Prediction of Th17/Treg cell balance on length of stay in intensive care units of patients with sepsis.

Background: Prolonged length of stay (LOS) of sepsis can drain a hospital's material and human resources. This study investigated the correlations between T helper type 17 (Th17) and regulatory T (Treg) balance with LOS in sepsis. Methods: A prospective clinical observational study was designed in Changhai Hospital affiliated to Naval Medical University in Shanghai, China, from January to October 2020. The patients diagnosed with sepsis and who met the inclusion and exclusion criteria were recruited and whether the levels of cytokines, procalcitonin, subtypes, and biomarkers of T cells in the peripheral blood were detected. We analyzed the correlation between these and LOS. Results: Sixty septic patients were classified into two groups according to whether their intensive care unit (ICU) stay exceeded 14 days. The patients with LOS ≥14 days were older ([72.6±7.5] years vs. [63.3±10.4] years, P=0.015) and had higher Sequential Organ Failure Assessment (SOFA) (median [interquartile range]: 6.5 [5.0-11.0] vs. 4.0 [3.0-6.0], P=0.001) and higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores (16.0 [13.0-21.0] vs. 8.5 [7.0-14.0], P=0.001). There was no difference in other demographic characteristics and cytokines, interleukin-6, tumor necrosis factor-α, and interleukin-10 between the two groups. The Th17/Treg ratio of sepsis with LOS <14 days was considerably lower (0.48 [0.38-0.56] vs. 0.69 [0.51-0.98], P=0.001). For patients with LOS ≥14 days, the area under the receiver operating characteristic curve for the Th17/Treg ratio was 0.766. It improved to 0.840 and 0.850 when combined with the SOFA and APACHE II scores, respectively. Conclusions: The Th17/Treg ratio was proportional to septic severity and can be used as a potential predictor of ICU stay in sepsis, presenting a new option for ICU practitioners to better care for patients with sepsis.

Effect of systemic lidocaine on postoperative quality of recovery, the gastrointestinal function, inflammatory cytokines of lumbar spinal stenosis surgery: a randomized trial.

Surgery is one of the most frequent and effective intervention strategies for lumbar spinal stenosis, however, one-third of patients are not satisfied with postoperative outcomes. It is not clear whether perioperative systemic lidocaine could accelerate the early postoperative quality of recovery in patients undergoing lumbar spinal stenosis surgery. 66 patients were enrolled in this trial. Lidocaine or placebo was administered at a loading dose of 1.5 mg/kg for 10 min and then infused at 2.0 mg/kg/hour till the end of surgery. Continued infusion by postoperative patient-controlled intravenous analgesia with a dose of 40 mg/hour. The primary outcome was the quality of recovery. Secondary outcomes included the time of the patient's first flatus, catheter removal time, underground time from the end of the surgery, pain score, levels of inflammatory factors (IL-6, IL-10, TNF-α), postoperative nausea and vomiting (PONV), sufentanil rescues, patients' satisfaction scores, and complications of lidocaine. Eventually, 56 patients were in the final analysis with similar age, Body Mass Index (BMI), duration of surgery and anesthesia, and median QoR-15 score (a development and Psychometric Evaluation of a Postoperative Quality of Recovery Score). The difference in median QoR-15 score in placebo versus lidocaine patients was statistically significant (IQR, 106 (104-108) versus 114 (108.25-119.25), P < 0.001). The Numeric Rating Scale (NRS) score at the 12th hour, median sufentanil rescue consumption, IL-6, tumor necrosis factor-alpha (TNF-α) of patients treatment with lidocaine were lower. Nevertheless, patients given lidocaine had high satisfaction scores. Suggesting that lidocaine enhanced the postoperative quality of recovery, met early postoperative gastrointestinal function recovery, provided superior pain relief, lessened inflammatory cytokines, etc., indicating it may be a useful intervention to aid recovery following lumbar spinal stenosis surgery.

GSDMD-mediated NETosis promotes the development of acute respiratory distress syndrome.

Gasdermin D (GSDMD) is a classical molecule involved in pyroptosis. It has been reported to be cleaved into N-terminal fragments to form pores in the neutrophil membrane and promote the release of neutrophil extracellular traps (NETs). However, it remains unclear if GSDMD is involved in neutrophil regulation and NET release during ARDS. The role of neutrophil GSDMD in the development of ARDS was investigated in a murine model of ARDS induced by lipopolysaccharide (LPS) using the neutrophil specific GSDMD-deficient mice. The neutrophil GSDMD cleavage and its relationship with NETosis were also explored in ARDS patients. The cleavage of GSDMD in neutrophils from ARDS patients and mice was upregulated. Inhibition of GSDMD by genetic knockout or inhibitors resulted in reduced production of NET both in vivo and in vitro, and attenuation of LPS-induced lung injury. Moreover, in vitro experiments showed that the inhibition of GSDMD attenuated endothelial injury co-cultured with neutrophils from ARDS patients, while extrinsic NETs reversed the protective effect of GSDMD inhibition. Collectively, our data suggest that the neutrophil GSDMD cleavage is crucial in NET release during ARDS. The NET release maintained by cleaved GSDMD in neutrophils may be a key event in the development of ARDS.

Corrigendum: PD-L1 maintains neutrophil extracellular traps release by inhibiting neutrophil autophagy in endotoxin-induced lung injury.

[This corrects the article DOI: 10.3389/fimmu.2022.949217.].

PD-L1 maintains neutrophil extracellular traps release by inhibiting neutrophil autophagy in endotoxin-induced lung injury.

Programmed death ligand 1 (PD-L1) is not only an important molecule in mediating tumor immune escape, but also regulates inflammation development. Here we showed that PD-L1 was upregulated on neutrophils in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS). Neutrophil specific knockout of PD-L1 reduced lung injury in ARDS model induced by intratracheal LPS injection. The level of NET release was reduced and autophagy is elevated by PD-L1 knockout in ARDS neutrophils both in vivo and in vitro. Inhibition of autophagy could reverse the inhibitory effect of PD-L1 knockout on NET release. PD-L1 interacted with p85 subunit of PI3K at the endoplasmic reticulum (ER) in neutrophils from ARDS patients, activating the PI3K/Akt/mTOR pathway. An extrinsic neutralizing antibody against PD-L1 showed a protective effect against ARDS. Together, PD-L1 maintains the release of NETs by regulating autophagy through the PI3K/Akt/mTOR pathway in ARDS. Anti-PD-L1 therapy may be a promising measure in treating ARDS.

Protective Effect of Poria Cocos Polysaccharides on Fecal Peritonitis-Induced Sepsis in Mice Through Inhibition of Oxidative Stress, Inflammation, Apoptosis, and Reduction of Treg Cells.

This study was conducted to investigate the potential pharmacological effects of Poria cocos polysaccharides (PCPs) on fecal-induced peritonitis (FIP) mice. Consequently, the fecal peritonitis (FP)-induced septic mice with the higher levels of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), IL-1ß, malondialdehyde (MDA), myeloperoxidase (MPO), histopathological lesion and bacterial burden, and lower levels of superoxide dismutase (SOD) and glutathione (GSH). Interestingly, PCP pre-treatment reduced inflammatory cytokines and oxidative stress in plasma and spleen and improved the resistance to FIP. Inflammatory infiltration and cell death in thymus or splenic tissue were alleviated with PCP pretreatment. Furthermore, Treg cells were moderated in the spleen with PCP pre-administration. In addition, PCP pretreatment downregulated Annexin-V in the thymus of FP-induced septic mice, and apoptosis of splenic cells was dose-dependent. In conclusion, PCPs have pharmacological and biological effects on FP-induced septic mice, and its molecular mechanism is related to antioxidative, anti-inflammation, anti-apoptosis, and the reduction of Treg activity in splenic cells.

A randomized placebo-controlled double-blind study of dexmedetomidine on postoperative sleep quality in patients with endoscopic sinus surgery.

BACKGROUND: Postoperative sleep disorder is common and may cause aggravated postoperative pain, delirium, and poor prognosis. We accessed the effect of intraoperative intravenous dexmedetomidine on postoperative sleep quality in patients with endoscopic sinus surgery.  METHODS: This single-center, double-blind, placebo-controlled randomized clinical trial enrolled a total of 110 participants aged 18 years to 65 years who were scheduled to receive endoscopic sinus surgery. Placebo (normal saline) or dexmedetomidine infusion (load dose 0.5 µg kg-1 over 10 min, followed by maintenance dose 0.2 ug kg-1 h-1) during surgery. The primary outcome was postoperative sleep quality. Secondary outcomes were postoperative Ramsay sedation scores, Visual Analog Scale (VAS) scores, serum cortisol, 5-hydroxytryptamine (5-HT) and hypocretin, delirium, and postoperative nausea and vomiting (PONV). RESULTS: Among enrolled 110 patients, 55 were randomized to administer intraoperative dexmedetomidine and placebo. In total, 14 patients (7 in each group) were excluded because of protocol deviations, and 96 patients (48 in each group) were included in the per-protocol analysis. The dexmedetomidine group had a significantly higher sleep efficiency index(SEI) (66.85[3.00] vs 65.38[3.58]), the ratio of rapid eye movement sleep to total sleep(REM)(13.63[1.45] vs 12.38[2.11]) and lower arousal index (AI) (7.20[1.00] vs 8.07[1.29]), higher Ramsay sedation score at post-operation 1 h, 12 h point, lower VAS scores at post-operation 1 h, 12 h, 24 h point, lower cortisol, higher 5-HT and hypocretin in serum than the placebo group. CONCLUSION: In this randomized clinical trial, dexmedetomidine can improve the sleep quality of patients undergoing endoscopic sinus surgery. These results suggest that this therapy may be a viable strategy to enhance postoperative sleep quality in patients with endoscopic sinus surgery. TRIAL REGISTRATION: The study was approved by the Bethune International Peace Hospital Ethics Committee (2021-KY-129) and registered in the Chinese Clinical Trial Registry ( ChiCTR2100051598 , 28/09/2021).

An explainable machine learning algorithm for risk factor analysis of in-hospital mortality in sepsis survivors with ICU readmission.

BACKGROUND AND OBJECTIVE: Patients who survive sepsis in the intensive care unit (ICU) (sepsis survivors) have an increased risk of long-term mortality and ICU readmission. We aim to identify the risk factors for in-hospital mortality in sepsis survivors with later ICU readmission and visualize the quantitative relationship between the individual risk factors and mortality by applying machine learning (ML) algorithm. METHODS: Data were obtained from the Medical Information Mart for Intensive Care III (MIMIC-III) database for sepsis and non-sepsis ICU survivors who were later readmitted to the ICU. The data on the first day of ICU readmission and the in-hospital mortality was combined for the ML algorithm modeling and the SHapley Additive exPlanations (SHAP) value of the correlation between the risk factors and the outcome. RESULTS: Among the 2970 enrolled patients, in-hospital mortality during ICU readmission was significantly higher in sepsis survivors (n = 2228) than nonsepsis survivors (n = 742) (50.4% versus 30.7%, P<0.001). The ML algorithm identified 18 features that were associated with a risk of mortality in these groups; among these, BUN, age, weight, and minimum heart rate were shared by both groups, and the remaining mean systolic pressure, urine output, albumin, platelets, lactate, activated partial thromboplastin time (APTT), potassium, pCO2, pO2, respiration rate, Glasgow Coma Scale (GCS) score for eye-opening, anion gap, sex and temperature were specific to previous sepsis survivors. The ML algorithm also calculated the quantitative contribution and noteworthy threshold of each factor to the risk of mortality in sepsis survivors. CONCLUSION: 14 specific parameters with corresponding thresholds were found to be associated with the in-hospital mortality of sepsis survivors during the ICU readmission. The construction of advanced ML techniques could support the analysis and development of predictive models that can be used to support the decisions and treatment strategies made in a clinical setting in critical care patients.

Tissue Inhibitor of Metalloproteinases-2 Mediates Kidney Injury during Sepsis.

INTRODUCTION: Urinary tissue inhibitor of metalloproteinases (TIMP)-2 has been identified as a predictive marker for acute kidney injury (AKI), including sepsis-associated AKI (S-AKI). Whether TIMP-2 might be causally related to AKI and hence represent a viable drug target is unclear. OBJECTIVE: The aim of this study was to evaluate whether suppression of TIMP-2 attenuates S-AKI. METHODS: Balb/c mice were randomized to sham or cecal ligation and puncture surgery and treated with or without a TIMP-2-neutralizing antibody. Animals were followed for 48 h and then sacrificed for analysis of TIMP-2 expression, cell cycle, and histology. RESULTS: Anti-TIMP-2 resulted in decreased lumen TIMP-2 expression which markedly increased cell cycle progression and attenuated epithelial cell injury by histology. CONCLUSIONS: TIMP-2 mediates S-AKI and appears to be a viable drug target.

Efficacy and safety of tocilizumab in COVID-19 patients.

In this retrospective study we assessed the efficacy and safety of tocilizumab in patients with critical or severe coronavirus disease 2019 (COVID-19). We enrolled 181 patients admitted to Huoshenshan Hospital (Wuhan, China) with confirmed COVID-19 between January 2020 and February 2020. Ninety-two patients were treated with tocilizumab, and 89 patients were treated conventionally. We analyzed the clinical manifestations, changes in CT scan images, and laboratory tests before and after tocilizumab treatment, and compared these results with the conventionally treated group. A significant reduction in the level of C-reactive protein was observed 1 week after tocilizumab administration. In some cases this meant the end of the IL-6-related cytokine storm. In addition, tocilizumab relieved fever, cough, and shortness of breath with no reported adverse drug reactions. These findings suggest tocilizumab improves clinical outcomes and is effective for treatment of patients with critical or severe COVID-19. However, future clinical trials are needed to better understand the impact of tocilizumab interference with IL-6 and provide a therapeutic strategy for treatment of COVID-19.

Plasma metabolomics of early parenteral nutrition followed with enteral nutrition in pancreatic surgery patients.

Nutrition support is essential for surgical patients. Patients undergoing pancreaticoduodenectomy (PD) require tremendous nutrient support but also faced with risks of infection and gastrointestinal complications. Early parenteral nutrition has recently shown benefits while limited information provided about the influence on metabolism. This prospective single-center cohort study used plasma metabolomics to clarify metabolic alteration after early parenteral nutrition followed with enteral nutrition. Patients undergoing pancreaticoduodenectomy (n = 52) were enrolled. 36 patients received parenteral nutrition within 3 days postoperatively followed with EN (TPN group), 16 patients received standard fluids followed with EN (GIK group). We found that the weight loss is reduced in TPN group while the other clinical outcomes and inflammatory cytokines showed no statistical significance. The TPN group showed significance in amino acids, lipid, and phospholipids metabolism compared with the GIK group. Moreover, integration analysis indicated that early TPN could promote the metabolism of long-chain fatty acids, phospholipids, ketone bodies, and branched-chain amino acids. We conclude that early TPN support followed with EN for patients undergoing PD reduced the perioperative weight loss and promoted the metabolic transition to anabolic metabolism with the recovery of lipid metabolism, suggesting its benefits for the recovery of patients.

Effects of CXCL4/CXCR3 on the lipopolysaccharide-induced injury in human umbilical vein endothelial cells.

Chemokines and inflammatory response of endothelial cells is crucial in the development and progression of inflammatory disease. Lipopolysaccharide (LPS) is a well-known factor to trigger inflammatory response and induce damage of endothelial cells. The present study used lipopolysaccharide (LPS)-treated human vascular endothelial cells (HUVECs) to investigate the function of chemokine CXC chemokine ligand 4 (CXCL4) and its receptor CXC chemokine receptor 3 (CXCR3) in inflammatory-induced endothelial injury. LPS exposure (50, 100, 200 ng/ml) to HUVECs induced a dose- and time-dependent increase in CXCL4 and CXCR3 expression at both mRNA and protein levels. The LPS-induced endothelium hyperpermeability was inhibited by the addition of CXCL4 neutralizing antibody. Moreover, the addition of CXCL4 neutralizing antibody abolished the effects of LPS on tight junction (TJ) protein expression (occludin claudin-4 and Zonula occluden-1[ZO-1]) and p38 phosphorylation, which is supported by the observation of increased TJ protein expression and decreased p38 phosphorylation in LPS-treated HUVECs. SB203580, a p38 inhibitor, protected HUVECs from CXCL4-stimulated damage. In conclusion, CXCL4/CXCR3, which was enhanced by LPS, may be involved in endothelial proliferation, apoptosis, and permeability via the p38 signaling pathway.

IGFBP7 regulates sepsis-induced acute kidney injury through ERK1/2 signaling.

IGFBP7 as an early biomarker has been used to identify patients at risk of developing acute kidney injury (AKI). Nevertheless, its role in AKI remains obscure. The aim of our study is to determine the role and mechanism of IGFBP7 in lipopolysaccharide (LPS)-induced HK-2 cells in vitro and on sepsis-induced AKI by cecal ligation and puncture (CLP) in vivo. Here, we identified that IGFBP7 expression was increased in patients with AKI and HK-2 cells with LPS (1, 2, and 5 µg/mL) induction. HK-2 cells with LPS induction showed cell cycle arrest at G1-G0 phases and cell apoptosis and activated ERK1/2 parallel with the changes in the proteins belonging to the ERK1/2 pathway, including Cyclin D1, P21, Bax, and Bcl-2, which were inhibited by the IGFBP7 knockdown. Moreover, IGFBP7 overexpression significantly induced cell cycle arrest at G1-G0 phases and cell apoptosis of HK-2 cells, which were inhibited by PD98509, an ERK1/2 signaling inhibitor. IGFBP7 knockdown effectively alleviated the severity of the renal injury, evidenced by decreases in the urinary levels of creatinine, blood urea nitrogen, and albumin, cell apoptosis, and activation of ERK1/2 signaling in CLP mice. Taken together, our findings indicate that IGFBP7 regulates sepsis-induced AKI through ERK1/2 signaling.

FcRγ deficiency improves survival in experimental sepsis by down-regulating TLR4 signaling pathway.

Fc receptor common γ signaling chain (FcRγ), a common subunit shared by Fc receptors (FcγRI, III, IV, FcαRI, and FcεRI), is an important immune regulator both in innate and adaptive immunity. Previous studies have shown that FcRγ was a potential target of inflammatory diseases, whereas the role of FcRγ in sepsis has been poorly understood. In this study, we found that deficiency of FcRγ resulted in increased survival in lipopolysaccharide (LPS)/D-galactosamine and E. coli-induced sepsis in mice. This protective effect was characterized by decreased TNF-α, IL-6, and IL-10. Further experiments in bone marrow-derived macrophages (BMDMs) in vitro also showed that FcRγ deficiency resulted in decreased production of TNF-α, IL-6, and IL-10 upon LPS stimulation. The mechanism study showed that FcRγ was physiologically associated with toll-like receptor 4 (TLR4), and tyrosine phosphorylation of FcRγ mediated TLR4 signaling pathway, followed by increased ERK phosphorylation upon LPS stimulation. Our results suggest that FcRγ might be a potential therapeutic target of sepsis.

MiR-4505 aggravates lipopolysaccharide-induced vascular endothelial injury by targeting heat shock protein A12B.

Heat shock protein family A member 12B (HSPA12B) is a heat shock protein primarily expressed in endothelial cells. Our previous study showed that it was protective against endothelial injury induced by lipopolysaccharide (LPS). The present study was performed to investigate whether micro (mi)RNA was involved in HSPA12B expression in endothelial cells challenged by LPS. We first screened the miRNA candidates potentially related to HSPA12B by bioinformatics analysis. Then the mimics of the miRNA candidates were transfected into human umbilical vein endothelial cells (HUVECs) to investigate the miRNAs that negatively regulated HSPA12B expression. The miRNA expression was also determined in LPS­stimulated HUVECs. Dual luciferase activity assay was performed to confirm the relationship between the candidate miRNA and HSPA12B. Role of nuclear factor (NF)­κB in the miRNA expression was investigated by using its inhibitor. Finally, the role of the miRNA on LPS induced injury was investigated. Eleven miRNAs were screened by bioinformatics analysis and 4 of them could inhibit HSPA12B expression at both mRNA and protein levels. Among the 4 miRNA candidates, only miR­4505 was highly expressed in HUVECs stimulated by LPS. Luciferase analysis showed that miR­4505 directly interacted with the 3'untranslated region of HSPA12B. LPS­induced upregulation of miR­4505 was blocked by NF­κB inhibitor. Transfection with miR­4505 mimics reduced the transendothelial electrical resistance and vascular endothelial­cadherin expression. The scratch test demonstrated that miR­4505 inhibited endothelial migration capacity. In conclusion, miR­4505 downregulates the expression of HSPA12B and aggravates the LPS­induced vascular endothelial cell injury.

Heat Shock Protein A12B Protects Vascular Endothelial Cells Against Sepsis-Induced Acute Lung Injury in Mice.

BACKGROUND: Pulmonary endothelial injury is a critical process in the pathogenesis of acute lung injury (ALI) during sepsis. Heat shock protein A12B (HSPA12B) is mainly expressed in endothelial cells and protects against several harmful factors. However, the effects of HSPA12B in sepsis-induced ALI and its potential mechanisms of action remain unclear. METHODS: For in vivo experiments, C57BL/6 mice were randomly divided into four groups (n=15): a sham operation group, a cecal ligation and puncture (CLP) group, a HSPA12B siRNA-CLP group and a negative control (NC) siRNA-CLP group. The mice were treated by nasal inhalation of 2-OMe-modified HSPA12B siRNA or NC siRNA. Sepsis was induced by CLP. Samples were harvested 24 and 48 hours post-CLP surgery. Pathological changes and scoring of lung tissue samples were monitored using hematoxylin and eosin staining. Levels of pro-inflammatory cytokines (e.g., interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-6) and myeloperoxidase activity in bronchoalveolar lavage fluid were analyzed by ELISA. Pulmonary edema was assessed using a wet-to-dry weight ratio. Neutrophils and alveolar macrophages were counted using flow cytometry. Pulmonary endothelial cell apoptosis was detected by TUNEL staining. Expression levels of MAPK family signaling molecules and caspase-3 were measured by Western blot analysis. In addition, 7-day survival was recorded. For in vitro experiments, human umbilical vein endothelial cells were pre-transfected with HSPA12B siRNA or pIRES2-EGFP-HSPA12B-Flag plasmid and treated with lipopolysaccharide; subsequently, the expression levels of MAPK family signaling molecules and caspase-3 were measured by Western blotting. RESULTS: Nasal inhalation of nano-polymer-encapsulated HSPA12B siRNA specifically downregulated mRNA and protein expression levels of HSPA12B in lung tissues. The administration of HSPA12B siRNA aggravated lung pathological injury, upregulated pro-inflammatory cytokine (e.g., IL-1ß, TNF-α, and IL-6) expression, and increased myeloperoxidase activity, neutrophil infiltration, pulmonary edema, and pulmonary endothelial cell apoptosis. Additionally, HSPA12B knockdown worsened survival after CLP surgery. The potential protective mechanisms of HSPA12B may involve the inhibition of ERK phosphorylation and caspase-3 activation in vivo and in vitro. CONCLUSION: HSPA12B protected against sepsis-induced ALI. The potential mechanism may be partly due to the inhibition of ERK phosphorylation and caspase-3 activation. These findings provide a potential therapeutic target for treating sepsis.

Heat shock protein A12B protects against sepsis-induced impairment in vascular endothelial permeability.

BACKGROUND: As a common and life-threatening infectious syndrome, sepsis contributes significantly to morbidity and mortality in clinical settings. Vascular endothelial injury and hyperpermeability play an important role in the development of sepsis-induced organ dysfunction. Heat shock protein A12B (HSPA12B) is one of the HSP70 superfamily members and is mainly expressed in vascular endothelial cells. The present study was performed to investigate the role of HSPA12B in endothelial barrier dysfunction during sepsis. METHODS: Human umbilical vein endothelial cells (HUVECs) were stimulated with 1 µg/mL of lipopolysaccharide (LPS) and harvested at 0, 3, 6, 9, 12, and 24 h. The messenger RNA and protein levels of HSPA12B were detected by Real Time-polymerase chain reaction and Western blot. Upregulation of HSPA12B was induced by transfection of pIRES2-EGFP plasmid carrying the HSPA12B complementary DNA. The in vitro effect of HSPA12B overexpression on endothelial permeability was manifested by the transendothelial electrical resistance value, expression of the adhesion molecules VE-cadherin, and the level of permeability-related kinase myosin light chain, SRC, and CDC42. Mice received cecal ligation and puncture surgery followed by nasal inhalation of nano-polymer-mediated siRNA. Lung endothelial permeability was assessed via intrajugular vein injection of Evans Blue 30 h after cecal ligation and puncture. RESULTS: After LPS induction, the messenger RNA and protein level of HSPA12B in HUVECs increased and peaked at 12 h, whereas they returned to the baseline level at 24 h. Overexpression of HSPA12B can reduce the permeability of HUVEC stimulated by LPS in vitro, while increasing the expression of VE-Cadherin, myosin light chain, and CDC42. On the other hand, downregulating the expression of HSPA12B can significantly increase lung permeability in mice with sepsis-induced vascular injury. CONCLUSIONS: HSPA12B plays a protective role in vascular endothelial barrier dysfunction by preserving the endothelial permeability during sepsis.

Gαi1 and Gαi3 regulate macrophage polarization by forming a complex containing CD14 and Gab1.

Heterotrimeric G proteins have been implicated in Toll-like receptor 4 (TLR4) signaling in macrophages and endothelial cells. However, whether guanine nucleotide-binding protein G(i) subunit alpha-1 and alpha-3 (Gαi1/3) are required for LPS responses remains unclear, and if so, the underlying mechanisms need to be studied. In this study, we demonstrated that, in response to LPS, Gαi1/3 form complexes containing the pattern recognition receptor (PRR) CD14 and growth factor receptor binding 2 (Grb2)-associated binding protein (Gab1), which are required for activation of PI3K-Akt signaling. Gαi1/3 deficiency decreased LPS-induced TLR4 endocytosis, which was associated with decreased phosphorylation of IFN regulatory factor 3 (IRF3). Gαi1/3 knockdown in bone marrow-derived macrophage cells (Gαi1/3 KD BMDMs) exhibited an M2-like phenotype with significantly suppressed production of TNF-α, IL-6, IL-12, and NO in response to LPS. The altered polarization coincided with decreased Akt activation. Further, Gαi1/3 deficiency caused LPS tolerance in mice. In vitro studies revealed that, in LPS-tolerant macrophages, Gαi1/3 were down-regulated partially by the proteasome pathway. Collectively, the present findings demonstrated that Gαi1/3 can interact with CD14/Gab1, which modulates macrophage polarization in vitro and in vivo.

Up-regulation of programmed cell death 1 ligand 1 on neutrophils may be involved in sepsis-induced immunosuppression: an animal study and a prospective case-control study.

BACKGROUND: Recent studies have shown that neutrophils may display an antigen-presenting function and inhibit lymphocyte proliferation by expressing programmed cell death 1 ligand 1 (PD-L1). The current study was performed to investigate the effect of neutrophils and their pathophysiological significance during sepsis. METHODS: Neutrophil PD-L1 expression was determined in both septic mice (n = 6) and patients (n = 41). Neutrophils from septic mice were subtyped into PD-L1 and PD-L1 populations to determine their phenotypes and functions. Septic neutrophils were cocultured with lymphocytes to observe the effect of septic neutrophils on lymphocyte apoptosis. RESULTS: The PD-L1 level on neutrophils from septic mice was significantly up-regulated (21.41 ± 4.76%). This level increased with the progression of sepsis and the migration of neutrophils from the bone marrow to the blood and peritoneal cavity. The percentages of CD11a, CD62L, and C-C chemokine receptor type 2 were lower, whereas the percentages of CD16 and CD64 were higher on PD-L1 neutrophils than on PD-L1 neutrophils. The migratory capacity of PD-L1 neutrophils was compromised. Septic neutrophils induced lymphocyte apoptosis via a contact mechanism, and this process could be reversed by anti-PD-L1 antibody. PD-L1 was also up-regulated on neutrophils from patients with severe sepsis (14.6% [3.75%, 42.1%]). The levels were negatively correlated with the monocyte human leukocyte antigen-DR level and positively correlated with the severity of septic patients. Neutrophil PD-L1 was a predictor for the prognosis of severe sepsis, with an area of 0.74 under the receiver operating curve. CONCLUSIONS: PD-L1 is up-regulated on neutrophils during sepsis, which may be related to sepsis-induced immunosuppression.