Mouse Model Of Sepsis Research Articles

Role of Vitamin D and E as Antioxidants Against Cerebral Endothelial Dysfunction: An In Vivo Study in White Rats (Rattus norvegicus) Sepsis Model

Sepsis is a life-threatening condition caused by the body's response to an infection, leading to organ dysfunction. A antioxidants can help neutralize harmful free radicals that cause cellular and tissue damage through oxidative stress. Vitamin D and E are two antioxidants that have been extensively studied for their potential effectiveness. This study aims to evaluate the effectiveness of vitamins D and E in reducing oxidative stress in the cerebral vascular endothelial cells of Wistar mice in a sepsis model. The study follows an experimental design and uses a posttest with a control group. The levels of NO and SOD in 24 sepsis model mice were measured using ELISA, and the cerebral endothelial tissues were examined histopathologically. An ANOVA test was performed, followed by the Post Hoc LSD test. NO and SOD levels decreased in sepsis rats from 66.88 ± 16.59 to 88.77 ± 12.83µmol/L. Sepsis mice given vitamin D and E showed significant results on changes in NO and SOD levels (p<0.05). Based on the histopathological results of necrosis, inflammation, and hemorrhagic cell damage in sepsis rats reached over 50% of the field of view, significantly different from sepsis mice that had been given vitamin D and E. Sepsis mice were given vitamin D and E influenced 96.2% and 98.7% on changes in NO, SOD, and cerebral endothelial dysfunction (p<0.05). These findings imply that vitamins D and E may be beneficial in managing sepsis-induced cerebral endothelial dysfunction, potentially impacting the treatment and outcomes of sepsis patients.

Mesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) Mitigates Neuroinflammation and Cognitive Impairment by Modulating Glial Activation in Sepsis-Associated Encephalopathy.

Sepsis-associated encephalopathy (SAE) is a severe neurological complication of sepsis, characterized by cognitive impairment and increased mortality. Owing to the established neuroprotective and immunomodulatory effects of Mesencephalic Astrocyte-derived Neurotrophic Factor (MANF) in a plethora of neurological disorders, our study aimed to investigate the role of MANF in SAE and evaluate its potential as a therapeutic target. Employing a cecal ligation and puncture (CLP) mouse model of sepsis, we analyzed MANF expression in the hippocampus and cortex, and evaluated the influence of intranasally administered recombinant human MANF (rhMANF) on symptoms of SAE. Our results disclosed a substantial increase in MANF protein levels within the hippocampus and cortex of septic mice, primarily found in neurons. Post-CLP surgical administration of rhMANF led to numerous favorable outcomes. Specifically, rhMANF therapy mitigated sepsis-induced behavioral deviations and cognitive impairments, as gauged by SHIRPA scores and Morris water maze tests, and enhanced survival rates in septic mice. These enhancements were concomitant with alterations in neuroinflammation and synaptic integrity. The rhMANF treatment attenuated activation of microglia and astrocytes in the hippocampus and cortex, as evidenced by diminished Iba-1 and GFAP positive cells. It also curtailed the generation of pro-inflammatory cytokines TNF-α and IL-6, and obstructed the p38 MAPK inflammatory pathway. Moreover, rhMANF sustained the expression of synaptic proteins PSD95 and SYN, and conserved neuronal integrity, as demonstrated by Nissl staining. In conclusion, our study underscores the potential of MANF as an innovative therapeutic target for SAE, emphasizing its anti-inflammatory and neuroprotective capabilities.

BMSCs Downregulate CXCL12 by Secreting Exosomal miR-20a-5p to Promote Macrophage M2 Polarization and Alleviate the Development of Sepsis

ABSTRACT Objective Sepsis is a syndrome of the systemic inflammatory response caused by infection that can endanger a patient’s life. The aim of this study was to explore the molecular mechanism by which bone marrow mesenchymal stem cells-derived exosomes (BMSCs-exo) carrying miR-20a-5p regulate the progression of sepsis. Methods Clinical samples from sepsis patients were collected. Mouse and cell models of sepsis were induced by lipopolysaccharide (LPS). The levels of related genes and proteins were determined by RT‒qPCR, Western blotting and ELISA. CCK-8 and flow cytometry assays were used to assess cell viability, apoptosis, and markers of macrophage polarization. Results In septic patients, miR-20a-5p levels were significantly lower and CXCL12 expression was significantly increased. After LPS induction, M2 polarization of macrophages was significantly reduced, the level of inflammatory factors was increased, and apoptosis was increased. The addition of BMSCs-exo increased the miR-20a-5p level and decreased the expression of CXCL12 in macrophages, thereby promoting macrophage M2 polarization and reducing the levels of inflammatory factors. Conclusion This study demonstrated for the first time that BMSCs-exo promoted the polarization of M2 macrophages through the miR-20a-5p/CXCL12 axis, thus alleviating the development of sepsis. These findings provide a new theoretical basis for the targeted treatment of sepsis with exosomes or miR-20a-5p.

Ciprofol prevents ferroptosis in LPS induced acute lung injury by activating the Nrf2 signaling pathway

BackgroundPatients who suffered from sepsis-induced acute lung injury (ALI) always need sedation for mechanical ventilation in intensive care unit (ICU). Ciprofol(Cip), a novel intravenous anesthetic, was revealed to have anti-inflammatory and antioxidative properties. Ferroptosis, categorized as a type of newly non-apoptotic cell death, participates in the development of lung injury. This study aimed to identify the effect of ciprofol on sepsis-induced ALI and to determine whether ferroptosis is involved.Methods and resultsTo create ALI models, MLE12 alveolar epithelial. Cells and lipopolysaccharide (LPS)-stimulated C57BL/6J mice were used. Our results displyed that Cip reduced lung injury and ferroptosis. In the LPS-induced sepsis mice model, Cip pretreatment partially reduced respiratory system damage, as evaluated by HE, TUNEL and inflammatory factors. By raising GSH levels, ciprofol activated the Nrf2 antioxidative pathway, blocked ferroptosis, increased ferroptosis-related protein (GPX4 and SLC7A11) expressions, and reduced Fe2+ content, as well as MDA and 4-HNE levels. However, the protective effects of Cip on lung injury and ferroptosis diminished in Nrf2-KO mice. Additionally, Cip activated the Nrf2 pathway and reduced cell death by preventing detrimental lipid peroxidation and ferroptosis in vitro. However, these effects were not observed in siNrf2-treated cells.ConclusionOur study demonstrated that Cip may prevent septic lung injury by suppressing ferroptosis through the Nrf2 pathway.

Plumbagin protect against sepsis-induced myocardial injury in mice by inhibiting the JAK2/STAT3 signaling pathway to reduce cardiomyocyte pyroptosis

To explore the mechanism of plumbagin for protecting against sepsis-induced myocardial injury in mice. Network pharmacology analysis was used to obtain the key targets of plumbagin and diseases, which were subjected to GO and KEGG analysis, and the binding energy was verified using molecular docking. In a mouse model of cecal ligation and puncture (CLP), the protective effect of plumbagin treatment prior to CLP against sepsis-induced myocardial injury was evaluated by examination of myocardial function and pathology using echocardiography and HE staining. Serum levels of CK-MB, LDH, MDA, IL-1β and IL-18 and myocardial ROS level in the mice were detected, and Western blotting was used to determine the protein expression levels of STAT3, GSDMD, caspase-11, JAK2, P-STAT3, P-JAK2, GSDMD-N and HMGB1 in the myocardial tissues. Five core targets were screened from the 10 intersecting genes. Molecular docking showed strong binding affinity of plumbagin to STAT3, p-STAT3, and JAK2. Compared with the sham-operated mice, the mouse models of CLP-induced sepsis had significantly decreased CO, LVEF, LVFS and SV and increased serum levels of CK-MB, LDH, MDA and myocardial inflammatory factors and ROS. HE staining and Western blotting showed obvious myocardial injury in the septic mice with increased expressions of JAK2/STAT3 signaling pathway and pyroptosis-related proteins (P < 0.05). Pretreatment with plumbagin significantly improved cardiac functions of CLP mice, lowered serum levels of CK-MB, LDH, MDA, inflammatory factors and myocardial ROS, and decreased the expression levels of JAK2/STAT3 signaling pathway and pyroptosis-related proteins. Plumbagin pretreatment alleviates myocardial injury in septic mice possibly by inhibiting the STAT3 signaling pathway to reduce cardiomyocyte pyroptosis.

Vitamin D can mitigate sepsis-associated neurodegeneration by inhibiting exogenous histone-induced pyroptosis and ferroptosis: Implications for brain protection and cognitive preservation

BackgroundSepsis-induced neurodegeneration and cognitive dysfunction remain critical challenges worldwide. Vitamin D was reported to reduce neuronal injury and neurotoxicity and its deficiency was associated with neurocognitive disorders. This study investigates the mechanisms by which vitamin D exerts neuroprotective potential against damage-associated molecular patterns (DAMPs), specifically extracellular histones, in sepsis-related brain dysfunction. MethodsThe cultured mouse hippocampal neuronal HT22 cells were exposed to 20 µg/ml exogenous histone for 24 h to induce pyroptosis and ferroptosis in the presence or absence of the active form of vitamin D, calcitriol (1 nM). A cecal ligation and puncture mouse sepsis model was used to evaluate histone release and pyroptosis/ferroptosis biomarkers in the brain together with neurobehavioral performance with or without calcitriol treatment (1 µg/kg, i.p. injection) at 24 h or 1 week after sepsis onset. ResultsIn vitro, histone exposure triggered both pyroptosis and ferroptosis in neuronal cells, which was significantly suppressed by calcitriol treatment with the reduced expression of caspase-1 by 38 %, GSDMD by 30 %, ACSL4 by 33 %, and the increased expression of GPX4 by 35 % (n = 6, P < 0.05). Similarly, in vivo, calcitriol treatment inhibited both neuronal pyroptosis and ferroptosis by reducing expression of pyroptosis marker, GSDMD/NeuN (11.6 ± 1.2 % vs. 19.4 ± 1.1 %) and increasing expression of ferroptosis marker, GPX4/NeuN (21.4 ± 1.7 % vs. 13.5 ± 1.1 %), in the brain of septic mice (n = 6, P < 0.01). In addition, calcitriol increased survival rate (72 % vs. 41 %) and ameliorated cognitive dysfunction of septic mice (n = 8–13, P < 0.05). ConclusionsThis study demonstrates that vitamin D exerts a neuroprotective effect against sepsis by attenuating histone-induced pyroptosis and ferroptosis. These findings highlight the potential therapeutic role of vitamin D supplementation in mitigating brain dysfunction associated with sepsis which needs for further investigation.

FGF8 protects against polymicrobial sepsis by enhancing the host's anti-infective immunity.

Sepsis is characterized by a life-threatening syndrome caused by an unbalanced host response to infection. Fibroblast Growth Factor 8 (FGF8) has been newly identified to play important roles in inflammation and innate immunity, but its role in host response to sepsis is undefined. A cecal ligation and puncture (CLP) -induced mouse sepsis model was established to evaluate the immunomodulatory function of FGF8 during sepsis. The underlying molecular mechanisms were elucidated by cell models using relevant molecular biology experiments. The clinical value of FGF8 in the adjuvant diagnosis of sepsis was evaluated using clinical samples. FGF8 protein concentrations were elevated in CLP-induced septic mice compared to controls. In vivo, FGF8 blockade using anti-FGF8 antibody significantly increased mortality and bacterial burden and was paralleled by significantly aggravated tissue injury after CLP. Therapeutic administration of recombinant FGF8 (rFGF8) improved the bacterial clearance and mortality of septic mice in a FGFR1-dependent manner. In vitro, FGF8 directly enhanced bacterial phagocytosis and killing of macrophages by enhancing the phosphorylation of the ERK1/2 signaling pathway, which could be abrogated with the ERK1/2 pathway inhibitor U0126. Clinically, serum FGF8 levels in both adult and pediatric patients with sepsis from ICU were significantly higher than those in healthy controls. These results present a previously unrecognized role of FGF8 in improving survival of sepsis by enhancing host immune defense. Therefore, targeting FGF8 may provide new strategies for the diagnosis and immunotherapy of sepsis.

Essential role of proline synthesis and the one-carbon metabolism pathways for systemic virulence of Streptococcus pneumoniae.

Virulence screens have indicated potential roles during Streptococcus pneumoniae infection for the one-carbon metabolism pathway component Fhs and proline synthesis mediated by ProABC. To define how these metabolic pathways affect S. pneumoniae virulence, we have investigated the phenotypes, transcription, and metabolic profiles of Δfhs and ΔproABC mutants. S. pneumoniae capsular serotype 6B BHN418 Δfhs and ΔproABC mutant strains had strongly reduced virulence in mouse sepsis and pneumonia models but could colonize the nasopharynx. Both mutant strains grew normally in complete media but had markedly impaired growth in chemically defined medium, human serum, and human cerebrospinal fluid. The BHN418 ΔproABC strain also had impaired growth under conditions of osmotic and oxidative stress. The virulence role of proABC was strain specific, as the D39 ΔproABC strain could still cause septicemia and grow in serum. Compared to culture in broth, in serum, the BHN418 Δfhs and ΔproABC strains showed considerable derangement in global gene transcription that affected multiple but different metabolic pathways for each mutant strain. Metabolic data suggested that Δfhs had an impaired stringent response, and when cultured in sera, BHN418 Δfhs and ΔproABC were under increased oxidative stress and had altered lipid profiles. Loss of proABC also affected carbohydrate metabolism and the accumulation of peptidoglycan synthesis precursors in the BHN418 but not the D39 background, linking this phenotype to the conditional virulence phenotype. These data identify the S. pneumoniae metabolic functions affected by S. pneumoniae one-carbon metabolism and proline biosynthesis, and the role of these genetic loci for establishing systemic infection.IMPORTANCERapid adaptation to grow within the physiological conditions found in the host environment is an essential but poorly understood virulence requirement for systemic pathogens such as Streptococcus pneumoniae. We have now demonstrated an essential role for the one-carbon metabolism pathway and a conditional role depending on strain background for proline biosynthesis for S. pneumoniae growth in serum or cerebrospinal fluid, and therefore for systemic virulence. RNAseq and metabolomic data demonstrated that the loss of one-carbon metabolism or proline biosynthesis has profound but differing effects on S. pneumoniae metabolism in human serum, identifying the metabolic processes dependent on each pathway during systemic infection. These data provide a more detailed understanding of the adaptations required by systemic bacterial pathogens in order to cause infection and demonstrate that the requirement for some of these adaptations varies between strains from the same species and could therefore underpin strain variations in virulence potential.

Brain imaging and machine learning reveal uncoupled functional network for contextual threat memory in long sepsis

Positron emission tomography (PET) utilizes radiotracers like [18F]fluorodeoxyglucose (FDG) to measure brain activity in health and disease. Performing behavioral tasks between the FDG injection and the PET scan allows the FDG signal to reflect task-related brain networks. Building on this principle, we introduce an approach called behavioral task–associated PET (beta-PET) consisting of two scans: the first after a mouse is familiarized with a conditioning chamber, and the second upon recall of contextual threat. Associative threat conditioning occurs between scans. Beta-PET focuses on brain regions encoding threat memory (e.g., amygdala, prefrontal cortex) and contextual aspects (e.g., hippocampus, subiculum, entorhinal cortex). Our results show that beta-PET identifies a biologically defined network encoding contextual threat memory and its uncoupling in a mouse model of long sepsis. Moreover, machine learning algorithms (linear logistic regression) and ordinal trends analysis demonstrate that beta-PET robustly predicts the behavioral defense response and its breakdown during long sepsis.

A peptide targeting outer membrane protein A of Acinetobacter baumannii exhibits antibacterial activity by reducing bacterial pathogenicity.

The World Health Organization has classified multidrug-resistant (MDR) Acinetobacter baumannii as a significant threat to human health, necessitating the urgent discovery of new antibacterial drugs to combat bacterial resistance. Outer membrane protein A of A. baumannii (AbOmpA) is an outer membrane-anchored β-barrel-shaped pore protein that plays a critical role in bacterial adhesion, invasion, and biofilm formation. Therefore, AbOmpA is considered a key virulence factor of A. baumannii. Herein, we screened three phage display peptide libraries targeting AbOmpA and identified several peptides. Among them, P92 (amino acid sequence: QMGFMTSPKHSV) exhibited the highest binding affinity with AbOmpA, with a KD value of 7.84 nM. In vitro studies demonstrated that although P92 did not directly inhibit bacterial growth, it significantly reduced the invasion and adhesion capabilities of multiple clinical isolates of MDR A. baumannii and concentration-dependently inhibited biofilm formation by acting on OmpA. Furthermore, the polymerase chain reaction results confirmed a significant positive correlation between the antibacterial effect of P92 and OmpA expression levels. Encouragingly, P92 also displayed remarkable therapeutic efficacy against A. baumannii infection in various models, including an in vitro cell infection model, a mouse skin infection model, and a mouse sepsis model. These results highlight P92 as a novel and highly effective antimicrobial molecule specifically targeting the virulence factor AbOmpA.

Upregulation of Cullin1 neddylation promotes glycolysis and M1 polarization of macrophage via NF-κB p65 pathway in sepsis.

This study aimed to explore the underlying mechanism of neddylation in macrophage polarization during sepsis. A mouse model of sepsis was established by cecal ligation and puncture (CLP). ELISA and Flow cytometry were performed to analyze the generation of pro-inflammatory factors and M1/M2 macrophage polarization, respectively. Western blotting was applied to detect NEDD8-mediated neddylation and glycolysis-related proteins. ECAR method was used to analyze the glycolysis level. HE staining was applied to detect the lung injury. The bacterial load in peritoneal cavity and peripheral blood was determined by counting the colony-forming units. The results showed the upregulated neddylation, M1 polarization and glycolysis of macrophage in patients with sepsis and CLP-challenged mice. NEDD8-mediated Cullin1 neddylation promoted M1 polarization and glycolysis to accelerate inflammation via NF-κB p65 pathway in E.coli-treated Raw264.7 cells. MLN4924 treatment alleviated sepsis by inhibiting neddylation to prevent M1 polarization in CLP-challenged mice. In summary, this study demonstrated that upregulation of NEDD8-mediated Cullin1 neddylation promotes glycolysis and M1 polarization of macrophage via NF-κB p65 pathway, accelerating inflammation in sepsis.

The role of Gαq in regulating NLRP3 inflammasome activation.

G proteins are a class of important signal transducers in mammalians. G proteins can corpoarated with G proteincoupled receptors (GPCRs) and transmit signals from extracellular stimuli into intracellular response, which will regulate a series of biological functions. G-proteins are heterotrimeric proteins composed of Gα, Gβ, and Gγ subunits. Based on structural and functional similarity of their α-subunits, G proteins are typically grouped into four classes (Gi, Gs, Gq/11, and G12/13). The Gq/11 subfamily consists of Gq, G11, G14, and G15/16 proteins. Gαq is the α-subunit of Gq protein and encoded by GNAQ. Our previous studies revealed that Gαq play an important role in regulating T cell survival and T cell differentiation. Inflammasomes are multiprotein complexes that play a critical role in modulating innate inflammatory response. NLRP3 inflammasome is currently the most extensively studied inflammasome. We found that Gαq suppressed NLRP3 inflammasome activation in macrophage, Gαq also suppressed NLRP3 inflammasome activation in a LPS-induced sepsis mouse model. Gαq can locate to mitochondria and Gαq was required for the maintenance of mitochondrial homeostasis. Gαq regulated NLRP3 inflammasome activation by modulating mitochondrial reactive oxygen species (mtROS). We found that Gαq suppressed NLRP3 inflammasome activation in macrophage, Gαq also suppressed NLRP3 inflammasome activation in a LPS-induced sepsis mouse model. Gαq can locate to mitochondria and Gαq was required for the maintenance of mitochondrial homeostasis. Gαq regulated NLRP3 inflammasome activation by modulating mitochondrial reactive oxygen species (mtROS). Our results indicate that Gαq regulates NLRP3 inflammasome activation by modulating mitochondrial ROS production. Our research provides new mechanistic insight into the activation of NLRP3 inflammasome. As it has been proved that NLRP3 inflammasome plays an important role in the pathogenesis many diseases such as Alzheimer's disease, cancer, and inflammatory bowel disease, Gαq might become a novel drug target for these diseases in future.

Gut microbiota-derived acetic acids promoted sepsis-induced acute respiratory distress syndrome by delaying neutrophil apoptosis through FABP4

In patients with sepsis, neutrophil apoptosis tends to be inversely proportional to the severity of sepsis, but its mechanism is not yet clear. This study aimed to explore the mechanism of fatty acid binding protein 4 (FABP4) regulating neutrophil apoptosis through combined analysis of gut microbiota and short-chain fatty acids (SCFAs) metabolism. First, neutrophils from bronchoalveolar lavage fluid (BALF) of patients with sepsis-induced acute respiratory distress syndrome (ARDS) were purified and isolated RNA was applied for sequencing. Then, the cecal ligation and puncture (CLP) method was applied to induce the mouse sepsis model. After intervention with differential SCFAs sodium acetate, neutrophil apoptosis and FABP4 expression were further analyzed. Then, FABP4 inhibitor BMS309403 was used to treat neutrophils. We found CLP group had increased lung injury score, lung tissue wet/dry ratio, lung vascular permeability, and inflammatory factors IL-1β, TNF-α, IL-6, IFN-γ, and CCL3 levels in both bronchoalveolar lavage fluid and lung tissue. Additionally, FABP4 was lower in neutrophils of ARDS patients and mice. Meanwhile, CLP-induced dysbiosis of gut microbiota and changes in SCFAs levels were observed. Further verification showed that acetic acids reduced neutrophil apoptosis and FABP4 expression via FFAR2. Besides, FABP4 affected neutrophil apoptosis through endoplasmic reticulum (ER) stress, and neutrophil depletion alleviated the promotion of ARDS development by BMS309403. Moreover, FABP4 in neutrophils regulated the injury of RLE-6TN through inflammatory factors. In conclusion, FABP4 affected by gut microbiota-derived SCFAs delayed neutrophil apoptosis through ER stress, leading to increased inflammatory factors mediating lung epithelial cell damage.

Histopathological Description of Mouse Liver in a Sepsis Model Infected with Escherichia coli Treated with Paederia foetida L. Leaf Extract for Sepsis Prevention

The leaf of Paederia foetida L. is one type of medicinal plant that can be used as a preventive medicine for sepsis. This plant contains secondary metabolites such as alkaloids, flavonoids, triterpenoids, saponins, and other active compounds. The objective of this study was to determine the histopathological description of the liver in a mouse sepsis model infected with E. coli, with the administration of Paederia foetida L. leaf extract for sepsis prevention, and to ascertain the influence and effective dosage of the leaf extract as a preventive measure against liver histopathology in the sepsis model induced by E. coli. The method employed was a Completely Randomized Design (CRD). The study used 24 male white mice divided into 6 (six) groups. Data analysis was conducted using One Way ANOVA. The results of the study revealed the histopathological profile of liver cell degeneration in group PI (100mg/kg BW) at 20.79%±0.03, group PII (200mg/kg BW) at 21.63%±0.02, and group PIII (500mg/kg BW) at 9.08%±0.02. Necrosis rates were observed in group PI (100mg/kgBW) at 22.62%±0.04, group PII (200mg/kg BW) at 17.63%±0.02, and group PIII (500mg/kg BW) at 6.05%±0.02. The presence of polymorphonuclear leukocytes (PMN) was detected in group PI (100mg/kgBW) at 39.56%±0.03, group PII (200mg/kgBW) at 28.05%±0.02, and group PIII (500mg/kg BW) at 18.45%±0.03. The test results showed a significant effect of P. foetida L. leaf extract as a preventive measure against liver histopathology in the mouse sepsis model infected with E. coli, with significant values for necrosis (p=0.000), cell degeneration (p=0.000), and PMN (p=0.000). The most effective dosage of P. foetida L. leaf extract as a preventive measure against liver histopathology in the mouse sepsis model infected with E. coli was the dosage used in group PIII (500mg/kgBW).

Salvianolic acid B improves the microcirculation in a mouse model of sepsis through a mechanism involving the platelet receptor CD226.

Salvianolic acid B (SalB) demonstrates diverse clinical applications, particularly in cardiovascular and cerebral protection. This study primarily investigated the effects of SalB on sepsis. The model of sepsis via caecal ligation puncture (CLP) was established in male C57BL/6 mice. Therapeutic effects of SalB on hepatic and pulmonary injury, inflammatory responses and microcirculatory disturbances in sepsis were evaluated. Platelet aggregation and adhesion were measured via flow cytometry and an adhesion test. After overexpression of platelet-related activating molecules by 293T cells, the efficient binding of SalB and platelet CD226 molecules was further evaluated. Finally, neutralizing antibody experiments were used to assess the mechanism of SalB in alleviating the progression of sepsis. SalB mitigated hepatic and pulmonary impairments, reduced inflammatory cytokine levels and enhanced mesenteric microvascular blood flow in septic mice. SalB enhanced CLP-induced reduction of platelet count and platelet pressure cumulative volume. SalB reduced platelet adhesion to endothelial cells and platelet aggregation to leukocytes. A high binding efficiency was observed between SalB and the platelet adhesion molecule CD226. Ex vivo, interactions between SalB and platelets from CD226-knockout mice were markedly decreased. In vivo administration of CD226 neutralizing antibodies significantly delayed disease progression and enhanced mesenteric microcirculation in septic mice. In our murine model of sepsis, treatment with SalB improved the microcirculatory disturbance and hindered the progression of sepsis by inhibiting platelet CD226 function. Our results suggest SalB is a promising therapeutic approach to the treatment of sepsis.

Senescence landscape in the liver following sepsis and senolytics as potential therapeutics.

Senescence, caused by cell-cycle arrest, is a hallmark of aging. Senescence has also been described in embryogenesis, wound healing, and acute injuries. Sepsis is characterized by a dysregulated host response to infection, leading to organ dysfunction and mortality. Most of the pathophysiology of human sepsis is recapitulated in the mouse model of polymicrobial sepsis, developed by cecal ligation and puncture (CLP). In this report, we demonstrate a rapid onset of cellular senescence in the liver of mice subjected to CLP-induced sepsis, characterized by the upregulation of p21, p53, and other senescence markers, including SA-βgal. Using RNAscope, confocal microscopy, and flow cytometry, we further confirm the emergence of p21-expressing senescence phenotype in the liver 24 h after sepsis induction. Senescence was observed in several cell types in the liver, including hepatocytes, endothelial cells, and macrophages. We determined the landscape of senescence phenotype in murine sepsis by single-cell sequencing, which further ascertained that this cell fate is not confined to any particular cell type but displays a heterogeneous distribution. Furthermore, we observed a significant reduction in mortality following sepsis when mice were treated with senolytics, a combination of dasatinib and quercetin, before the CLP surgery. Our experiments unequivocally demonstrated a rapid development of cellular senescence with sepsis and, for the first time, described the senescence landscape in the sepsis liver and the possible role of senescent cells in the worsening outcome following sepsis.

Nppb contributes to Sepsis-Induced myocardial injury by regulating Senescence-Related genes

BackgroundSepsis, a systemic inflammatory condition, is a leading cause of mortality due to cardiovascular injury. Sepsis and cellular senescence are closely related, yet the specific mechanisms are still unclear. This study aims to identify a novel therapeutic target for mitigating sepsis-induced myocardial injury. MethodsWe initially assessed serum inflammatory markers and myocardial injury indicators in septic mice. This involved observing inflammatory cell infiltration in ventricular muscle tissue, assessing cardiac function, and recording electrocardiograms. We examined the expression of connexin 40 (Cx40) and connexin 43 (Cx43) and analyzed mitochondrial structures in ventricular tissues. A conditional heart-specific Nppb knockout mouse model was then developed in mice to evaluate these changes. Ventricular tissues were analyzed via mRNA sequencing to identify differentially expressed genes (DEGs), which were cross-referenced with senescence-related genes to identify key hub genes. The expression and distribution of hub genes were subsequently analyzed by single-cell analysis. Finally, the expression of the senescence-related gene CCL2, along with cardiac structure and function, was validated in a conditional heart-specific Nppb knockout sepsis mouse model. ResultsMyocardial injury severity positively correlated with serum brain natriuretic peptide (BNP) in septic mice. Conditional heart-specific Nppb knockout improved myocardial injury outcomes in mice with sepsis. The DEGs identified in the conditional heart-specific Nppb knockout model overlapped with senescence-related genes, identifying seven upregulated genes associated with inflammation, cardiac contraction and apoptotic pathways. Single-cell analysis confirmed high CCL2 levels and an increased macrophage presence correlating with sepsis progression. Conditional heart-specific Nppb knockout reduced CCL2 levels, which were associated with improved cardiac structure and function. ConclusionThis study confirms that conditional heart-specific Nppb knockout reduces CCL2 expression, thereby ameliorating myocardial injury in septic mice. Targeting Nppb to regulate the senescence-related gene CCL2 may represent an effective strategy for treating myocardial injury in septic patients.

Protective effect of gut microbiota restored by fecal microbiota transplantation in a sepsis model in juvenile mice.

Restoring a balanced, healthy gut microbiota through fecal microbiota transplantation (FMT) has the potential to be a treatment option for sepsis, despite the current lack of evidence. This study aimed to investigate the effect of FMT on sepsis in relation to the gut microbiota through a sepsis model in juvenile mice. Three-week-old male mice were divided into three groups: the antibiotic treatment (ABX), ABX-FMT, and control groups. The ABX and ABX-FMT groups received antibiotics for seven days. FMT was performed through oral gavage in the ABX-FMT group over the subsequent seven days. On day 14, all mice underwent cecal ligation and puncture (CLP) to induce abdominal sepsis. Blood cytokine levels and the composition of fecal microbiota were analyzed, and survival was monitored for seven days post-CLP. Initially, the fecal microbiota was predominantly composed of the phyla Bacteroidetes and Firmicutes. After antibiotic intake, an extreme predominance of the class Bacilli emerged. FMT successfully restored antibiotic-induced fecal dysbiosis. After CLP, the phylum Bacteroidetes became extremely dominant in the ABX-FMT and control groups. Alpha diversity of the microbiota decreased after antibiotic intake, was restored after FMT, and decreased again following CLP. In the ABX group, the concentrations of interleukin-1β (IL-1β), IL-2, IL-6, IL-10, granulocyte macrophage colony-stimulating factor, tumor necrosis factor-α, and C-X-C motif chemokine ligand 1 increased more rapidly and to a higher degree compared to other groups. The survival rate in the ABX group was significantly lower (20.0%) compared to other groups (85.7%). FMT-induced microbiota restoration demonstrated a protective effect against sepsis. This study uniquely validates the effectiveness of FMT in a juvenile mouse sepsis model, offering potential implications for clinical research in critically ill children.

Cloperastine Reduces IL-6 Expression via Akt/GSK3/Nrf2 Signaling in Monocytes/Macrophages and Ameliorates Symptoms in a Mouse Sepsis Model Induced by Lipopolysaccharide.

Cloperastine (CLP) is a drug with a central antitussive effect that is used to treat bronchitis. Therefore, we have attempted to examine the anti-inflammatory effects of CLP. CLP reduced the secretion of interleukin (IL)-6, a pro-inflammatory cytokine, from RAW264.7 monocyte/macrophage-linage cells treated with lipopolysaccharide (LPS). IL-6 is a biomarker of sepsis and has been suggested to exacerbate its symptoms. We found that the intraperitoneal administration of CLP reduced IL-6 levels in the lungs and also improved hypothermia in mice with LPS-induced sepsis. CLP ameliorated kidney pathologies such as congestion and increased the survival rate of mice administered with a lethal dose of LPS. To reveal the mechanisms underlying the anti-inflammatory function of CLP, we analysed the intracellular signaling in LPS-treated RAW264.7 cells. CLP induced the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase 3 (GSK3) and also increased the amount of nuclear factor erythroid-2-related factor 2 (Nrf2) in RAW264.7 cells with/without LPS. Wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), reduced the upregulated phosphorylation levels of Akt and GSK3 and the increased amount of Nrf2. It also halted the reduction of IL-6 secretion caused by CLP. These results suggest that CLP has an anti-inflammatory function via Akt/GSK3/Nrf2 signaling and could be a candidate drug for the treatment of inflammatory diseases, including sepsis.

Bergapten attenuates sepsis-induced acute lung injury in mice by regulating Th17/Treg balance

Background The abnormality of the immune system caused by infection is a contributor to the organ dysfunctions associated with sepsis. The balance between Th17/Treg cells is essential for maintaining immune homeostasis. Bergapten is a natural furocoumarin and has been reported to alleviate the Th17/Treg imbalance. Here, we explored the effects of bergapten on the inflammation and immune state in mouse models of sepsis. Methods The model was established using the cecal ligation and puncture method. Mice were administered 30 mg/kg bergapten. Histological examination, RT-qPCR, enzyme-linked immunosorbent assay, immunoblotting, immunofluorescence, immunohistochemistry, and flow cytometry were used to evaluate the effects of bergapten in vivo. Results Bergapten ameliorated lung damage, reduced lung wet/dry weight ratio, inhibited myeloperoxidase activity, and reduced inflammatory cell infiltration. Bergapten also restrained sepsis-induced inflammation via inhibition of inflammatory cytokines and NF-κB signaling. These effects were accompanied by the restored Th17/Treg balance induced by bergapten. Bergapten decreased the number of Th17 cells and elevated the number of Tregs, and this effect was mediated by the signal transducer and activator of transcription 5 (STAT5)/Forkhead box P3 (Foxp3) and STAT3/retinoid-related orphan receptor-γt (RORγt) pathways. Conclusions Bergapten exerted anti-inflammatory effects in acute lung injury by improving the Th17/Treg balance, which suggested a potential of bergapten as an immunomodulatory drug treating sepsis-associated diseases.