Sestrin 2 protects against LPS-induced acute lung injury by inducing mitophagy in alveolar macrophages

Alliin alleviates LPS-induced pyroptosis via promoting mitophagy in THP-1 macrophages and mice

Pyroptosis is a new type of programmed cell death associated with inflammation. Excessive pyroptosis can cause body damage. Alliin is an organosulfur compound extracted from garlic, bearing anti-oxidation and anti-inflammatory properties. In this study, we revealed that alliin alleviated LPS-induced macrophage pyroptosis by detecting PI staining, IL-1β and IL-18 release in vitro and in vivo. In the study of mechanism, we found that alliin might reduce the activation of NLRP3 inflammosome by decreasing intracellular ROS generation. Subsequently, we detected the effect of alliin on mitophagy which degraded damaged mitochondria. The results showed that alliin promoted PINK 1/Parkin-mediated mitophagy. After adding the mitophagy inhibitor CsA, the alleviating effect of alliin on mitochondrial damage and mitochondrial ROS were reversed and the relieving effect of alliin on LPS-induced pyroptosis was inhibited. These results suggested that alliin might reduce intracellular ROS production by promoting mitophagy, thus alleviating LPS-induced macrophages pyroptosis. Our study provides a new perspective and theoretical basis for alliin to alleviate pyroptosis which could further induce body damage.

Bergamottin alleviates LPS-induced acute lung injury by inducing SIRT1 and suppressing NF-κB

Acute lung injury (ALI) is associated with a high mortality due to inflammatory cell infiltration and lung edema. The development of ALI commonly involves the activation of NF-κB. Since bergamottin is a natural furanocoumarin showing the ability to inhibit the activation of NF-κB, in this study we aimed to determine the effect of bergamottin on ALI. RAW264.7 mouse macrophages were pre-treated with bergamottin and then stimulated with LPS. Macrophage inflammatory responses were examined. Bergamottin (50 mg/kg body mass) was intraperitoneally administrated to mice 12 h before injection of LPS, and the effect of bergamottin on LPS-induced ALI was evaluated. Our results showed that LPS exposure led to increased production of TNF-α, IL-6, and monocyte chemoattractant protein-1 (MCP-1), which was impaired by bergamottin pre-treatment. In vivo studies confirmed that bergamottin pre-treatment suppressed LPS-induced lung inflammation and edema and reduced the levels of pro-inflammatory cytokines in lung tissues and bronchoalveolar lavage fluids. Mechanistically, bergamottin blocked LPS-induced activation of NF-κB signaling in lung tissues. Additionally, bergamottin treatment reduced NF-κB p65 protein acetylation, which was coupled with induction of SIRT1 expression. In conclusion, our results reveal the anti-inflammatory property of bergamottin in preventing ALI. Induction of SIRT1 and inhibition of NF-κB underlies the anti-inflammatory activity of bergamottin.

Anthocyanin Extract from Purple Sweet Potato Exacerbate Mitophagy to Ameliorate Pyroptosis in Klebsiella pneumoniae Infection

Given the rise of morbidity and mortality caused by Klebsiella pneumoniae (KP), the increasing number of strains resistant to antibiotics, and the emergence of hypervirulent Klebsiella pneumonia, treatment of KP infection becomes difficult; thus, novel drugs are necessary for treatment. Anthocyanins, or natural flavonoids, have an extensive effect against bacterial infection. However, few studies on anti-KP are identified. Here, we evaluated the therapeutic effect of purple sweet potato anthocyanins (PSPAs) on KP, containing 98.7% delphinidin 3-sambubioside. Results showed that KP-infected mice after PSPAs treatment manifested decreased mortality, weakened lung injury, dampened inflammatory responses, and reduced bacterial systemic dissemination in vivo. In Vitro, PSPAs significantly suppressed pyroptosis and restricted NLRP3 inflammasome activation in alveolar macrophages infected with KP. As for the mechanism, PSPAs promote mitophagy by recruiting Parkin to the mitochondria. PSPAs-conferred mitophagy increased mitochondrial membrane potential and decreased mitochondrial reactive oxygen species and mitochondrial DNA, resulting in impaired NLRP3 inflammasome activation. In addition, the promotion of mitophagy by PSPAs required the Nrf2 signaling pathway. Collectively, these findings suggest that PSPAs are a potential option for the treatment of KP infection.

Sestrin2 in hypoxia and hypoxia-related diseases

Objectives: Sestrin2 is a stress-inducible protein and play an important role in adapting stress states of cells. This article reviewed the role of Sestrin2 in hypoxia and hypoxia-related diseases to provide new perspectives for future research and new therapeutic targets for hypoxia-related diseases.

Methods: A review was conducted through an electronic search of PubMed and Medline databases. Keywords included Sestrin2, ROS, hypoxia, and hypoxia-related disease. Articles from 2008 to 2021 were mostly included and older ones were not excluded.

Results: Sestrin2 is upregulated under various stress conditions, especially hypoxia. Under hypoxic condition, Sestrin2 plays a protective role by reducing the generation of ROS through various pathways, such as adenosine monophosphatea-ctivated protein kinase (AMPK) / mammalian target of rapamycin (mTOR) pathway and nuclear factor-E2-related factor2 (Nrf2) pathway. In addition, Sestrin2 is involved in various hypoxia-related diseases, such as cerebral hypoxic disease, myocardial hypoxic disease, hypoxia-related respiratory disease, and diabetes.

Discussion: Sestrin2 is involved in various hypoxia-related diseases and maybe a therapeutic target. Furthermore, most studies focus on cerebral and myocardial ischemia reperfusion. More researches on hypoxia-related respiratory diseases, kidney injury, and diabetes are needed in future.

Particulate Matter-Induced Cardiovascular Dysfunction: A Mechanistic Insight

Air pollution and particulate matter (PM) are significant factors for adverse health effects most prominently cardiovascular disease (CVD). PM is produced from various sources, which include both natural and anthropogenic. It is composed of biological components, organic compounds, minerals, and metals, which are responsible for inducing inflammation and adverse health effects. However, the adverse effects are related to PM size distribution. Finer particles are a significant cause of cardiovascular events. This review discusses the direct and indirect mechanisms of PM-induced CVD like myocardial infarction, the elevation of blood pressure, cardiac arrhythmias, atherosclerosis, and thrombosis. The two potential mechanisms are oxidative stress and systemic inflammation. Prenatal exposure has also been linked with cardiovascular outcomes later in life. Moreover, we also mentioned the epidemiological studies that strongly associate PM with CVD.