Cecal Ligation And Puncture Research Articles

Induction of Early Pulmonary Senescence in Experimental Sepsis.

Background: Sepsis continues to pose a significant threat to human life and represents a substantial financial burden. In addition to replicative stress resulting from telomeric loss, recent studies have identified multiple factors contributing to cell cycle arrest. Furthermore, our understanding of pathways associated with cellular senescence, such as CD47-mediated suppression of efferocytosis, has expanded. However, beyond in vitro experiments, the impact of cell stress during complex systemic illnesses, including sepsis, remains poorly understood. Consequently, we conducted an investigation into molecular alterations related to senescence-associated pulmonary mechanisms during experimental non-pulmonary sepsis.Methods: Male C57BL/6JRj mice were anesthetized and subjected to either control conditions (sham) or cecal ligation and puncture (CLP) to induce sepsis. 24 h or 7 d after CLP, animals were sacrificed and blood, bronchoalveolar fluids and lungs were harvested and analyzed for morphological and biochemical changes.Results: Histological damage in pulmonary tissue, as well as increases in plasma levels of surfactant protein D, indicated development of alveolar-focused acute lung injury after CLP. Additionally, we observed a significant upregulation of the CD47-QPCTL-SHP-1-axis in lungs of septic mice. Whereas the expression of p16, a marker primarily indicating manifested forms of senescence, was decreased after CLP, the early marker of cellular senescence, p21, was increased in the lungs during sepsis. Later, at 7 d after CLP, pulmonary expression of CD47 and QPCTL-1 was decreased, whereas SHP-1 was significantly enhanced.Conclusion: Our findings suggest an activation of senescent-associated pathways during experimental sepsis. However, expanding the experiments to other organ systems and in vivo long-term models are necessary to further evaluate the sustained mechanisms and immunopathophysiological consequences of cellular senescence triggered by septic organ injury.

Macrophage S1PR2 Drives Sepsis-induced Immunosuppression by Exacerbating Mitochondrial Fragmentation.

Macrophage mitochondrial dysfunction is associated with immunosuppression and poor prognosis of septic patients. Mitochondrial fragmentation drives mitochondrial dysfunction. Our previous study has found that S1PR2 regulates macrophage phagocytosis during sepsis, while the role of S1PR2 in immunosuppression and the mechanisms remain further studied. This study aimed to unveil the relationship between macrophage mitochondrial fragmentation and sepsis-induced immunosuppression, as well as the S1PR2-related mechanisms thereof. Peripheral blood monocytes were collected from healthy controls (n = 12), nonseptic critical controls (n = 13) and septic patients (n = 19). Peritoneal macrophages were harvested from wildtype and S1pr2-/- mice (MMRRC strain iD, 12830) after cecal ligation and puncture (CLP). Mitochondrial ultrastructure was evaluated using transmission electron microscopy. The impact of mitochondrial ultrastructure alteration on immunosuppression of monocytes-macrophages was evaluated. Compared with nonseptic and healthy controls, peripheral blood monocytes from septic patients exhibited increased S1PR2 expression, mitochondrial fragmentation, and mitochondrial dysfunction. Mitochondrial fragmentation was negatively associated with HLA-DR expression. S1PR2 expression was positively correlated with mitochondrial fragmentation and negatively correlated with HLA-DR expression. In mice subjected to CLP, S1PR2 depletion ameliorated macrophage mitochondrial fragmentation and dysfunction, boosted immunity, and improved survival. Mechanistically, in response to sepsis, S1PR2 activates ROCK I to induce Drp1 phosphorylation, resulting in Drp1-dependent mitochondrial fragmentation of macrophages. Drp1 inhibition by Mdivi-1 mitigated S1PR2-induced macrophage immunosuppression and improved the prognosis of mice following CLP. In conclusion, S1PR2-induced mitochondrial fragmentation is a crucial factor mediating septic immunosuppression, highlighting its potential as a promising therapeutic target in sepsis.

Investigating the efficacy of dapsone in treating sepsis induced by cecal ligation and puncture surgery in male mice.

Sepsis is a life-threatening condition caused by the body's response to an infection. Dapsone is a sulfone with antibiotic properties, and experimental evidence suggests it has significant anti-inflammatory and anti-oxidative stress effects. The objective of this study was to investigate the efficacy of dapsone in mice after CLP (cecal ligation and puncture) surgery, which is a model for inducing sepsis. The study divided animals into five groups: CLP, sham, and three groups receiving different doses of dapsone (0.5, 1, 2mg/kg). Sepsis was induced through CLP surgery, followed by dapsone administration. In each group, half of the mice were used to evaluate levels of various markers and pathological changes at 24h post-CLP, while the other half was used to record the mortality rates within 96h. The results showed that single-dose administration of dapsone at (0.5, 1, 2mg/kg) after CLP surgery improved survival compared to the CLP group. Dapsone was also associated with a significant reduction in pro-inflammatory cytokines TNF-α, IL-1β, IL-6, NO, and MPO, as well as lactate and creatinine serum levels. However, dapsone did not have a significant effect on urea serum levels. In conclusion, the data suggest that dapsone treatment leads to increased survival in septic mice after CLP, and due to its ability to reduce TNF-α, IL-1β, IL-6, MPO,and lactate levels, it has anti-inflammatory effects in sepsis. The sepsis treatment with dapsone in mice protects against inflammation and oxidative stress.

5'tiRNA-33-CysACA-1 promotes septic cardiomyopathy by targeting PGC-1α-mediated mitochondrial biogenesis

BackgroundWe revealed for the first time that the expression of 158 tRNA-derived small RNAs (tsRNAs) was altered in septic cardiomyopathy (SCM) by microarray analysis, and we selected 5'tiRNA-33-CysACA-1, which was the most significantly up-regulated, as a representative to explore the roles and mechanisms of tsRNAs in SCM. MethodsWe constructed a sepsis model by cecum ligation and puncture (CLP) in mice and detected the expression of 5'tiRNA-33-CysACA-1 using quantitative real-time PCR (qRT-PCR). The supernatant generated after LPS stimulation of macrophages was used as the conditional medium (CM) to stimulate H9C2 and established the injured cell model. CCK-8 and LDH release assays were used to detect cell viability and cell death. Mitochondrial membrane potential (MMP), ATP production, ROS production, and Mitotracker Red mitochondrial morphology were assayed to assess mitochondrial function. Expression of mRNA for molecules related to the mitochondrial quality control system was verified by qRT-PCR. The mechanism by which 5'tiRNA-33-CysACA-1 regulates peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) expression was examined by western blot, mRNA stability analysis, and rescue experiments. ResultsExpression of 5'tiRNA-33-CysACA-1 was elevated in cardiac tissue and H9C2 cells during septic myocardial injury. Stimulation of the CM resulted in cardiomyocyte injury and impaired mitochondrial function. Transfection of 5'tiRNA-33-CysACA-1 mimic in CM further downregulated PGC-1α expression, inhibited mitochondrial biogenesis thereby impairing mitochondrial function and leading to decreased cardiomyocyte activity and increased cell death. In contrast, transfection of the inhibitor ameliorated the above biological processes. In addition, mRNA stability assay and bioinformatics analysis showed that 5'tiRNA-33-CysACA-1 led to a decrease in the stability of PGC-1α mRNA, which in turn downregulated the expression of PGC-1α and promoted the development of SCM. Conclusions5'tiRNA-33-CysACA-1 expression is upregulated in SCM and inhibits mitochondrial biogenesis by targeting PGC-1α and decreasing the stability of PGC-1α mRNA, leading to mitochondrial dysfunction and promoting the development of SCM.

IRGM Deficiency Exacerbates Sepsis-Induced Acute Lung Injury by Inhibiting Autophagy Through the AKT/mTOR Signaling Pathway.

Sepsis is a life-threatening condition characterized by organ dysfunction due to an impaired immune response to infection. The lungs are highly susceptible to infection, often resulting in acute lung injury (ALI). The immune-related GTPase M (IRGM) and its murine homolog Irgm1 mediate autophagy and are implicated in inflammatory diseases, yet their roles in sepsis-induced ALI remain unclear. We used RNA sequencing and bioinformatics to explore IRGM regulation. Sepsis-induced ALI was modeled in mice using cecal ligation and puncture (CLP). An in vitro model was created by stimulating A549 cells with lipopolysaccharide (LPS). In A549 cells, LPS treatment induced upregulation of IRGM expression and enhanced autophagy levels. IRGM knockdown exacerbated LPS-induced ALI, characterized by suppressed autophagy and increased apoptosis, along with significantly elevated levels of p-AKT and p-mTOR. Further investigation revealed that treatment with the AKT inhibitor MK2206 effectively reversed the autophagy inhibition caused by IRGM knockdown and reduced apoptosis. These findings suggest that the AKT/mTOR signaling pathway plays a crucial role in IRGM-mediated protection against sepsis-related ALI. This study identifies the protective role of IRGM in sepsis-induced ALI and reveals that IRGM mitigates ALI by promoting autophagy through inhibition of the AKT/mTOR pathway. These findings provide insights into the pathogenesis of sepsis-related ALI and highlight IRGM as a potential therapeutic target.

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.

Melatonin attenuates sepsis-induced muscle atrophy by regulating the PI3K/Akt signaling pathway

BackgroundIn intensive care units, sepsis-related muscle atrophy is a severe complication of numerous diseases, yet the underlying mechanism and potential therapeutic options remain elusive. Recent research has identified melatonin as a promising candidate for attenuating organ dysfunction triggered by sepsis. MethodsWe used in vitro and in vivo models to simulate sepsis, C2C12 myotubes were treated with LPS, and the mice underwent cecal ligation and puncture (CLP) surgery. Following a pretreatment regimen involving melatonin and the AKT inhibitor MK-2206 2HCl, we analyzed changes in p-Akt and MuRF1 protein levels, fiber cross-sectional areas, and myotube diameters. The analyses included RNA sequencing, Western blotting, qRT–PCR, and immunofluorescence staining. ResultsActivation of the PI3K/Akt pathway in skeletal muscle occurred 24 h post-CLP surgery in mice. This was accompanied by upregulated MuRF1 expression and reduced muscle fiber cross-sectional area, which culminated in muscle atrophy. However, these detrimental effects were attenuated when the mice were pretreated with melatonin via intraperitoneal injection for seven consecutive days. Similarly, LPS treatment of C2C12 myotubes activated the PI3K/Akt pathway, elevated MuRF1 expression, and markedly reduced myotube diameter after 48 h, leading to muscle atrophy. Pretreatment of C2C12 myotubes with melatonin 24 h in advance mitigated these adverse effects. However, cotreatment of C2C12 myotubes with melatonin and MK-2206 2HCl attenuated the beneficial effects of melatonin. ConclusionMelatonin can attenuate sepsis-induced muscle atrophy by regulating the PI3K/Akt pathway.

Clemastine mitigates sepsis-induced acute kidney injury in rats; the role of α-Klotho/TLR-4/MYD-88/NF-κB/ Caspase-3/ p-P38 MAPK signaling pathways

Sepsis is a fatal condition, with an annual incidence of more than 48 million cases as well as 11 million deaths resulting from it. Moreover, sepsis continues to rank as the fifth most prevalent cause of mortality globally. The objective of this study is to investigate if Clemastine (CLM) pretreatment protects against acute kidney injury (AKI) caused by cecal ligation and puncture ( CLP) via modulating Toll-like receptor-4 (TLR-4), Myeloid differentiation primary response 88 (MYD-88), nuclear factor kappa B (NF-κB), Bcl-2-associated X (Bax), B-cell lymphoma-2 (Bcl-2), and caspase-3 signaling pathways. CLM markedly attenuated sepsis-caused molecular, biochemical, and histopathological alterations. CLM downregulated the levels of the proinflammatory markers, suppressed the expression of cleaved caspase-3, TLR-4 and MYD-88 as well as inactivating NF-κB p-P65 and p-P38 proteins, inhibited Bax, NF-κB, and caspase-3 genes expression, and augmented α-Klotho protein expression as well as Bcl-2 gene expression. Finally, CLM pretreatment protected against acute kidney injury by preventing TLR-4/ p-P38 pathway-mediated apoptotic cell death in rats.

Exosomal miR-146a-5p Derived from HSCs Accelerates Sepsis-induced Liver Injury by Suppressing KLF-4.

This study aimed to investigate whether and how lipopolysaccharide (LPS) activated hepatic stellate cells (HSCs) regulate macrophage activity and to explore the impact of microRNAs (miRNAs) in exosomes from HSCs on this process. Mice subjected to LPS or cecal ligation and puncture (CLP) were used to explore sepsis-induced liver injury. Liver injury was evaluated using HE staining, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured. LPS-Exo or N-LPS-Exo from HSCs were added to hepatic macrophages, and iNOS, IL-1β, and TNF-α expression was detected via Western blotting. miRNA microarray analysis and PCR were used to evaluate differentially expressed miRNAs between LPS-Exo and N-LPS-Exo. Target genes were screened using the TargetScan database and verified with luciferase assays and WB. Inflammation and macrophage activity were observed in vivo using HE and CD86 staining in mice injected with PKH67-labeled LPS-Exo or N-LPS-Exo. Sepsis-related liver injury activates hepatic stellate cells, which regulate macrophage activity through exosomes. Specifically, exosomal miR-146a-5p secreted by hepatic stellate cells targets KLF-4, regulating the macrophage inflammatory response through the JNK signaling pathway. Exosomes containing miRNA-146a-5p released from HSCs following LPS treatment may increase macrophage sensitivity to LPS and trigger an inflammatory response. Exosomal miR-146a-5p derived from HSCs accelerates sepsis-induced liver injury by suppressing KLF-4 expression.

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.

Maresin-1 Ameliorates Sepsis-Induced Microglial Activation Through Modulation of the P38 MAPK Pathway.

Sepsis is a life-threatening disease characterized by a dysregulated immune response to infection, often leading to neuroinflammation. As a known immunomodulator, Maresin-1 (MaR1) may have potential applications in the treatment of sepsis-induced neuroinflammation, but its effects in this context are unknown. We used a mouse cecum ligation and puncture (CLP)-induced sepsis model and an in vitro lipopolysaccharide (LPS)-induced neuroinflammatory model of BV2 microglia. Expression of microglial cell markers (IBA1, CD11B, CD68, CD86 and CD206) and pro-inflammatory markers (iNOS and COX2) was assessed. The role of MaR1 in regulating the P38 MAPK pathway was explored using the P38 MAPK inhibitor SB203580. In the CLP model, an increased proportion of M1-type microglia was observed, and MaR1 was able to reverse it. However, the combination of SB203580 and MaR1 did not enhance the therapeutic effect compared to SB20580 alone. In vitro experiments, MaR1 inhibited LPS-induced P38 MAPK nuclear translocation and decreased the expression of pro-inflammatory markers such as iNOS and COX2. As with the animal results, no stacking effect could be obtained with the co-administration of SB203580 and MaR1. Our findings suggest that MaR1 attenuates sepsis-induced neuroinflammation mainly by inhibiting phosphorylation of P38 MAPK in microglial cells. This suggests that MaR1 may have a potential therapeutic role in the treatment of sepsis neuroinflammation.

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.

Lipid Nanoparticles from L. meyenii Walp Mitigate Sepsis through Multimodal Protein Corona Formation.

Plant-derived nanoparticles (PDNP) are nano-sized particles isolated from various edible plants that contain bioactive components involved in regulating cellular immune responses against pathogenic intrusion and inflammation. This study describes a novel PDNP derived from Lepidium meyenii Walp (maca) that efficiently captures pro-inflammatory cytokines and acute phase proteins in its protein corona to enhance survival in two representative lethal models of sepsis. Lipid nanoparticles were isolated from maca (MDNP) and triacylglycerols and phytoceramides were identified as major constituents using lipidomics. The physicochemical properties of MDNPs were determined, anti-inflammatory effects of MDNP were evaluated using in vitro models and in vivo using endotoxemia and cecal ligation and puncture (CLP) polymicrobial sepsis models. Proteomic analysis of MDNP in healthy or LPS-induced inflammatory plasma was used to determine the composition and inflammatory pathways modulated due to the MDNP protein corona. In vitro studies showed that MDNP were non-toxic, reduced macrophage activation, and effectively sequestered pro-inflammatory cytokines to mitigate NF- κ B activity under lipopolysaccharide (LPS) stimulation. In a pre-established LPS-induced endotoxemia model, MDNP-treated mice showed significantly reduced systemic pro-inflammatory cytokines and enhanced survival. Untargeted proteomics and pathway analysis of the MDNP protein corona identified an enrichment in acute phase proteins in MDNP-LPS plasma coronas. MDNP treatment also significantly improved survival in the CLP sepsis model in the absence of antibiotics. This work identified MDNP as an efficient, plant-derived lipid NP that broadly sequesters and neutralizes a compilation of inflammatory mediators in their coronas, offering multimodal therapeutic potential for treating inflammatory diseases.

Abstract PR015: Sepsis-induced inflammation alters natural killer cell-mediated surveillance of liver metastasis

Abstract A majority of pancreatic ductal adenocarcinoma (PDAC) patients who undergo surgery for primary tumor resection will develop lethal metastases, despite having no evidence of metastasis at the time of their initial diagnosis. Liver metastases constitute nearly half of recurrences detected within the first six months following PDAC resection. Several clinical and experimental studies provide evidence that perioperative inflammation, including infectious complications like sepsis, positively correlates with liver metastasis across several malignancies. Despite these observations, it is still unknown whether there is a causal link between perioperative inflammation and PDAC liver metastasis. To gain mechanistic insight into the regulation of PDAC liver metastasis in the context of perioperative inflammation, we established mouse models that combine experimental PDAC liver metastasis with either the cecal ligation and puncture (CLP) model of polymicrobial sepsis or the lipopolysaccharide (LPS) model of acute sterile endotoxemia. Mice challenged with CLP prior to seeding PDAC cells in the liver had increased metastatic burden at endpoint compared to sham laparotomy controls. In contrast, mice challenged with LPS prior to PDAC cell seeding had reduced metastatic burden at endpoint compared to PBS-injected controls. We hypothesized that these opposing pro- and anti-metastatic effects of CLP and LPS, respectively, were due to qualitatively distinct inflammatory responses elicited in the liver. Our profiling of the host response to either CLP or LPS revealed shared systemic changes, including activation of the acute-phase protein response. However, LPS-associated inflammation uniquely upregulated a distinct set of interferon-regulated genes in the liver important for modifying immune cell activity (i.e., Ccl2, Ccl5, Cxcl9, Cxcl10). Accordingly, immunostaining and flow cytometry of the liver revealed that LPS uniquely increased the abundance of activated natural killer (NK) cells and MPO+ myeloid cells. We utilized Tlr4 -/- mice, which lack the primary receptor for LPS, to determine that the anti-metastatic effect of LPS required a host-facilitated response downstream of TLR4-mediated signaling. Through a series of genetic models and short-term depletion experiments, we determined that NK cells restrict PDAC cell seeding and outgrowth in our experimental liver metastasis model, and that this protective effect is further enhanced by activation of type-I interferon signaling in the host. Our findings confirm prior work identifying NK cell-mediated surveillance of disseminated cancer cells as an important mechanism in protecting against liver metastasis and show sterile endotoxemia and its associated inflammation establish a protective ‘anti-metastatic niche’ marked by enhanced NK cell activity. Further insights into the establishment of this niche may reveal potential therapeutic strategies to reduce the incidence of liver metastasis among resected PDAC patients. Citation Format: Nicole Sivetz, Patrick J. Cunniff, Christopher R. Vakoc, Semir Beyaz, Mikala Egeblad. Sepsis-induced inflammation alters natural killer cell-mediated surveillance of liver metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr PR015.

Acute hyperglycemia exacerbates neuroinflammation and cognitive impairment in sepsis-associated encephalopathy by mediating the ChREBP/HIF-1α pathway

ObjectivesDelirium is a prominent symptom of sepsis-associated encephalopathy (SAE) and is highly prevalent in septic patients hospitalized in the intensive care unit, being closely connected with raised mortality rates. Acute hyperglycemia (AH) has been recognized as a separate risk factor for delirium and a worse prognosis in critically sick patients. Nevertheless, the exact contribution of AH to the advancement of SAE is still unknown.MethodsThis research retrospectively evaluated the connection between blood glucose levels (BGLs) and the incidence of delirium and death rates in septic patients in the ICU of a tertiary comprehensive hospital. In addition, a septic rat model was induced through cecal ligation and puncture (CLP), after which continuous glucose infusion was promptly initiated via a central venous catheter post-surgery to evaluate the potential implications of AH on SAE. Next, septic rats were assigned to four groups based on target BGLs: high glucose group (HG, ≥ 300 mg/dL), moderate glucose group (MG, 200–300 mg/dL), normal glucose group (NG, < 200 mg/dL), and a high glucose insulin-treated group (HI, 200–300 mg/dL) receiving recombinant human insulin treatment (0.1 IU/kg/min). The sham group (SG) received an equivalent volume of saline infusion and denoted the NG group. The effects of AH on neuroinflammation and cognitive function in septic rats were evaluated using behavioral tests, histopathological examination, TUNEL staining, ELISA, and Western blot. The effects of glucose levels on microglial activation and glucose metabolism following lipopolysaccharide (LPS, 1 μg/mL) exposure were assessed using CCK8 assay, qRT-PCR, Western blot, and ELISA.ResultsOur findings revealed that AH during sepsis was a separate risk factor for delirium and assisted in predicting delirium occurrence. AH raised the levels of systemic and central inflammatory cytokines in septic rats, promoting neuronal apoptosis, blood–brain barrier disruption, and cognitive impairment. In addition, both in vivo and in vitro, an elevated glucose challenge increased the ChREBP, HIF-1α, glycolytic enzymes, and inflammatory cytokines expressions in microglia after exposure to CLP or LPS.ConclusionsThese results collectively suggest that hyperglycemia can exacerbate neuroinflammation and delirium by enhancing microglial glycolysis under septic conditions, potentially mediated by upregulation of the ChREBP/HIF-1α signaling pathway.Graphical abstract

Impact of metabolic syndrome on cardiovascular, inflammatory and hematological parameters in female mice subjected to severe sepsis

The aim of the study was to evaluate the effect of metabolic syndrome (MetS) on female Swiss mice subjected to severe polymicrobial sepsis induced by cecal ligation and puncture (CLP). MetS was induced in neonatal Swiss mice by subcutaneous injection of monosodium glutamate (MSG) at 4 mg/g body weight from day 1 to day 5 after birth, while animals in the control group (CTL) were treated with equimolar saline solution at the same volume and period. On the 75th day of life, the CLP model was used to induce severe polymicrobial sepsis. For inflammatory parameters, we assessed nitric oxide (NO), determined by the cadmium/Griess technique, and quantified IL-6 and IL1β using the ELISA technique. Glucose levels were measured 24 h before and after CLP using a glucose monitor, and the lipid profile was assessed using commercial kits. Cardiovascular parameters were measured using the CODA platform, and hematological evaluation was determined by standard counting. Unlike male mice, MetS did not alter the survival of females subjected to severe sepsis. Both CTL and MetS CLP groups exhibited hypotension and hypoglycemia, accompanied by leukopenia and increased inflammatory cytokine IL-6. The cytokine IL1β Only increased in MetS CLP group compared to CTL CLP and MetS Sham. It was also observed that MetS attenuated some parameters during sepsis, such as hematological parameters and resistance to NO increase. We can conclude that the obesity paradox theory is not observed in females. Thus, our findings provide new insights for the literature linking MetS and sepsis.

Deletion of MAPL ameliorates septic cardiomyopathy by mitigating mitochondrial dysfunction

AimMitochondrial dysfunction is a critical factor in the pathogenesis of septic cardiomyopathy (SCM). Mitochondrial anchored protein ligase (MAPL), a small ubiquitin-like modifier (SUMO) E3 ligase, plays a significant role in mitochondrial function. However, the role of MAPL in SCM remains unclear.MethodsTo investigate the role of MAPL in SCM, cardiomyocyte-specific MAPL knockout mice were generated. A cecal ligation and puncture (CLP) procedure was employed to induce a sepsis-like condition.ResultsThe expression of MAPL in heart tissues and H9C2 cardiomyocytes was elevated following CLP challenge or lipopolysaccharide (LPS) stimulation. MAPL deficiency ameliorated CLP-induced cardiac injury, dysfunction, and inflammation, and also improved the survival rate of mice following CLP operation. Additionally, MAPL deficiency or knockdown inhibited LPS-induced cardiomyocyte apoptosis, improved mitochondrial structural abnormalities, and increased ATP production. Furthermore, MAPL knockdown mitigated LPS-induced reductions in mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) production. Mechanistically, the expression of dynamin-related protein 1 (drp1) in the mitochondria of heart tissues or H9C2 cardiomyocytes was elevated under septic conditions. Accordingly, the SUMOylation of drp1 in heart tissues or H9C2 cardiomyocytes was increased under sepsis conditions, which was reduced by MAPL knockout or knockdown.ConclusionOur results reveal that MAPL promotes cardiac injury/dysfunction and inflammation in SCM. Deficiency or knockdown of MAPL alleviates SCM by reducing drp1 SUMOylation as well as drp1-mediated mitochondrial dysfunction. These findings suggest that targeting MAPL may represent a therapeutic strategy for patients with SCM.

Thermoregulation and survival during sepsis: insights from the cecal ligation and puncture experimental model

BackgroundSepsis remains a major global health concern due to its high prevalence and mortality. Changes in body temperature (Tb), such as hypothermia or fever, are diagnostic indicators and play a crucial role in the pathophysiology of sepsis. This study aims to characterize the thermoregulatory mechanisms during sepsis using the cecal ligation and puncture (CLP) model and explore how sepsis severity and ambient temperature (Ta) influence Tb regulation and mortality. Rats were subjected to mild or severe sepsis by CLP while housed at thermoneutral (28 °C) or subthermoneutral (22 °C) Ta, and their Tb was monitored for 12 h. Blood and hypothalamus were collected for cytokines and prostaglandin E2 (PGE2) analysis.ResultsAt 28 °C, febrile response magnitude correlated with sepsis severity and inflammatory response, with tail vasoconstriction as the primary heat retention mechanism. At 22 °C, Tb was maintained during mild sepsis but dropped during severe sepsis, linked to reduced UCP1 expression in brown adipose tissue and less effective vasoconstriction. Despite differences in thermoregulatory responses, both Ta conditions induced a persistent inflammatory response and increased hypothalamic PGE2 production. Notably, mortality in severe sepsis was significantly higher at 28 °C (80%) compared to 22 °C (0%).ConclusionsOur findings reveal that ambient temperature and the inflammatory burden critically influence thermoregulation and survival during early sepsis. These results emphasize the importance of considering environmental factors in preclinical sepsis studies. Although rodents in experimental settings are often adapted to cold environments, these conditions may not fully translate to human sepsis, where cold adaptation is rare. Thus, researchers should carefully consider these variables when designing experiments and interpreting translational implications.Graphical Graphical representation of the thermoregulatory and inflammatory responses to mild and severe sepsis in rats housed at thermoneutral (28 °C) and subthermoneutral (22 °C) ambient temperatures (Ta). The model highlights distinct body temperature outcomes: fever and hypothermia. At thermoneutral Ta, severe sepsis induces a high fever, associated with increased hypothalamic PGE2, cytokine levels, and mortality, while mild sepsis leads to a moderate fever. In contrast, at subthermoneutral Ta, severe sepsis results in hypothermia with decreased UCP1 expression and lower mortality, whereas mild sepsis maintains normal body temperature. The impact of Ta on sepsis severity, thermoregulatory mechanisms, and survival is emphasized.

Inhibiting SIRT2 Attenuates Sepsis-Induced Acute Kidney Injury via FOXO1 Acetylation-Mediated Autophagy Activation.

Sepsis-associated acute kidney injury (SAKI), a common complication in intensive care units (ICUs), is linked to high morbidity and mortality. Sirtuin 2 (SIRT2), an NAD+-dependent deacetylase, has been shown to have distinct effects on autophagy regulation compared to other sirtuins, but its role in SAKI remains unclear. This study explored the potential of SIRT2 as a therapeutic target for SAKI. We found that inhibition of SIRT2 with the antagonist AGK2 improved the survival of septic mice. SIRT2 inhibition reduced kidney injury, as indicated by lower levels of KIM-1, NGAL, serum creatinine (Scr), blood urea nitrogen (BUN), and proinflammatory cytokines following cecal ligation and puncture (CLP). Pretreatment with AGK2 in septic mice increased autophagosome and autolysosome formation in renal tubular epithelial cells (RTECs) and upregulated LC3 II expression in the renal cortex. Consistent with in vivo findings, SIRT2 gene silencing promoted autophagy in LPS-treated HK-2 cells, whereas SIRT2 overexpression inhibited it. Mechanistically, SIRT2 inhibition increased FOXO1 acetylation, inducing its nuclear-to-cytoplasmic translocation, which promoted kidney autophagy and alleviated SAKI. Our study suggests SIRT2 as a potential target for SAKI therapy.

Pharmacological effects of koumine on acute lung injury in septic mice: From in vivo experiments and network pharmacology studies

Acute lung injury (ALI) caused by sepsis is one of the most common critical diseases, which is difficult to treat and has a high fatality rate. Koumine is one of the main active components of Gelsemium plants and has been confirmed to have potential for drug development; however, its therapeutic effects on ALI have not yet been studied. This study established ALI due to sepsis using cecal ligation and puncture (CLP) and assessed the therapeutic effects of koumine by measuring mouse survival rates, lung tissue pathological damage, inflammatory factors, and oxidative stress levels. Additionally, network pharmacology was utilized to explore the underlying mechanisms. The results showed that koumine inhibited the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β), thereby inhibiting inflammatory response, reducing lung injury score and lung wet to dry ratio. In addition, koumine reduced oxidative stress in mice by reducing myeloperoxidase (MPO) and malondialdehyde (MDA) and increasing superoxide dismutase (SOD) content. Network pharmacology analysis showed that 52 putative targets were relevant, and SLC6A4, HTR3A, JAK2 and JAK3 were the key targets. GO and KEGG pathway enrichment analysis showed that the related mechanisms involved neuroactive ligand-receptor interaction, calcium signaling pathway, serotonergic synapses, cholinergic synapses, etc. In summary, this study confirmed the potential therapeutic effect of koumine in sepsis induced ALI, suggesting its development prospect as a novel candidate drug for ALI, and providing data support.