Protective effects of Eleutheroside E against high-altitude pulmonary edema by inhibiting NLRP3 inflammasome-mediated pyroptosis

Ligustrazine hydrochloride Prevents Ferroptosis by Activating the NRF2 Signaling Pathway in a High-Altitude Cerebral Edema Rat Model

High-altitude cerebral edema (HACE) is a disorder caused by low pressure and hypoxia at high altitudes. Nevertheless, as of now, there is still a scarcity of safe and effective prevention and treatment methods. The active component of Ligusticum Chuanxiong, namely Ligustrazine hydrochloride (LH), has shown potential in the prevention and treatment of HACE due to its anti-inflammatory, antioxidant, and neuroprotective effects in nervous system disorders. Consequently, the potential protective effect of LH on HACE and its mechanism still need to be further explored. Prior to modeling, 90 male Sprague-Dawley rats were pretreated with different doses of drugs, including LH (100 mg/kg and 50 mg/kg), dexamethasone (4 mg/kg), and ML385 (30 mg/kg). Subsequently, the pretreated rats were placed in a low-pressure anoxic chamber simulating a plateau environment to establish the rat HACE model. The effects and mechanisms of LH on HACE rats were further elucidated through determination of brain water content, HE staining, ELISA, immunofluorescence, molecular docking, molecular dynamics simulation, western blot, and other techniques. The results showed, first of all, that LH pretreatment can effectively reduce brain water content; down-regulate the expression of AQP4, HIF-1α, and VEGF proteins; and alleviate damage to brain tissue and nerve cells. Secondly, compared with the HACE group, LH pretreatment can significantly reduce MDA levels and increase GSH and SOD levels. Additionally, LH decreased the levels of inflammatory factors IL-1β, IL-6, and TNF-α; reduced total iron content in brain tissue; increased the expression of ferroptosis-related proteins such as SLC7A11, GPX4, and FTH1; and alleviated ferroptosis occurrence. Molecular docking and molecular dynamics simulations show that LH has a strong binding affinity for NRF2 signaling. Western blot analysis further confirmed that LH promotes the translocation of NRF2 from the cytoplasm to the nucleus and activates the NRF2 signaling pathway to exert an antioxidant effect. The NRF2 inhibitor ML385 can reverse the anti-oxidative stress effect of LH and its protective effect on HACE rat brain tissue. In summary, LH may have a protective effect on HACE rats by activating the NRF2 signaling pathway, inhibiting ferroptosis, and resisting oxidative stress.

Characteristics of transcriptome and chromatin accessibility in the peripheral blood after acute hypoxia exposure

BACKGROUND

Human responses and acclimation to the environmental stresses of high altitude and low oxygen are multifaceted and regulated by multiple genes. However, the mechanism of how the body adjusts in a low-oxygen environment is not yet clear.

RESULTS

Hence, we performed RNA sequencing (RNA-seq) and ATAC sequencing (ATAC-seq) to observe the changes of transcriptome and chromatin accessibility in the peripheral blood of eight individuals at 1 h post adaptation in a simulated plateau environment with 3500 m and 4500 m altitude, respectively. Differential expression analysis and the Boruta algorithm identified differentially expressed genes (DEGs) and differentially accessible regions (DARs) associated with hypoxia adaptation. Specifically, RNA-seq identified 93 and 7 DEGs after 1 h post adaptation with 3500 m altitude and 45 and 8 DEGs after 1 h adaptation with 4500 m. Additionally, ATAC-seq screened 12 and 4 DARs in 3500 m altitude adaption and 15 and 5 DARs in 4500 m altitude adaption. Moreover, the combined analysis of RNA-seq and ATAC-seq revealed that 10 hub genes were independently identified from the protein-protein interaction (PPI) network for each altitude. Gene enrichment analysis displayed that most hub genes were related with hypoxia pathways.

CONCLUSIONS

Our results can provide the reference for the early response of the organism to hypoxic adaptation.

A stable rat model of high altitude pulmonary edema established by hypobaric hypoxia combined diurnal temperature fluctuation and exercise

Hypobaric hypoxia (HH) is regarded as the main cause of high-altitude pulmonary edema (HAPE), however, the effect of diurnal temperature fluctuation and exercise has been overlooked. The aim of current study was to elucidate the role of diurnal temperature fluctuation and exercise in the development of HAPE and establish a reliable experimental rat model. Male SPF Wistar rats were assigned to control group (1400 m, 25 °C) and five model groups: Model Ⅰ group (6000 m, 25 °C), Model Ⅱ group (6000 m, 2 °C), Model Ⅲ group (6000 m, 12 °C/2 °C light/dark cycle), Model IV group (6000 m, 2 °C, and exercise) and Model V group (6000 m, 12 °C/2 °C light/dark cycle, and exercise). After exposure for 72 h, the blood and lung tissues were collected for further research. The rats in Model I group did not show signs of HAPE. Compared with Model I group, the rats in Model II and Model III groups were suffered from more damage, evidence by enhanced oxidative stress and inflammatory reaction, but still did not show signs of HAPE. Model IV and Model V could induce HAPE, display the obvious pathological changes and edema, more serious oxidative stress and inflammatory reaction in lung tissues, suggesting that the key role of exercise in the development of HAPE. The rats in the Model V group showed the best performance in terms of modeling indicators, indicating that diurnal temperature fluctuation could further aggravate the degree of lung edema. In summary, HH combined with diurnal temperature fluctuation and exercise is a stable and reliable modeling method for HAPE, which can be used for subsequent research on the prevention and treatment of HAPE.

TNF-α and RPLP0 drive the apoptosis of endothelial cells and increase susceptibility to high-altitude pulmonary edema

High-altitude pulmonary edema (HAPE) is a fatal threat for sojourners who ascend rapidly without sufficient acclimatization. Acclimatized sojourners and adapted natives are both insensitive to HAPE but have different physiological traits and molecular bases. In this study, based on GSE52209, the gene expression profiles of HAPE patients were compared with those of acclimatized sojourners and adapted natives, with the common and divergent differentially expressed genes (DEGs) and their hub genes identified, respectively. Bioinformatic methodologies for functional enrichment analysis, immune infiltration, diagnostic model construction, competing endogenous RNA (ceRNA) analysis and drug prediction were performed to detect potential biological functions and molecular mechanisms. Next, an array of in vivo experiments in a HAPE rat model and in vitro experiments in HUVECs were conducted to verify the results of the bioinformatic analysis. The enriched pathways of DEGs and immune landscapes for HAPE were significantly different between sojourners and natives, and the common DEGs were enriched mainly in the pathways of development and immunity. Nomograms revealed that the upregulation of TNF-α and downregulation of RPLP0 exhibited high diagnostic efficiency for HAPE in both sojourners and natives, which was further validated in the HAPE rat model. The addition of TNF-α and RPLP0 knockdown activated apoptosis signaling in endothelial cells (ECs) and enhanced endothelial permeability. In conclusion, TNF-α and RPLP0 are shared biomarkers and molecular bases for HAPE susceptibility during the acclimatization/adaptation/maladaptation processes in sojourners and natives, inspiring new ideas for predicting and treating HAPE.

Potential therapeutic effects of traditional Chinese medicine in acute mountain sickness: pathogenesis, mechanisms and future directions

Background and objectives

Acute mountain sickness (AMS) is a pathology with different symptoms in which the organism is not adapted to the environment that occurs under the special environment of high altitude. Its main mechanism is the organism's tissue damage caused by acute hypobaric hypoxia. Traditional Chinese medicine (TCM) theory focuses on the holistic concept. TCM has made remarkable achievements in the treatment of many mountain sicknesses. This review outlines the pathogenesis of AMS in modern and traditional medicine, the progress of animal models of AMS, and summarizes the therapeutic effects of TCM on AMS.

Methods

Using the keywords "traditional Chinese medicine," "herbal medicine," "acute mountain sickness," "high-altitude pulmonary edema," "high-altitude cerebral edema," "acute hypobaric hypoxia," and "high-altitude," all relevant TCM literature published up to November 2023 were collected from Scopus, Web of Science, PubMed, and China National Knowledge Infrastructure databases, and the key information was analyzed.

Results

We systematically summarised the effects of acute hypobaric hypoxia on the tissues of the organism, the study of the methodology for the establishment of an animal model of AMS, and retrieved 18 proprietary Chinese medicines for the clinical treatment of AMS. The therapeutic principle of medicines is mainly invigorating qi, activating blood and removing stasis. The components of botanical drugs mainly include salidroside, ginsenoside Rg1, and tetrahydrocurcumin. The mechanism of action of TCM in the treatment of AMS is mainly through the regulation of HIF-1α/NF-κB signaling pathway, inhibition of inflammatory response and oxidative stress, and enhancement of energy metabolism.

Conclusion

The main pathogenesis of AMS is unclear. Still, TCM formulas and components have been used to treat AMS through multifaceted interventions, such as compound danshen drip pills, Huangqi Baihe granules, salidroside, and ginsenoside Rg1. These components generally exert anti-AMS pharmacological effects by inhibiting the expression of VEGF, concentration of MDA and pro-inflammatory factors, down-regulating NF-κB/NLRP3 pathway, and promoting SOD and Na + -K + -ATPase activities, which attenuates acute hypobaric hypoxia-induced tissue injury. This review comprehensively analyses the application of TCM in AMS and makes suggestions for more in-depth studies in the future, aiming to provide some ideas and insights for subsequent studies.

Alleviation of Splenic Injury by CB001 after Low-Dose Irradiation Mediated by NLRP3/Caspase-1-BAX/Caspase-3 Axis

Low-dose radiation has been extensively employed in clinical practice, including tumor immunotherapy, chronic inflammation treatment and nidus screening. However, the damage on the spleen caused by low-dose radiation significantly increases the risk of late infection-related mortality, and there is currently no corresponding protective strategy. In the present study, a novel compound preparation named CB001 mainly constituted of Acanthopanax senticosus (AS) and Oldenlandia diffusa (OD) was developed to alleviate splenic injury caused by fractionated low-dose exposures. As our results show that, white pulp atrophy and the excessive apoptosis in spleen tissue induced by radiation exposure were significantly ameliorated by CB001. Mechanistically, BAX-caspase-3 signaling and nucleotide-binding domain and leucine-rich-repeat-containing family pyrin 3 (NLRP3) inflammasome signaling were demonstrated to be involved in the radio-protective activity of CB001 with the selective activators. Furthermore, the crosstalk between apoptosis signaling and NLRP3 inflammasome signaling in mediating the radio-protective activity of CB001 was clarified, in which the pro-apoptotic protein BAX but not the anti-apoptotic protein Bcl2 was found to be downstream of NLRP3. Our study demonstrated that the use of a novel drug product CB001 can potentially facilitate the alleviation of radiation-induced splenic injury for patients receiving medical imaging diagnosis or fractionated radiation therapy.

Sesamin ameliorates nonalcoholic steatohepatitis through inhibiting hepatocyte pyroptosis in vivo and in vitro

Sesamin (Ses) is a natural lignan abundantly present in sesame and sesame oil. Pyroptosis, a newly identified type of pro-inflammatory programmed necrosis, contributes to the development of non-alcoholic steatohepatitis (NASH) when hepatocyte pyroptosis is excessive. In this study, Ses treatment demonstrated an improvement in hepatic damage in mice with high-fat, high-cholesterol diet-induced NASH and palmitate (PA)-treated mouse primary hepatocytes. Notably, we discovered, for the first time, that Ses could alleviate hepatocyte pyroptosis both in vivo and in vitro. Furthermore, treatment with phorbol myristate acetate, a protein kinase Cδ (PKCδ) agonist, increased PKCδ phosphorylation and attenuated the protective effects of Ses against pyroptosis in PA-treated mouse primary hepatocytes. Mechanistically, Ses treatment alleviated hepatocyte pyroptosis in NASH, which was associated with the regulation of the PKCδ/nod-like receptor family CARD domain-containing protein 4/caspase-1 axis. This study introduces a novel concept and target, suggesting the potential use of functional factors in food to alleviate liver damage caused by NASH.