Alcohol inhibits alveolar fluid clearance through the epithelial sodium channel via the A2 adenosine receptor in acute lung injury

Evaluation and Characterization of Acute respiratory distress syndrome in tree shrews through TMT proteomic method

Acute respiratory distress syndrome (ARDS), a common cause of acute fatal respiratory, is characterized by severe inflammatory lung injury as well as hallmarks of increased pulmonary vascular permeability, neutrophil infiltration, and macrophage accumulation. Tree shrew, a squirrel-like small animal model, has been confirmed to have more similar traits to human ARDS with one-hit intratracheal instillation of LPS in our previous study. In this study, we characterized protein profile changes induced by intranasal LPS challenge in the tree shrew model through tandem mass tag (TMT)-based quantitative proteomics and type II alveolar epithelial cells through pathological analysis. In total, 4070 proteins (p <  0.05) were identified from lung tissues of the LPS-induced group and PBS group. Among the differential expression proteins (DEPs) detected by t-test (≥|1.5-fold|), 529 DEPs were identified, of which 304 were upregulated, and 225 were downregulated. The most important pathways involved in the process of ARDS had been identified by enrichment analysis: oxidative stress, apoptosis, inflammatory responses, and vascular endothelial injury. In addition, proteins have been reported in animal models or clinical patients also detail investigated for further analysis, such as ceruloplasmin (CP), hemopexin (HPX), sphingosine kinase 1 (SphK1), lactotransferrin (LTF), and myeloperoxidase (MPO) were upregulated in induced tissues and confirmed by western blot analysis. Overall, this study not only reveals a comprehensive proteomic analysis of the ARDS tree shrew model but also provides novel insights into multi-pathways responses induced by the LPS challenge of tree shrews. We highlight shared and unique proteomic changes in the lungs of ARDS tree shrews and identify novel pathways for acute lung injury, which may promote the model into basic research and translational research.

A2AR regulate inflammation through PKA/NF-κB signaling pathways in intervertebral disc degeneration

BACKGROUND

Reduction of inflammatory damage and inhibition of nucleus pulposus (NP) apoptosis are considered to be the main effective therapy idea to reverse the intervertebral disc degeneration (IDD) and alleviate the chronic low back pain. The adenosine A2A receptor (A2AR), as a member of G protein-coupled receptor families, plays an important role in the anti-inflammation and relieving pain. So far, the impact of A2AR on IDD therapy is unclear. The aim of this study was to explore the role of Adenosine A2A receptor (A2AR) in the intervertebral disc degeneration (IDD) and clarify potential mechanism.

MATERIALS AND METHODS

IL-1β and acupuncture was used to establish IDD model rats. A2AR agonist CGS-21680 and A2AR antagonist SCH442416 were used to investigate the therapeutical effects for IDD. Histological examination, western blotting analysis and RT-PCR were employed to evaluate the the association between A2AR and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway.

RESULTS

A2AR activity of the intervertebral disc tissues was up-regulated in feedback way, and cAMP, PKA and CREB expression were also increased. But in general, IL-1β-induced IDD promoted the significant up-regulation the expression of inflammatory factors. The nucleus pulposus (NP) inflammation was exacerbated in result of MMP3 and Col-II decline through activating NF-κB signaling pathway. A2AR agonist CGS-21680 exhibited a disc protective effect through significantly increasing A2AR activity, then further activated cAMP/PKA signaling pathway with attenuating the release of TNF-α and IL-6 via down-regulating NF-κB. In contrast, SCH442416 inhibited A2AR activation, consistent with lower expression levels of cAMP and PKA, further leading to the acceleration of IDD.

CONCLUSIONS

The activation of A2AR can prevent inflammatory responses and mitigates degradation of IDD thus suggest a potential novel therapeutic strategy of IDD.

Effect of ω-9MUFAs in Fat Emulsion on Serum Interleukin-6 in Rats with Lipopolysaccharide-induced Lung Injury

AIM

This study aimed to investigate how ω-9 MUFAs in fat emulsion affect serum IL- 6 levels in rats with lipopolysaccharide (LPS)-induced lung injury.

BACKGROUND

Research suggests that acute lung injury (ALI) develops acute respiratory distress syndrome (ARDS) due to the activation of many inflammatory factors. ALI may be treated by reducing inflammation. Fat emulsion is used in parenteral nutrition for critically ill patients to regulate the body's inflammatory response. It is mostly made up of ω-9 MUFAs (Clinoleic), which can regulate the inflammatory response.

OBJECTIVE

The effect of ω-9MUFAs on the secretion of IL-6 in ALI rats was studied in order to provide a basis for the rational use of fat emulsion in clinical practice and provide new ideas for the diagnosis and treatment of ALI.

METHODS

The control, model, and -9MUFAs groups consisted of 18 female Sprageue-Dawley (SD) young rats (180 ± 20 g). The SD young rats received normal saline and were not operated. LPS-induced ALI animals received tail vein injections of normal saline. SD young rats were first triggered with acute lung injury by LPS (3 mg/kg) and then injected with 3 mg/kg of ω-9MUFAs via the tail vein. The expression levels of IL-6, an activator of signal transduction transcription 3 (STAT3), transforming growth factor-β (TGF-β), and glycoprotein 130 (GP130) in serum and lung tissues were determined by ELISA and Western blot methods.

RESULTS

Compared with the model group, the survival rate of rats in the ω-9 MUFAs group was significantly increased, and the difference was statistically significant (p<0.05). Compared with the model group, the lung pathology of rats in the ω-9 MUFAs group was significantly improved, and the expression levels of IL-6, TGF-β1, GP130, IL-1 and other proteins were significantly decreased. The difference was statistically significant (p<0.05).

CONCLUSION

In LPS-induced lung injury, ω-9MUFAs may alleviate symptoms by inhibiting the IL-6/GP130/STAT3 pathway.

Antioxidant mitoquinone ameliorates EtOH-LPS induced lung injury by inhibiting mitophagy and NLRP3 inflammasome activation

Chronic ethanol abuse is a systemic disorder and a risk factor for acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD). However, the mechanisms involved are unknown. One explanation is that ethanol produces damaging reactive oxygen species (ROS) and disturbs the balance of mitochondria within the lungs to promote a pro-injury environment. We hypothesized that targeting an antioxidant to the mitochondria would prevent oxidative damage and attenuate EtOH-LPS-induced lung injury. To test this, we investigated the effects of mitochondria-targeted ubiquinone, Mitoquinone (MitoQ) on ethanol-sensitized lung injury induced by LPS. Lung inflammation, ROS, mitochondria function, and mitophagy were assessed. We demonstrated that chronic ethanol feeding sensitized the lung to LPS-induced lung injury with significantly increased reactive oxygen species ROS level and mitochondrial injury as well as lung cellular NLRP3 inflammasome activation. These deleterious effects were attenuated by MitoQ administration in mice. The protective effects of MitoQ are associated with decreased cellular mitophagy and NLRP3 inflammasome activation in vivo and in vitro. Taken together, our results demonstrated that ethanol aggravated LPS-induced lung injury, and antioxidant MitoQ protects from EtOH-LPS-induced lung injury, probably through reducing mitophagy and protecting mitochondria, followed by NLRP3 inflammasome activation. These results will provide the prevention and treatment of ethanol intake effects with new ideas.

JMJD3 deficiency alleviates lipopolysaccharide‑induced acute lung injury by inhibiting alveolar epithelial ferroptosis in a Nrf2‑dependent manner

Acute respiratory distress syndrome (ARDS) is a deadly illness which presents with severe hypoxemia as well as diffuse alveolar damage. Jumonji domain‑containing 3 (JMJD3), which belongs to the UTX/UTY JmjC‑domain protein subfamily, is involved in infection, development, aging and immune disorders. However, the role of JMJD3 in acute lung injury (ALI) is still unclear. The present study explored the roles and potential mechanisms of JMJD3 in ALI. Alveolar epithelial cell‑specific knockout of JMJD3 mice and A549 alveolar epithelial cells were used to investigate the function of JMJD3 in ALI. Lipopolysaccharide (LPS) was used to establish an in vivo and in vitro ALI model. The expression of JMJD3 in murine lung tissue and alveolar epithelial cells was detected. Pathological injury of lung tissue and alveolar epithelial cells was also investigated following inhibition of JMJD3. The results showed that JMJD3 expression was significantly increased in murine lung tissues and in A549 cells following LPS stimulation. JMJD3‑deficient mice in alveolar epithelial cells exhibited alleviated lung pathological injury and ferroptosis following h stimulation. Mechanistically, it was found that JMJD3 knockout could increase the expression of nuclear factor erythroid‑2‑related factor‑2 (Nrf2) in lung tissues challenged with h. However, Nrf2 overexpression by adenovirus could further enhance the anti‑ferroptotic effect from JMJD3 silence in h‑treated A549 cells. Taken together, the present study revealed that JMJD3 deficiency may relieve LPS‑induced ALI by blocking alveolar epithelial ferroptosis in a Nrf2‑dependent manner, which may serve as a novel therapeutic target against ALI.