Injury In Septic Mice Research Articles

Prim-O-glucosycimifugin attenuates liver injury in septic mice by inhibiting NLRP3 inflammasome/caspase-1 signaling cascades in macrophages

BackgroundLiver dysfunction and liver failure are serious complications of sepsis, directly leading to septic progression and death. Now, there is no specific therapeutics available for sepsis-related liver dysfunction. Prim-O-glucosylcimifugin (POG), a chromone richest in the roots of Saposhnikovia divaricata (Turcz.) Schischk, is usually used to treat headache, rheumatoid arthritis and tetanus. While, the underlying mechanisms of POG against sepsis-induced liver damage and dysfunction are still not clear. PurposeTo study the anti-sepsis effect of POG, and its pharmacological mechanism to protect liver injury by weakening the function of macrophages in septic livers through inhibiting NOD-like receptor protein 3 (NLRP3) inflammasome pathway. MethodIn vivo experiments, septic mouse model was induced by cecal ligation and puncture (CLP), and then the mortality was detected, liver inflammatory damages and plasma biomarkers of liver injury were evaluated by histopathological staining and biochemical assays, respectively. In vitro experiments, mouse primary peritoneal macrophages were treated with lipopolysaccharide (LPS) and ATP, and then the activated-inflammasomes, macrophage migration and polarization were detected by ASC immunofluorescence staining, transwell and flow cytometry assays, respectively. NLRP3 inflammasome components NLRP3, caspase-1, IL-1β and IL-18 protein expressions were detected using western blot assays, and the contents of IL-1β and IL-18 were measured by ELISA assays. ResultsPOG treatment significantly decreased the mortality, liver inflammatory damages, hepatocyte apoptosis and plasma biomarkers of liver injury in CLP-challenged male WT mice, which were comparable to those in ibuprofen (a putative anti-inflammatory drug)-supplemented septic male WT mice and septic NLRP3 deficient-male mice. POG supplementation significantly suppressed NLRP3 inflammasome activation in septic liver tissues and cultured macrophages, by significantly reducing NLRP3, cleaved-caspase-1, IL-1β and IL-18 levels, the activated-inflammasome ASC specks, and macrophage infiltration and migration, as well as M1-like polarization, but significantly increasing M2-like polarization. These findings were similar to the pharmacological effects of ibuprofen, NLRP3 deficiency, and a special NLRP3 inhibitor, MCC950. ConclusionPOG protected against sepsis by inhibiting NLRP3 inflammasome-mediated macrophage activation in septic liver and attenuating liver inflammatory injury, indicating that it may be a potential anti-sepsis drug candidate.

Protective effect of excretory-secretory proteins from Trichinella spiralis muscle larvae against myocardial injury in septic mice

To evaluate the protective effect of excretory-secretory proteins from Trichinella spiralis muscle larvae (Ts-MES) on sepsis-induced myocardial injury in mice. Eighty male BALB/C mice were randomized equally into sham-operated group, myocardial injury group, Ts-MES treatment group and dexamethasone treatment group. In the latter 3 groups, sepsis-induced myocardial injury models were established by cecal ligation and perforation; the sham operation was performed by exposure of the cecum without ligation or perforation. Forty minutes after the operation, the mice were given intraperitoneal injections 150 μL PBS, 20 μg TS-MES or 0.3 mg/kg dexamethasone as indicated. At 12 h after the operation, 6 mice were randomly selected from each group for echocardiography, and 8 mice were used for observing the survival rate within 72 h. The remaining 6 mice were examined for myocardial pathologies with HE staining and serum levels of NTPro-BNP and cTnI with ELISA; the expressions of TNF-α, IL-6, IL-10 and TGF-β in the serum and myocardial tissue were detected using ELISA and qRT-PCR. Compared with the sham-operated mice, the septic mice showed significantly decreased cardiac function indexes (LVEF, LVFS, and E/A) with lowered survival rate within 72 h (P < 0.001) and significantly higher myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.01). Treatment with TS-MES significantly improved the cardiac function and 72-h survival rate (P < 0.05) and lowered the myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.05) in the septic mice. Compared with the sham-operated mice, the septic mice had obviously increased TNF-α and IL-6 levels in the serum and myocardial tissue (P < 0.001), which were significantly lowered by treatment with TS-MES (P < 0.05). TS-MES and dexamethasone both increased the levels of IL-10 and TGF-β in the septic mice, but the changes were significant only in TS-MES-treated mice (P < 0.05). Ts-MES are capable of protecting against myocardial injury in septic mice by reducing the production of pro-inflammatory cytokines and enhancing the levels of regulatory cytokines.

IL-1R1 blockade attenuates liver injury through inhibiting the recruitment of myeloid-derived suppressor cells in sepsis

Myeloid-derived suppressor cells (MDSCs) mobilize and migrate from bone marrow to peripheral tissues or immune organs, which is associated with poor prognosis in sepsis. Intervention of MDSCs might be a potential target for the effective treatment of sepsis. In the present study, we demonstrated that IL-1R1 blockade with either recombinant human IL-1R antagonist Anakinra or IL-1R1 deficiency had a protective effect on the liver injury in septic mice. The possible mechanism was that Anakinra treatment and IL-1R1 knockout inhibited the migration of MDSCs to the liver in sepsis, thus attenuating the immune suppression of MDSCs on effector T cells characterized with the decrease in proportion of CD4+ and CD8+ T cells. Furthermore, the switch from pro-inflammatory M1 macrophage to anti-inflammatory M2 phenotype and the ability of bacterial clearance in the liver of septic mice were enhanced obviously by Anakinra and IL-1R1 deficiency, which contributes to the attenuated liver injury. Taken together, these findings provide new ideas for revealing the relationship between IL-1R1 and MDSCs in sepsis, thereby providing a potentially effective target for ameliorating septic liver injury.

LncRNA SNHG1 promotes sepsis-induced myocardial injury by inhibiting Bcl-2 expression via DNMT1.

Myocardial injury is a frequently occurring complication of sepsis. This study aims to investigate the molecular mechanism of long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1)‐mediated DNA methyltransferase 1/B‐cell lymphoma‐2 (DNMT1/Bcl‐2) axis in sepsis‐induced myocardial injury. Mice and HL‐1 cells were treated with lipopolysaccharide (LPS) to establish animal and cellular models simulating sepsis and inflammation. LncRNA SNHG1 was screened out as a differentially expressed lncRNA in sepsis samples through microarray profiling, and the upregulated expression of lncRNA SNHG1 was confirmed in myocardial tissues of LPS‐induced septic mice and HL‐1 cells. Further experiments suggested that silencing of lncRNA SNHG1 reduced the inflammation and apoptotic rate of LPS‐induced HL‐1 cells. LncRNA SNHG1 inhibited Bcl‐2 expression by recruiting DNMT1 to Bcl‐2 promoter region to cause methylation. Inhibition of Bcl‐2 promoter methylation reduced the inflammation and apoptotic rate of LPS‐induced HL‐1 cells. In vivo experiments substantiated that lncRNA SNHG1 silencing alleviated sepsis‐induced myocardial injury in mice. Taken together, lncRNA SNHG1 promotes LPS‐induced myocardial injury in septic mice by downregulating Bcl‐2 through DNMT1‐mediated Bcl‐2 methylation.

Activation of CD4+ T Cell-Derived Cannabinoid Receptor 2 Signaling Exacerbates Sepsis via Inhibiting IL-10.

The cannabinoid receptor 2 (CB2) is a receptor mainly expressed in immune cells and believed to be immunosuppressive in infective or inflammatory models. However, its role in sepsis has not been fully elucidated. In this study, we delineate the function and mechanism of CB2 in the cecal ligation and puncture-induced septic model in mice. The activation of CB2 signaling with HU308 led to decreased survival rates and more severe lung injury in septic mice, and lower IL-10 levels in peritoneal lavage fluid were observed in the CB2 agonist group. The mice with conditional knockout of CB2-encoding gene CNR2 in CD4+ T cells (CD4 Cre CNR2fl/fl) improved survival, enhanced IL-10 production, and ameliorated pulmonary damage in the sepsis model after CB2 activation. In addition, double-knockout of the CNR2 gene (Lyz2 Cre CD4 Cre CNR2fl/fl) decreased the susceptibility to sepsis compared with Lyz2 Cre CNR2fl/fl mice. Mechanistically, the blockade of IL-10 with the anti-IL-10 Ab abolished its protection in CD4 Cre CNR2fl/fl mice. In accordance with the animal study, in vitro results revealed that the lack of CNR2 in CD4+ cells elevated IL-10 production, and CB2 activation inhibited CD4+ T cell-derived IL-10 production. Furthermore, in the clinical environment, septic patients expressed enhanced CB2 mRNA levels compared with healthy donors in PBMCs, and their CB2 expression was inversely correlated with IL-10. These results suggested that the activation of CD4+ T cell-derived CB2 increased susceptibility to sepsis through inhibiting IL-10 production.

Fudosteine attenuates acute lung injury in septic mice by inhibiting pyroptosis via the TXNIP/NLRP3/GSDMD pathway

There is a dearth of effective pharmacotherapies for sepsis-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS) to which oxidative stress and excessive inflammation are major contributors. We hypothesized that fudosteine, a cysteine derivative, may protect against sepsis-induced ALI/ARDS given its anti-oxidant capacity. This study aimed to investigate the effects and mechanisms of fudosteine in a mouse model of sepsis-induced ALI. Sepsis was induced by cecal ligation and puncture (CLP). The intragastrical administration of fudosteine (25 mg/kg, 50 mg/kg, and 100 mg/kg) dose-dependently decreased proinflammatory cytokine levels in bronchoalveolar lavage fluid (BALF) and serum and reduced BALF/serum albumin and lung wet/dry weight ratios in septic mice. The lung injury score was significantly lowered by fudosteine [e.g., 0.18 ± 0.03 (100 mg/kg) vs. 0.42 ± 0.03 (CLP), P < 0.0001]. Fudosteine also reduced the biomarkers of lung epithelial injury in BALF and markedly improved oxidative stress indicators in lung tissues [e.g., malondialdehyde: 337.70 ± 23.78 (100 mg/kg) vs. 686.40 ± 28.36 (CLP) nmol/mg protein, P < 0.0001]. Lung tissue transcriptomics analyses revealed suppressed inflammatory responses and oxidative stress with fudosteine and the involvement of the inflammasome and pyroptosis pathways. Western blot analyses indicated that fudosteine inhibited the sepsis-induced activation of gasdermin D (GSDMD) and caspase-1 and the upregulation of thioredoxin-interacting protein (TXNIP), nucleotide-binding domain, leucine-rich repeat-containing receptor, pyrin domain-containing-3 (NLRP3), and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). Fudosteine therefore protects against sepsis-induced ALI in mice, and the inhibition of pyroptosis via the TXNIP/NLRP3/GSDMD pathway may be an underlying mechanism.

Effects of exosomes from human adipose-derived mesenchymal stem cells on pulmonary vascular endothelial cells injury in septic mice and its mechanism

Effects of exosomes from human adipose-derived mesenchymal stem cells on pulmonary vascular endothelial cells injury in septic mice and its mechanism

Inhibiting ferroptosis attenuates myocardial injury in septic mice: the role of lipocalin-2

To explore the contribution of ferroptosis to myocardial injury in mouse models of sepsis and the role lipocalin-2 (Lcn2) in ferroptosis. Adult male C57BL/6 mice were randomized equally into sham-operated group, cecal ligation and puncture (CLP)-induced sepsis group, and CLP + Fer-1 group where the mice received intraperitoneal injection of 5 mg/mL Fer-1 (5 mg/kg) 1 h before CLP. The left ventricular functions (including LVEF%, LVFS%, LVIDd and LVIDs) of the mice were assessed by echocardiography at 24 h after CLP. Myocardial injury in the mice was observed with HE staining, and the changes of myocardial ultrastructure and mitochondria were observed using transmission electron microscopy (TEM). Serum TNF-α level was measured with ELISA, and the changes of myocardial iron content were detected using tissue iron kit. The protein expressions of myocardial Lcn2, glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) were determined with Western blotting. The septic mice showed significantly decreased LVEF%, LVFS% and LVIDd and increased LVIDs at 24 h after CLP (P < 0.05), and these changes were significantly improved by Fer-1 treatment. Sepsis caused obvious myocardial pathologies and changes in myocardial ultrastructure and mitochondria, which were significantly improved by Fer-1 treatment. Fer-1 treatment also significantly ameliorated sepsis-induced elevations of serum TNF-α level, myocardial tissue iron content, and Lcn2 protein expression and the reduction of GPX4 and FSP1 protein expression levels (P < 0.05). GPX4- and FSP1-mediated ferroptosis are involved in myocardial injury in mice with CLP-induced sepsis, and inhibition of ferroptosis can attenuate septic myocardial injury, in which Lcn2 may play a role.

TNFAIP8 modulates the survival and immune activity of Th17 cells via p53/ p21/ MDM2 pathway after acute insult

Th17 cells induced immunosuppression plays a vital role in sepsis. As a member of the tumor necrosis factor α induced protein 8 (TNFAIP8) family, TNFAIP8 is associated with different physiopathological conditions with immunological responses. However, its potential roles in regulating Th17 cells after the acute insult have not been fully elucidated. In this study, sepsis was induced by cecal ligation and puncture (CLP) in the male adult C57BL/6 mice. The stable TNFAIP8 knockdown (KD) Th17 cells were established by infecting with lentivirus carrying TNFAIP8-specific shRNA. CCK-8 assay was conducted to evaluate Th17 cell proliferation, and Annexin V/7-AAD assay was applied for apoptosis measurement by flow cytometry. The alterations of p53/ p21/ MDM2 pathway were assessed by Western blot. We observed that a high TNFAIP8 expression level was related to acute injury in septic mice. TNFAIP8 silencing suppressed Th17 cell proliferation and cytokine production in vivo and in vitro. In addition, TNFAIP8 KD increased Th17 cell apoptosis in septic mice. Furthermore, TNFAIP8 seems to affect the immune function of Th17 cells by regulating p53/ p21/ MDM2 signaling processes. We found that TNFAIP8 KD caused the up-regulation of P21 and MDM2, and also elevated p53 protein level during sepsis. Pharmacological inhibition of p53 partially rescued cell proliferation and apoptotic effects of TNFAIP8 KD. In summary, our work suggests that TNFAIP8 modulates the survival and immune function of Th17 cells after acute insult, which was possibly mediated through the p53/ p21/ MDM2 pathway.

Trichostatin A improves the inflammatory response and liver injury in septic mice through the FoxO3a/autophagy signaling pathway.

Sepsis-induced liver injury is a fatal complication of sepsis. Trichostatin A (TSA) regulates inflammation and autophagy in some human diseases, and forkhead box O3a (FoxO3a) has been shown to regulate autophagy. The present study aims to investigate whether TSA exerts its effects on septic liver injury through the FoxO3a/autophagy signaling pathway. A sepsis mouse model was constructed by the cecal ligation and puncture (CLP) method, and AML12 cells were pretreated with lipopolysaccharide (LPS) (1 μg/mL) to establish a sepsis cell model. Forty mice were divided into four groups, namely control group, TSA group, CLP group, and CLP+TSA group, with 10 mice in each group. Cells were divided into control group, TSA group, LPS group, and LPS+TSA group. Hematoxylin-eosin (H&E) staining and biochemical methods were used to evaluate liver tissue injury. Enzyme-linked immunosorbent assay (ELISA) was applied to detect the expression of proinflammatory cytokines, and Western blotting and immunofluorescence were used to measure autophagy-related protein expression. Compared with the CLP group (mice), the proinflammatory cytokines (interleukin-β [IL-β] 2,665.27±324.90 pg/mL to 2,080.26±373.66 pg/mL; interleukin-6 [IL-6] 399.01±60.98 pg/mL to 221.90±46.89 pg/mL) and the hepatocyte injury markers (aspartate transaminase [AST] from 198.18±27.07 U/L to 128.42±20.55 U/L; alanine aminotransferase [ALT] from 634.98±74.10 U/L to 478.60±32.56 U/L) were notably decreased after TSA intervention. Moreover, LC3 II and FoxO3a showed an obvious increase and P62 showed an obvious decrease in the CLP+TSA group. Cell experiment results showed the similar trend. After FoxO3a gene was knocked down in AML12 cells, the promotion of autophagy and the improvement of liver enzyme index and inflammation by TSA were weakened. TSA may improve the inflammatory response and liver injury in septic mice through FoxO3a/autophagy.

Peripheral 5-hydroxytryptophan aggravates lung injury in septic mice by inducing the formation of neutrophils extracellular trap

To observe the effect of peripheral 5-hydroxytryptophan (5-HT)-induced neutrophil extracellular trap (NET) on lung injury in septic mice. Wild-type (WT type) and Tph1 knockout (KO) C57 mice (6-8 weeks) were selected and divided into WT mice sham group, WT mice sepsis group, Tph1KO mice sham group and Tph1KO mice sepsis group according to the random number table method. Mice in the sham group received sham surgery (only open the abdominal cavity to flip the cecum without ligation and puncture, and then close the abdominal cavity); the mice in the sepsis group received cecal ligation and perforature (CLP) to establish sepsis model. The mice were sacrificed 12 hours after the operation, and the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in bronchialalveolar lavage fluid (BALF) were detected by enzyme linked immunoadsordent assay (ELISA); at the same time, the lung tissues were collected, and the pathological changes of lung tissues were observed under light microscope, and the production of NET in lung tissues was observed by immunofluorescence microscope. The pathological results suggested that the lung tissue structure in sham groups was intact without exudation, while the alveolar structures of mice in the sepsis groups were damaged, with obvious exudation in the alveolar cavity and thickened alveolar walls accompanied by a large number of inflammatory cell infiltration, and the degree of lung injury in the sepsis group of WT mice was more severe than that of the sepsis group of Tph1KO mice. ELISA results showed that there was no statistically significant difference in the contents of TNF-α and IL-6 in mice BALF from different strains of the sham group; while the contents of TNF-α and IL-6 in BALF of septic mice group were significantly higher than those in sham group [WT mice: TNF-α (μg/L) was 158.20±28.46 vs. 14.00±3.28, IL-6 (μg/L) was 304.98±21.78 vs. 57.70±12.30; Tph1KO mice: TNF-α (μg/L) was 85.88±20.13 vs. 14.95±1.53, IL-6 (μg/L) was 169.50±45.61 vs. 55.05±12.68, all P < 0.01], and the above index levels in the sepsis group of WT mice were significantly higher than the sepsis group of Tph1KO mice [TNF-α (μg/L): 158.20±28.46 vs. 85.88±20.13, IL-6 (μg/L): 304.98±21.78 vs. 169.50±45.61, both P < 0.01]. Immunofluorescence staining showed that a very small amount of NET formation was detected in the mice lungs from the sham group; a large amount of NET formation was detected in the lung tissues in the sepsis group, which were significantly higher than those in sham group [WT mice: (34.75±7.27)% vs. (1.75±0.96)%, Tph1KO mice: (14.25±5.74)% vs. (2.50±1.29)%, both P < 0.01], and the amount of NET produced in the lung tissues of the WT mice sepsis group was significantly higher than that of the Tph1KO mice sepsis group [(34.75±7.27)% vs. (14.25±5.74)%, P < 0.01]. In sepsis, the increased production of inflammatory factors in the mice lung tissues induces to lung injury. The mechanism may relate to the increased production of NET in the lung tissues mediated by peripheral 5-HT synthesized by enterochromaffin cells and released into the blood; inhibiting the production of 5-HT in the peripheral blood can effectively reduce the production of NET in the lung tissues, thereby reducing lung injury.

The multiomics landscape of serum exosomes during the development of sepsis

IntroductionSepsis is an infection-induced severe inflammatory disorder leading to multiple organ dysfunction. It remains a highly lethal condition for which early diagnosis and therapy achieve unsatisfactory results. Circulating exosomes containing biomarkers and mediators of sepsis have recently received attention, but the progress has been far from optimal. ObjectivesThe present study focuses on the profiles of molecular dynamics in serum exosomes and explores the potential molecular mechanisms on serum exosomes during the process of sepsis. MethodsWe used high-performance liquid chromatography-tandem mass spectrometry and RNA-seq to detect the dynamic profiles of exosome proteins and RNAs (including mRNAs, lncRNAs and miRNAs) in serum exosomes from 3 healthy individuals and 9 septic patients at the different stages. Then integrative multiomics analyses were performed and the results were validated by qRT-PCR, LiquiChip assay and metabolomics analysis on mice subjected to cecal ligation and puncture (CLP) modeling. ResultsA total of 354 proteins, 195 mRNAs, 82 lncRNAs and 55 miRNAs were identified as differentially expressed molecules in serum exosomes from septic patients. Integrative multiomics analysis showed that exosome components were associated with cytokine storm, complement and clotting cascades, the endothelial barrier, 20S proteasome-dependent protein degradation and vitamin metabolism. Importantly, pretreatment with serum exosomes derived from mice subjected to CLP significantly restrained proinflammatory cytokine expression and alleviated tissue injury in septic mice. Further metabolomics analysis demonstrated that pretreatment with septic serum exosomes significantly affected the metabolites associated with vitamin digestion and absorption in CLP mice. ConclusionOur study for the first time describes the landscape of the molecular dynamics of serum exosomes during the development of sepsis and proposes some hypothetical molecular mechanisms by integrative multiomics analysis, which may provide helpful diagnostic and therapeutic insights for the ongoing battle against sepsis.

Norisoboldine Attenuates Sepsis-Induced Acute Lung Injury by Modulating Macrophage Polarization via PKM2/HIF-1α/PGC-1α Pathway.

This study aimed to investigate the effect of norisopoldine (NOR) on acute lung injury in septic mice. Lipopolysaccharide (LPS) was used to establish sepsis induced acute lung injury (ALI) in mice. The dry and wet weight of mice lung was detected, and the pathological changes of lung were observed by hematoxylin and eosin (H&E) staining. Bronchoalveolar lavage fluid (BALF) was detected. Inflammatory factors in BALF were detected by enzyme-linked immunosorbent assay (ELISA). The polarization of macrophages in lung tissue was detected by flow cytometry. The markers of M1 and M2 macrophages were detected by RT-PCR. LPS induced RAW264.7 cells were treated with NOR. Inflammatory response, macrophage polarization, glycolysis, and M2 pyruvate kinase (PKM2)/hypoxia inducible factor-1α (HIF-1α)/peroxisome proliferator activated receptor-γ co-activator 1-α (PGC-1α) signaling pathway were detected. NOR could effectively alleviate sepsis induced ALI, and reduce the number of total cells, total protein concentration, neutrophils, macrophages in BALF. NOR decreased the level of inflammatory factors and promoted macrophages from M1 to M2 type in vivo and vitro. Moreover, NOR could activated PKM2, and inhibited PKM2 from cytoplasm to nuclear, attenuated HIF-1α expression, and increased PGC-1α and peroxisome proliferator-activated receptor (PPAR)-γ expression. In addition, NOR inhibited glycolysis and promoted oxidative phosphorylation in RAW264.7 cells. Furthermore, PKM2 inhibitors could reverse the effect of NOR on PKM2/HIF-1α/PGC-1α signaling pathway in RAW264.7 cells. NOR alleviated sepsis induced AIL in mice, inhibited the inflammatory response, promote M2 polarization of macrophages through regulating PKM2/HIF-1α/PGC-1α signaling pathway.

Bone marrow-mesenchymal stem cell-derived exosomal microRNA-141 targets PTEN and activates β-catenin to alleviate myocardial injury in septic mice

Background Mesenchymal stem cells (MSCs) and their derived exosomes have shown potentials in the control of myocardial dysfunction. This study aimed to reveal the function of bone marrow (BM)-MSC-derived exosomes in sepsis-induced myocardial injury and the molecular mechanism. Methods BM-MSC-derived exosomes were obtained and identified. A mouse model with sepsis was induced by cecalligation puncture (CLP) and treated with exosomes. The myocardial function of mice, the production of creatine kinase MB (CK-MB) and lactate dehydrogenase (LDH) in serum, the phosphorylation of a key myocardial contractility-related protein phospholamban (PLB), and the pathological changes in the myocardial tissues were examined. A microRNA (miRNA) microarray analysis was performed to examine the candidate miRNAs carried by the exosomes. Rescue experiments were conducted to validate the involvement of miR-141. Results CLP treatment led to sepsis and notably reduced the myocardial function in mice. Further treatment of BM-MSC-derived exosomes alleviated the CLP-induced myocardial impairment, production of CK-MB and LDH, and inflammatory infiltration and cell apoptosis in mouse myocardial tissues, and restored the PLB phosphorylation. miR-141 was the most upregulated miRNA in the myocardial tissues after exosome treatment. Downregulation of miR-141 blocked the myocardium-protective functions of the exosomes. miR-141 was found to bind to and suppress PTEN expression, which further enhanced the activity of β-catenin. Conclusion This study suggested that BM-MSC derived exosomes ameliorates myocardial injury in septic mice through conveying miRNA-141 and regulating the PTEN/β-catenin axis, and exosomes may serve as promising tools for the management of myocardial injury induced by sepsis or other factors.

Protective effect of isosteviol sodium against LPS-induced multiple organ injury by regulating of glycerophospholipid metabolism and reducing macrophage-driven inflammation

Sepsis is a severe inflammatory disorder that can lead to multiple organ injury. Isosteviol sodium (STV-Na) is a terpenoid derived from stevioside that exerts anti-inflammatory, antioxidant and antiapoptotic activities. However, the influence of STV-Na on sepsis remains unknown. Here, we assessed the potential effects of STV-Na on sepsis and multiple organ injury induced by lipopolysaccharide (LPS). We found that STV-Na increased the survival rate of mice treat with LPS, significantly improved the functions of the heart, lung, liver, and kidney, reduced the production of inflammatory cytokines and decreased macrophage infiltration. Moreover, Multiorgan metabolomics analysis demonstrated that glutathione metabolism, purine metabolism, glycerophospholipid metabolism and pantothenate and CoA biosynthesis, were significantly altered by STV-Na. This study provides novel insights into the metabolite changes of multiple organ injury in septic mice, which may help characterize the underlying mechanism and provide an improved understanding of the therapeutic effects of STV-Na on sepsis.

Protective effect and mechanism of Baicalin on acute kidney injury in septic mice

To observe the protective effect and mechanism of different doses of Baicalin (BAI) on acute kidney injury (AKI) in septic mice. According to the random number table, 100 mice were divided into sham operation group (Sham group), cecal ligation and perforation (CLP) induced sepsis model group (CLP group) and BAI pretreatment groups. The mice in BAI pretreatment groups were divided into low-, medium- and high-dose groups (BAI-L+CLP, BAI-M+CLP, BAI-H+CLP groups), with 20 mice in each group. A murine sepsis associated-acute kidney injury (SA-AKI) model was reproduced using CLP. The mice in the Sham group were only opened and closed the abdomen, without ligating or perforating the cecum. The mice in the BAI pretreatment groups were given BAI 25, 50 and 100 mg/kg daily for 3 days, and CLP was performed at 6 hours after administration of BAI at the 3rd day to reproduce sepsis model. The mice in the Sham group and CLP group were given the same amount of distilled water as control. Ten mice were sacrificed at 24 hours after operation to collect orbital blood for renal function determination [serum creatinine (SCr), blood urea nitrogen (BUN), plasma neutrophil gelatinase-associated lipocalin (pNGAL) and plasma kidney injury molecule-1 (pKIM-1)] by enzyme linked immunosorbent assay (ELISA). The kidney tissue was collected to observe the kidney tissue injury under light microscope after hematoxylin-eosin (HE) staining. The TdT-mediated dUTP nick-end labeling (TUNEL) was used to detect the apoptosis of renal tubular epithelial cells. Western blotting was used to detect the expression of cell FLICE like inhibitory protein (c-FLIP) in renal tissue. The remaining 10 mice in each group were used to calculate the survival rate of 7 days after operation. The renal tubular epithelial cells in the CLP group were massively degenerated with necrosis, the renal tubular lumen was significantly expanded, and inflammatory cells were widely infiltrated in the renal interstitium. Furthermore, the renal function deteriorated rapidly. Compared with the CLP group, the renal function of mice pretreated with low dose of BAI was improved, but the difference was not significant. Compared with the CLP group, the renal function in the mice pretreated with medium and high doses of BAI was significantly improved, the SCr, BUN, pNGAL and pKIM-1 were significantly reduced [SCr (μmol/L): 135.16±5.18, 125.70±5.26 vs. 170.42±5.42; BUN (mmol/L): 33.59±1.77, 27.29±1.61 vs. 45.68±1.39; pNGAL (μg/L): 91.29±4.68, 73.40±3.77 vs. 131.50±6.55; pKIM-1 (μg/L): 6.34±0.30, 5.51±0.35 vs. 8.03±0.29; all P < 0.01], the pathological injury of renal tissue was significantly decreased, the apoptotic number of renal tubular epithelial cells was significantly reduced (cells/HP: 16.20±0.49, 13.10±0.66 vs. 29.60±0.49, both P < 0.01), and the expression of c-FLIP protein in renal tissue was significantly increased [c-FLIP protein (c-FLIP/GAPDH): 0.35±0.02, 0.46±0.02 vs. 0.21±0.01, both P < 0.01]. No mouse in the Sham group died within 7 days. Compared with the CLP group, the average survival time of the mice within 7 days in the BAI-L+CLP, BAI-M+CLP and BAI-H+CLP groups was significantly prolonged with a dose-dependent manner (days: 3.5±2.5, 5.4±2.2, 5.9±1.9 vs. 2.1±1.2; Log-Rank test: χ2 = 73.410, P < 0.001). Pretreatment with medium and high doses of BAI can significantly improve the renal function in mice with SA-AKI, decrease the pathological damage and increase the survival of mice, and its mechanism may be related to promoting the increase of c-FLIP protein expression and inhibiting cell apoptosis.

Cynaroside prevents macrophage polarization into pro-inflammatory phenotype and alleviates cecal ligation and puncture-induced liver injury by targeting PKM2/HIF-1α axis

The treatment of sepsis is still challenging and the liver is an important target of sepsis-related injury. Macrophages are important innate immune cells in liver, and modulation of macrophages M1/M2 polarization may be a promising strategy for septic liver injury treatment. Macrophage polarization and inflammation of liver tissue has been shown regulated by pyruvate kinase M2 (PKM2)-mediated aerobic glycolysis and immune inflammatory pathways. Therefore, modulating PKM2-mediated immunometabolic reprogramming presents a novel strategy for inflammation-associated diseases. In this study, cynaroside, a flavonoid compound, promoted macrophage phenotypic transition from pro-inflammatory M1 to anti-inflammatory M2, and mitigated sepsis-associated liver inflammatory damage. We established that cynaroside reduced binding of PKM2 to hypoxia-inducible factor-1α (HIF-1α) by abolishing translocation of PKM2 to the nucleus and promoting PKM2 tetramer formation, as well as suppressing phosphorylation of PKM2 at Y105 in vivo and in vitro. Moreover, cynaroside restored pyruvate kinase activity, inhibited glycolysis-related proteins including PFKFB3, HK2 and HIF-1α, and inhibited glycolysis-related hyperacetylation of HMGB1 in septic liver. Therefore, this study reports a novel function of cynaroside in hepatic macrophage polarization, and cecum ligation and puncture-induced liver injury in septic mice. The findings provide crucial information with regard to therapeutic efficacy of cynaroside in the treatment of sepsis.

Luteolin attenuates hepatic injury in septic mice by regulating P2X7R-based HMGB1 release.

P2X7 receptor (P2X7R) and NLRP3 cooperatively participate in inflammation and hepatocyte damage during hepatic injury induced by lipopolysaccharides (LPS). High-mobility group box 1 (HMGB1) released from immune cells in response to such stimuli plays a vital role in mediating inflammation via TLR4 and the receptor for advanced glycation end products (RAGE), a receptor for HMGB1. However, the correlation among P2X7R, RAGE and TLR4 in regulating the release of HMGB1 has not been elucidated. Increasing the number of daily foods is found to be beneficial for hepatocyte damage in septic hepatic injury. Hence, we investigated the effects of luteolin, a natural flavonoid mainly existing in vegetables and fruits, on liver injury, focusing on how luteolin participates in hepatitis based on the P2X7R-RAGE-TLR4 axis by regulating the release of HMGB1. The results demonstrated that the indicators of hepatic injury such as increased ALT, AST in the serum and infiltration of immune cells were attenuated after luteolin treatment in LPS-induced mice. Luteolin could also suppress the production and release of HMGB1 and the activation of caspase 1 both in LPS-induced mice and LPS/ATP-stimulated HepG2 cells. Collectively, luteolin reversed LPS-induced hepatic injury, especially inflammation, likely by regulating the release of HMGB1 through the P2X7R-RAGE-TLR4 axis.

Anti‐Interleukin‐16 Neutralizing Antibody Treatment Alleviates Sepsis‐Induced Cardiac Injury and Dysfunction via the Nuclear Factor Erythroid‐2 Related Factor 2 Pathway in Mice

Several interleukin (IL) members have been reported to participate in sepsis. In this study, the effects of IL-16 on sepsis-induced cardiac injury and dysfunction were examined, and the related mechanisms were detected. IL-16 expression in septic mice was first measured, and the results showed that both cardiac and serum IL-16 expression levels were increased in mice with sepsis induced by LPS or cecal ligation and puncture (CLP) compared with control mice. Then, IL-16 was neutralized, and the effects on lipopolysaccharide- (LPS-) induced cardiac injury were detected. The results showed that an anti-IL-16 neutralizing antibody (nAb) significantly reduced mortality and increased serum lactate dehydrogenase (LDH), creatine kinase myocardial bound (CK-MB), and cardiac troponin T (cTnT) levels while improving cardiac function in mice with LPS-induced sepsis. Neutralization of IL-16 also increased the activation of antioxidant pathways and the expression of antioxidant factors in septic mice while decreasing the activation of prooxidant pathways and the expression of prooxidants. Treatment with the anti-IL-16 nAb increased mitochondrial apoptosis-inducing factor (AIF) expression, decreased nuclear AIF and cleaved poly-ADP-ribose polymerase (PARP) expression, and decreased TUNEL-positive cell percentages in LPS-treated mice. Additionally, treatment with CPUY192018, the nuclear factor erythroid-2 related factor 2 (Nrf2) pathway, significantly increased mortality and reversed the above effects in mice treated with LPS and the anti-IL-16 nAb. Our results showed that the anti-IL-16 nAb regulates oxidative stress through the Nrf2 pathway and participates in the regulation of cardiac injury in septic mice. Neutralization of IL-16 may be a beneficial strategy for the prevention of cardiac injury and dysfunction in sepsis patients.

MiR-139-5p protects septic mice with acute lung injury by inhibiting Toll-like receptor 4/Myeloid differentiation factor 88/Nuclear factor-κB signaling pathway

OBJECTIVES:To investigate the role of miR-139-5p and the TLR4/MyD88/NF-κB signaling pathway in acute lung injury in septic mice.METHOD:A total of 140 healthy male SPF C57BL/6 mice were divided into seven groups, i.e., Normal, Control, NC, miR-139-5p mimic, miR-139-5p inhibitor, TAK-242, and miR-139-5p inhibitor+TAK-242 groups. The levels of miR-139-5p, proteins related to the TLR4/MyD88/NF-κB signaling pathway (TLR4, MyD88, and p-NF-κB p50), and MPO, SOD, GSH, and MDA in lung tissue were measured. The lung tissue wet-to-dry mass ratio (W/D), arterial oxygen partial pressure (PaO2), and carbon dioxide partial pressure (PaCO2) were measured.RESULTS:A web-based bioinformatic tool predicted that MyD88 was a target of miR-139-5p, which was verified by a dual luciferase reporter assay. Compared with those in the Normal group, the levels of miR-139-5p, PaO2, SOD, and GSH were significantly lower, while those of TLR4, MyD88, p-NF-κB p50, W/D, PaCO2, IL-1β, TNF-α, IL-6, MPO, and MDA were higher in all other groups. Moreover, compared with their levels in the Control group, these indicators exhibited contrasting results in the miR-139-5p mimic and TAK-242 groups, but were similar in the miR-139-5p inhibitor group. In the miR-139-5p inhibitor+TAK-242 group, acute lung injury, aggravated by miR-139-5p inhibitor, was partially rescued by TAK-242.CONCLUSION:miR-139-5p inhibits the TLR4/MyD88/NF-κB signaling pathway to alleviate acute lung injury in septic mice.