Background: Liquidambaris Fructus (LF) is the infructescence ofLiquidambar formosana. In Traditional Chinese Medicine, LF has been used to treat joint pain, a common symptom of arthritis and rheumatism; however, a lack of pharmacological evidence has limited its applications in modern clinics. Therefore, this study aims to explore the protective effect of LF on rheumatoid arthritis (RA) and to identify its active ingredients.Methods: Rats with adjuvant-induced arthritis (AIA) were divided into 4 groups and administered petroleum ether extract of LF (PEL), ethyl acetate extract of LF (EEL), water extract of LF (WEL), or piroxicam (PIR) respectively for 3 weeks. Two additional groups were used as normal control (NC) and model control (MC) and administered distilled water as a placebo. The clinical scores for arthritis, bone surface, synovial inflammation and cartilage erosion were used to evaluate the therapeutic efficacy of each treatment. The serum IL-1β and TNF-α level and the expression of NLRP3, IL-1β and caspase-1 p20 in the synovial tissue of AIA rats were evaluated by ELISA and Western blot. The active ingredients of LF were investigated using network pharmacology and molecular docking methods, and their inhibition of NLRP3 inflammasome activation was verified in the human rheumatoid arthritis fibroblast-like synovial cells (RA-FLS) model.Results: PEL could alleviate paw swelling, bone and joint destruction, synovial inflammation and cartilage erosion in the AIA rats, with significantly superior efficacy to that of EEL and WEL. PEL reduced IL-1β and TNF-α serum levels, and attenuated the upregulation of NLRP3, IL-1β and caspase-1 p20 expression in the synovial tissue of AIA rats. Network pharmacology and molecular docking results indicated that myrtenal and β-caryophyllene oxide were the main two active ingredients of PEL, and these two compounds showed significant inhibition on TNF-α, NLRP3, IL-1β and caspase-1 p20 expression in RA-FLS.Conclusions: Myrtenal and β-caryophyllene oxide screened from PEL could suppress the activation of NLRP3 inflammasome, thereby alleviating RA symptoms.

Epidemiological data have shown that methamphetamine (MA) abuse significantly increases the risk of developing pulmonary arterial hypertension (PAH). To investigate whether MA could induce PAH and its possible mechanism, rats were exposed daily to MA for 5 weeks in the absence or presence of fluoxetine. The results showed that the pulmonary arterial pressure was not significantly increased, but the pulmonary arterial remodelling was markedly developed in the MA exposure group. The protein expressions of the serotonin transporter (5‐HTT) and 5‐HT_1B receptor were increased in the lungs and in the pulmonary arteries of MA‐treated rats. Fluoxetine attenuated the pulmonary arterial remodelling and down‐regulated the protein expression of 5‐HTT and 5‐HT_1B receptor in pulmonary arteries of MA‐treated rats. These findings suggest that fluoxetine has a novel potential suppressive effect on the chronic MA‐induced pulmonary vascular remodelling and also suggest that 5‐HTT and 5‐HT_1B receptor may be involved as part of its mechanism.

BACKGROUND: Pulmonary hypertension (PH) is a major complication linked to adverse outcomes in heart failure with preserved ejection fraction (HFpEF), yet no specific therapies exist for PH associated with HFpEF (PH-HFpEF). We have recently reported on the role of skeletal muscle SIRT3 (sirtuin-3) in modulation of PH-HFpEF, suggesting a novel endocrine signaling pathway for skeletal muscle modulation of pulmonary vascular remodeling. METHODS: Using skeletal muscle-specific Sirt3 knockout mice ( Sirt3 ^skm-/- ) and mass spectrometry-based comparative secretome analysis, we attempted to define the processes by which skeletal muscle SIRT3 defects affect pulmonary vascular health in PH-HFpEF. RESULTS: Sirt3 ^skm-/- mice exhibited reduced pulmonary vascular density accompanied by pulmonary vascular proliferative remodeling and elevated pulmonary pressures. Comparative analysis of secretome by mass spectrometry revealed elevated secretion levels of LOXL2 (lysyl oxidase homolog 2) in SIRT3-deficient skeletal muscle cells. Elevated circulation and protein expression levels of LOXL2 were also observed in plasma and skeletal muscle of Sirt3 ^skm-/- mice, a rat model of PH-HFpEF, and humans with PH-HFpEF. In addition, expression levels of CNPY2 (canopy fibroblast growth factor signaling regulator 2), a known proliferative and angiogenic factor, were increased in pulmonary artery endothelial cells and pulmonary artery smooth muscle cells of Sirt3 ^skm-/- mice and animal models of PH-HFpEF. CNPY2 levels were also higher in pulmonary artery smooth muscle cells of subjects with obesity compared with nonobese subjects. Moreover, treatment with recombinant LOXL2 protein promoted pulmonary artery endothelial cell migration/proliferation and pulmonary artery smooth muscle cell proliferation through regulation of CNPY2-p53 signaling. Last, skeletal muscle–specific Loxl2 deletion decreased pulmonary artery endothelial cell and pulmonary artery smooth muscle cell expression of CNPY2 and improved pulmonary pressures in mice with high-fat diet–induced PH-HFpEF. CONCLUSIONS: This study demonstrates a systemic pathogenic impact of skeletal muscle SIRT3 deficiency in remote pulmonary vascular remodeling and PH-HFpEF. This study suggests a new endocrine signaling axis that links skeletal muscle health and SIRT3 deficiency to remote CNPY2 regulation in the pulmonary vasculature through myokine LOXL2. Our data also identify skeletal muscle SIRT3, myokine LOXL2, and CNPY2 as potential targets for the treatment of PH -HFpEF.

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by (mal)adaptive remodeling of the pulmonary vasculature, which is associated with inflammation, fibrosis, thrombosis, and neovascularization. Vascular remodeling in PAH is associated with cellular metabolic and inflammatory reprogramming that induce profound endothelial and smooth muscle cell phenotypic changes. Multiple signaling pathways and regulatory loops act on metabolic and inflammatory mediators which influence cellular behavior and trigger pulmonary vascular remodeling in vivo. This review discusses the role of bioenergetic and inflammatory impairments in PAH development.

Sphingosine kinase 1 (SPHK1) and the sphingosine-1-phosphate (S1P) signaling pathway have been shown to play a role in pulmonary arterial hypertension (PAH). S1P is an important stimulus for pulmonary artery smooth muscle cell (PASMC) proliferation and pulmonary vascular remodeling. We aimed to examine the specific roles of SPHK1 in PASMCs during pulmonary hypertension (PH) progression. We generated smooth muscle cell-specific, Sphk1-deficient (Sphk1^f/f TaglnCre⁺) mice and isolated Sphk1-deficient PASMCs from SPHK1 knockout mice. We demonstrated that Sphk1^f/f TaglnCre⁺ mice are protected from hypoxia or hypoxia/Sugen-mediated PH, and pulmonary vascular remodeling and that Sphk1-deficient PASMCs are less proliferative compared with ones isolated from wild-type (WT) siblings. S1P or hypoxia activated yes-associated protein 1 (YAP1) signaling by enhancing its translocation to the nucleus, which was dependent on SPHK1 enzymatic activity. Further, verteporfin, a pharmacologic YAP1 inhibitor, attenuated the S1P-mediated proliferation of hPASMCs, hypoxia-mediated PH, and pulmonary vascular remodeling in mice and hypoxia/Sugen-mediated severe PH in rats. Smooth muscle cell-specific SPHK1 plays an essential role in PH via YAP1 signaling, and YAP1 inhibition may have therapeutic potential in treating PH.

Background: M⁷G methylation modification plays an important role in cardiovascular disease development. Dysregulation of the immune microenvironment is closely related to the pathogenesis of PAH. However, it is unclear whether m⁷G methylation is involved in the progress of PAH by affecting the immune microenvironment.Methods: The gene expression profile of PAH was obtained from the GEO database, and the m⁷G regulatory factors were analyzed for differences. Machine learning algorithms were used to screen characteristic genes, including the least absolute shrinkage and selection operator, random forest, and support vector machine recursive feature elimination analysis. Constructed a nomogram model, and receiver operating characteristic was used to evaluate the diagnosis of disease characteristic genes value. Next, we used an unsupervised clustering method to perform consistent clustering analysis on m⁷G differential genes. Used the ssGSEA algorithm to estimate the relationship between the m⁷G regulator in PAH and immune cell infiltration and analyze the correlation with disease-characteristic genes. Finally, the listed drugs were evaluated through the screened signature genes.Results: We identified 15 kinds of m⁷G differential genes. CYFIP1, EIF4E, and IFIT5 were identified as signature genes by the machine learning algorithm. Meanwhile, two m⁷G molecular subtypes were identified by consensus clustering (cluster A/B). In addition, immune cell infiltration analysis showed that activated CD4 T cells, regulatory T cells, and type 2 T helper cells were upregulated in m⁷G cluster B, CD56 dim natural killer cells, MDSC, and monocyte were upregulated in the m⁷G cluster A. It might be helpful to select Calpain inhibitor I and Everolimus for the treatment of PAH.Conclusion: Our study identified CYFIP1, EIF4E, and IFIT5 as novel diagnostic biomarkers in PAH. Furthermore, their association with immune cell infiltration may facilitate the development of immune therapy in PAH.