SIRT1-autophagy axis may inhibit oxidative stress-induced ferroptosis in human nucleus pulposus cells

Fisetin regulates the biological effects of rat nucleus pulposus mesenchymal stem cells under oxidative stress by sirtuin-1 pathway

BACKGROUND

Excessive oxidative stress has been accepted as one of the critical factors for intervertebral disc degeneration (IDD), which is associated with low back pain (LBP). Fisetin (Fis) is a bioactive flavonoid that possesses strong bioactive activity. In present study, we aimed to illuminate the role of Fis on nucleus pulposus mesenchymal stem cells (NPMSCs).

METHODS

NPMSCs were isolated and cultured from rat NP tissues and identified by flow cytometry and multilinear differentiation. The cytotoxicity of Fis, EX-527, and hydrogen peroxide (H₂ O₂ ) on NPMSCs was validated using Cell Counting Kit-8 tests. Cell apoptosis was tested by flow cytometry and TUNEL assay. Inflammatory mediators were assessed by Elisa tests, RT-PCR. Extracellular matrix (ECM) metabolism was measured by Western blot analysis and RT-qPCR. The expression of the SIRT1 was evaluated by Western blot analysis.

RESULTS

NPMSCs were successfully isolated and cultured from rat NP tissues, and it has been identified by flow cytometry and multilinear differentiation. The results showed that Fis attenuated H₂ O₂ -induced apoptosis, inflammation, and ECM degradation of NPMSCs. Moreover, the above protective effects of Fis can be inhibited by EX-527, a unique SIRT1 inhibitor, indicating that SIRT1 may involve in the mechanism of Fis in protecting NPMSCs from oxidative stress.

CONCLUSIONS

As a natural compound with little cytotoxicity on NPMSCs, Fis alleviate H₂ O₂ -induced apoptosis, inflammation, and ECM degradation by suppressing oxidative stress, this finding may add the theoretical basis for research on new treatment of IDD based on NPMSCs.

The roles of sirtuins in ferroptosis

Ferroptosis represents a novel non-apoptotic form of regulated cell death that is driven by iron-dependent lipid peroxidation and plays vital roles in various diseases including cardiovascular diseases, neurodegenerative disorders and cancers. Plenty of iron metabolism-related proteins, regulators of lipid peroxidation, and oxidative stress-related molecules are engaged in ferroptosis and can regulate this complex biological process. Sirtuins have broad functional significance and are targets of many drugs in the clinic. Recently, a growing number of studies have revealed that sirtuins can participate in the occurrence of ferroptosis by affecting many aspects such as redox balance, iron metabolism, and lipid metabolism. This article reviewed the studies on the roles of sirtuins in ferroptosis and the related molecular mechanisms, highlighting valuable targets for the prevention and treatment of ferroptosis-associated diseases.

Ferroptosis-Related Proteins Are Potential Diagnostic Molecular Markers for Patients with Preeclampsia

Preeclampsia (PE) is the leading cause of maternal and fetal mortality and morbidity. Early and accurate diagnosis is critical to reduce mortality. Placental oxidative stress has been identified as a major pathway to the development of PE. Ferroptosis, a new form of regulated cell death, is associated with iron metabolism and oxidative stress, and has been suspected to play a role in the pathophysiology of PE, although the mechanism is yet to be elucidated. The identification of potential ferroptosis-related biomarkers is of great significance for the early diagnosis and treatment of PE. A gene expression dataset of peripheral blood samples was downloaded from the Gene Expression Omnibus (GEO) dataset. Differentially expressed genes (DEGs) were filtrated with the R package “limma”. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the DEGs were then conducted. Ferroptosis-related DEGs were screened by overlapping the ferroptosis-related genes with DEGs. The protein−protein interaction (PPI) network was used to identify the key ferroptosis-related DEGs. Enzyme-linked immunosorbent assay (ELISA) was used to validate changes in the selected key ferroptosis-related DEGs. The correlations between the key genes and clinical and pathological characteristics were analyzed. Finally, the diagnostic value of these key genes for PE was confirmed by a receiver operating characteristic (ROC) curve. A total of 5913 DEGs were identified and 45 ferroptosis-related DEGs were obtained. Besides, ferroptosis-related pathways were enriched by KEGG using DEGs. The PPI network showed that p53 and c-Jun were the critical hub genes. ELISA showed that p53 in the serum of PE patients was higher than that of the control group, while c-Jun was lower than that of the control group. Analysis of the clinicopathological features showed that p53 and c-Jun were correlated with the PE characteristics. Finally, based on the area under curve (AUC) values, c-Jun had the superior diagnostic power (AUC = 0.87, p < 0.001), followed by p53 (AUC = 0.75, p < 0.001). Our study identified that two key genes, p53 and c-Jun, might be potential diagnostic biomarkers of PE.