scholarly journals Fn14 Exacerbates Acute Lung Injury by Activating the NLRP3 Inflammasome in Mice

Author(s):  
Xin-Xin Guan ◽  
Hui-Hui Yang ◽  
Wen-Jing Zhong ◽  
Jia-Xi Duan ◽  
Chen-Yu Zhang ◽  
...  

Abstract Background: Uncontrolled inflammation is an important factor in the occurrence and development of acute lung injury (ALI). Fibroblast growth factor-inducible 14 (Fn14) takes part in the pathological process of a variety of inflammatory diseases. However, the role of Fn14 in ALI has not yet been elucidated. Methods: C57BL/6J mice were used in this study. ALI model was induced by intratracheal injection of lipopolysaccharide (LPS, 5 mg/kg). The effects of Fn14 receptor blocker ATA (20 mg/kg) on lung injury, inflammatory cell infiltration, inflammatory factor secretion, and oxidative stress in mice were observed. The activation of NLRP3 inflammasome was detected by qPCR, Western blot, and ELISA. Prophylactic or therapeutic ATA was administered to observe its effect on the survival rate of ALI mice. In vitro, primary mouse peritoneal macrophages were used to activate the NLRP3 inflammasome by LPS or LPS+ATP. Fn14 was activated by recombinant TWEAK, or knockdown by lentivirus, and the effects on NLRP3 inflammasome activation was detected.Results: We found that ATA significantly downregulated the expression of Fn14 in the lungs and improved the survival rate of mice receiving a lethal dose of LPS. ATA also attenuated lung tissue damage by decreasing the infiltration of macrophages and neutrophils, reducing inflammation, and suppressing oxidative stress. Interestingly, we found that ATA strongly inhibited the activation of NLRP3 inflammasome in the lungs of ALI mice. Furthermore, in vitro, exogenous TWEAK, a natural ligand of Fn14, enhanced the levels of NLRP3 and Caspase-1 p10 and the maturation and secretion of IL-1β in the primary murine macrophages, eventually leading to the activation of NLRP3 inflammasome. In addition, the expression of Fn14, NLRP3, and Caspase-1 p10 and the production of IL-1β were effectively blocked by Fn14 shRNA in macrophages. In mechanism, the activation of Fn14 promoted the production of reactive oxygen species in activated macrophages. Conclusion:Our study first reports that the activation of Fn14 aggravates ALI by amplifying the activation of NLRP3 inflammasome. Therefore, blocking Fn14 may be a potential way to treat ALI.

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Wenfang Xia ◽  
Zhou Pan ◽  
Huanming Zhang ◽  
Qingshan Zhou ◽  
Yu Liu

Inflammation and oxidative stress are critical pathologies that contribute to sepsis-induced acute lung injury (ALI). This study investigated the regulatory role of estrogen-related receptor alpha (ERRα) in an experimental model of sepsis-induced ALI. In vivo, a cecal ligation and puncture- (CLP-) induced ALI model was established in anesthetized rats. Animals were then randomly assigned to receive an intraperitoneal injection of vehicle or ERRα inverse agonist (XCT-790, 2.5 mg/kg). Administration of XCT-790 significantly aggravated a sepsis-induced increase in pathological damage of lung tissues, lung endothelial permeability, myeloperoxidase (MPO) activity in lung tissues, production of serum inflammatory factors, and inflammatory cell accumulation in bronchoalveolar lavage fluid. In addition, XCT-790 treatment exacerbated a CLP-induced decrease in lung superoxide dismutase and an increase in lung malondialdehyde levels. In vitro, the exposure of rat pulmonary microvascular endothelial cells (PMVECs) to lipopolysaccharide (LPS) resulted in increased endothelial permeability and reduced expression of tight junction protein ZO-1, Occludin, JAM-A, and adherens junction protein VE-cadherin, which were further deteriorated by knockdown of ERRα. In addition, LPS-triggered inflammatory factor production and increase in the expression of phosphorylated IκBα and NF-κB p65 were also exacerbated by silencing ERRα gene. Meanwhile, knockdown of ERRα dramatically promoted LPS-activated mitochondrial reactive oxygen species production and LPS-induced downregulation of Sirt3 protein levels in rat PMVECs. Taken together, our present study provides evidences that ERRα functions as a novel negative modulator of sepsis-induced ALI in rats. The underlying mechanisms responsible for ERRα-elicited effects are largely dependent on the regulation of inflammatory response and oxidative stress.


2021 ◽  
Author(s):  
Haijin Lv ◽  
Xiaofeng Yuan ◽  
Jiebin Zhang ◽  
Tongyu Lu ◽  
Jia Yao ◽  
...  

Abstract Objectives: Acute lung injury (ALI) remains one of the common causes of morbidity and mortality worldwide, so far, without any effective therapeutic approach. Previous researches have revealed that topical administration of umbilical cord-derived mesenchymal stem cells (UC-MSCs) can attenuate pathological changes in experimental acute lung injury. Heat shock (HS) pretreatment has been identified as a method to enhance survival and function of cells. The present study aimed to assess whether HS-pretreated mesenchymal stem cells (MSCs) could strengthen the immunomodulation and recovery from ALI. Materials and Methods: HS pretreatment was defined 42℃ for 1h, the changes of biological characteristics and the secreted functions were detected. In the mouse model of ALI, we intranasally dripped the pretreated UC-MSCs in vivo, confirmed their therapeutic effects and detected the phenotypes of macrophages in bronchoalveolar lavage fluid (BALF). To elucidate their mechanisms, we co-cultured the pretreated UC-MSCs with macrophages in vitro, and the expression levels of inflammasome-related proteins in macrophages were assessed. Finally, Apoptozole was used for further determine the role of HSP70 in HS-pretreated UC-MSCs-based therapy. Results: The data showed that UC-MSCs did not represented significant changes in viability and biological characterizations after received HS pretreatment. Administration of HS-pretreated UC-MSCs into the ALI model, improved pathological changes and lung damage-related indexes, reduced of the levels of pro-inflammatory cytokines and modulated the balance of M1/M2. Mechanistically, both in vivo and in vitro studies demonstrated that HS pretreatment enhanced the protein level of HSP70 in UC-MSCs and subsequently upregulated the synthesis and secretion of PGE2, which negatively modulated the NLRP3 inflammasome activation of alveolar macrophages. And these effects was partially reversed by Apoptozole. Conclusion: HS pretreatment can strengthen the beneficial effects of UC-MSCs on inhibiting NLRP3 inflammasome activation of macrophages in ALI. The mechanism may be contributed to the upregulated expression of HSP70 to further induce PGE2 synthesis and secretion.


2021 ◽  
Vol 12 (10) ◽  
Author(s):  
Deqiang Luo ◽  
Wei Dai ◽  
Xiaojin Feng ◽  
Chengzhi Ding ◽  
Qiang Shao ◽  
...  

AbstractAcute lung injury (ALI) is a common lung pathology that is accompanied by alveolar macrophage (AM) activation and inflammatory response. This study investigated the role of the long non-coding RNA NONRATT004344 (hereafter named lncRNA NLRP3) in regulating the Nod-like receptor protein 3 (NLRP3)-triggered inflammatory response in early ALI and the underlying mechanism as well. We established LPS-induced ALI models to explore their interactive mechanisms in vitro and in vivo. Luciferase reporter assays were performed to determine that miR-138-5p could bind to lncRNA NLRP3 and NLRP3. We observed increased lncRNA NLRP3 expression, decreased miR-138-5p expression, NLRP3 inflammasome activation, and upregulated caspase-1, IL-1β, and IL-18 expression in the LPS-induced ALI model. Furthermore, lncRNA NLRP3 overexpression activated the NLRP3 inflammasome and promoted IL-1β and IL-18 secretion; the miR-138-5p mimic abolished these effects in vivo and in vitro. Consistently, miR-138-5p inhibition reversed the effects of lncRNA NLRP3 silencing on the expression of NLRP3-related molecules and inhibition of the NLRP3/caspase-1/IL-1β signalling pathway. Mechanistically, lncRNA NLRP3 sponging miR-138-5p facilitated NLRP3 activation through a competitive endogenous RNA (ceRNA) mechanism. In summary, our results suggested that lncRNA NLRP3 binding miR-138-5p promotes NLRP3-triggered inflammatory response via lncRNA NLRP3/miR-138-5p/NLRP3 ceRNA network (ceRNET) and provides insights into the treatment of early ALI.


2021 ◽  
Author(s):  
yuhan liu ◽  
jiabin zhou ◽  
yingying luo ◽  
jinxiao li ◽  
luorui shang ◽  
...  

Abstract Background Honokiol (HKL) has been reported to ameliorate lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, its potential mechanism imparting the protective effects remains unclear. In this study, the protective mechanism of HKL on LPS-induced ALI was explored in vivo and in vitro. Methods In vivo, the SD rats were intratracheally instilled with LPS (5 mg/kg) to establish an acute lung injury model and then treated with HKL (1.25/2.5/5 mg/kg) or ML385 (30 mg/kg) intraperitoneally. In vitro, the human bronchial epithelial cell line (BEAS-2B) was stimulated with LPS and ATP to induce pyroptosis and treated with HKL (12.5/25/50 µM). Small interfering RNA (siRNA) technique was used to knockdown Nrf2 in BEAS-2B cells. The protein and mRNA expression levels of Nrf2, HO-1, NLRP3, ASC, CASP1, and GSDMD in cells and lung tissues were detected by western blot and real time-PCR. The expression levels of interleukin (IL)-1β, IL-18, MPO, MDA, and SOD in bronchoalveolar lavage fluid (BALF) and supernatant were determined by ELISA. The degree of pathological injury of lung tissue was evaluated by H&E staining. Results The results showed that HKL could alleviate the oxidative stress and inflammatory responses by regulating the levels of MPO, MDA, SOD, IL-1β, IL-18 in supernatant. And HKL inhibited the expression levels of NLRP3, ASC, CASP1, GSDMD via activation of Nrf2 in BEAS-2B cells. Further studies revealed that HKL could attenuate the pathological injury in LPS-induced ALI rats and the molecular mechanism was consistent with the results in vitro. Conclusions Our study demonstrated that HKL could alleviate LPS-induced ALI by reducing the oxidative stress and inhibiting NLRP3 inflammasome-mediated pyroptosis, which was partly dependent on the Nrf2 activation.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuhan Liu ◽  
Jiabin Zhou ◽  
Yingying Luo ◽  
Jinxiao Li ◽  
Luorui Shang ◽  
...  

Abstract Background Honokiol (HKL) has been reported to ameliorate lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, its potential mechanism of its protective effects remains unclear. In this study, the protective mechanism of HKL on LPS-induced ALI was explored in vivo and in vitro. Methods In vivo, the SD rats were intratracheally instilled with LPS (5 mg/kg) to establish an acute lung injury model and then treated with HKL (1.25/2.5/5 mg/kg) or ML385 (30 mg/kg) intraperitoneally. In vitro, the human bronchial epithelial cell line (BEAS-2B) was stimulated with LPS and ATP to induce pyroptosis and treated with HKL (12.5/25/50 μM). Small interfering RNA (siRNA) technique was used to knockdown Nrf2 in BEAS-2B cells. The protein and mRNA expression levels of Nrf2, HO-1, NLRP3, ASC, CASP1, and GSDMD in cells and lung tissues were detected by western blot and real time-PCR. The expression levels of interleukin (IL)-1β, IL-18, MPO, MDA, and SOD in bronchoalveolar lavage fluid (BALF) and supernatant were determined by ELISA. The degree of pathological injury of lung tissue was evaluated by H&E staining. Results The results showed that HKL could alleviate oxidative stress and inflammatory responses by regulating the levels of MPO, MDA, SOD, IL-1β, IL-18 in supernatant. And it could also inhibit the expression levels of NLRP3, ASC, CASP1, GSDMD via activation of Nrf2 in BEAS-2B cells. Further studies revealed that HKL could attenuate the pathological injury in LPS-induced ALI rats, and the molecular mechanism was consistent with the results in vitro. Conclusions Our study demonstrated that HKL could alleviate LPS-induced ALI by reducing the oxidative stress and inhibiting NLRP3 inflammasome-mediated pyroptosis, which was partly dependent on the Nrf2 activation. Graphical Abstract


2017 ◽  
Vol 42 (5) ◽  
pp. 1907-1919 ◽  
Author(s):  
Qiuyue Zhang ◽  
Di Wu ◽  
Yang Yang ◽  
Tingting Liu ◽  
Hongyu Liu

Background/Aims: Dexmedetomidine (Dex), a specific agonist of α2-adrenoceptor, has been reported to have extensive pharmacological effects. In this study, we focused on the protective effect of Dex on hyperoxia-induced acute lung injury and further explored its possible molecular mechanisms. Methods: The model of hyperoxia-induced acute lung injury was established by continuous inhalation of oxygen (FiO2= 0.90) for 7 d in neonatal rats in vivo. The in vitro experiments were carried out in LPS/ATP or hyperoxia-treated RAW264.7 cells. ELISA, western blot, TUNEL staining, and immunohistochemistry staining assays were performed and the commercial kits were used to assess the beneficial effect of Dex on hyperoxia-induced acute lung injury. Results: According to our results, Dex treatment attenuated hyperoxia-induced acute lung injury via decreasing the lung wet/dry(W/D) weight ratio and mitigating pathomorphologic changes. Moreover, the oxidative stress injury, inflammatory reaction, and apoptosis in lung epithelial cells were inhibited by Dex treatment. In addition, the activation of NLRP3 inflammasome was restrained by Dex both in lung tissue in vivo and RAW264.7 cells in vitro. Conclusion: These data provide evidence that Dex may ameliorate hyperoxia-induced acute lung injury, which suggests a potential clinical application of Dex in long-term supplemental oxygen therapy.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haijin Lv ◽  
Xiaofeng Yuan ◽  
Jiebin Zhang ◽  
Tongyu Lu ◽  
Jia Yao ◽  
...  

Abstract Objectives Acute lung injury (ALI) remains a common cause of morbidity and mortality worldwide, and to date, there is no effective treatment for ALI. Previous studies have revealed that topical administration of mesenchymal stem cells (MSCs) can attenuate the pathological changes in experimental acute lung injury. Heat shock (HS) pretreatment has been identified as a method to enhance the survival and function of cells. The present study aimed to assess whether HS-pretreated MSCs could enhance immunomodulation and recovery from ALI. Materials and methods HS pretreatment was performed at 42 °C for 1 h, and changes in biological characteristics and secretion functions were detected. In an in vivo mouse model of ALI, we intranasally administered pretreated umbilical cord-derived MSCs (UC-MSCs), confirmed their therapeutic effects, and detected the phenotypes of the macrophages in bronchoalveolar lavage fluid (BALF). To elucidate the underlying mechanisms, we cocultured pretreated UC-MSCs with macrophages in vitro, and the expression levels of inflammasome-related proteins in the macrophages were assessed. Results The data showed that UC-MSCs did not exhibit significant changes in viability or biological characteristics after HS pretreatment. The administration of HS-pretreated UC-MSCs to the ALI model improved the pathological changes and lung damage-related indexes, reduced the proinflammatory cytokine levels, and modulated the M1/M2 macrophage balance. Mechanistically, both the in vivo and in vitro studies demonstrated that HS pretreatment enhanced the protein level of HSP70 in UC-MSCs, which negatively modulated NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in alveolar macrophages. These effects were partially reversed by knocking down HSP70 expression. Conclusion HS pretreatment can enhance the beneficial effects of UC-MSCs in inhibiting NLRP3 inflammasome activation in macrophages during ALI. The mechanism may be related to the upregulated expression of HSP70. Graphical abstract


2021 ◽  
pp. 175342592110354
Author(s):  
Caixia Liu ◽  
Benlong Cai ◽  
Dan Li ◽  
Yuan Yao

Sepsis is a complex clinical syndrome with high incidence and mortality. Acute lung injury (ALI) is a common complication of sepsis. At present, there is no effective therapeutic strategy to treat ALI. The SET domain–containing histone methyltransferase Wolf–Hirschhorn syndrome candidate 1 (WHSC1) regulates cancer progression, while its role in sepsis-induced ALI remains unclear. Thus, this study aimed to study the effect of WHSC1 on sepsis-induced ALI and to explore the potential mechanism of action. In the study, LPS treatment induced lung injury. WHSC1 was highly expressed in LPS-induced ALI. Knockdown of WHSC1 attenuated LPS-induced ALI and pyroptosis in vivo. Besides, knockdown of WHSC1 attenuated LPS-induced alveolar macrophage pyroptosis in vitro. Furthermore, NIMA-related kinase-7 (NEK7) expression could be regulated by WHSC1, and NEK7 bound to NLRP3 in alveolar macrophages. Moreover, WHSC1 regulated alveolar macrophage pyroptosis through modulating NEK7-mediated NLRP3 inflammasome activation. In conclusion, WHSC1 was highly expressed in LPS-induced ALI. WHSC1 facilitated alveolar macrophage pyroptosis in sepsis-induced ALI through NEK7-mediated NLRP3 inflammasome activation. WHSC1 may be a valuable target for the therapy of sepsis-induced ALI.


Author(s):  
Hang Zhang ◽  
Zheyi Jiang ◽  
Chuanbin Shen ◽  
Han Zou ◽  
Zhiping Zhang ◽  
...  

5-Hydroxymethylfurfural (5-HMF) is a common reaction product during heat processing and the preparation of many types of foods and Traditional Chinese Medicine formulations. The aim of this study was to evaluate the protective effect of 5-HMF on endotoxin-induced acute lung injury (ALI) and the underlying mechanisms. Our findings indicate that 5-HMF attenuated lipopolysaccharide (LPS)-induced ALI in mice by mitigating alveolar destruction, neutrophil infiltration and the release of inflammatory cytokines. Furthermore, the activation of macrophages and human monocytes in response to LPS was remarkably suppressed by 5-HMF in vitro through inhibiting the NF-κB signaling pathway, NLRP3 inflammasome activation and endoplasmic reticulum (ER) stress. The inhibitory effect of 5-HMF on NLRP3 inflammasome was reversed by overexpressing ATF4 or CHOP, indicating the involvement of ER stress in the negative regulation of 5-HMF on NLRP3 inflammasome-mediated inflammation. Consistent with this, the ameliorative effect of 5-HMF on in vivo pulmonary dysfunction were reversed by the ER stress inducer tunicamycin. In conclusion, our findings elucidate the anti-inflammatory and protective efficacy of 5-HMF in LPS-induced acute lung injury, and also demonstrate the key mechanism of its action against NLRP3 inflammasome-related inflammatory disorders via the inhibition of ER stress.


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