Siglec-F+ neutrophils in the spleen induce immunosuppression following acute infection.

Background: The mechanisms underlying the increased mortality of secondary infections during the immunosuppressive phase of sepsis remain elusive. Objectives: We sought to investigate the role of Siglec-F+ neutrophils on splenic T lymphocytes in the immunosuppressed phase of sepsis and on secondary infection in PICS mice, and to elucidate the underlying mechanisms. Methods: We established a mouse model of sepsis-induced immunosuppression followed by secondary infection with LPS or E. coli. The main manifestation of immunosuppression is the functional exhaustion of splenic T lymphocytes. Treg depletion reagent Anti-IL-2, IL-10 blocker Anti-IL-10R, macrophage depletion reagent Liposomes, neutrophil depletion reagent Anti-Ly6G, neutrophil migration inhibitor SB225002, Siglec-F depletion reagent Anti-Siglec-F are all used on PICS mice. The function of neutrophil subsets was investigated by adoptive transplantation and the experiments in vitro. Results: Compared to other organs, we observed a significant reduction in pro-inflammatory cytokines in the spleen, accompanied by a marked increase in IL-10 production, primarily by infiltrating neutrophils. These infiltrating neutrophils in the spleen during the immunosuppressive phase of sepsis undergo phenotypic change in the local microenvironment, exhibiting high expression of neutrophil biomarkers such as Siglec-F, Ly6G, and Siglec-E. Depletion of neutrophils or specifically targeting Siglec-F leads to enhance the function of T lymphocytes and a notable improvement in the survival of mice with secondary infections. Conclusions: We identified Siglec-F+ neutrophils as the primary producers of IL-10, which significantly contributed to T lymphocyte suppression represents a novel finding with potential therapeutic implications.

Comparison of different machine learning classification models for predicting deep vein thrombosis in lower extremity fractures.

Deep vein thrombosis (DVT) is a common complication in patients with lower extremity fractures. Once it occurs, it will seriously affect the quality of life and postoperative recovery of patients. Therefore, early prediction and prevention of DVT can effectively improve the prognosis of patients. This study constructed different machine learning models to explore their effectiveness in predicting DVT. Five prediction models were applied to the study, including Extreme Gradient Boosting (XGBoost) model, Logistic Regression (LR) model, RandomForest (RF) model, Multilayer Perceptron (MLP) model, and Support Vector Machine (SVM) model. Afterwards, the performance of the obtained prediction models was evaluated by area under the curve (AUC), accuracy, sensitivity, specificity, F1 score, and Kappa. The prediction performances of the models based on machine learning are as follows: XGBoost model (AUC = 0.979, accuracy = 0.931), LR model (AUC = 0.821, accuracy = 0.758), RF model (AUC = 0.970, accuracy = 0.921), MLP model (AUC = 0.830, accuracy = 0.756), SVM model (AUC = 0.713, accuracy = 0.661). On our data set, the XGBoost model has the best performance. However, the model still needs external verification research before clinical application.

Tissue-resident macrophages exacerbate lung injury after remote sterile damage.

Remote organ injury, which is a common secondary complication of sterile tissue damage, is a major cause of poor prognosis and is difficult to manage. Here, we report the critical role of tissue-resident macrophages in lung injury after trauma or stroke through the inflammatory response. We found that depleting tissue-resident macrophages rather than disrupting the recruitment of monocyte-derived macrophages attenuated lung injury after trauma or stroke. Our findings revealed that the release of circulating alarmins from sites of distant sterile tissue damage triggered an inflammatory response in lung-resident macrophages by binding to receptor for advanced glycation end products (RAGE) on the membrane, which activated epidermal growth factor receptor (EGFR). Mechanistically, ligand-activated RAGE triggered EGFR activation through an interaction, leading to Rab5-mediated RAGE internalization and EGFR phosphorylation, which subsequently recruited and activated P38; this, in turn, promoted RAGE translation and trafficking to the plasma membrane to increase the cellular response to RAGE ligands, consequently exacerbating inflammation. Our study also showed that the loss of RAGE or EGFR expression by adoptive transfer of macrophages, blocking the function of RAGE with a neutralizing antibody, or pharmacological inhibition of EGFR activation in macrophages could protect against trauma- or stroke-induced remote lung injury. Therefore, our study revealed that targeting the RAGE-EGFR signaling pathway in tissue-resident macrophages is a potential therapeutic approach for treating secondary complications of sterile damage.

The different subtelomeric structure among 1RS arms in wheat-rye 1BL.1RS translocations affecting their meiotic recombination and inducing their structural variation.

BACKGROUND: The 1RS arm of wheat-rye 1BL.1RS translocations contains several subtelomeric tandem repeat families. To study the effect of the difference in the composition of these tandem repeats on the meiotic recombination of 1RS arms can help to enrich the genetic diversity of 1BL.1RS translocation chromosomes. RESULTS: Five wheat-rye 1BL.1RS translocation cultivars/lines were used to build two cross combinations including group 1 (20T401 × Zhou 8425B, 20T401 × Lovrin 10 and 20T401 × Chuannong 17) and group 2 (20T360-2 × Zhou 8425B, 20T360-2 × Lovrin 10 and 20T360-2 × Chuannong 17). Oligonucleotide (oligo) probes Oligo-s120.3, Oligo-TR72, and Oligo-119.2-2 produced the same signal pattern on the 1RS arms in lines 20T401 and 20T360-2, and another signal pattern in the three cultivars Zhou 8425B, Lovrin 10 and Chuannong 17. The Oligo-pSc200 signal disappeared from the 1RS arms of the line 20T401, and the signal intensity of this probe on the 1RS arms of the line 20T360-2 was weaker than that of the three cultivars. The five cultivars/lines had the same signal pattern of the probe Oligo-pSc250. The recombination rate of 1RS arms in group 1 was significantly lower than that in group 2. In the progenies from group 1, unequal meiotic recombination in the subtelomeric pSc119.2 and pSc250 tandem repeat regions, and a 1BL.1RS with inversion of 1RS segment between the pSc200 and the nucleolar organizer region were found. CONCLUSIONS: This study provides a visual tool to detect the meiotic recombination of 1RS arms. The meiotic recombination rate of 1RS arms was affected by the variation of pSc200 tandem repeat, indicating the similar composition of subtelomeric tandem repeats on these arms could increase their recombination rate. These results indicate that the 1RS subtelomeric structure will affect its recombination, and thus the localization of genes on 1RS by means of meiotic recombination might also be affected.

EGFR-TNFR1 pathway in endothelial cell facilitates acute lung injury by NF-κB/MAPK-mediated inflammation and RIP3-dependent necroptosis.

Tumor necrosis factor-α (TNFα) has emerged as a pivotal effector critically correlated with disease severity in acute lung injury (ALI). Because both the excessive activation of epidermal growth factor receptor (EGFR) and tumor necrosis factor receptor 1 (TNFR1) in sepsis-induced vasculitis are markedly diminished through EGFR tyrosine kinase inhibitor, a specific mechanism must exist to modulate TNFR1 cellular fates regulated by EGFR. Here, we demonstrated that EGFR, a specific binding partner of TNFR1, exhibited an increased NF-κB/MAPK-mediated inflammation that was governed by enhanced recruitment of TNFR-associated factor 2 (TRAF2) to TNFR1 complex I in endothelial cell (EC). Moreover, EGFR activation triggered a remarkable increase in the phosphorylation of receptor-interacting protein 1 (RIP1) and its binding with receptor-interacting protein 3 (RIP3) which led to enhanced frequency of necroptosis in complex IIb. Inhibiting the kinase of EGFR disrupted the formation of complex I and complex IIb and prevents EC from NF-κB/MAPK-mediated inflammation and RIP3-dependent necroptosis. Consistently, pharmacological inhibition of EGFR can limit the destructive effects of neutrophils activation and the hyperpermeability of lung vascular in hyperinflammation period. Collectively, we have identified EC-EGFR as a modulator of TNFR1-mediated inflammation and RIP3-dependent necroptosis, providing a possible explanation for the immunological basis of anti-EGFR therapy in sepsis-induced ALI.

EGFR tyrosine kinase activity and Rab GTPases coordinate EGFR trafficking to regulate macrophage activation in sepsis.

EGFR phosphorylation is required for TLR4-mediated macrophage activation during sepsis. However, whether and how intracellular EGFR is transported during endotoxemia have largely been unknown. Here, we show that LPS promotes high levels cell surface expression of EGFR in macrophages through two different transport mechanisms. On one hand, Rab10 is required for EEA1-mediated the membrane translocation of EGFR from the Golgi. On the other hand, EGFR phosphorylation prevents its endocytosis in a kinase activity-dependent manner. Erlotinib, an EGFR tyrosine kinase inhibitor, significantly reduced membrane EGFR expression in LPS-activated macrophage. Mechanistically, upon LPS induced TLR4/EGFR phosphorylation, MAPK14 phosphorylated Rab7a at S72 impaired membrane receptor late endocytosis, which maintains EGFR membrane localization though blocking its lysosomal degradation. Meanwhile, Rab5a is also involved in the early endocytosis of EGFR. Subsequently, inhibition of EGFR phosphorylation switches M1 phenotype to M2 phenotype and alleviates sepsis-induced acute lung injury. Mechanistic study demonstrated that Erlotinib suppressed glycolysis-dependent M1 polarization via PKM2/HIF-1ɑ pathway and promoted M2 polarization through up-regulating PPARγ induced glutamine metabolism. Collectively, our data elucidated a more in-depth mechanism of macrophages activation, and provided stronger evidence supporting EGFR as a potential therapeutic target for the treatment of sepsis.

Chrysophanol-8-O-glucoside protects mice against acute liver injury by inhibiting autophagy in hepatic stellate cells and inflammatory response in liver-resident macrophages.

Acute liver failure (ALF) is an unfavorable condition characterized by the rapid loss of liver function and high mortality. Chrysophanol-8-O-glucoside (CPOG) is an anthraquinone derivative isolated from rhubarb. This study aims to evaluate the protective effect of CPOG on lipopolysaccharide (LPS)/D-GalN-induced ALF and its underlying mechanisms. LPS/D-GalN-induced mice ALF model and LPS treatment model in RAW 264.7 and LX2 cells were established. It was found that CPOG ameliorated LPS/D-GalN-induced liver injury and improved mortality as indicated by Hematoxylin-eosin (H&E) staining. Molecularly, qPCR and ELISA results showed that CPOG alleviated LPS/D-GalN-induced release of alanine aminotransferase and aspartate transaminase and the secretion of TNF-α and IL-1ß in vivo. LPS/D-GalN-induced intracellular ROS production was also attenuated by CPOG in liver tissue. Further, CPOG attenuated ROS generation and inhibited the expression of p-IκB and p-p65 as well as the expression of TNF-α and IL-1ß stimulated by LPS in RAW 264.7 cells. In addition, CPOG alleviated LPS-induced up-regulation of LC3B, p62, ATG5 and Beclin1 by attenuating ROS production and inhibiting MAPK signaling in LX2 cells. Taken together, our data indicated that the CPOG protected against LPS/D-GalN-induced ALF by inhibiting oxidative stress, inflammation response and autophagy. These findings suggest that CPOG could be potential drug for the treatment of ALF in clinic.