Correction to “Luteolin Regulates the Differentiation of Regulatory T Cells and Activates IL‐10‐Dependent Macrophage Polarization against Acute Lung Injury”

Alveolar macrophage polarization and role on alveolar repair during human acute respiratory distress syndrome remain unclear. This study aimed to determine during human acute respiratory distress syndrome: the alveolar macrophage polarization, the effect of alveolar environment on macrophage polarization, and the role of polarized macrophages on epithelial repair. Experimental ex vivo and in vitro investigations. Four ICUs in three teaching hospitals. Thirty-three patients with early moderate-to-severe acute respiratory distress syndrome were enrolled for assessment of the polarization of alveolar macrophages. Polarization of acute respiratory distress syndrome macrophages was studied by flow cytometry and quantitative polymerase chain reaction. Modulation of macrophage polarization was studied in vitro using phenotypic and functional readouts. Macrophage effect on repair was studied using alveolar epithelial cells in wound healing models. Ex vivo, alveolar macrophages from early acute respiratory distress syndrome patients exhibited anti-inflammatory characteristics with high CD163 expression and interleukin-10 production. Accordingly, early acute respiratory distress syndrome-bronchoalveolar lavage fluid drives an acute respiratory distress syndrome-specific anti-inflammatory macrophage polarization in vitro, close to that induced by recombinant interleukin-10. Culture supernatants from macrophages polarized in vitro with acute respiratory distress syndrome-bronchoalveolar lavage fluid or interleukin-10 and ex vivo acute respiratory distress syndrome alveolar macrophages specifically promoted lung epithelial repair. Inhibition of the hepatocyte growth factor pathway in epithelial cells and hepatocyte growth factor production in macrophages both reversed this effect. Finally, hepatocyte growth factor and soluble form of CD163 concentrations expressed relatively to macrophage count were higher in bronchoalveolar lavage fluid from acute respiratory distress syndrome survivors. Early acute respiratory distress syndrome alveolar environment drives an anti-inflammatory macrophage polarization favoring epithelial repair through activation of the hepatocyte growth factor pathway. These results suggest that macrophage polarization may be an important step for epithelial repair and acute respiratory distress syndrome recovery.

Alveolar macrophage (AM) polarization plays a pivotal role in the inflammatory response during acute lung injury (ALI). As reported previously, vasodilator-stimulated phosphoprotein (VASP) may function as an anti-inflammatory agent in hepatic tissues. However, the specific role of VASP in ALI-induced macrophage polarization remains unclear. To elucidate the role of VASP in ALI, we established a lipopolysaccharide (LPS)-induced M1 polarization model of MH-S cells. RNA sequencing was performed to identify differentially expressed genes during macrophage polarization. The results revealed significant upregulation of the VASP gene. Subsequently, VASP gene knockdown in the lungs was achieved by intratracheal delivery of VASP-AAV6, and the resulting ALI symptoms and macrophage polarization were assessed. The VASP gene was also knocked down in MH-S cells; these cells were then stimulated with LPS for 24h, and polarization-related markers of macrophages were analyzed. Finally, to validate the involvement of the PKG-VASP signaling pathway, experiments were conducted with a PKG agonist (8-Br-cGMP) and inhibitor (KT5823), and the effects of modulating the PKG-VASP pathway on macrophage polarization were investigated. VASP knockdown notably ameliorated ALI symptoms in these mice with LPS-induced ALI. Additionally, in vitro experiments showed that the PKG-VASP signaling pathway plays a pivotal role in macrophage polarization. VASP knockdown protected mice from LPS-induced ALI by inhibiting M1 polarization, and its protective effects were partially mediated by the cGMP-PKG signaling pathway.

BackgroundUncontrolled inflammation caused by macrophages and monocytes plays a crucial role in worsening acute respiratory distress syndrome (ARDS). Previous studies have highlighted the importance of IFIH1 in regulating macrophage polarisation in ARDS triggered by pneumonia. However, the mechanisms by which IFIH1 is activated in ARDS remain unclear.MethodsIn this study, we utilised multiomics sequencing and molecular interaction experiments to explore the molecular mechanisms underlying IFIH1 activation in ARDS. Through the use of conditional gene knockout mice and primary cells, we demonstrated the significant role of these mechanisms in the development of ARDS. Additionally, we validated the associations between these mechanisms and ARDS by quantitative PCR analysis of CD14+ cells obtained from the peripheral blood of 140 ARDS patients.ResultsOur investigation revealed that lipopolysaccharide, a critical component derived from Gram‐negative bacteria, activated IFIH1 by upregulating a novel transcript known as IFIH1‐binding RNA1 (IBR1) in monocytes and macrophages. Specifically, as an endogenous double‐stranded RNA, IBR1 bind to the helicase domain of IFIH1 because of its unique double‐stranded structure. Deletion of IBR1 significantly reduced the activation of IFIH1, M1 polarisation of macrophages, and inflammatory lung injury in ARDS. Moreover, IBR1 directly induced M1 polarisation of macrophages and ARDS, whereas deletion of IFIH1 inhibited IBR1‐induced macrophage M1 polarisation and inflammatory lung injury. Importantly, we observed a notable increase in IBR1 expression in ARDS patients with pneumonia caused by Gram‐negative bacteria. Furthermore, we demonstrated that the delivery of IFIH1 mutants through exosomes effectively counteracted IBR1, thereby reducing pulmonary inflammation and alleviating lung injury.ConclusionsThis study revealed a novel mechanism involving IBR1, an endogenous double‐stranded RNA (dsRNA) that binds to IFIH1, shedding light on the complex process of macrophage polarisation in ARDS. The administration of IFIH1 variants has the potential to eliminate pulmonary dsRNA and alleviate inflammatory lung injury in ARDS.HighlightsIn monocytes and macrophages, the endogenous double‐stranded RNA, IFIH1‐binding RNA 1 (IBR1), binds to the helicase domain of IFIH1 because of its unique double‐stranded structure.IBR1 plays a significant role in macrophage polarisation and the development of acute respiratory distress syndrome (ARDS) induced by Gram‐negative bacteria or lipopolysaccharide (LPS).Administration of IFIH1 variants has potential for eliminating pulmonary IBR1 and reducing inflammatory lung injury in ARDS patients.

Objective To investigate the expression and function of tumor necrosis factor receptor-1 (TNFR-1) and caveolin-1 (Cav-1) in the lung of acute pancreatitis-associated lung injury rats, and to determine the potential role of Qingyitang. Methods Wistar rats were randomly divided into sham operation (SHAM) group, acute lung injury (ALI) group, dexamethasone (DEX) group and Qingyitang (QYT)group. ALI was induced by retrograde injection of deoxycholate into biliopancreatic duct of rats. Blood and lung tissues were drawn after 24 h. Serum amylase, lung wet/dry (W/D) ratio and pathological section were examined to evaluate the degree of lung injury. Immunoradioassay was used to detect serum tumor necrosis factor-α (TNF-α). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were applied to detect the expression levels of TNFR-1 and Cav-1 mRNA and protein respectively. Results The concentration of serum amylase, the W/D ratio, TNF-α (4.82 ± 0.14 vs 2.96 ± 0. 30, P ＜0. 01 ) and the degree of pathological lung injury were obviously increased in ALI rats. The expression of TNFR-1 mRNA was increased in ALI rats (1.29 ±0. 15 vs 0.43 ±0.05,P＜0.01), but Cav-1 mRNA expression was decreased ( 1.14 ±0. 10 vs 2.00 ±0. 10,P ＜0.01 ). The expression of TNFR-1 protein in both lipid rafts and non-lipid rafts was increased, but that of Cav-1 in both of the two fractions was decreased. As compared with ALI rats, the concentration of serum amylase, W/D ratio, TNF-αt ( DEX: 3.79 ± 0. 11,QYT: 3.66 ±0. 10, ALI: 4.82 ±0. 14,P ＜0.01 ) and the degree of pathological lung injury were obviously decreased in DEX and QYT rats. The expression of TNFR-1 mRNA was decreased in both DEX and QYT groups (DEX: 0.48±0.01, QYT: 0.49 ±0.02, ALI: 1.29 ±0. 15,P＜0.01), but that of Cav-1 mRNA was up-regulated (DEX: 1.66 ±0.06, QYT: 1.52 ±0.04, ALI: 1.14 ±0. 10,P＜0.01). The expression of TNFR-1 protein in both lipid rafts and non-lipid rafts was decreased, but that of Cav-1 protein was increased.Conclusion The up-regulated expression of TNF-α/TNFR-1 and the down-regulated expression of Cav-1 suggest that both of them may play an important role in acute pancreatitis-associated lung injury. DEX and QYT may relieve lung injury effectively by regulating the expression of TNFR-1 and Cav-1. Key words: Acute pancreatitis; Acute lung injury; TNFR-1; Caveolin-1

Baicalein ameliorates high-altitude hypoxic lung injury via macrophage polarization remodeling by downregulating ALOX15 pathway in ferroptosis.

Acute lung injury (ALI) is a common clinical critical disease, with a high mortality. The imbalance of alveolar macrophage (AMs) polarization plays an important role in the occurrence and development of ALI inflammation. The study of the regulation mode and mechanism of macrophage polarization can provide more theoretical basis for clinical prevention and treatment of ALI. In recent years, it has been found that epigenetics and immune metabolic microenvironment can affect the macrophage polarization and the immune inflammatory response of ALI. In this review, the progress of macrophage polarization, epigenetics and immune metabolism regulating macrophage polarization, the relationship between macrophage polarization and ALI were summarized, so as to clarify the effect and significance of regulating macrophage polarization on ALI, and provide new ideas for the prevention and treatment of ALI in clinic.

To determine the role of matrix metalloproteinase-8 (MMP-8) in acute lung injury (ALI), we delivered LPS or bleomycin by the intratracheal route to MMP-8(-/-) mice versus wild-type (WT) mice or subjected the mice to hyperoxia (95% O(2)) and measured lung inflammation and injury at intervals. MMP-8(-/-) mice with ALI had greater increases in lung polymorphonuclear neutrophils (PMNs) and macrophage counts, measures of alveolar capillary barrier injury, lung elastance, and mortality than WT mice with ALI. Bronchoalveolar lavage fluid (BALF) from LPS-treated MMP-8(-/-) mice had more MIP-1alpha than BALF from LPS-treated WT mice, but similar levels of other pro- and anti-inflammatory mediators. MIP-1alpha(-/-) mice with ALI had less acute lung inflammation and injury than WT mice with ALI, confirming that MIP-1alpha promotes acute lung inflammation and injury in mice. Genetically deleting MIP-1alpha in MMP-8(-/-) mice reduced the increased lung inflammation and injury and mortality in MMP-8(-/-) mice with ALI. Soluble MMP-8 cleaved and inactivated MIP-1alpha in vitro, but membrane-bound MMP-8 on activated PMNs had greater MIP-1alpha-degrading activity than soluble MMP-8. High levels of membrane-bound MMP-8 were detected on lung PMNs from LPS-treated WT mice, but soluble, active MMP-8 was not detected in BALF samples. Thus, MMP-8 has novel roles in restraining lung inflammation and in limiting alveolar capillary barrier injury during ALI in mice by inactivating MIP-1alpha. In addition, membrane-bound MMP-8 on activated lung PMNs is likely to be the key bioactive form of the enzyme that limits lung inflammation and alveolar capillary barrier injury during ALI.

to investigate the expression and location of caveolin-1 (Cav-1), aquaporin 1 (AQP1) and AQP5 in the lung of acute pancreatitis-associated lung injury rats and to determine the role of these molecules in the pathologic progress and the potential therapeutic mechanisms of Qingyitang. forty Wistar rats were randomly divided into sham operation (SHAM) group, acute lung injury (ALI) group, dexamethasone (DEX) group and Qingyitang (QYT) group. ALI was induced by reverse injection of deoxycholate into biliopancreatic duct of rats. Blood and lung tissues were collected after 24 h. Serum amylase, lung wet/dry (W/D) ratio and pathological section were detected to evaluate the degree of lung injury. reverse transcription-polymerase chain reaction was taken to detect the mRNA levels of Cav-1, AQP1 and AQP5. Lipid rafts were prepared for detection of the distribution and expression level of Cav-1, AQP1 and AQP5 proteins by Western blot. the concentration of serum amylase, the value of W/D and the degree of pathological lung injury obviously increased in ALI rats. Cav-1, AQP1 and AQP5 were present in the lung while the mRNA level decreased in ALI rats. Cav-1 appeared mainly in lipid rafts and less in non-lipid rafts. AQP1 was localized to lipid rafts while AQP5 to non-lipid rafts. The localization of these three molecules in the lung of ALI rats did not change compared with SHAM rats while their protein levels decreased. Compared with ALI rats, the concentration of serum amylase, the value of W/D and the degree of pathological lung injury obviously decreased in DEX and QYT rats. The mRNA and the protein expression of Cav-1, AQP1 and AQP5 increased in various degrees by DEX or QYT treatment. Cav-1 and AQP1 are enriched in lipid rafts while AQP5 in non-lipid rafts. The down-regulated expression of these three molecules may play important role in acute pancreatitis-associated lung injury. DEX and QYT may relieve lung injury effectively by up-regulating the expressions of Cav-1, AQP1 and AQP5.

COUNTERPOINT: Should Corticosteroids Be Routine Treatment in Early ARDS? No

Pyroptosis and polarization are significant contributors to the onset and development of many diseases. At present, the relationship between pyroptosis and polarization in acute lung injury (ALI) caused by sepsis remains unclear. The ALI model for sepsis was created in mice and categorized into the blank control, lipopolysaccharide(LPS) group, LPS + low-dose Belnacasan group, LPS + high-dose Belnacasan group, LPS + low-dose Wedelolactone group, LPS + high-dose Wedelolactone group, and positive control group. The wet-dry specific gravity was evaluated to compare pulmonary edema. Hematoxylin-eosin, Masson, and terminal deoxynucleotidyl transferase dUTP nick end labelingstaining techniques were conducted to observe and contrast the pathological changes in lung tissue. ELISA was utilized to identify M1 and M2 macrophages and correlated inflammatory factors. Immunohistochemical staining and flow cytometry were employed to identify markers of M1 and M2 macrophages in lung tissue. Propidium iodidestaining, together with flow cytometry, was utilized to observe the degree and positive rate of pyroptosis of alveolar macrophages. Western blot analysis was conducted to detect the expression levels of Caspase 1, Caspase 11, GSDMD, and IL-18 in the lung tissues of each group. The real-time quantitative polymerase chain reactionmethod was used to ascertain relative expression levels of NLRP3, Caspase 1, Caspase 11, GSDMD, IL-18, iNOS, and Arg-1 in lung tissues of all groups. In mice with sepsis-induced ALI, both classical and nonclassical pathways of pyroptosis are observed. Inhibiting pyroptosis has been found to ameliorate lung injury, pulmonary edema, and inflammation induced by LPS. Notably, the expression of NLRP3, Caspase 1, Caspase 11, GSDMD, IL-1β, IL-18, TGF-β, CD86, CD206, iNOS, and Arg-1 were all altered in this process. Additionally, alveolar macrophages were polarized along with pyroptosis in mice with ALI caused by sepsis. Pyroptosis of alveolar macrophages in the context of ALI in mice infected with sepsis has been linked to the polarization of alveolar macrophages towardtype M1.

Acute lung injury (ALI) is characterized by damage to the alveoli and an overabundance of inflammation. Representing a serious inflammatory condition, ALI lacks a precise treatment approach. Despite the recognized benefit impacts of Fibroblast growth factor-10 (FGF10) on ALI, the underlying mechanisms remain unelucidated. To study the role of FGF10 in ALI, C57BL/6J mice were intratracheally injected with 5mg/kg Lipopolysaccharide (LPS) with FGF10 (5mg/kg) or an equal volume of PBS. Inflammatory factors were quantified in bronchoalveolar lavage fluid (BALF) and plasma using ELISA. RNA sequencing of F4/80+Ly6G- macrophages in BALF explored changes in macrophage phenotype and potential mechanisms. Macrophage polarization in BALF was assessed using qRT-PCR, flow cytometry, and Western blot analysis. In vitro, a Transwell co-culture of mouse lung epithelial cells (MLE12) and bone marrow macrophages (BMDM) validated the role of FGF10 in modulating LPS-induced macrophage phenotypic changes. FGF10 ameliorated LPS-induced ALI by diminishing pro-inflammatory factors (IL-1β, TNF-α, and IL-6) and the neutrophil accumulation in BALF. FGF10 also increased the levels of anti-inflammatory factor IL-10. The FGF10 intervention group exhibited enhanced gene expression of macrophage arginine biosynthesis marker (ARG1), and expression of M2-type marker CD206 in monocytes and macrophages. In addition, phosphorylated STAT3 expression increased in isolated monocyte-derived macrophages. Experiments in vitro confirmed that FGF10 could elevate macrophage M2 marker ARG1 expression through the JAK2/STAT3 pathway. FGF10 ameliorates acute LPS-induced lung injury by modulating the polarization of monocyte-derived macrophages recruited in the alveolar space to the M2 type.

The pathogenesis of sepsis-induced Acute lung injury (ALI) progresses rapidly, and no effective treatment drugs are known, resulting in a high mortality rate. NLR family pyrin domain containing 3 (NLRP3) inflammasome activation plays an important role in the pathological progression of ALI, and often coincide with the inflammatory activation and polarization of macrophages. NLR family CARD domain-containing protein 3 (NOD3) was reported protecting against sepsis-induced pulmonary pathological injury and inhibiting the inflammatory response in lung tissue. NOD3 can also inhibit NLRP3 inflammasome activation by competitively inhibiting the binding of pro-caspase-1 to apoptosis-related ASC or reducing NLRP3/cryopyrin-induced ASC speckle formation. In this study, we aimed to explore whether NOD3 decrease sepsis-induced lung injury by interfering with NLRP3 inflammasome activation and regulating alveolar macrophages (AMs) polarization. To investigate whether NOD3 reduce sepsis-induced ALI by inhibiting the activation of NLRP3 inflammasome to regulate the polarization of AMs. Sepsis-induced WT (C57BL/6) and NLRC3-/--C57BL/6 mice ALI models were established by intraperitoneal injection of lipopolysaccharide (LPS). In vitro experiments, AMs and bone marrow-derived macrophages (BMDMs) were isolated from WT and NLRC3-/- mice. Using in vivo and in vitro experiments, we found that NOD3 knockout promoted the sepsis-induced inflammatory response in lung tissue. In addition, NOD3 knockout promoted the activation of the TRAF6-NF-κB signaling pathway and the NLRP3 inflammasome in AMs, enhanced the M1-type polarization of AMs and decreased the M2-type polarization of AMs in sepsis-induced lung injury model mice. NOD3 interfered with NLRP3 inflammasome activation by inhibiting NLRP3 inflammasome assembly or negatively regulating the TRAF6-NF-κB signaling pathway, and regulating the polarization of AMs, thereby alleviating sepsis-induced lung injury.

MEF2 intervened LPS-induced acute lung injury by binding to KLF2 promoter and modulating macrophage phenotype

Shikonin ameliorated LPS-induced acute lung injury in mice via modulating MCU-mediated mitochondrial Ca2+ and macrophage polarization

Zanubrutinib ameliorates lipopolysaccharide-induced acute lung injury via regulating macrophage polarization