Search Results (132)

Sepsis is characterized by the over-production of pro-inflammatory cytokines. Cecal ligation and puncture (CLP) is a well-accepted model for recreating sepsis-induced renal injury in mice. The current study investigates how citronellol, a naturally occurring substance with a variety of biological characteristics, can prevent acute kidney inflammation brought on by CLP. In the CLP mouse model, citronellol was administered orally at doses of 50 and 100 mg/kg. Serum levels of creatinine and urea were used as markers of renal function, and the Murine Sepsis Score (MSS) was used to assess the severity of sepsis. According to our findings, CLP caused a decline in renal function, as shown by higher serum urea and creatinine levels in comparison to control mice. Nevertheless, administering citronellol as pretreatment at doses of 50 and 100 mg/kg alleviated the deterioration in renal functions. Citronellol decreased levels of serum urea and creatinine. Citronellol demonstrated an anti-inflammatory effect by reducing pro-inflammatory cytokines (TNF-α, NF-κB, AP-1) and KIM-1. Overall, our study suggests that citronellol holds a promise as a potential therapeutic agent for mitigating kidney inflammation. Full article

The Salmonella enterica serovar Typhimurium (ST) mutant lacking the msbB gene (ΔmsbB) has been widely studied as a candidate for attenuated bacterial vectors in therapeutic applications. Deletion of msbB results in LPS with under-acylated lipid A, which lowers endotoxicity while maintaining structural integrity. This attenuation has traditionally been attributed to reduced TLR4 activation due to weaker interaction between the modified lipid A and TLR4. In our study, we confirmed that ΔmsbB ST was less lethal than wild-type (WT) ST in a mouse sepsis model. However, this difference persisted even in TLR4- and caspase-11-deficient mice, suggesting that LPS signaling is not the primary determinant of virulence. In vitro, bone marrow–derived macrophages (BMDMs) from TLR4- or caspase-11-deficient mice showed only modest reductions in ST-induced cell death and cytokine production. Importantly, ΔmsbB ST behaved similarly to WT ST in these assays, further indicating that LPS-mediated signaling is not central to the observed attenuation. Our previous studies showed that ST-induced mortality in mice is primarily mediated through NLRC4 activation. Using qPCR and immunoblotting, we found that expression of NLRC4 activators was diminished in the ΔmsbB strain. Additionally, the mutant exhibited increased outer membrane permeability—likely contributing to its heightened antibiotic sensitivity—and reduced motility due to lower flagellin protein levels. In summary, the attenuation of virulence observed in the ΔmsbB strain is not directly due to altered LPS–TLR4 interactions, but rather an indirect effect of diminished expression of virulence factors that activate the NLRC4 inflammasome. Full article

Background: Patients with sepsis-associated encephalopathy (SAE) present with cognitive impairments. Serotonergic neurotransmission plays a critical role in regulating cognitive processes, and its dysfunction may contribute to SAE-related deficits. However, the effect of 5-hydroxytryptophan (5-HTP), a direct serotonin precursor, on SAE has not been investigated. We hypothesized that 5-HTP could alleviate cognitive dysfunction in SAE. Methods: The SAE mouse model was induced via intraperitoneal administration of lipopolysaccharide (LPS, 10 mg/kg). Cognitive function and locomotor activity were assessed using the Barnes maze, novel object recognition test, and open-field test to evaluate the effects of 5-hydroxytryptophan (5-HTP). Additionally, WAY100635, a selective 5-HT1A receptor antagonist, was co-administered with 5-HTP to investigate the potential mechanisms underlying its effects on SAE-related cognitive dysfunction. The effects of 5-HTP and WAY100635 on cognition and motor activity were also investigated in healthy mice. Results: LPS-induced sepsis caused a learning deficit. A dose of 10 mg/kg 5-HTP improved cognitive dysfunction, whereas doses of 25 and 100 mg/kg worsened cognitive dysfunction. Moreover, 100 mg/kg 5-HTP increased mortality in SAE mouse models. Neither 5-HTP (10 mg/kg) nor WAY100635 (1 mg/kg) alone exerted a significant impact on the locomotor activity or cognitive function of healthy mice. The cognition-enhancing effect of 5-HTP (10 mg/kg) was reversed by WAY100635 (1 mg/kg). Conclusions: improvement in cognitive dysfunction by 5-HTP suggests that serotonergic transmission plays a role in the pathophysiology of SAE, and 5-HTP, an over-the-counter supplement approved for human use, may hold clinical potential for the prevention and treatment of SAE. Full article

Background: Hepcidin not only sustains systemic iron homeostasis but also functions as an antimicrobial peptide. During this study, we sought to analyze the ability of hepcidin to protect against sepsis-associated acute kidney injury (SAKI) and elucidated its underlying mechanisms in mediating ferroptotic pathways. Methods: A SAKI mouse model was created via cecal ligation and puncture (CLP), along with an LPS-induced Human Kidney-2 (HK-2) cell model, to study the protective mechanism of hepcidin against SAKI. Through the analysis of renal injury biomarkers and ferroptosis-related molecules, combined with quantitative detection of nuclear factor-erythroid 2-related factor-2 (Nrf2) nuclear translocation and glutathione peroxidase 4 (GPX4), a regulatory protein of ferroptosis, we uncovered the hepcidin-mediated mechanisms underlying ferroptosis in SAKI. Results: Hepcidin significantly attenuated renal function impairment in mice with SAKI and reduced the sepsis-driven increase in inflammatory mediators. As sepsis was associated with enhanced renal ferroptosis, hepcidin exerted a therapeutic effect by mitigating ferroptosis to a degree comparable with that of the ferroptosis inhibitor Ferrostatin-1 (Fer-1). Furthermore, hepcidin conferred renoprotective effects in SAKI by promoting the nuclear translocation of Nrf2, which in turn mediated the upregulation of the downstream anti-ferroptotic protein GPX4. Importantly, the Nrf2 inhibitor ML385 abrogated both the hepcidin-induced nuclear translocation of Nrf2 and the subsequent increase in GPX4 expression. Conclusions: Protective effects of hepcidin against SAKI are mediated by the Nrf2/GPX4 ferroptosis pathway, underscoring its therapeutic potential for SAKI. Full article

Sepsis-induced cardiomyopathy is a life-threatening complication lacking targeted therapies. While empagliflozin (Empa), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, confers robust cardioprotection, its specific efficacy in treating sepsis-induced cardiomyopathy and the Empa mechanisms remain poorly defined, limiting its targeted therapeutic use. In this study, we investigated Empa’s effects and its novel mechanisms in a murine lipopolysaccharide (LPS)-induced model of septic cardiomyopathy. Empa pre-treatment effectively prevented LPS-induced cardiac dysfunction, preserving ejection fraction and mitigating myocardial injury (assessed by histology and ELISA) and fibrosis. Transcriptomic analysis revealed that Empa’s protective effects were profoundly linked to the preservation of cardiomyocyte cytoskeletal pathways, alongside its anti-inflammatory actions. The results indicate that LPS induced a pathological dissociation of the matrix protein Integrin α5 (ITGA5) from the cell–cell adhesion protein Desmocollin-2 (DSC2), a structural disruption completely abrogated by Empa in vivo. This ITGA5-DSC2 stabilization was further confirmed to be a cardiomyocyte-intrinsic effect, recapitulated in vitro in both neonatal mouse cardiomyocytes and human AC16 cells. Building on this mechanistic insight, a computational design was successfully employed to develop 13 novel helical protein binders specifically targeting the ITGA5, yielding candidates with favorable structural properties as potential therapeutic leads. These findings establish the cardiomyocyte structural homeostasis via the ITGA5-DSC2 adhesion axis as a novel, key SGLT2-independent mechanism for empagliflozin’s cardioprotection, revealing promising new therapeutic approaches for sepsis-induced cardiomyopathy. Full article

Midkine (MDK) is a multifunctional heparin-binding growth factor, and has been shown to regulate cell growth, survival, and migration. It also plays important roles in several inflammatory diseases such as sepsis. However, the role of MDK in the lungs has not yet been elucidated. In the present study, we investigated the role of MDK in pulmonary inflammation experiments using a mouse lipopolysaccharide (LPS)-induced pulmonary inflammation model and human bronchial cells. Wild-type and MDK-deficient mice were administered intratracheally with LPS, and several inflammatory parameters were analyzed. In the wild-type mice, MDK mRNA and protein in lung tissues were significantly increased after intratracheal LPS administration. The MDK-deficient mice showed significantly lower counts of total cells and neutrophils, as well as lower concentrations of total protein and neutrophil chemokines, KC and MIP-2 in bronchoalveolar lavage fluid, compared to wild-type mice. Moreover, mRNA expressions of TNF-α, keratinocyte chemoattractant (KC), and macrophage inflammatory protein (MIP)-2 in lung tissues, as well as the histopathological lung inflammation score, were significantly lower in the MDK-deficient mice. Furthermore, in in vitro experiments using bronchial epithelial cells, LPS stimulation increased mRNA expression of MDK, and MDK knockdown by siRNA decreased LPS-induced TNF-α and CXCL8 upregulation. These findings suggest that deficiency of MDK attenuates LPS-induced pulmonary inflammation, at least in part, through inhibiting inflammatory cytokine and chemokine upregulation in the lungs. Full article

There is a present need to develop alternative biotherapeutic drugs to mitigate the exacerbated inflammatory immune responses characteristic of sepsis. The potent endotoxin lipopolysaccharide (LPS), a major component of Gram-negative bacterial outer membrane, activates the immune system via Toll-like receptor 4 (TLR4), triggering macrophages and a persistent cascade of inflammatory mediators. Our previous studies have demonstrated that Fh15, a recombinant member of the Fasciola hepatica fatty acid binding protein family, can significantly increase the survival rate by suppressing many inflammatory mediators induced by LPS in a septic shock mouse model. Although Fh15 has been proposed as a TLR4 antagonist, the specific mechanisms underlying its immunomodulatory effect remained unclear. In the present study, we employed a quantitative proteomics approach using tandem mass tag (TMT) followed by LC-MS/MS analysis to identify and quantify differentially expressed proteins that participate in signaling pathways downstream TLR4 of macrophages, which can be dysregulated by Fh15. Data are available via ProteomeXchange with identifier PXD065520. Based on significant fold change (FC) cut-off of 1.5 and p-value ≤ 0.05 criteria, we focused our attention to 114 proteins that were upregulated by LPS and downregulated by Fh15. From these proteins, TNFα, IL-1α, Lck, NOS2, SOD2 and CD36 were selected for validation by Western blot on murine bone marrow-derived macrophages due to their relevant roles in the NF-κB, iNOS, oxidative stress, and phagosome signaling pathways, which are closely associated with sepsis pathogenesis. These results suggest that Fh15 exerts a broad spectrum of action by simultaneously targeting multiple downstream pathways activated by TLR4, thereby modulating various aspects of the inflammatory responses during sepsis. Full article

The objectives of this study were to design, synthesize, and evaluate the antibacterial activity of a series of novel aminoguanidine-tetralone derivatives. Thirty-four new compounds were effectively synthesized through nucleophilic substitution reaction and guanidinylation reaction. Chemical structures of all the desired compounds were identified by NMR and HR-MS spectroscopy. Most of the synthesized compounds showed significant antibacterial activity against ESKAPE pathogens and clinically resistant Staphylococcus aureus (S. aureus) isolates. S. aureus is an important pathogen that has the capacity to cause a variety of diseases, including skin infections, pneumonia, and sepsis. The most active compound, 2D, showed rapid bactericidal activity against S. aureus ATCC 29213 and MRSA-2 with MIC/MBC values of 0.5/4 µg/mL and 1/4 µg/mL, respectively. The hemolytic activity and cytotoxicity of 2D was low, with HC₅₀ and IC_{50(HEK 293-T)} values of 50.65 µg/mL and 13.09 µg/mL, respectively. Compound 2D induced the depolarization of the bacterial membrane and disrupted bacterial membrane integrity, ultimately leading to death. Molecular docking revealed that dihydrofolate reductase (DHFR) may be a potential target for 2D. In the mouse skin abscess model caused by MRSA-2, 2D reduced the abscess volume, decreased bacterial load, and alleviated tissue pathological damage at doses of 5 and 10 mg/kg. Therefore, compound 2D may be a promising drug candidate for antibacterial purposes against S. aureus. Full article

Background/Objectives: This study aims to develop and evaluate neutrophil-membrane-coated nanoparticles (Siv@NMs) encapsulating sivelestat for the treatment of sepsis-induced endothelial injury. Leveraging the intrinsic chemotactic properties of neutrophil membranes, Siv@NMs are engineered to achieve site-specific delivery of sivelestat to damaged endothelia, thereby overcoming the limitations of conventional therapies in mitigating endothelial dysfunction and multiorgan failure associated with sepsis. Methods: Siv@NMs were synthesized through a combination of ultrasonication and extrusion techniques to encapsulate sivelestat within neutrophil-membrane-derived vesicles. Comprehensive physicochemical characterization included analysis of particle size distribution, zeta potential, and encapsulation efficiency. Stability profiles and controlled release kinetics were systematically evaluated under simulated conditions. In vitro investigations encompassed (1) endothelial cell biocompatibility assessment via cytotoxicity assays, (2) investigation of the targeting efficiency in suppressing endothelial neutrophil extracellular trap generation during inflammation, and (3) ROS-scavenging capacity quantification using flow cytometry with DCFH-DA fluorescent probes. In vivo therapeutic efficacy was validated using a cecal ligation and puncture (CLP) sepsis mouse model, with multiparametric monitoring of endothelial function, inflammatory markers, ROS levels, and survival outcomes. Results: The optimized Siv@NMs exhibited an average particle size of approximately 150 nm, and a zeta potential of −10 mV was achieved. Cellular studies revealed that (1) Siv@NMs selectively bound to inflammatory endothelial cells with minimal cytotoxicity, and (2) Siv@NMs significantly reduced ROS accumulation in endothelial cells subjected to septic stimuli. In vitro experiments demonstrated that Siv@NMs treatment markedly attenuated endothelial injury biomarkers’ expression (ICAM-1 and iNOS), suppressed formation of neutrophil extracellular traps, and improved survival rates compared to treatment with free sivelestat. Conclusions: The neutrophil-membrane-coated nanoparticles loaded with sivelestat present a breakthrough strategy for precision therapy of sepsis-associated endothelial injury. This bioengineered system synergistically combines targeted drug delivery with multimodal therapeutic effects, including ROS mitigation, anti-inflammatory action, and endothelial protection. These findings substantiate the clinical translation potential of Siv@NMs as a next-generation nanotherapeutic for sepsis management. Full article

Background/Objectives: Phytochemicals are increasingly recognized for their therapeutic potential in treating various diseases, including vascular disorders. High mobility group box 1 (HMGB1), a key mediator of late-stage sepsis, triggers the release of proinflammatory cytokines, leading to inflammation and systemic complications. Elevated plasma levels of HMGB1 impair diagnosis and prognosis while worsening outcomes in inflammatory conditions. 3-deoxysappanchalcone (3-DSC), a compound derived from Biancaea sappan (L.) Tod., has demonstrated anti-influenza and anti-allergic effects, though its role in HMGB1-mediated severe vascular inflammation remains unclear. This study hypothesized that 3-DSC could modulate lipopolysaccharide-induced HMGB1 activity and its downstream inflammatory pathways in human umbilical vein endothelial cells (HUVECs). Methods: In vitro and in vivo permeability; cell viability, adhesion, and excavation of leukocytes; the development of cell adhesion molecules; and lastly, the production of proinflammatory substances were investigated on human endothelial cells and mouse disease models to investigate the efficacy of 3-DSC in inflammatory conditions. Results: Experiments revealed that 3-DSC inhibited HMGB1 translocation from HUVECs, reduced neutrophil adhesion and extravasation, suppressed HMGB1 receptor formation, and blocked nuclear factor-κB (NF-κB) activation and tumor necrosis factor-α (TNF-α) synthesis. Conclusions: These findings suggest that 3-DSC effectively mitigates HMGB1-driven inflammation, offering promise as a therapeutic candidate for inflammatory diseases. Full article

Background: Sepsis is a life-threatening condition that is characterized by systemic inflammation and organ dysfunction, with adrenal dysfunction being a significant complication. This study aimed to investigate the role of necroptosis and hydrogen sulfide (H₂S) in sepsis-induced adrenal dysfunction. Methods: A cecal ligation and puncture (CLP)-induced sepsis mouse model was employed. Adrenocortical-specific mixed lineage kinase domain-like pseudokinase (MLKL) knockout (MLKL-KO) and cystathioneine β-synthase (CBS) knockout (CBS-KO) mice were generated using Cre-loxP technology and adrenocortical-specific Cre tool mice. In vitro experiments utilized TNFα-stimulated Y1 adrenocortical cells. The treatments included the H₂S donor NaHS, TNFα inhibitor R-7050, necroptosis inhibitor NSA and CBS inhibitor AOAA. Pathological assessment involved hematoxylin–eosin (H&E) staining and a Western blot analysis of necroptosis markers (the phosphorylation of MLKL (p-MLKL) and phosphorylation of receptor-interacting protein kinases 1 (p-RIPK1)). Results: Sepsis induced adrenal congestion, elevated TNFα levels, and activated necroptosis (increased p-MLKL/p-RIPK1) in wild-type mice. H₂S treatment attenuated adrenal damage, reduced TNFα, and suppressed necroptosis. MLKL knockout reduced septic adrenal dysfunction, whereas CBS knockout exacerbated septic adrenal dysfunction. In vitro, TNFα induced Y1 cell necroptosis, which was reversed by H₂S or NSA. AOAA exacerbated TNFα-induced necroptosis in Y1 cells. Conclusions: H₂S inhibits TNFα-mediated necroptosis, thereby preserving adrenal integrity in sepsis. Targeting the TNFα–necroptosis axis and enhancing endogenous H₂S production may represent novel therapeutic strategies for sepsis-associated adrenal dysfunction. Full article

Emerging resistance to colistin in Acinetobacter baumannii is concerning because of the limited therapeutic options for this important clinical pathogen. Given the shortage of new antibiotics, one strategy that has been proven to be therapeutically effective is to overcome antibiotic-resistant pathogens by combining existing antibiotics with another antibiotic or non-antibiotic. This study was designed to investigate the potential synergistic antibacterial activity of amorolfine, a morpholine antifungal drug, in combination with colistin against A. baumannii. In this work, antibiotic susceptibility testing, checkerboard assays, and time-kill curves were used to investigate the synergistic efficacy of colistin combined with amorolfine. The molecular mechanisms of combination therapy were analyzed using fluorometric assays, UV-vis spectroscopy, and molecular docking. Finally, we evaluated the in vivo efficacy of combination therapy against A. baumannii. In brief, the combination therapy showed significant synergistic activity against A. baumannii (FICI = 0.094). In addition, the combination of amorolfine improved the membrane disruption of colistin, and amorolfine exhibited the capacity of binding to DNA. Moreover, in a mouse sepsis model, this combination therapy increased survival compared to colistin monotherapy. Our findings demonstrated that amorolfine serves as a potential colistin adjuvant against Acinetobacter baumannii. Full article

Introduction: Septic patients have low levels of high-density lipoproteins (HDLs), which is a risk factor. Replenishing HDLs with synthetic HDLs (sHDLs) has shown promise as a therapy for sepsis. This study aimed to develop a computational approach to design and test new types of sHDLs for sepsis treatment. Methods: We used a three-step computational approach to design sHDL nanoparticles based on the structure of HDLs and their binding to endotoxins. We tested the efficacy of these sHDLs in two sepsis mouse models—cecal ligation and puncture (CLP)-induced and P. aeruginosa-induced sepsis models—and assessed their impact on inflammatory signaling in cells. Results: We designed four sHDL nanoparticles: two based on the ApoA-I sequence (YGZL1 and YGZL2) and two based on the ApoE sequence (YGZL3 and YGZL4). We demonstrated that an ApoE-based sHDL nanoparticle, YGZL3, provides effective protection against CLP- and P. aeruginosa-induced sepsis. The sHDLs effectively suppressed inflammatory signaling in HEK-blue or RAW264 cells. Conclusions: Unlike earlier approaches, we developed a new approach that employs computational simulations to design a new type of sHDL based on HDL’s structure and function. We found that YGZL3, an ApoE sequence-based sHDL, provides effective protection against sepsis in two mouse models. Full article

Sepsis is a leading cause of death in hospitalized patients. The underlying pathophysiologic mechanisms of sepsis have not been fully elucidated thus far. The receptor of programmed cell death 1 (PD-1) and its ligand (PD-L1), in combination with the Toll-like receptors (TLRs), seem to contribute considerably in systematic responses during sepsis. Investigating the relationship between them and identifying potential target pathways is important in the future management of sepsis, especially in relation to acute lung injury. This study investigated the interactions between TLR-5, -6, and -9 and PD-1/PD-L1 expression in a septic mouse model. Sixty C57BL/6J mice were included and categorized in six study groups. Three sepsis (S) groups (24 h, 48 h, and 72 h) and three sham (Sh) groups (24 h, 48 h, and 72 h) were created. Cecal ligation and puncture (CLP) was utilized to simulate sepsis in the S groups. Hematological analysis and lung tissue histopathological analysis were performed after 24 h, 48 h, and 72 h. Significant decreases in S groups compared to Sh groups in WBC and lymphocyte counts at 24, 48, and 72 h were observed. Significant increases in S groups compared to Sh groups in RBC and monocyte counts, IL-6 and IL-10 levels, alveolar flooding, and alveolar collapse were demonstrated by histopathological analysis. This study suggested a strong correlation between TLR expression and PD-1/PD-L1 up-regulation in lung tissue during sepsis. These molecules, also, seem to contribute to the histopathological changes in lung tissue during sepsis, leading to acute lung injury. Full article

Sepsis is a severe condition with high mortality, in which immune dysfunction plays a critical role. Poor oral health has been linked to frailty, but its impact on sepsis outcomes remains unclear. Therefore, we used a mouse model of malocclusion and sepsis to investigate how tooth loss affects immune responses during sepsis. Adult male C57BL/6 mice were divided into four groups: Control, Malocclusion (Mal), Sepsis (CS), and Malocclusion with Sepsis (Mal + CS). Malocclusion was induced by tooth extraction, and sepsis was induced using cecal slurry injection. We assessed survival rates, immune cell counts, and biochemical markers. The Mal + CS group exhibited significantly lower survival rates and greater weight loss compared to the CS group. The flow cytometry showed reduced neutrophils, monocytes, and T cells in the Mal + CS group. Elevated ALT and AST levels indicated liver damage. No significant differences in bacterial loads were observed, but immune suppression was exacerbated in the Mal + CS group. Malocclusion worsens sepsis outcomes by impairing both innate and adaptive immune responses. These findings emphasize the importance of oral health in improving sepsis prognosis and immune function during critical illnesses. Full article