP) is one of the most common gastrointestinal emergencies, often resulting in self-digestion, edema, hemorrhage, and even necrosis of pancreatic tissue. When AP progresses to severe acute pancreatitis (SAP), it often causes multi-organ damage, leading to a high mortality rate. However, the molecular mechanisms underlying SAP-mediated organ damage remain unclear. This study aims to systematically mine SAP data from public databases and combine experimental validation to identify key molecules involved in multi-organ damage caused by SAP. Retrieve transcriptomic data of mice pancreatic tissue for AP, lung and liver tissue for SAP, and corresponding normal tissue from the Gene Expression Omnibus (GEO) database. Conduct gene differential analysis using Limma and DEseq2 methods. Perform enrichment analysis using the clusterProfiler package in R software. Score immune cells and immune status in various organs using single-sample gene set enrichment analysis (ssGSEA). Evaluate mRNA expression levels of core genes using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Validate serum amylase, TNF-α, IL-1β, and IL-6 levels in peripheral blood using enzyme-linked immunosorbent assay (ELISA), and detect the formation of neutrophil extracellular traps (NETs) in mice pancreatic, liver, and lung tissues using immunofluorescence. Differential analysis reveals that 46 genes exhibit expression dysregulation in mice pancreatic tissue for AP, liver and lung tissue for SAP, as well as peripheral blood in humans. Functional enrichment analysis indicates that these genes are primarily associated with neutrophil-related biological processes. ROC curve analysis indicates that 12 neutrophil-related genes have diagnostic potential for SAP. Immune infiltration analysis reveals high neutrophil infiltration in various organs affected by SAP. Single-cell sequencing analysis shows that these genes are predominantly expressed in neutrophils and macrophages. FPR1, ITGAM, and C5AR1 are identified as key genes involved in the formation of NETs and activation of neutrophils. qPCR and IHC results demonstrate upregulation of FPR1, ITGAM, and C5AR1 expression in pancreatic, liver, and lung tissues of mice with SAP. Immunofluorescence staining shows increased levels of neutrophils and NETs in SAP mice. Inhibition of NETs formation can alleviate the severity of SAP as well as the levels of inflammation in the liver and lung tissues. This study identified key genes involved in the formation of NETs, namely FPR1, ITGAM, and C5AR1, which are upregulated during multi-organ damage in SAP. Inhibition of NETs release effectively reduces the systemic inflammatory response and liver-lung damage in SAP. This research provides new therapeutic targets for the multi-organ damage associated with SAP.

Exosomes of different cellular origins: prospects and challenges in the treatment of acute lung injury after burns

Acute lung injury (ALI) is a critical clinical disease caused by direct factors (inhalation injury, gastroesophageal reflux, etc.) or indirect factors (including infection, sepsis, burn, shock, trauma, acute pancreatitis, fat embolism, drug overdose, etc.). ALI is characterized mainly by diffuse interstitial and alveolar edema caused by an uncontrolled inflammatory response and damage to the alveoli-capillary barrier and has very high morbidity and mortality rates. Currently, there is no effective treatment strategy other than mechanical ventilation, fluid management or other supportive treatments. Exosomes are nanovesicle-like vesicles with double-membrane structures detached from the cell membrane or secreted by cells. These vesicles can be used as drug carriers because of their unique biological properties, such as anti-inflammatory, anti-apoptotic, pro-cell growth and immunomodulatory functions, and have been applied in the treatment of ALI in recent years. In this study, the mechanism and pathophysiological characteristics of ALI were first systematically described. The different cellular sources and characteristics of exosomes are summarized, and their functions and value as drug carriers in the treatment of ALI are discussed, as are the challenges that may be faced in the treatment of ALI with exosomes.

Cell-cell crosstalk in the pathogenesis of acute lung injury and acute respiratory distress syndrome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are the result of an exaggerated inflammatory response triggered by a variety of pulmonary and systemic insults. The lung tissues are comprised of a variety of cell types, including alveolar epithelial cells, pulmonary vascular endothelial cells, macrophages, neutrophils, and others. There is mounting evidence that these diverse cell populations within the lung interact to regulate lung inflammation in response to both direct and indirect stimuli. The aim of this review is to provide a summary and discussion of recent advances in the understanding of the importance of cell-cell crosstalk in the pathogenesis of ALI/ARDS, with a specific focus on the cell-cell interactions that may offer prospective therapeutic avenues for ALI/ARDS.

β-Catenin disruption decreases macrophage exosomal α-SNAP and impedes Treg differentiation in acute liver injury

Hepatic macrophages and regulatory T cells (Tregs) play an important role in the maintenance of liver immune homeostasis, but the mechanism by which hepatic macrophages regulate Tregs in acute liver injury remains largely unknown. Here, we found that the hepatic Treg proportion and β-catenin expression in hepatic macrophages were associated with acetaminophen- and d-galactosamine/LPS-induced acute liver injury. Interestingly, β-catenin was markedly upregulated only in infiltrating macrophages but not in resident Kupffer cells. Myeloid-specific β-catenin-knockout mice showed an increased inflammatory cell infiltration and hepatocyte apoptosis. Moreover, myeloid β-catenin deficiency decreased the hepatic Treg proportion in the injured liver. Mechanistically, in vitro coculture experiments revealed that macrophage β-catenin modulated its exosome composition and influenced Treg differentiation. Using mass spectrometry-based proteomics, we identified that macrophage β-catenin activation increased the level of exosomal alpha soluble NSF attachment protein (α-SNAP), which in turn promoted Treg differentiation. Overall, our findings demonstrated a molecular mechanism that macrophage β-catenin regulated the Treg proportion in the liver by enhancing the expression of exosomal α-SNAP, providing insights into the pathophysiology of acute liver injury.

Dual-Aptamer Recognition of DNA Logic Gate Sensor-Based Specific Exosomal Proteins for Ovarian Cancer Diagnosis

Clinical diagnosis of ovarian cancer lacks high accuracy due to the weak selection of specific biomarkers along with the circumstance biomarkers localization. Clustering analysis of proteins transported on exosomes enables a more precise screening of effective biomarkers. Herein, through bioinformatics analysis of ovarian cancer and exosome proteomes, two coexpressed proteins, EpCAM and CD24, specifically enriched, were identified, together with the development of an as-derived dual-aptamer targeted exosome-based strategy for ovarian cancer screening. In brief, a DNA ternary polymer with aptamers targeting EpCAM and CD24 was designed to present a logic gate reaction upon recognizing ovarian cancer exosomes, triggering a rolling circle amplification chemiluminescent signal. A dynamic detection range of 6 orders of magnitude was achieved by quantifying exosomes. Moreover, for clinical samples, this strategy could accurately differentiate exosomes from healthy persons, other cancer patients, and ovarian cancer patients, enabling promising in situ detection. By accurately selecting biomarkers and constructing a dual-targeted exosomal protein detection strategy, the limitation of insufficient specificity of traditional protein markers was circumvented. This work contributed to the development of exosome-based prognosis monitoring in ovarian cancer through the identification of disease-specific exosome protein markers.