LPS-induced Inflammatory Response Research Articles

Hesperetin derivative 2a inhibits lipopolysaccharide-induced acute liver injury in mice via downregulation of circDcbld2.

Acute liver injury (ALI) is a complex, life-threatening inflammatory liver disease, and persistent liver damage leads to rapid decline and even failure of liver function. However, the pathogenesis of ALI is still not fully understood, and no effective treatment has been discovered. Recent evidence shows that many circular RNAs (circRNAs) are associated with the occurrence of liver diseases. In this study we investigated the mechanisms of occurrence and development of ALI in lipopolysaccharide (LPS)-induced ALI mice. We found that expression of the circular RNA circDcbld2 was significantly elevated in the liver tissues of ALI mice and LPS-treated RAW264.7 cells. Knockdown of circDcbld2 markedly alleviates LPS-induced inflammatory responses in ALI mice and RAW264.7 cells. We designed and synthesized a series of hesperidin derivatives for circDcbld2, and found that hesperetin derivative 2a (HD-2a) at the concentrations of 2, 4, 8 μM effectively inhibited circDcbld2 expression in RAW264.7 cells. Administration of HD-2a (50, 100, 200 mg/kg. i.g., once 24 h in advance) effectively relieved LPS-induced liver dysfunction and inflammatory responses. RNA sequencing analysis revealed that the anti-inflammatory and hepatoprotective effects of HD-2a were mediated through downregulating circDcbld2 and suppressing the JAK2/STAT3 pathway. We conclude that HD-2a downregulates circDcbld2 to inhibit the JAK2/STAT3 pathway, thereby inhibiting the inflammatory responses in ALI. The results suggest that circDcbld2 may be a potential target for the prevention and treatment of ALI, and HD-2a may have potential as a drug for the treatment of ALI.

Retracted: Puerarin Attenuates LPS-Induced Inflammatory Responses and Oxidative Stress Injury in Human Umbilical Vein Endothelial Cells through Mitochondrial Quality Control.

[This retracts the article DOI: 10.1155/2021/6659240.].

Fangji Fuling Decoction Alleviates Sepsis by Blocking MAPK14/FOXO3A Signaling Pathway.

To examine the therapeutic effect of Fangji Fuling Decoction (FFD) on sepsis through network pharmacological analysis combined with in vitro and in vivo experiments. A sepsis mouse model was constructed through intraperitoneal injection of 20 mg/kg lipopolysaccharide (LPS). RAW264.7 cells were stimulated by 250 ng/mL LPS to establish an in vitro cell model. Network pharmacology analysis identified the key molecular pathway associated with FFD in sepsis. Through ectopic expression and depletion experiments, the effect of FFD on multiple organ damage in septic mice, as well as on cell proliferation and apoptosis in relation to the mitogen-activated protein kinase 14/Forkhead Box O 3A (MAPK14/FOXO3A) signaling pathway, was analyzed. FFD reduced organ damage and inflammation in LPS-induced septic mice and suppressed LPS-induced macrophage apoptosis and inflammation in vitro (P<0.05). Network pharmacology analysis showed that FFD could regulate the MAPK14/FOXO signaling pathway during sepsis. As confirmed by in vitro cell experiments, FFD inhibited the MAPK14 signaling pathway or FOXO3A expression to relieve LPS-induced macrophage apoptosis and inflammation (P<0.05). Furthermore, FFD inhibited the MAPK14/FOXO3A signaling pathway to inhibit LPS-induced macrophage apoptosis in the lung tissue of septic mice (P<0.05). FFD could ameliorate the LPS-induced inflammatory response in septic mice by inhibiting the MAPK14/FOXO3A signaling pathway.

LncRNA MEG8 ameliorates Parkinson's disease neuro-inflammation through miR-485-3p/FBXO45 axis.

Studies suggest that LncRNA maternally expressed 8, small nucleolar RNA host gene (MEG8) contributes to inflammatory regulation, while the function and potential mechanisms of MEG8 in Parkinson's disease (PD) are unknown. This study aimed to assess the clinical value and biological function of MEG8 in PD. One hundred and two PD patients, eighty-six AD patients, and eighty healthy controls were enrolled in this study. Lipopolysaccharide (LPS)-induced microglia BV2 constructs an in vitro cell model. RT-qPCR was conducted to quantify the levels of MEG8, miR-485-3p, and FBXO45 in serum and cells. ROC curve was employed to examine the diagnostic value of MEG8 in PD. Serum and cellular pro-inflammatory factor secretion were quantified by ELISA. Dual-luciferase reporter and RIP assay to validate the targeting relationship between miR-485-3p and FBXO45. MEG8 and FBXO45 were significantly decreased in the serum of PD patients and LPS-induced bv2, while miR-485-3p was increased (P < 0.05). ROC curve confirmed that serum MEG8 has high sensitivity and specificity to identify PD patients from healthy controls and AD patients, respectively. Elevated MEG8 alleviated LPS-induced inflammatory factor overproduction compared with LPS-induced BV2 (P < 0.05), but this alleviating effect was eliminated by miR-485-3p (P < 0.05). The LPS-induced inflammatory response was suppressed by the low expression of miR-485-3p but significantly reversed by silencing of FBXO45. MEG8 was a sponge for miR-485-3p and inhibited its levels and promoted FBXO45 expression (P < 0.05). Elevated MEG8 is a potential diagnostic biomarker for PD and may mitigate inflammatory damage in PD via the miR-485-3p/FBXO45 axis.

Lactobacillus reuteri Ameliorates Lipopolysaccharide-Induced Acute Lung Injury by Modulating the Gut Microbiota in Mice.

Acute lung injury (ALI) causes lung inflammation and edema as well as resulting in gut microbiota disorder. Probiotics, however, can improve the gut microbiota composition and modulate its immune response, playing an important role in ALI pathogenesis. Therefore, our study aims to investigate the effect of Lactobacillus reuteri on Lipopolysaccharide (LPS)-induced ALI in mice and to probe the mechanism of its synergistic modulatory effect on the lungs and intestines. We assessed the therapeutic effects of L. reuteri in the ALI mouse model by histopathology, alveolar lavage fluid and serum inflammatory factor analysis and explored microbiome and transcriptome alterations. L. reuteri intervention effectively attenuated lung tissue injury and significantly reduced the LPS-induced inflammatory response and macrophage and neutrophil infiltration. Additionally, L. reuteri improved the intestinal barrier function and remodeled the disordered microbiota. In conclusion, our study showed that L. reuteri attenuated the inflammatory response, ameliorated the pulmonary edema, repaired the intestinal barrier, and remodeled the gut microbiota in ALI mice. This study provides new perspectives on the clinical treatment of ALI.

Mitochondrion-NLRP3 inflammasome activation in macrophages: A novel mechanism of the anti-inflammatory effect of Notopterygium in rheumatoid arthritis treatment

ObjectiveThe mechanism by which Notopterygium (NE) regulates the nucleotide‐binding, oligomerization domain (NOD)‐like receptor family and pyrin domain-containing 3 (NLRP3) inflammasome to treat rheumatoid arthritis (RA) was investigated to reveal the scientific implications of NE in RA treatment. MethodsAdjuvant arthritis (AA) rats were replicated. After NE intervention, the anti-inflammatory efficacy of NE in vivo was determined. The mechanism of NE in RA treatment was predicted by network pharmacology, and the key target for further experiments was found through the analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG). The effect of NE on the NLRP3 inflammasome in AA rats was verified. Furthermore, with the induction of inflammation in RAW264.7 cells by lipopolysaccharide (LPS), several techniques, such as Griess assay, enzyme linked immunosorbent assays, electron microscopy, and fluorescence probe technology, were used to investigate the anti-inflammatory and related mechanisms of NE in RA treatment. ResultsNE could inhibit inflammation in AA rats. KEGG results showed that NLRP3 participated in the top three pathways of NE in RA treatment. Through Western blotting and immunofluorescence assays, this study demonstrated that NE can regulate NLRP3, pro-Caspase-1, Caspase-1, and CD11b in the ankle joint of AA rats. NE may significantly reduce the LPS-induced inflammatory response of RAW264.7 cells by alleviating mitochondrial damage, reducing the number of mitochondrial deoxyribonucleic Acid and mitochondrial reactive oxygen species, inhibiting NLRP3 inflammasome activation. ConclusionThe anti-inflammatory and antirheumatic effect of NE may involve regulating NLRP3 inflammasome activation through mitochondria. NLRP3 is probably the key target molecule of NE in the treatment of RA.

Genes Involved by Dexamethasone in Prevention of Long-Term Memory Impairment Caused by Lipopolysaccharide-Induced Neuroinflammation.

Inflammatory activation within the brain is linked to a decrease in cognitive abilities; however, the molecular mechanisms implicated in the development of inflammatory-related cognitive dysfunction and its prevention are poorly understood. This study compared the responses of hippocampal transcriptomes 3 months after the striatal infusion of lipopolysaccharide (LPS; 30 µg), resulting in memory loss, or with dexamethasone (DEX; 5 mg/kg intraperitoneal) pretreatment, which abolished the long-term LPS-induced memory impairment. After LPS treatment, a significant elevation in the expression of immunity/inflammatory-linked genes, including chemokines (Cxcl13), cytokines (Il1b and Tnfsf13b), and major histocompatibility complex (MHC) class II members (Cd74, RT1-Ba, RT1-Bb, RT1-Da, and RT1-Db1) was observed. DEX pretreatment did not change the expression of these genes, but significantly affected the expression of genes encoding ion channels, primarily calcium and potassium channels, regulators of glutamate (Slc1a2, Grm5, Grin2a), and GABA (Gabrr2, Gabrb2) neurotransmission, which enriched in such GO biological processes as "Regulation of transmembrane transport", "Cognition", "Learning", "Neurogenesis", and "Nervous system development". Taken together, these data suggest that (1) pretreatment with DEX did not markedly affect LPS-induced prolonged inflammatory response; (2) DEX pretreatment can affect processes associated with glutamatergic signaling and nervous system development, possibly involved in the recovery of memory impairment induced by LPS.

Glycyrrhizin inhibits LPS-induced inflammatory responses in goat ruminal epithelial cells in vitro

Inflammation plays a crucial role in the progression of Subacute Ruminal Acidosis (SARA). The experiment was designed to investigate anti-inflammatory effects of glycyrrhizin on goats ruminal epithelial cells (GREC) which were induced SARA by Lipopolysaccharide (LPS) in vitro. The GREC were induced SARA by adding LPS at the concentration of 5 μm and glycyrrhizin was added at different concentration of 0, 60, 90, 120, 150 μm. The structural integrity of LPS-induced GREC with the treatment of glycyrrhizin were observed by electron microscope; The levels of inflammatory factors TNF-α, IL-1β, IL-6, IL-8 and IL-12 were measured by ELISA; The number of Zo-1 and Occludin were measured, the expression of tight junction protein Occludin were measured by Western blot, and the mRNA expression of NF-κB, TNF-α, IL-1β, IL-6, IL-8 and IL-12 were measured in vitro. The results showed that higher concentration treatment of glycyrrhizin led to better morphology in LPS-induced GREC. Glycyrrhizin inhibited the growth of inflammatory factors TNF-α, IL-1β, IL-6, IL-8 and IL-12 in a dose-dependent manner. The number of ZO-1 and Occludin increased with the increase of adding of glycyrrhizin. Western blot analysis showed that the expression of tight junction protein Occludin in LPS-induced GREC increased with the adding of glycyrrhizin in a dose-dependent manner. Furthermore, the mRNA expression of NF-κB, TNF-α, IL-1β, IL-6, IL-8 and IL-12 decreased significantly with the increase treatment of glycyrrhizin. Glycyrrhizin significantly inhibits LPS-induced inflammatory mediators in GREC and the effects are better with the increase treatment of glycyrrhizin in vitro.

Costunolide attenuates LPS-induced inflammation and lung injury through inhibiting IKK/NF-κB signaling.

Inflammation is an important pathological process of many acute and chronic diseases, such as sepsis, arthritis, and cancer. Many factors can lead to an inflammatory state of the body, among which bacterial infection plays an important role. Bacterial infection often leads to sepsis, acute lung injury (ALI), or its more serious form of acute respiratory distress syndrome, which are the main fatal diseases in intensive care units. Costunolide has been reported to possess excellent anti-inflammatory activity; however, whether it can affect inflammation induced by gram-negative bacterial is still unclear. Lipopolysaccharide (LPS) stimulated mouse peritoneal macrophages (MPMs) to release proinflammatory cytokines was used as the cell model. The mouse model of sepsis and ALI was built through injecting intravenously and intratracheally of LPS. In the present study, costunolide inhibited LPS-induced inflammatory response through IKK/NF-κB signaling pathway in macrophages. In vivo, costunolide attenuated LPS-induced septic death in mice. Meanwhile, costunolide treatment alleviated LPS-induced lung injury and inflammation via inhibiting the infiltration of inflammatory cells and the expression of inflammatory cytokines. Taken together, these results demonstrated that costunolide could attenuate gram-negative bacterial induced inflammation and diseases and might be a potential candidate for the treatment of inflammatory diseases.

γ-Secretase inhibitor alleviates lipopolysaccharide-induced myocardial injury through regulating JAK2/STAT3 signaling.

Septic myocardial injury is one of the most life-threatening organ dysfunction. The γ-secretase-based approaches have been developed as potential strategies for diverse diseases management. Unfortunately, the role of γ-secretase inhibitor in septic myocardial injury is unclarified. The present study aims to investigate the effect of γ-secretase inhibitor in septic myocardial injury and reveal its mechanism. The mouse model of septic myocardial injury was established by intraperitoneally injection of lipopolysaccharide (LPS), and γ-secretase inhibitor MW167 was applied in this model. RNA-sequencing analysis and further bioinformatics analyses were used to screen differential expressed genes (DEGs) and potentially enriched pathways between LPS and LPS + MW167 mice. Pathological examination was performed using haematoxylin and eosin (HE) staining. SD-1029 was used to block JAK2/STAT3 signaling in H9C2 cells and western blot analysis quantified JAK2/STAT3-related proteins. LPS induced myocardial injury accompanied with significant inflammatory infiltration and more apoptotic cells. Transcriptome sequencing screened 36 DEGs and bioinformatics identified JAK2/STAT3 signaling pathway was significantly enriched. Further in vitro experiments showed that γ-secretase inhibitor MW167 activated JAK2/STAT3 pathway. Additionally, MW167 restored cell viability, decreased myocardial injury markers including cardiac troponin I (cTnI) and brain natriuretic peptide (BNP), inhibited pro-inflammatory cytokines such as interleukin (IL)-1β and tumor necrosis factor-α (TNF-α) and reduced nitric oxide (NO), cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) release. Application of SD-1029 reversely deteriorated LPS-induced myocardial injury and inflammatory response in γ-secretase inhibitor-treated myocardial cells. The results demonstrate that γ-secretase inhibitor alleviates septic myocardial injury via activating JAK2/STAT3 signaling, and provide novel therapeutic direction for septic myocardial injury.

Investigation of the effects of urotensin II receptors in LPS-induced inflammatory response in HUVEC cell line through calcineurin/NFATc/IL-2 pathway

PurposeThe effect of urotensin II (U-II), a powerful endogenous vasoconstrictor substance, on the immune system and its mediators is very important.It was herein aimed to demonstrate the possible relationship between the calcineurin/nuclear factor of activated T-cells cytoplasmic 1/interleukin-2 (CaN/NFATc/IL-2) pathway and urotensin receptors (UTRs) in inflammatory response due to lipopolysaccharide (LPS). MethodsAn LPS-induced inflammation model was used on the human umbilical vein endothelial cells (HUVEC) cell line and drugs were applied accordingly, forming the following groups: Control Group, LPS Group, Agonist Group (10−8 ​M U-II), Antagonist Group (10−6 ​M palosuran), Tacrolimus (TAC) Group (10 ​ng/mL FK-506), Agonist ​+ ​TAC Group, and Antagonist ​+ ​TAC Group. Gene expression analyses were performed using real-time polymerase chain reaction (RT-PCR). ResultsIn the analysis of the cell viability at 48 and 72 ​h, there was a decrease in the Agonist Group, while in the Agonist ​+ ​TAC Group, the cell viability increased. In the Antagonist Group, cell viability was maintained when compared to the LPS Group, while in the TAC Group, this effect was reduced. The mRNA expression levels of UTR, CaN, NFATc, IL-2 receptor (IL-2R), IL-6 and nuclear factor kappa B (NF-κB) were higher in the LPS Group than in the Control Group, and even the UTR, CaN, NFATc, IL-2R were higher with agonist administration. This effect of the agonist was shown to be completely mitigated in the presence of the CaN inhibitor. ConclusionU-II and its receptors can perform key functions regarding the endothelial cell damage via the CaN/NFATc/IL-2 pathway.

Morphological and Molecular Biological Features of the Systemic Inflammatory Response in Old Wistar Rats with High and Low Resistance to Hypoxia.

Morphological and molecular biological features of LPS-induced systemic inflammatory response were assessed in old male Wistar rats with high (HR) and low (LR) resistance to hypoxia. The systemic inflammatory response was modeled by intraperitoneal injection of E. coli O26:B6 LPS; the animals were sacrificed after 6 h. In histological sections, the number of neutrophils in the interalveolar septa and the area of necrosis in the liver were determined. The expression levels of Hif1a, Hif2a, Nfkb, Vegf, Il1b, Il6, Il10, and Tgfb mRNA in the liver and serum concentrations of HIF-1α and IL-1β were determined. In 4-6 h after LPS injection, 3 (43%) of 7 HR rats died, whereas no deaths were observed among LR rats. At 6 h after LPS injection, the number of neutrophils in the interalveolar septa of the lungs in LR rats was significantly higher than in HR rats, while the area of necrosis in the liver did not differ. At the same time, the mRNA expression levels of the proinflammatory cytokine genes Il1b and Il6 increased in the liver of both HR and LR rats, whereas the expression of Il10 increased only in HR rats. The expression of the Hif1a gene in the liver was higher in LR rats, but the content of HIF-1α protein in blood serum was higher in HR animals. These data should be taken into account when developing new approaches to the therapy of systemic inflammatory response in infectious and inflammatory diseases in the elderly.

Downregulation of MicroRNA-29-3p Following Percutaneous Coronary Intervention: An Implication of YY1/IRAK1 Pathway in the Post-Vascular Injury Inflammation.

This study explored the expression of microRNA (miR)-29b-3p following percutaneous coronary intervention (PCI) and the implication of its downstream Yin Yang 1 (YY1)/interleukin (IL)-1 receptor-associated kinase 1 (IRAK1) pathway in post-vascular injury inflammation. Blood samples were collected for analysis of plasma miR-29b-3p from patients with acute coronary syndrome before surgery, 1 day after PCI, and 30 days after PCI. Lipopolysaccharide (LPS)-treated human coronary artery endothelial cells (HCAECs) were transfected with miR-29b-3p mimic/inhibitor or YY1 shRNA and underwent viability tests. Enzyme-linked immunosorbent assay was performed to detect the levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), IL-1β, IL-6, and tumor necrosis factor (TNF)-α in serum and cell culture supernatant. Dual-luciferase reporter and RNA/chromatin immunoprecipitation were used to confirm the targeting relationships among miR-29b-3p, YY1, and IRAK1. A rat model of intraluminal injury of the common femoral artery was established to address the role of miR-29b-3p and relevant mechanisms. miR-29b-3p was lowly expressed, and sVCAM-1, IL-1β, IL-6, and TNF-α were upregulated 1 day after PCI and 24 h after LPS treatment. miR-29b-3p overexpression or YY1 knockdown alleviated LPS-induced inflammatory responses and improved the viability of HCAECs. miR-29b-3p inhibition aggravated LPS-induced inflammatory injury in HCAECs. miR-29b-3p bound to YY1 mRNA and inhibited the expression of YY1 protein. YY1 bound to the IRAK1 promoter and activated the transcription of IRAK1. Upregulation of miR-29b-3p suppressed the inflammatory response after intraluminal injury of the common femoral artery in rats. In conclusion, dysregulation of the YY1/IRAK1 pathway via miR-29b-3p downregulation may be implicated in post-vascular injury inflammation.

Nuclear factor-kappa B p50-induced microRNA-20a-3p plays a detrimental role in sepsis-induced acute kidney injury.

Sepsis is the most common cause of acute kidney injury (AKI). Based on microarray-based clustering analysis of miRNAs altered in the kidneys of LPS-AKI mice, miR-20a-3p was upregulated in the kidney tissues of lipopolysaccharide (LPS)-treated mice. We aimed to reveal the functions of miR-20a-3p in septic AKI by establishing the LPS-stimulated mouse model of AKI and constructing the LPS-stimulated HK-2 cells. Reverse transcription-quantitative PCR was used to quantify miR-20a-3p expression and inflammation-associated factors including MCP-1, TNF-α, and IL-6. Silencing of miR-20a-3p reduced inflammation and apoptosis in kidneys as well as alleviated AKI symptoms in mice. The LPS-induced inflammatory response and apoptosis in HK-2 cells were rescued by miR-20a-3p silence. Moreover, nuclear factor-kappa B (NF-κB) is a transcriptional factor for miR-20a-3p to increase its expression. The binding of NF-κB p50 and miR-20a-3p promoter was verified by ChIP assay. To sum up, miR-20a-3p is transcriptionally activated by NF-κB p50, playing a harmful role in sepsis-induced AKI by inducing inflammation and apoptosis.

Aspirin eugenol ester ameliorates LPS-induced inflammatory responses in RAW264.7 cells and mice.

Introduction: Inflammation is a defensive response of the body and the pathological basis of many diseases. However, excessive inflammation and chronic inflammation impair the homeostasis of the organism. Arachidonic acid (AA) has a close relationship with inflammation and is the main mediator of the pro-inflammatory response. Based on the prodrug principle, the new pharmaceutical compound aspirin eugenol ester (AEE) was designed and synthesized. However, the effects of AEE on key enzymes, metabolites and inflammatory signaling pathways in the AA metabolic network have not been reported. Methods: In this study, the anti-inflammation effects of AEE were first investigated in mice and RAW264.7 cells in LPS induced inflammation model. Then, the changes of the key enzymes and AA metabolites were explored by RT-PCR and targeted metabolomics. Moreover, the regulatory effects on NF-kB and MAPKS signaling pathways were explored by Western Blotting. Results: Results indicated that AEE significantly reduced the number of leukocyte and increased the lymphocyte percentage. AEE decreased the expression levels of IL-1β, IL-6, IL-8 and TNF-α both in vivo and in vitro. In the liver of mice, AEE downregulated the levels of AA, prostaglandin D2 (PGD2) and upregulated 12- hydroxyeicosatetraenoic acid (12-HETE). However, the changes of PGE2, PGF2α, 6-keto-prostaglandin F1α (6-KETO-PGF1α), 9-hydroxy-octadecenoic acid (9- HODE), 13-HODE, 15-HETE, docosahexaenoic acid (DHA) and thromboxane B2 (TXB2) were not significant. Additionally, it was found that AEE decreased the relative mRNA expression levels of p65 and p38 and the ratio of p-p65/p65. Discussion: It was concluded that AEE might inhibit the LPS-induced inflammatory response through the regulation of AA metabolism. This study provides the theoretical foundation for the development of AEE as a medicinal anti-inflammatory drug.

Mechanisms of inhibition of nucleus pulposus cells pyroptosis through SDF1/CXCR4-NFkB-NLRP3 axis in the treatment of intervertebral disc degeneration by Duhuo Jisheng Decoction

Intervertebral disc degeneration (IVDD) is one of the leading causes of lower back pain and the most common health problem in the world. Inflammasomes, which is mainly caused by NLRP3, mediated nucleus pulposus pyroptosis has been discovered to be strongly related to IVDD. In addition, Duhuo Jisheng Decoction (DHJSD) has anti-inflammatory and regulatory effects on NLRP3 inflammasome, but the molecular mechanism of whether DHJSD can regulate pyroptosis through NLRP3 to treat IVDD is unclear. In this study, we used a bioinformatics way to discover the molecular mechanism of DHJSD regulation of pyroptosis in IVDD, and validated our predictions through vitro and vivo experiments. Through bioinformatics, we found that NLRP3, GSDMD, IL-1βand other hub proteins of pyroptosis were highly expressed in IVDD SD rats, and network pharmacology discovered that DHJSD may control cellular senescence, apoptosis, and pyroptosis in order to treat IVDD. Additional findings demonstrated that DHJSD could successfully treat IVDD brought on by imaging and histomorphological analysis. Western blot showed that NLRP3, a key protein of pyroptosis, was elevated in rat degenerated nucleus pulposus tissue and lipopolysaccharide-treated Nucleus pulposus Cells (NPCs), and that DHJSD intervention was effective in reducing LPS-induced inflammatory responses and further suppressing the expression of pyroptosis related proteins to improve IVDD. The specific mechanism is that DHJSD inhibits NPCs pyroptosis via the SDF-1/CXCR4-NF-kB-NLRP3 axis. In conclusion, we revealed the intrinsic mechanism of DHJSD regulation of NPCs pyroptosis to improve IVDD and its intrinsic value for IVDD treatment.

The connexin hemichannel inhibitor D4 produces rapid antidepressant-like effects in mice.

Depression is a common mood disorder characterized by a range of clinical symptoms, including prolonged low mood and diminished interest. Although many clinical and animal studies have provided significant insights into the pathophysiology of depression, current treatment strategies are not sufficient to manage this disorder. It has been suggested that connexin (Cx)-based hemichannels are candidates for depression intervention by modifying the state of neuroinflammation. In this study, we investigated the antidepressant-like effect of a recently discovered selective Cx hemichannel inhibitor, a small organic molecule called D4. We first showed that D4 reduced hemichannel activity following systemic inflammation after LPS injections. Next, we found that D4 treatment prevented LPS-induced inflammatory response and depressive-like behaviors. These behavioral effects were accompanied by reduced astrocytic activation and hemichannel activity in depressive-like mice induced by repeated low-dose LPS challenges. D4 treatment also reverses depressive-like symptoms in mice subjected to chronic restraint stress (CRS). To test whether D4 broadly affected neural activity, we measured c-Fos expression in depression-related brain regions and found a reduction in c-Fos+ cells in different brain regions. D4 significantly normalized CRS-induced hypoactivation in several brain regions, including the hippocampus, entorhinal cortex, and lateral septum. Together, these results indicate that blocking Cx hemichannels using D4 can normalize neuronal activity and reduce depressive-like symptoms in mice by reducing neuroinflammation. Our work provides evidence of the antidepressant-like effect of D4 and supports glial Cx hemichannels as potential therapeutic targets for depression.

Exacerbating effects of single-dose acute ethanol exposure on neuroinflammation and amelioration by GPR110 (ADGRF1) activation

BackgroundNeuroinflammation is a widely studied phenomenon underlying various neurodegenerative diseases. Earlier study demonstrated that pharmacological activation of GPR110 in both central and peripheral immune cells cooperatively ameliorates neuroinflammation caused by systemic lipopolysaccharide (LPS) administration. Ethanol consumption has been associated with exacerbation of neurodegenerative and systemic inflammatory conditions. The goal of this study is to determine the effects of single-dose acute ethanol exposure and GPR110 activation on the neuro-inflammation mechanisms.MethodsFor in vivo studies, GPR110 wild type (WT) and knockout (KO) mice at 10–12 weeks of age were given an oral gavage of ethanol (3 g/kg) or maltose (5.4 g/kg) at 1–4 h prior to the injection of LPS (1 mg/kg, i.p.) followed by the GPR110 ligand, synaptamide (5 mg/kg). After 2–24 h, brains were collected for the analysis of gene expression by RT-PCR or protein expression by western blotting and enzyme-linked immunosorbent assay (ELISA). Microglial activation was assessed by western blotting and immunohistochemistry. For in vitro studies, microglia and peritoneal macrophages were isolated from adult WT mice and treated with 25 mM ethanol for 4 h and then with LPS (100 ng/ml) followed by 10 nM synaptamide for 2 h for gene expression and 12 h for protein analysis.ResultsSingle-dose exposure to ethanol by gavage before LPS injection upregulated pro-inflammatory cytokine expression in the brain and plasma. The LPS-induced Iba-1 expression in the brain was significantly higher after ethanol pretreatment in both WT and GPR110KO mice. GPR110 ligand decreased the mRNA and/or protein expression of these cytokines and Iba-1 in the WT but not in GPR110KO mice. In the isolated microglia and peritoneal macrophages, ethanol also exacerbated the LPS-induced expression of pro-inflammatory cytokines which was mitigated at least partially by synaptamide. The expression of an inflammasome marker NLRP3 upregulated by LPS was further elevated with prior exposure to ethanol, especially in the brains of GPR110KO mice. Both ethanol and LPS reduced adenylate cyclase 8 mRNA expression which was reversed by the activation of GPR110. PDE4B expression at both mRNA and protein level in the brain increased after ethanol and LPS treatment while synaptamide suppressed its expression in a GPR110-dependent manner.ConclusionSingle-dose ethanol exposure exacerbated LPS-induced inflammatory responses. The GPR110 ligand synaptamide ameliorated this effect of ethanol by counteracting on the cAMP system, the common target for synaptamide and ethanol, and by regulating NLRP3 inflammasome.

Runx1 Deficiency Promotes M2 Macrophage Polarization Through Enhancing STAT6 Phosphorylation.

Our previous study had demonstrated that Runx1 promoted LPS-induced macrophage inflammatory response, however, the role of Runx1 in M2 macrophage polarization still remains largely unknown. This study was conducted to investigate the role of Runx1 in IL-4/IL-13-induced M2 macrophage polarization and its potential regulatory mechanism. We found that exposure of macrophages to IL-4/IL-13 induced a remarkable increasement in Runx1 expression level. Specifically, we established genetically modified mice lacking Runx1 in myeloid cells, including macrophages. RNA-Seq was performed to identify differentially expressed genes (DEGs) between Runx1 knockout and WT control bone marrow-derived macrophages (BMDMs). We identified 686 DEGs, including many genes which were highly expressed in M2 macrophage. In addition, bioinformatics analysis indicated that these DEGs were significantly enriched in extracellular matrix-related processes. Moreover, RT-qPCR analysis showed that there was an obvious upregulation in the relative expression levels of M2 marker genes, including Arg1, Ym1, Fizz1, CD71, Mmp9, and Tgm2, in Runx1 knockout macrophages, as compared to WT controls. Consistently, similar results were obtained in the protein and enzymatic activity levels of Arg1. Finally, we found that the STAT6 phosphorylation level was significantly enhanced in Runx1 knockout macrophages, and the STAT6 inhibitor AS1517499 partly reduced the upregulated effect of Runx1 deficiency on the M2 macrophage polarization. Taken together, Runx1 deficiency facilitates IL-4/IL-13-induced M2 macrophage polarization through enhancing STAT6 phosphorylation.

The antimicrobial peptide chensinin-1b alleviates the inflammatory response by targeting the TLR4/NF-κB signaling pathway and inhibits Pseudomonas aeruginosa infection and LPS-mediated sepsis

Excessive inflammatory responses are a major contributor to the high mortality associated with sepsis, a prevalent global complication. Therefore, the potential therapeutic strategy for sepsis involves targeting macrophages and reducing proinflammatory cytokine release. Chensinin-1b, an analog of the natural antimicrobial peptide derived from Rana chensinensis skin secretion, exhibits broad-spectrum antibacterial activity and adopts a random coil conformation in both PBS and membrane solution. By efficiently neutralizing LPS, chensinin-1b holds promise in alleviating LPS-induced inflammatory responses. In this study, we established a mouse septic shock model by exposing mice to multiple-drug-resistant Pseudomonas aeruginosa, as well as an endotoxin-mediated sepsis model induced by LPS. Administering chensinin-1b significantly prolonged the survival of the experimental mice, concurrently mitigating inflammatory responses and reducing organ damage. Additionally, we investigated the anti-inflammatory mechanism of chensinin-1b using a constructed LPS-induced mouse macrophage RAW264.7 inflammatory model. Our findings demonstrated that chensinin-1b effectively mitigated the excessive activation of the TLR4/NF-κB signaling pathway by directly neutralizing extracellular LPS, thus ameliorating the inflammatory response. Moreover, upon blocking the TLR4 signaling pathway, chensinin-1b further reduced the release of proinflammatory cytokines induced by LPS, indicating alternative modes of regulation. Notably, chensinin-1b rapidly entered RAW264.7 cells within 30 min via endocytosis, diffusing into the cytoplasm while retaining its anti-inflammatory properties intracellularly. Although further investigations are warranted to comprehensively elucidate the intracellular anti-inflammatory mechanism of chensinin-1b, our findings substantiate its possession of anti-inflammatory properties both intracellularly and extracellularly. Thus, chensinin-1b emerges as a promising candidate for mitigating excessive inflammatory responses associated with sepsis.