Inhibition of soluble epoxide hydrolase relieves adipose inflammation via modulating M1/M2 macrophage polarization to alleviate airway inflammation and hyperresponsiveness in obese asthma

Inhibition of NSUN6 protects against intermittent hypoxia-induced oxidative stress and inflammatory response in adipose tissue through suppressing macrophage ferroptosis and M1 polarization

AIMS

Accumulating studies have demonstrated obstructive sleep apnea (OSA) is strongly associated with metabolic syndrome (MetS) and inflammatory response in adipose tissue. Chronic intermittent hypoxia (CIH) has been proved leading to M1 macrophage polarization that contributes to adipose tissue inflammation, but the molecular mechanism remains unclear. Epigenetic regulation of RNA has been found playing crucial roles in incremental diseases.

MAIN METHODS

Based on mining the GEO database, we constructed an IH (8 weeks) C57/6 J mice model to investigate the changes and interactions of key gene expression, M1 macrophage infiltration, and inflammatory markers in white adipose tissue. We also used an IH-treated (24 h) RAW 264.7 cells to further explore the mechanisms of hypoxia-induced M1 polarization, oxidative stress, and inflammatory response.

KEY FINDINGS

According to the analysis of datasets, CIH increases the level of NSUN6 in adipose tissue and NSUN6 shows good diagnostic value of OSA. In the mice model, CIH exposure is also demonstrated to increases NSUN6 level and M1 macrophage infiltration in adipose tissue, which can be reversed by ferroptosis inhibitor. Studies show that CIH leads to ferroptosis and M1 macrophage polarization by promoting the expression of NSUN6 in vitro, thus resulting in inflammatory response.

SIGNIFICANCE

Our findings provide a better understanding of the mechanisms of CIH-induced inflammation in adipose tissue. NSUN6 is firstly suggested to participate in macrophages ferroptosis and M1 polarization. Inhibition of NSUN6 in macrophages could protects against CIH-induce oxidative stress and inflammatory response in adipose tissue, thus becoming a potential therapeutic target to OSA-associated MetS.

AMPK Regulates M1 Macrophage Polarization through the JAK2/STAT3 Signaling Pathway to Attenuate Airway Inflammation in Obesity-Related Asthma

Abstract-Obesity-related asthma is primarily characterized by nonallergic inflammation, with pathogenesis involving oxidative stress, metabolic imbalance, and immunoinflammatory mechanisms. M1 macrophages, which predominantly secrete pro-inflammatory factors, mediate insulin resistance and systemic metabolic inflammation in obese individuals. Concurrently, adenosine monophosphate-activated protein kinase (AMPK) serves as a critical regulator of intracellular energy metabolism and is closely associated with macrophage activation. However, their specific roles and associated mechanisms in obesity-related asthma remain to be explored. In this study, we investigated the macrophage polarization status and potential interventional mechanisms through obesity-related asthmatic models and lipopolysaccharide (LPS) -treated RAW264.7 cell with a comprehensive series of evaluations, including HE, PAS and Masson staining of lung histopathology, immunohistochemical staining, immunofluorescence technology, qRT-PCR, Western Blot, and ELISA inflammatory factor analysis. The results revealed M1 macrophage polarization in obesity-related asthmatic lung tissue alongside downregulation of AMPK expression. Under LPS stimulation, exogenous AMPK activation attenuated M1 macrophage polarization via the Janus kinase 2/ signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Additionally, in obesity-related asthmatic mice, AMPK activation was found to alleviate airway inflammation by regulating M1 macrophage polarization, the mechanism closely associated with the JAK2/STAT3 pathway. These findings not only advance our understanding of macrophage polarization in obesity-related asthma, but also provide new therapeutic targets for its treatment.

The role of soluble epoxide hydrolase in the intestine

The soluble epoxide hydrolase (sEH; encoded by the EPHX2 gene) is an α/β hydrolase fold protein that is, widely distributed throughout the body. Recent studies have highlighted that sEH, in the metabolism of polyunsaturated fatty acids, plays a part in the pathogenesis of various diseases, including cardiovascular disease, Alzheimer's disease and intestine-associated disease. This review discusses the current findings on the role of sEH in the development of intestine- and intestine-associated diseases, including colitis, colorectal cancer, and other intestinal diseases, as well as the potential underlying mechanisms involved.

sEH activity is associated with mortality in patients with ARDS: a retrospective cohort study

Aim: We hypothesized plasma sEH activity correlates with mortality in acute respiratory distress syndrome (ARDS) patients.Methods: Adult patients diagnosed with ARDS enrolled between 2017 and 2019 were included in this study.Results: A total of 337 adult patients met our inclusion criteria. Among them, 107 patients died within 28 days. The plasma sEH activity was higher in nonsurvivors relative to survivors. And a receiver operating characteristic curve with the area under the curve of 0.81 (95% confidence interval: 0.74-0.89) for the prediction of 28-day mortality was obtained. Its sensitivity and specificity were 72.5% and 74.6%, respectively.Conclusion: Elevated plasma sEH activity is associated with higher 28-day mortality in adult patients with ARDS.

Celastrol alleviates airway hyperresponsiveness and inflammation in obese asthma through mediation of alveolar macrophage polarization

Obese asthma is a unique asthma phenotype that decreases sensitivity to inhaled corticosteroids, and currently lacks efficient therapeutic medication. Celastrol, a powerful bioactive substance obtained naturally from the roots of Tripterygium wilfordii, has been reported to possess the potential effect of weight loss in obese individuals. However, its role in the treatment of obese asthma is not fully elucidated. In the present study, diet-induced obesity (DIO) mice were used with or without ovalbumin (OVA) sensitization, the therapeutic effects of celastrol on airway hyperresponsiveness (AHR) and airway inflammation were examined. We found celastrol significantly decreased methacholine-induced AHR in obese asthma, as well as reducing the infiltration of inflammatory cells and goblet cell hyperplasia in the airways. This effect was likely due to the inhibition of M1-type alveolar macrophages (AMs) polarization and the promotion of M2-type macrophage polarization. In vitro, celastrol yielded equivalent outcomes in Lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells, featuring a reduction in the expression of M1 macrophage makers (iNOS, IL-1β, TNF-α) and heightened M2 macrophage makers (Arg-1, IL-10). Mechanistically, the PI3K/AKT signaling pathway has been implicated in these processes. In conclusion, we demonstrated that celastrol assisted in mitigating various parameters of obese asthma by regulating the balance of M1/M2 AMs polarization.