The role of dendritic cells regulated by HMGB1/TLR4 signalling pathway in myocardial ischaemia reperfusion injury

Inflammatory response plays an important role in ischaemia reperfusion injury (IRI) through a variety of inflammatory cells. Apart from neutrophils, macrophages and lymphocytes, the role of dendritic cells (DCs) in IRI has been noticed. The study was aimed at investigating whether the high‐mobility group protein box‐1/toll like receptor 4 (HMGB1/TLR4) signalling pathway regulate the migration, adhesion and aggregation of DCs to the myocardium, induce DCs activation and maturation, stimulate the expression of surface costimulatory molecules and participate in myocardial IRI. In vivo, migration, adhesion, and aggregation of DCs was enhanced; the expression of peripheral blood DCs CD80 and CD86, myocardial adhesion molecules were increased; and the infarct size was increased during myocardial ischaemia reperfusion injury myocardial ischemic/reperfusion injury (MI/RI). These responses induced by MI/RI were significantly inhibited by HMGB1 specific neutralizing antibody treatment. Cellular experiments confirmed that HMGB1 promoted the release of inflammatory cytokines through TLR4/MyD88/NF‐κB, upregulated CD80 and CD86 expression, mediated the damage of cardiomyocytes and accelerated the apoptosis. Our results indicate that DCs activation and maturation, stimulate the expression of surface costimulatory molecules by promoting the release of inflammatory factors through NF‐κB pathway and participate in myocardial IRI.     

Fluvastatin attenuated ischemia/reperfusion-induced autophagy and apoptosis in cardiomyocytes through down-regulation HMGB1/TLR4 signaling pathway

Molecular Biology Reports - Fluvastatin, a traditional fat-decreasing drug, is widely used for curing cardiovascular disease. Previous reports demonstrated that fluvastatin pretreatment protected...     

Deficiency of tenascin-C attenuated cardiac injury by inactivating TLR4/NLRP3/caspase-1 pathway after myocardial infarction

Inflammation and pyroptosis play a deleterious role in cardiac dysfunction after myocardial infarction (MI). NLRP3/caspase-1 is a well-established axis in pyroptosis and inflammation. In this study, we examined the effects of TN-C on pyroptosis through NLRP3 is unclear. We constructed 18 TN-C-knockout and 38 WT male mice model and divided into WT sham (n = 16), WT MI (n = 22), TNKO sham (n = 6), TNKO MI (n = 12). Elisa, immunostaining, TTC, qPCR, CCK8, flow cytometry, and western blot, echocardiographic, TUNEL staining technologies were applied. Here, we found a positive correlation between TN-C and NLRP3 in heart tissue via the GEPIA database (r = 0.52, p < 0.05). The findings indicate that TN-C was elevated and peaked on the fifth day after MI. TN-C deficiency alleviated cardiac dysfunction (LVEF, FS, LVIDd, and LVIDs) and cardiomyocyte death. Though the intracellular levels of pyroptosis-related cytokine caspase-1, cleaved caspase-1, NLRP3, IL-18, IL-1β were upregulated both in MI and H₂O₂ stimulation, knockout of TN-C resisted such injury and alleviated cardiac pyroptosis, which further decreased IL-6, TNF-α, MCP-1 expression. TN-C knockdown inhibited TLR4 expression, reduces the release of downstream factors by inactivating the TLR4/NF-kB pathway, while protects the cardiomyocytes. And TLR4 inhibitor TAK-242 significantly reduced NLRP3 expression levels after MI. We demonstrated for the first time a direct link between MI-induced TN-C upregulation and caspase-1-dependent cardiomyocyte pyroptosis, a process mediated, at least in part, by TLR4/NF-kB/NLRP3 and IL-18, IL-1β signaling pathways. These findings provide new insights into the role of TN-C in post-MI cardiomyocytes' pyroptosis and inflammation.     

表没食子儿茶素没食子酸酯抑制肥胖大鼠肝中TLR4炎症通路及胰岛素抵抗

目的探讨表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对肥胖大鼠肝组织中Toll样受体4(Toll-like receptor 4,TLR4)炎症通路以及胰岛素抵抗的影响。方法将30只雄性SD大鼠随机分为普食组(NC)和高脂饮食组(HFD)。喂养16周后,将高脂饮食组随机分为HFD组与EGCG组继续喂养16周,检测相关代谢指标,测定肝组织甘油三酯含量,并进行油红染色评估肝脂质聚集情况;实时荧光定量PCR检测其肝脏中TLR4和TNF受体相关因子6(TNF receptor associated factor 6,TRAF6)mRNA水平;蛋白质印记检测其肝组织中TLR4信号通路及胰岛素信号通路相关蛋白水平。结果EGCG明显降低大鼠肝脏甘油三酯浓度及脂质聚集、TLR4和TRAF6 mRNA水平,TLR4信号通路相关蛋白水平及胰岛素信号通路相关蛋白水平。结论EGCG抑制肥胖大鼠肝组织中TLR4通路以及胰岛素抵抗。     

LPS/TLR4 signal transduction pathway

The stimulation of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) induces the release of critical proinflammatory cytokines that are necessary to activate potent immune responses. LPS/TLR4 signaling has been intensively studied in the past few years. Here we review molecules involved in TLR4-mediated signaling, including players that are involved in the negative regulation of this important pathway.     

Extracellular HMGB1 augments macrophage inflammation by facilitating the endosomal accumulation of ALD-DNA via TLR2/4-mediated endocytosis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with unclear pathogenesis. We previously reported that syngenetic, activated lymphocyte-derived DNA (ALD-DNA) could robustly elicit macrophage activation, which plays an important role in the pathogenesis of murine lupus nephritis. In addition, extracellular HMGB1 obviously facilitated the accumulation of ALD-DNA in endosomes and promoted macrophage inflammation. While the detailed mechanism was still unknown. In this study, we found that HMGB1 could obviously change the DNA uptake pathways in macrophages. ALD-DNA alone was mainly uptake by the low efficient and unselective macropinocytosis, while extracellular HMGB1 potently promoted the more efficient and specific clathrin-/caveolin-1-dependent receptor-mediated endocytosis pathways, and led to the rapid and abundant aggregation of ALD-DNA in endosomes. This effect relied on the DNA binding ability and TLR2/TLR4 of HMGB1. Our study not only helped us to understand the promotion mechanisms of extracellular HMGB1 on ALD-DNA-induced macrophage inflammation, but also provided some clues to the pathogenesis of SLE.     

Modulation of Macrophage Polarization and HMGB1-TLR2/TLR4 Cascade Plays a Crucial Role for Cardiac Remodeling in Senescence-Accelerated Prone Mice

The aim of this study was to investigate the role of macrophage polarization in aging heart. Macrophage differentiation is pathogenically linked to many inflammatory and immune disorders. It is often preceded by myocardial inflammation, which is characterized by increased cardiac damage and pro-inflammatory cytokine levels. Therefore, we investigated the hypothesis that senescence accelerated-prone (SAMP8) mice cardiac tissue would develop macrophage polarization compared with senescence-resistant control (SAMR1) mice. Both SAMP8 and SAMR1 mice were sacrificed when they became six month old. We evaluated, histo-pathological changes and modifications in protein expression by Western blotting and immuno-histochemical staining for M1 and M2 macrophage markers, high mobility group protein (HMG)B1 and its cascade proteins, pro-inflammatory factors and inflammatory cytokines in cardiac tissue. We observed significant upregulation of HMGB1, toll-like receptor (TLR)2, TLR4, nuclear factor (NF)κB p65, tumor necrosis factor (TNF)α, cyclooxygenase (COX)2, interferon (IFN)γ, interleukin (IL)-1β, IL-6 and M1 like macrophage specific marker cluster of differentiation (CD)68 expressions in SAMP8 heart. In contrast, M2 macrophage specific marker CD36, and IL-10 expressions were down-regulated in SAMP8 mice. The results from the study demonstrated that, HMGB1-TLR2/TLR4 signaling cascade and induction of phenotypic switching to M1 macrophage polarization in SAMP8 mice heart would be one of the possible reasons behind the cardiac dysfunction and thus it could become an important therapeutic target to improve the age related cardiac dysfunction.     

有氧运动抑制自发性高血压大鼠心肌中HMGB1/TLR4炎症通路

目的:探讨有氧运动对自发性高血压大鼠心肌中高迁移率族蛋白1(high mobility group box-1 protein, HMGB1)/Toll样受体4(toll like receptor 4,TLR4)炎症通路的影响。方法:成年雄性大鼠分为三组:同源正常血压大鼠(Wistar-Kyoto rats,WKY),自发性高血压大鼠(spontaneoully hypertensive rat, SHR),自发性高血压大鼠运动组(SHR+exercise,SHR+EX)。运动为中等强度跑台运动,自制跑台,倾斜角设置为10度,运动强度逐步增强,持续12周。尾动脉检测血压,收集左心室,Masson染色检测心肌组织纤维化水平,RT-PCR法检测心肌中纤维化相关基因的m RNA水平,ELISA法检测炎症因子白介素6(Interleukin 6, IL-6)和肿瘤坏死因子α(tumor necrosis factor alpha, TNF-α)的蛋白水平,Western blot法检测HMGB1和TLR4的蛋白表达。结果:有氧运动可以明显降低SHR大鼠心肌中HMGB1(P0.05)和TLR4(P0.05)的蛋白表达以及炎症因子IL-6(P0.05)和TNF-α(P0.05)的蛋白水平。经过的有氧运动之后,SHR大鼠的体重(P0.05)、收缩压(P0.05)、舒张压明显降低(P0.05);心肌纤维化水平和心肌中I型胶原(P0.05)、转化生长因子-β(transforming growth factor-β,TGF-β,P0.05)、α平滑肌肌动蛋白(α-smooth muscle actin,α-SMA,P0.05)的m RNA水平出现显著下降。结论:有氧运动可抑制自发性高血压大鼠心肌中HMGB1/TLR4炎症通路。     

Antrodia camphorata polysaccharide improves inflammatory response in liver injury via the ROS/TLR4/NF‐κB signal

Antrodia Camphorata Polysaccharide (ACP) refers to a kind of polysaccharide extracted from the natural porous fungus Antrodia camphorata. This study investigated the mechanism of action of ACP in protecting the liver. The results showed that ACP suppressed the LPS‐induced KC cell activation, reduced the expression of inflammatory factors, increased the SOD level and suppressed ROS expression. In addition, N‐acetylcysteine (NAC) was adopted for pre‐treatment to suppress ROS. The results indicated that NAC synergistically exerted its effect with ACP, suggesting that ACP played its role through suppressing ROS. Further detection revealed that ACP activated the Nrf2 signal. It was discovered in the mouse model that, ACP effectively improved liver injury in mice, decreased ALT and AST levels, and suppressed the expression of inflammatory factors. This study suggests that ACP can exert its effect against oxidative stress via the Nrf2‐ARE signalling, which further improves the production of ROS and the activation of TLR4‐NF‐κB signalling, and protects the liver against liver injury.     

Glycyrrhizin regulates rat TMJOA progression by inhibiting the HMGB1‐RAGE/TLR4‐NF‐κB/AKT pathway

To investigate the role of glycyrrhizin on the progression of temporomandibular joint osteoarthritis (TMJOA) and the underlying mechanism by regulation of the high‐mobility group box 1 (HMGB1) receptor for advanced glycation end products (RAGE)/toll‐like receptor 4 (TLR4)‐nuclear factor kappa B (NF‐κB)/protein kinase B (AKT) pathway. After a rat model of TMJOA was built by intra‐articular injection of monosodium iodoacetate, glycyrrhizin was intragastrically administered at low concentration (20 mg/kg) or high concentration (50 mg/kg). Micro‐computed tomography, histological and immunohistochemical analysis were used to reveal the progression of TMJOA. Rat TMJ chondrocytes and disc cells were cultured in inflammatory condition with different doses of glycyrrhizin. Western blot was used to evaluate the effect of glycyrrhizin on the HMGB1‐RAGE/TLR4‐NF‐κB/AKT pathway. Administration of glycyrrhizin alleviated cartilage degeneration, lowered the levels of inflammatory and catabolic mediators and reduced the production of HMGB1, RAGE and TLR4 in TMJOA animal model. Increased production of RAGE and TLR4, and activated intracellular NF‐κB and/or AKT signalling pathways in chondrocytes and disc cells were found in inflammatory condition. Upon activation, matrix metalloprotease‐3 and interleukin‐6 were upregulated. Glycyrrhizin inhibited not only HMGB1 release but also RAGE and TLR4 in inflammatory condition. Glycyrrhizin alleviated the pathological changes of TMJOA by regulating the HMGB1‐RAGE/TLR4‐NF‐kB/AKT signalling pathway. This study revealed the potential of glycyrrhizin as a novel therapeutic drug to suppress TMJ cartilage degradation.     

神经元-小胶质细胞EphA4/ephrin通路调控小胶质细胞介导的缺血后炎性损伤

目的观察神经元-小胶质细胞间EphA4/ephrin信号通路在脑缺血后的炎性损伤中的作用及机制。方法建立神经元-小胶质细胞混合培养体系和糖氧剥夺再复氧(oxygen-glucose deprivation and reperfusion, OGD/R)模型,使用预聚集化的EphA4-Fc激动小胶质细胞ephrin配体,检测OGD/R后的细胞凋亡、小胶质细胞增殖和亚型极化以及小胶质细胞功能改变。结果 EphA4受体高表达于原代神经元,与对照组相比,预聚集化EphA4-Fc干预加重OGD/R导致的细胞凋亡,促进小胶质细胞增殖以及向M1型(促炎型)极化(炎症表型)。结论神经元-小胶质细胞间EphA4/ephrin信号通路通过调控小胶质细胞亚型极化参与脑缺血后的炎性损伤的过程。     

Sphingosine kinase 1 regulates HMGB1 translocation by directly interacting with calcium/calmodulin protein kinase II-δ in sepsis-associated liver injury

Previously, we confirmed that sphingosine kinase 1 (SphK1) inhibition improves sepsis-associated liver injury. High-mobility group box 1 (HMGB1) translocation participates in the development of acute liver failure. However, little information is available on the association between SphK1 and HMGB1 translocation during sepsis-associated liver injury. In the present study, we aimed to explore the effect of SphK1 inhibition on HMGB1 translocation and the underlying mechanism during sepsis-associated liver injury. Primary Kupffer cells and hepatocytes were isolated from SD rats. The rat model of sepsis-associated liver damage was induced by intraperitoneal injection with lipopolysaccharide (LPS). We confirmed that Kupffer cells were the cells primarily secreting HMGB1 in the liver after LPS stimulation. LPS-mediated HMGB1 expression, intracellular translocation, and acetylation were dramatically decreased by SphK1 inhibition. Nuclear histone deacetyltransferase 4 (HDAC4) translocation and E1A-associated protein p300 (p300) expression regulating the acetylation of HMGB1 were also suppressed by SphK1 inhibition. HDAC4 intracellular translocation has been reported to be controlled by the phosphorylation of HDAC4. The phosphorylation of HDAC4 is modulated by CaMKII-δ. However, these changes were completely blocked by SphK1 inhibition. Additionally, by performing coimmunoprecipitation and pull-down assays, we revealed that SphK1 can directly interact with CaMKII-δ. The colocalization of SphK1 and CaMKII-δ was verified in human liver tissues with sepsis-associated liver injury. In conclusion, SphK1 inhibition diminishes HMGB1 intracellular translocation in sepsis-associated liver injury. The mechanism is associated with the direct interaction of SphK1 and CaMKII-δ.Subject terms: Hepatotoxicity, Sepsis     

A novel pathway of HMGB1-mediated inflammatory cell recruitment that requires Mac-1-integrin

High-mobility group box 1 (HMGB1) is released extracellularly upon cell necrosis acting as a mediator in tissue injury and inflammation. However, the molecular mechanisms for the proinflammatory effect of HMGB1 are poorly understood. Here, we define a novel function of HMGB1 in promoting Mac-1-dependent neutrophil recruitment. HMGB1 administration induced rapid neutrophil recruitment in vivo. HMGB1-mediated recruitment was prevented in mice deficient in the beta2-integrin Mac-1 but not in those deficient in LFA-1. As observed by bone marrow chimera experiments, Mac-1-dependent neutrophil recruitment induced by HMGB1 required the presence of receptor for advanced glycation end products (RAGE) on neutrophils but not on endothelial cells. In vitro, HMGB1 enhanced the interaction between Mac-1 and RAGE. Consistently, HMGB1 activated Mac-1 as well as Mac-1-mediated adhesive and migratory functions of neutrophils in a RAGE-dependent manner. Moreover, HMGB1-induced activation of nuclear factor-kappaB in neutrophils required both Mac-1 and RAGE. Together, a novel HMGB1-dependent pathway for inflammatory cell recruitment and activation that requires the functional interplay between Mac-1 and RAGE is described here.     

Targeting TLR4 signaling by TLR4 Toll/IL-1 receptor domain-derived decoy peptides: identification of the TLR4 Toll/IL-1 receptor domain dimerization interface

Agonist-induced dimerization of TLR4 Toll/IL-1R (TIR) domains initiates intracellular signaling. Therefore, identification of the TLR4-TIR dimerization interface is one key to the rational design of therapeutics that block TLR4 signaling. A library of cell-permeating decoy peptides, each of which represents a nonfragmented patch of the TLR4 TIR surface, was designed such that the peptides entirely encompass the TLR4 TIR surface. Each peptide was synthesized in tandem with a cell-permeating Antennapedia homeodomain sequence and tested for the ability to inhibit early cytokine mRNA expression and MAPK activation in LPS-stimulated primary murine macrophages. Five peptides--4R1, 4R3, 4BB, 4R9, and 4αE--potently inhibited all manifestations of TLR4, but not TLR2 signaling. When tested for their ability to bind directly to TLR4 TIR by F?rster resonance energy transfer using time-resolved fluorescence spectroscopy, Bodipy-TMR-X-labeled 4R1, 4BB, and 4αE quenched fluorescence of TLR4-Cerulean expressed in HeLa or HEK293T cells, whereas 4R3 was partially active, and 4R9 was least active. These findings suggest that the area between the BB loop of TLR4 and its fifth helical region mediates TLR4 TIR dimerization. Moreover, our data provide direct evidence for the utility of the decoy peptide approach, in which peptides representing various surface-exposed segments of a protein are initially probed for the ability to inhibit protein function, and then their specific targets are identified by F?rster resonance energy transfer to define recognition sites in signaling proteins that may be targeted therapeutically to disrupt functional transient protein interactions.     

Cutting edge: TLR4 activation mediates liver ischemia/reperfusion inflammatory response via IFN regulatory factor 3-dependent MyD88-independent pathway

The triggering molecular mechanism of ischemia-reperfusion injury (IRI), which in clinical settings results in excessive and detrimental inflammatory responses, remains unclear. This study analyzes the role of the TLR system in an established murine model of liver warm ischemia followed by reperfusion. By contrasting in parallel TLR knockout mice with their wild-type counterparts, we found that TLR4, but not TLR2, was specifically required in initiating the IRI cascade, as manifested by liver function (serum alanine aminotransferase levels), pathology, and local induction of proinflammatory cytokines/chemokines (TNF-alpha, IL-6, IFN-inducible protein 10). We then investigated the downstream signaling pathway of TLR4 activation. Our results show that IFN regulatory factor 3, but not MyD88, mediated IRI-induced TLR4 activation leading to liver inflammation and hepatocellular damage. This study documents the selective usage of TLR in a clinically relevant noninfectious disease model, and identifies a triggering molecular mechanism in the pathophysiology of liver IRI.     

Shizukaol A exerts anti-inflammatory effect by regulating HMGB1/Nrf2/HO-1 pathway

BackgroundSarcandra glabra (Thunb.) Makino (Chloranthaceae) has a long history of being used in Traditional Chinese medicines (TCMs) to treat painful joints, fractures, arthritis, and other diseases caused by inflammation. It has been reported that lindenane-type sesquiterpenoid dimers are main anti-inflammatory ingredient of S. glabra. Meanwhile, shizukaol A, the precursor of these sesquiterpene dimers, possesses a good inhibitory effect on nitric oxide (NO) in our previous study. But its anti-inflammatory mechanism is still unclear.PurposeThis study aimed to explore the possible anti-inflammatory mechanism and potential targets of shizukaol A in lipopolysaccharide (LPS)-induced RAW 264.7 cells.MethodsThe release of NO and inflammatory cytokines in LPS-stimulated RAW 264.7 cells were measured by Griess reagent and ELISA, respectively. The relevant proteins including inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB) p65, High mobility group box 1 (HMGB1) were detected by western blot. Nuclear translocation of p65, HMGB1 and nuclear factor E2-related factor 2 (Nrf2) were examined by immunofluorescence. The level of reactive oxygen species (ROS) was tested by flow cytometry. The target of shizukaol A was investigated by molecular docking and Drug Affinity Responsive Target Stability (DARTS).ResultsShizukaol A had a good inhibitory effect on NO with half maximal inhibitory concentration (IC₅₀) of 13.79 ± 1.11 μM. Shizukaol A could down-regulate the expression of iNOS and COX-2. Further studies demonstrated that shizukaol A can significantly inhibit phosphorylation and nuclear translocation of NF-κB. Meanwhile, shizukaol A decreased the level of ROS and enhanced the expression of heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1). Furthermore, shizukaol A up-regulated the expression of Nrf2 and its nuclear translocation. More importantly, shizukaol A could inhibit activation of HMGB1 by targeting HMGB1.ConclusionShizukaol A inhibited inflammation by targeting HMGB1 to regulate the Nrf2/HO-1 signaling pathway. Thus, shizukaol A may be an attractive therapeutic candidate for inflammatory diseases.     

The HIV Protease Inhibitor Saquinavir Inhibits HMGB1-Driven Inflammation by Targeting the Interaction of Cathepsin V with TLR4/MyD88

Extracellular high-mobility group box 1 (HMGB1) (disulfide form), via activation of toll-like receptor 4 (TLR4)-dependent signaling, is a strong driver of pathologic inflammation in both acute and chronic conditions. Identification of selective inhibitors of HMGB1-TLR4 signaling could offer novel therapies that selectively target proximal endogenous activators of inflammation. A cell-based screening strategy led us to identify first generation HIV-protease inhibitors (PI) as potential inhibitors of HMGB1-TLR4 driven cytokine production. Here we report that the first-generation HIV-PI saquinavir (SQV), as well as a newly identified mammalian protease inhibitor STO33438 (334), potently block disulfide HMGB1-induced TLR4 activation, as assayed by the production of TNF-α by human monocyte-derived macrophages (THP-1). We further report on the identification of mammalian cathepsin V, a protease, as a novel target of these inhibitors. Cellular as well as recombinant protein studies show that the mechanism of action involves a direct interaction between cathepsin V with TLR4 and its adaptor protein MyD88. Treatment with SQV, 334 or the known cathepsin inhibitor SID26681509 (SID) significantly improved survival in murine models of sepsis and reduced liver damage following warm liver ischemia/reperfusion (I/R) models, both characterized by strong HMGB1-TLR4 driven pathology. The current study demonstrates a novel role for cathepsin V in TLR4 signaling and implicates cathepsin V as a novel target for first-generation HIV-PI compounds. The identification of cathepsin V as a target to block HMGB1-TLR4-driven inflammation could allow for a rapid transition of the discovery from the bench to the bedside. Disulfide HMGB1 drives pathologic inflammation in many models by activating signaling through TLR4. Cell-based screening identified the mammalian protease cathepsin V as a novel therapeutic target to inhibit TLR4-mediated inflammation induced by extracellular HMGB1 (disulfide form). We identified two protease inhibitors (PIs) that block cathepsin V and thereby inhibit disulfide HMGB1-induced TLR4 activation: saquinavir (SQV), a first-generation PI targeting viral HIV protease and STO33438 (334), targeting mammalian proteases. We discovered that cathepsin V binds TLR4 under basal and HMGB1-stimulated conditions, but dissociates in the presence of SQV over time. Thus cathepsin V is a novel target for first-generation HIV PIs and represents a potential therapeutic target of pathologic inflammation.     

Ginsenoside Rb3 alleviates smoke-induced lung injury via the H19/miR-29b-3p/HGMB1/TLR4 signalling pathway

The over-activation of inflammation is involved in the pathogenesis of smoke-induced lung injury (SILI), while Rb3 treatment may alleviate smoke-induced lung injury by down-regulating the expression of H19, a regulator of miR-29b expression. Moreover, HMGB1 is an important mediator of inflammation. Therefore, in this study, we set up an animal model of SILI and treated it with Rb3 to study the effect of Rb3 on the treatment of SILI and the involvement of H19/miR-29b/HMGB1/TLR4 signalling. SILI mice treated with Rb3 before H&E staining and TUNEL assay were conducted to observe the pathological damages and status of apoptosis in each group. Real-time PCR, Western blot, computational analysis and luciferase assays were utilized to establish the signalling pathway involved in the pathogenesis of SILI and the action of Rb3 treatment. Rb3 treatment alleviated pathological changes in the lungs while decreasing the levels of W/D ratio and cell apoptotic index. H19 was validated to sponge miR-29b-3p, while HMGB1 mRNA was validated to be a target gene of miR-29b-3. As a result, a signalling pathway of H19/miR-29b-3p/HMGB1 was established. Cell viability was evidently reduced after 72 hours of treatment with CSE, but the treatment of Rb3 elevated the expression of H19 and HMBG1 in the presence of CSE. Also, CSE-induced inhibition of miR-29b-3p expression was restored by Rb3. The findings of this study collectively demonstrated that Rb3 exhibited its therapeutic effect during the treatment of SILI via modulating the H19/miR-29b-3p/HMBG1 signalling pathway.