Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025014
Ferroptosis is a novel form of regulated cell death characterized by the iron-dependent accumulation of lipid peroxides. Recent research has suggested that ferroptosis in osteoblasts contributes to steroid-induced osteonecrosis of the femoral head (SONFH). However, the relationship between ferroptosis and SONFH remains unclear. In this study, in vitro experiments show that dexamethasone (Dex) treatment reduces the expressions of key ferroptosis regulators, SLC7A11 and GPX4, in MC3T3-E1 cells. This reduction leads to a decrease in intracellular glutathione (GSH) levels, accompanied by elevated levels of total iron, malondialdehyde (MDA), and reactive oxygen species (ROS). Importantly, the ferroptosis inhibitor ferrostatin-1 (Fer-1) effectively reverses Dex-induced ferroptosis in MC3T3-E1 cells. Furthermore, RNA-seq analysis reveals that the long noncoding RNA (lncRNA) XR_877193.1 is significantly upregulated in Dex-treated MC3T3-E1 cells. Functional studies demonstrate that the knockdown of lncRNA XR_877193.1 promotes osteogenic differentiation by inhibiting Dex-induced ferroptosis in MC3T3-E1 cells, whereas its overexpression exacerbates cell death via ferroptosis. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis reveals that the differentially expressed lncRNA XR_877193.1 is enriched in ferroptosis-related pathways, including the PI3K/AKT signaling pathway. Moreover, PI3K/AKT inhibitors reverse ferroptosis in MC3T3-E1 cells inhibited by lncRNA XR_877193.1 knockdown. Collectively, our findings indicate that lncRNA XR_877193.1 knockdown exerts anti-ferroptosis effects by stimulating the PI3K/AKT signaling pathway, suggesting a promising therapeutic strategy for attenuating SONFH.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2024096
Autophagy is a cellular mechanism for self-renewal that involves the breakdown of cytoplasmic proteins or organelles within lysosomes. Although preeclampsia (PE) exhibits several characteristics that could imply disrupted autophagy, there is limited evidence supporting the notion that impaired placental autophagy directly causes PE, as indicated by differential expression profiling of whole placental tissue. In this study, we aim to explore the significance of autophagy in maintaining pregnancy and its association with PE. First, the RNA-seq results show that 218 genes are differentially expressed in placentas from preeclamptic pregnancies. Notably, KEGG pathway analysis reveals significant enrichment of genes related to autophagy-related signaling pathways, including the PI3K-Akt signaling pathway, the AMPK signaling pathway, and the mTOR signaling pathway. Additionally, our findings indicate an increase in autophagy in placentas from pregnancies complicated by preeclampsia as well as in trophoblasts subjected to hypoxic conditions. Next, we examine the impact of 3-methyladenine (3-MA), a targeted inhibitor of autophagy, on the progression of PE. The administration of 3-MA profoundly alleviates the severity of PE-like symptoms in rats subjected to reduced uterine perfusion pressure (RUPP). The findings from our study suggest that inhibiting autophagy may serve as a promising approach for adjuvant chemotherapy for PE.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025096
Ferroptosis, a novel form of regulated necrosis, has drawn the attention of the scientific community. Nevertheless, few studies have focused on the impact of ferroptosis on MC3T3-E1 cells in the context of steroid-induced osteonecrosis of the femoral head (SONFH). In this study, we explore the relationship between the degree of ferroptosis induced by dexamethasone (Dex) and the expression of silent information regulatory protein 1 (Sirt1). The results indicate that the ferroptosis level induced by Dex is mediated by the downregulation of Sirt1. Overexpression of Sirt1 increases the levels of the ferroptosis-related proteins SLC7A11 and GPX4 in MC3T3-E1 cells following Dex exposure. Moreover, the effect of Dex on Sirt1 expression is regulated by hypermethylation of the Sirt1 promoter, which is catalyzed by DNA methyltransferase 3a (DNMT3a). In summary, this study reveals that Dex can trigger ferroptosis by promoting DNMT3a-mediated DNA methylation and downregulating Sirt1 expression. Our findings provide an additional new mechanism for Dex-induced ferroptosis in MC3T3-E1 cells.
Chinese Journal of Tissue Engineering Research•2026•DOI: 10.12307/2026.21315
BACKGROUND: Studies have confirmed that A disintegrin and metalloproteinase with thrombospondin motifs 8 (ADAMTS8) plays a regulatory role in fibrosis, so it is of great clinical significance to explore the mechanism of ADAMTS8 in hypertrophic scars. OBJECTIVE: To investigate the regulatory effect of ADAMTS8 on hypertrophic scars. METHODS: (1) Immunohistochemical staining was used to detect the expression of type I collagen, type III collagen, alpha-smooth muscle actin and ADAMTS8 in normal human skin and hypertrophic scar tissues. Western blot was used to detect ADAMTS8 protein expression in normal skin and hypertrophic scar tissues. With hypertrophic scar as positive sample and normal skin as negative sample, receiver operating characteristic curve was drawn to analyze the ability of ADAMTS8 to predict and distinguish normal skin from hypertrophic scar. (2) STRING 12.0 platform was used to construct a protein-protein interaction network for ADAMTS8, and GO functional enrichment and KEGG pathway enrichment analyses were performed on the obtained targets. (3) Fibroblasts from human hypertrophic scar tissue were isolated and cultured. The 3rd to 6th generation fibroblasts were divided into three groups: control group (routine culture), Ad-NC group (transfected with empty adenovirus), and Ad-ADAMTS8 group (transfected with adenovirus overexpressing ADAMTS8). CCK-8 assay and EdU staining were used to detect cell proliferation activity, and flow cytometry and TUNEL staining were used to detect cell apoptosis. RESULTS AND CONCLUSION: (1) Immunohistochemical staining showed that the expression of type I collagen, type III collagen and alpha-smooth muscle actin in hypertrophic scars was higher than that in normal skin (P < 0.001), while ADAMTS8 expression was lower than that in normal skin (P < 0.001). Western blot showed that ADAMTS8 protein expression in hypertrophic scars was lower than that in normal skin (P < 0.001). Receiver operating characteristic curve showed that the area under the curve of ADAMTS8 predicting hypertrophic scar was 0.86, indicating that ADAMTS8 has good ability to distinguish hypertrophic scar from normal skin. (2) The top 41 genes were screened through STRING database. KEGG enrichment showed that ADAMTS8 was mainly involved in extracellular matrix receptor interaction, phosphatidylinositol-3-kinase-protein kinase B signaling pathway, efferocytosis and other biological processes and key mechanisms. GO enrichment showed that ADAMTS8 was involved in apoptosis-related pathway enrichment, including negative regulation of fibroblast growth factor receptor signaling pathway, fibroblast growth factor binding, negative regulation of apoptosis and apoptotic process. (3) CCK-8 assay and EdU staining showed that overexpression of ADAMTS8 inhibited the proliferation of hypertrophic scar fibroblasts; flow cytometry and TUNEL staining showed that overexpression of ADAMTS8 promoted apoptosis of hypertrophic scar fibroblasts. (4) These results indicate that ADAMTS8 expression is decreased in human hypertrophic scars, and overexpression of ADAMTS8 can inhibit proliferation and promote apoptosis of hypertrophic scar fibroblasts.
Chinese Journal of Tissue Engineering Research•2026•DOI: 10.12307/2026.21475
BACKGROUND: The pathogenesis of steroid-induced osteonecrosis of the femoral head remains unclear; however, it is closely associated with mitochondrial damage in osteoblasts. OBJECTIVE: To explore the impact of dexamethasone on mitochondrial dysfunction in osteoblasts following steroid-induced osteonecrosis of the femoral head and to analyze its regulatory roles in osteoblast apoptosis and autophagy. METHODS: MC3T3-E1 cells were cultured in vitro and divided into control group (no treatment) and dexamethasone group (1 μmol/L dexamethasone treatment for 24 hours). Osteoblast differentiation capacity was assessed by alizarin red staining and qRT-PCR. Mitochondrial morphology was examined using transmission electron microscopy, MitoTracker Red fluorescence staining, and flow cytometry. Mitochondrial membrane potential and energy metabolism were evaluated by JC-1 fluorescence staining and ATP content detection. Mitochondrial superoxide levels were measured using MitoSOX fluorescence probe and flow cytometry. Intracellular total reactive oxygen species and glutathione content were also measured to assess oxidative stress status. Additionally, Western blot and qRT-PCR were used to detect the expression of apoptosis-related proteins (Bax, Bcl-2) and autophagy markers (LC3B, p62), flow cytometry was used to analyze apoptosis rate, and autophagy flux was observed via mRFP-GFP-LC3 adenovirus transfection combined with confocal microscopy. RESULTS AND CONCLUSION: Compared with the control group, the dexamethasone group showed significantly reduced osteogenic differentiation capacity of MC3T3-E1 cells, abnormal mitochondrial structure (swelling, cristae disruption), decreased mitochondrial membrane potential, reduced ATP synthesis, increased mitochondrial superoxide and total reactive oxygen species levels, and increased glutathione consumption (P < 0.05). The dexamethasone group showed significantly upregulated pro-apoptotic protein Bax (P < 0.01), significantly downregulated anti-apoptotic protein Bcl-2 (P < 0.01), increased LC3B-II/I ratio (P < 0.01), and decreased p62 levels (P < 0.01); dexamethasone treatment significantly increased the apoptosis rate (P < 0.01). mRFP-GFP-LC3 adenovirus tracing revealed increased formation of autophagosomes and autolysosomes. These results indicate that dexamethasone induces mitochondrial dysfunction and oxidative stress, synergistically regulating apoptosis and autophagy in MC3T3-E1 cells, thereby impairing bone formation and repair function. This mechanism may be a key pathological basis for the pathogenesis of steroid-induced osteonecrosis of the femoral head.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025096
Steroid-induced osteonecrosis of the femoral head (SONFH) is a progressive bone disorder driven by prolonged glucocorticoid exposure, with limited therapeutic options. Ferroptosis, a regulated form of necrosis, has emerged as a potential contributor to SONFH pathogenesis, yet its mechanistic link to osteoblast dysfunction remains poorly defined. This study investigates the relationship between dexamethasone (Dex)-induced ferroptosis and silent information regulator 1 (Sirt1) in MC3T3-E1 osteoblastic cells. Dex treatment downregulated Sirt1 expression and increased ferroptosis markers, while Sirt1 overexpression elevated the ferroptosis-related proteins SLC7A11 and GPX4 following Dex exposure. Mechanistically, Dex promoted hypermethylation of the Sirt1 promoter via DNA methyltransferase 3a (DNMT3a), leading to Sirt1 suppression. These findings establish a novel epigenetic axis—DNMT3a-mediated Sirt1 promoter hypermethylation—that drives Dex-induced ferroptosis in osteoblasts. The study was conducted exclusively in vitro, and the pathophysiological relevance requires validation in animal models. Nevertheless, this work provides a foundation for understanding the epigenetic regulation of osteoblast ferroptosis and suggests potential therapeutic avenues for preventing SONFH.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025021
Homocysteine (Hcy) is an independent risk factor for atherosclerosis, and defective macrophage autophagy accelerates plaque formation. Pyruvate dehydrogenase (PDH), a key component of the PDH complex, links energy metabolism to autophagy, but its role in Hcy-induced atherosclerosis remains undefined. Proteomic profiling of Hcy-treated macrophages identified 748 upregulated and 760 downregulated proteins, with KEGG enrichment in amino acid biosynthesis, carbon metabolism, and glycolysis/gluconeogenesis. In ApoE–/– mice, Hcy treatment markedly reduced PDH expression and activity, leading to impaired autophagy. PDH activation restored autophagy by promoting assembly of the ULK1-FIP200-Atg13 complex via modulation of AMPK/mTOR signaling. These findings suggest that PDH activation may serve as a therapeutic strategy for Hcy-induced atherosclerosis.