Background and Aims:Portal vein thrombosis (PVT) is a challenging complication in liver cirrhosis, with no currently available sensitive diagnostic markers. This study aimed to investigate the potential of neutrophil extracellular traps (NETs) and Deoxyribonuclease (DNase) as diagnostic indicators for PVT in chronic hepatitis B (CHB)-related decompensated cirrhosis. Methods:We analyzed 145 CHB-related decompensated cirrhosis patients from the Ditan study and 33 from the Changgung validation study, categorizing them based on PVT occurrence. Plasma samples were assessed for NET markers, including cell-free DNA (cfDNA) and histone-DNA complexes, along with DNase activity. Results:PVT patients exhibited elevated levels of cfDNA and histone-DNA complexes, and reduced DNase activity. This pattern persisted regardless of hepatocellular carcinoma (HCC) status. Histone-DNA levels, DNase activity, and hemoglobin were identified as independent risk factors for PVT. Receiver operating characteristic curve analysis revealed that high histone-DNA levels may serve as a potential diagnostic marker for PVT, with an area under the curve of 0.8628 in the Ditan study and 0.7521 in the Changgung study. When combined with cfDNA and DNase activity, the area under the curve improved to 0.8774 in the Ditan study and 0.7975 in the Changgung study. Conclusions:Imbalances in NET homeostasis are associated with PVT in CHB-related decompensated cirrhosis, including cases involving HCC. Histone-DNA complexes, a significant risk factor for PVT, show potential as a diagnostic marker for PVT in decompensated cirrhosis, particularly in HBV-related HCC.

Pneumocystis pneumonia (PCP) is a fungal pulmonary disease with high mortality in immunocompromised patients. Neutrophils are essential in defending against fungal infections; however, their role in PCP is controversial. Here we aim to investigate the effects of neutrophil extracellular traps (NETs) on Pneumocystis clearance and lung injury using a mouse model of PCP. Intriguingly, although neutrophils play a fundamental role in defending against fungal infections, NETs failed to eliminate Pneumocystis, but instead impaired the killing of Pneumocystis. Mechanically, Pneumocystis triggered Leukotriene B4 (LTB4)-dependent neutrophil swarming, leading to agglutinative NET formation. Blocking Leukotriene B4 with its receptor antagonist Etalocib significantly reduced the accumulation and NET release of neutrophils in vitro and in vivo, enhanced the killing ability of neutrophils against Pneumocystis, and alleviated lung injury in PCP mice. This study identifies the deleterious role of agglutinative NETs in Pneumocystis infection and reveals a new way to prevent NET formation, which provides new insights into the pathogenesis of PCP.

目的 构建肺孢子菌肺炎(Pneumocystis pneumonia,PCP)小鼠模型并进行免疫学评价.方法 采用重度联合免疫缺陷(severe combined immunodeficiency,SCID)小鼠气管滴注肺孢子菌构建PCP模型,通过实时荧光定量PCR及肺组织六胺银染色进行病原学鉴定,通过苏木素-伊红染色评估肺组织损伤程度,通过免疫荧光染色和流式细胞术进行免疫学评价.结果 模型组小鼠感染6周后,肺组织肺孢子菌rRNA拷贝数显著高于假手术组,六胺银染色可见肺孢子菌滋养体和包囊,肺组织肺泡壁增厚,肺间质增宽,大量Gr-1+中性粒细胞CD68+巨噬细胞浸润,中性粒细胞活化标志物髓过氧化物酶(myeloperoxidase,MPO)和巨噬细胞活化标志物一氧化氮合酶(inducible nitric oxide synthase,iNOS)活化水平显著升高,肺内及肺泡灌洗液的中性粒细胞和单核细胞数量及比例显著高于对照组和假手术组.结论 采用SCID小鼠进行气管滴注肺孢子菌能构建稳定的PCP小鼠模型,该模型表现出与临床相似的免疫学特征.

The pathogenesis of liver fibrosis in nonalcoholic fatty liver disease (NAFLD) remains unclear and the effective treatments have not been explored yet. The activation of hepatic stellate cells (HSCs) is the most critical factor in the progression of liver fibrosis. Macroautophagy/autophagy has recently been identified as a new mechanism to regulate HSC activation. In a recent study, we found that type 2 (M2) macrophages promote HSC autophagy by secreting prostaglandin E2 (PGE2) to bind its receptor PTGER4/EP4 on HSCs, consequently activating the MAPK/ERK pathway to promote autophagy and activation of HSCs. A specific PGE2-PTGER4 antagonist, E7046, significantly inhibits HSC autophagy and improves liver fibrosis and histopathology in NAFLD mice. Our findings provide novel mechanistic insights into liver fibrosis and suggest E7046 as a promising therapy to prevent NASH progression.

The pathogenesis of liver fibrosis in nonalcoholic fatty liver disease (NAFLD) remains unclear and the effective treatments have not been explored yet. The activation of hepatic stellate cells (HSCs) is considered as the most critical factor in the progression of liver fibrosis and cirrhosis. Autophagy has recently been identified as a new mechanism to regulate HSC activation. Here, we found that liver macrophages were polarized toward type 2 (M2) during the progression of nonalcoholic steatohepatitis (NASH) and liver fibrosis in both patients and NAFLD mice. Using the methionine–choline-deficient (MCD) diet NAFLD murine model and the in vitro cell culture system, we identified that the M2 macrophages promoted HSC autophagy by secreting prostaglandin E2 (PGE2) and binding its receptor EP4 on the surface of HSCs, which consequently enhanced HSC activation, extracellular matrix deposition, and liver fibrosis. Mechanistically, PGE2/EP4 signals enhanced HSC autophagy through the Erk pathway. A specific PGE2/EP4 antagonist E7046 significantly inhibited M2 macrophage-mediated HSC autophagy and improved liver fibrosis and histopathology in NAFLD mice. Our study provides novel mechanistic insights into the regulation of HSC activation and liver fibrosis. Our findings suggest that the PGE2/EP4 pathway is a promising therapeutic target to prevent NASH progression into cirrhosis.

The fundamental basis for the pathogenesis of sepsis is an inflammatory imbalance, which is considered to be the main target for treatment. Taurine is an intracellular free amino acid that has anti-inflammatory and antioxidant effects. To investigate the protective mechanism of taurine in sepsis, we used in vitro and in vivo experiments to explore the effects of taurine on neutrophil and monocyte immune function. Metabolomic analysis showed large amounts of taurine in neutrophils and monocytes and a dramatic decrease in taurine levels after LPS exposure. Taurine supplementation decreased the expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) in LPS-challenged neutrophils and monocytes and reduced the formation of neutrophil extracellular traps by restricting reactive oxygen species. Moreover, taurine protected septic mice from death, improved tissue injuries in the lung, liver, and kidney by reducing neutrophil infiltration and TNF-α production. Our data indicate that a supplement with taurine might be a promising therapeutic strategy for sepsis to reduce hyper inflammation and improve multi-organ dysfunctions.

Cytokine storm syndrome is a fatal condition related to infectious and autoimmune diseases. Here, we aim to investigate the regulatory mechanisms of Blimp-1 on multiple cytokine production. The Blimp1 shRNA was transfected into RAW264.7 macrophages, followed by Toll-like receptor (TLR) ligand stimulation. The mRNA and protein levels of cytokines were detected by real-time PCR and flow cytometric bead array. The nuclear translocation of AP-1 and NF-κB p65 was measured by immunofluorescence staining. The transcriptional activity was detected by luciferase reporter assay with 5 × NF-κB reporter or with IL6 promoter reporter. Blimp-1 significantly inhibited the expression and secretion of IL-1β, IL-6, and IL-18 in macrophages during stimulation with a variety of TLR ligands. The immunofluorescence staining results showed that Blimp-1 strictly controlled the nuclear translocation of NF-κB p65 in LPS-challenged macrophages. Furthermore, Blimp-1 directly inhibited the transcriptional activity of NF-κB and the transcription of IL6 gene. Blimp-1 represses the production of multiple pro-inflammatory cytokines by directly binding the genomic region and restricting the nuclear translocation and transcriptional activity of NF-κB. This finding may provide potential therapeutic strategies for the cytokine storm-related diseases.

Abstract ObjectiveCytokine storm syndrome is a fatal condition related to infectious and autoimmune diseases. Here we aim to investigate the regulatory mechanisms of Blimp-1 on cytokine storm.Methods The Blimp1 shRNA was transfected into RAW264.7 macrophages, followed by Toll-like receptor (TLR) ligand stimulation. The mRNA and protein levels of cytokines were detected by real-time PCR and flow cytometric bead array. The genomic binding sites of Blimp-1 were analyzed with chromatin immunoprecipitation-sequencing (ChIP-seq). The nuclear translocation of AP-1 and NF-κB p65 were measured by immunofluorescence staining.Results Blimp-1 significantly inhibited the expression and secretion of IL-1β, IL-6, and IL-18 in macrophages during stimulation with a variety of TLR ligands. ChIP-seq data showed that Blimp-1 stably combined with the promoters of Il1b and Tnf and the enhancers of Il6 and Il18, indicating a direct transcriptional repression of Blimp-1 on the pro-inflammatory cytokines. In addition, Blimp-1 strictly controlled nuclear translocation of NF-κB p65 in LPS-challenged macrophages, suggesting the regulatory mechanism of Blimp-1 on NF-κB activation.ConclusionBlimp-1 represses the production of multiple pro-inflammatory cytokines by directly binding the genomic region and restricting NF-κB p65 nuclear translocation. This finding may provide potential therapeutic strategies for the cytokine storm-related diseases.