Hypothermia alleviated LPS-induced acute lung injury in Rat models through TLR2/MyD88 pathway

Palmatine Attenuated Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting M1 Phenotype Macrophage Polarization via NAMPT/TLR2/CCR1 Signaling

The present work was conducted to research the potential mechanism of palmatine (PAL) on lipopolysaccharide (LPS)-caused acute lung injury (ALI). Network pharmacology and bioinformatic analyses were carried out. Mice were intragastrically treated with PAL and intratracheally stimulated with LPS. LPS-induced RAW264.7 cells were employed for the in vitro model. The MPO activity, W/D ratio, neutrophils, total cell number in BALF, and histopathological alteration were examined. The levels of TNF-α, IL-1β, IL-6, IL-18, IL-4, and IL-10 in serum, BALF, and supernatant were examined by ELISA. The mRNA expressions of iNOS, CD68, Arg1, Ym1, and CD206 and protein expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome were detected by PCR, WB, and immunofluorescence. The NAMPT inhibitor FK866, TLR2 inhibitor C29, CCR1 inhibitor BX471, NAMPT-overexpression (OE) plasmid, and TLR2-OE plasmid were used for mechanism research. As a result, PAL relieved the symptoms of ALI. PAL inhibited M1 phenotype indices and promoted M2 phenotype indices in both LPS-induced mice and RAW264.7 cells. PAL also inhibited the expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome. The treatments with FK866, NAMPT-OE plasmid, C29, TLR2-OE plasmid, and BX471 proved that PAL exerted its effect via NAMPT/TLR2/CCR1. Molecular docking suggested that PAL might combine with NAMPT. In conclusion, PAL ameliorated LPS-induced ALI by inhibiting M1 phenotype macrophage polarization via NAMPT/TLR2/CCR1 signaling.

Mild Hypothermia Alleviates CLP-induced Multiple Organ Dysfunction by Mitigating Pyroptosis Through the TLR4/NF-κB/NLRP3 Signaling Pathway

BACKGROUND

Multiple organ failure secondary to severe sepsis leads to increased morbidity and mortality and is often accompanied by inflammation and immune system dysfunction. Mild hypothermia has been shown to have anti-inflammatory properties, but whether it can exert a protective effect in cases of multiple organ failure remains unclear. Thus, in this study, we investigated the protective effect of mild hypothermia on septic multiple organ failure and the underlying mechanism for this effect.

METHOD

Sepsis was induced through the cecal ligation and puncture (CLP) method. Rats were then housed at normal (36-38°C) or mild hypothermic (32-34°C) temperature for 10 h.

RESULTS

CLP-induced effects on inflammatory cytokines and biochemical markers in serum were reversed by mild hypothermia. The pathological injury score and the expressions of pyroptosis markers, including TLR4, MyD88 and NF-κB signaling molecules, showed a similar trend. Moreover, 3 d survival of CLP rats was improved by mild hypothermia.

CONCLUSIONS

Mild hypothermia alleviated CLP-induced organ failure and the downstream effects on pyroptosis, probably through the TLR4/NF-κB/NLRP3 signaling pathway.

Aspirin eugenol ester alleviates lipopolysaccharide-induced acute lung injury in rats while stabilizing serum metabolites levels

Aspirin eugenol ester (AEE) was a novel drug compound with aspirin and eugenol esterified. AEE had various pharmacological activities, such as anti-inflammatory, antipyretic, analgesic, anti-oxidative stress and so on. In this study, it was aimed to investigate the effect of AEE on the acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rats. In vitro experiments evaluated the protective effect of AEE on the LPS-induced A549 cells. The tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) were measured in the cell supernatant. The Wistar rats were randomly divided into five groups (n = 8): control group, model group (LPS group), LPS + AEE group (AEE, 54 mg·kg−1), LPS + AEE group (AEE, 108 mg·kg−1), LPS + AEE group (AEE, 216 mg·kg−1). The lung wet-to-dry weight (W/D) ratio and immune organ index were calculated. WBCs were counted in bronchoalveolar lavage fluid (BALF) and total protein concentration was measured. Hematoxylin-Eosin (HE) staining of lung tissue was performed. Glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), antioxidant superoxide dismutase (SOD), total antioxidant capacity (T-AOC), lactate dehydrogenase (LDH), C-reactive protein (CRP), myeloperoxidase (MPO), malondialdehyde (MDA), macrophage mobility inhibitory factor (MIF), TNF-α, IL-6, and IL-1β activity were measured. The metabolomic analysis of rat serum was performed by UPLC-QTOF-MS/MS. From the results, compared with LPS group, AEE improved histopathological changes, reduced MDA, CRP, MPO, MDA, and MIF production, decreased WBC count and total protein content in BALF, pro-inflammatory cytokine levels, immune organ index and lung wet-dry weight (W/D), increased antioxidant enzyme activity, in a dose-dependent manner. The results of serum metabolomic analysis showed that the LPS-induced ALI caused metabolic disorders and oxidative stress in rats, while AEE could ameliorate it to some extent. Therefore, AEE could alleviate LPS-induced ALI in rats by regulating abnormal inflammatory responses, slowing down oxidative stress, and modulating energy metabolism.

Berberine Ameliorates Inflammation in Acute Lung Injury via NF-κB/Nlrp3 Signaling Pathway

The inflammatory response is the key pathophysiological character of acute lung injury (ALI). Berberine (BBR), a natural quaternary ammonium alkaloid, plays a functional role in anti-inflammation both in vitro and in vivo. However, the underlying mechanism between BBR and ALI has not been expounded. Here, we found that BBR improved the permeability of pulmonary and repressed the inflammatory factors in the lipopolysaccharides (LPSs)-induced ALI model. We demonstrated that BBR could suppress the expression of phosphorylated nuclear factor-kappa B (NF-κB) and further restrain the downstream gene nucleotide-binding domain and leucine-rich repeat protein-3 (Nlrp3). Moreover, we also revealed that BBR could directly interact with Nlrp3 protein. After knocked down of Nlrp3 by using siRNA, the protective role of BBR was abrogated in vitro. The expression of IL-1β and IL-18 was downregulated by BBR via the two signaling pathways. Notably, in Nlrp3 deficient mice, the protective effect of BBR was abolished. These findings demonstrate that BBR has a depressant effect on inflammatory response caused by LPS via regulating NF-κB/Nlrp3 signaling pathway, providing a potential therapeutic strategy in ALI.

Protective Effects of Carbon Dots Derived from Armeniacae Semen Amarum Carbonisata Against Acute Lung Injury Induced by Lipopolysaccharides in Rats

Introduction

The charcoal processed product of Armeniacae Semen Amarum (ASA), ASA Carbonisata (ASAC), has long been used for its anti-inflammatory effects. However, the material basis and mechanism of action of ASAC remain unclear.

Aim

To explore the anti-inflammatory effects of Armeniacae Semen Amarum Carbonisata-derived carbon dots (ASAC-CDs).

Methods

The physicochemical properties of ASAC-CDs including morphology, optical properties, functional groups were characterized by a series of methods, mainly including electron microscopy, optical technology and X-ray photoelectron spectroscopy. The anti-inflammatory effect of ASAC-CDs was evaluated and confirmed using acute lung injury (ALI) induced by lipopolysaccharides (LPS) in rats.

Results

The ASAC-CDs ranged from 1.5 to 5.5 nm in diameter, with a quantum yield of 3.17%. ASAC-CDs alleviated LPS-induced inflammation, as demonstrated by reducing the levels of IL-6, IL-1β and TNF-α and increasing the contents of IL-10 in rat serum. More interestingly, ASAC-CDs reduce the content of MDA and MPO and increase the activity of SOD and the content of GSH, indicating the antioxidant activity of ASAC-CDs.

Conclusion

These results demonstrate the remarkable anti-inflammatory effects of ASAC-CDs against ALI induced by LPS, which provide an important basis for the application of ASAC-CDs in clinical anti-pneumonia, and lay an experimental foundation for the research and development of novel nano-drugs.

Protective effects of wogonin on lipopolysaccharide-induced inflammation and apoptosis of lung epithelial cells and its possible mechanisms

Background

Wogonin (5, 7-dihydroxy-8-methoxyflavone) is a natural di-hydroxyl flavonoid extracted from the root of Scutellaria baicalensis Georgi. This paper was intended to investigate the mechanism of action of wogonin in alleviating the inflammation and apoptosis in acute lung injury (ALI).

Materials and methods

Lipopolysaccharide (LPS) was used to establish the in vitro model of ALI. After wogonin treatment, the cell viability and apoptosis of LPS-induced A549 cells were, respectively, measured by CCK-8, TUNEL assays and acridine orange/ethidium bromide dual staining, while the contents of inflammatory cytokines and oxidative stress markers were estimated by RT-qPCR, ELISA assay, western blot analysis and commercial kits. Western blot was also conducted to assess the expression of proteins involved. Subsequently, the effect of wogonin on the sirtuin 1 (SIRT1)-mediated high-mobility group box 1 protein (HMGB1) deacetylation was investigated. SIRT1 inhibitor EX527 was used to evaluate the regulatory effects of wogonin on SIRT1-mediated HMGB1 deacetylation in A549 cells under LPS stimulation.

Results

LPS induced inflammation, oxidative stress and apoptosis of A549 cells, which was abolished by wogonin. It was also found that wogonin promoted the HMGB1 deacetylation, accompanied by upregulated SIRT1 expression. However, SIRT1 inhibitor EX527 partially reversed the protective effects of wogonin on the inflammation and apoptosis of LPS-induced A549 cells.

Conclusion

Wogonin alleviated the inflammation and apoptosis in LPS-induced A549 cells by SIRT1-mediated HMGB1 deacetylation, which might represent the identification of a novel mechanism by which wogonin exerts protective effects on ALI and provide ideas for the application of wogonin to ALI treatment.

Hydrogen-Rich Saline Inhibits Lipopolysaccharide-Induced Acute Lung Injury and Endothelial Dysfunction by Regulating Autophagy through mTOR/TFEB Signaling Pathway

Background

Hydrogen-rich saline (HRS) has strong anti-inflammatory, antioxidative stress, and antiapoptotic properties. The study focused on the protection of HRS on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rat models and the relationship with autophagic regulation and mTOR/TFEB signaling pathway. Material and Methods. The LPS-induced ALI rats' model was established. Pathohistological change in lung tissue was detected by hematoxylin-eosin staining. The inflammatory cytokines were examined by enzyme-linked immunosorbent assay (ELISA). The key apoptosis proteins and autophagy-relevant proteins were analyzed by western blotting. In vitro, HPMEC models of ALI were treated with LPS. The inflammatory cytokines were detected. Apoptosis rate was determined by flow cytometry. The autophagy and mTOR/TFEB signaling pathway-related proteins were detected by western blot and immunohistochemical staining.

Results

HRS attenuated LPS-induced ALI and apoptosis both in vivo and in vitro. HRS attenuated inflammatory response, inhibited apoptosis, induced and activated autophagy in LPS-induced ALI model, and downregulated mTOR/TFEB signaling pathway. The protection of HRS can be blocked by autophagy inhibitor. Moreover, mTOR activator reversed HRS protection and mTOR inhibitor enhanced HRS protection in LPS-induced model and HRS activated autophagy via mTOR/TFEB signaling pathway.

Conclusion

The results confirmed the protection of HRS in LPS-induced ALI by regulating apoptosis through inhibiting the mTOR/TFEB signaling pathway.