Objective To explore the role of E1A binding protein p300 (EP300)-mediated crotonylation (Kcr) modification of malic enzyme 1 (ME1) in ferroptosis of renal tubular epithelial cells. Methods C57BL/6 mice were divided into Sham operation group (Sham group), DMSO vehicle control + ischemia-reperfusion (IR) injury group (Vehi + IR group), and EP300 inhibitor C646 + IR injury group (C646 + IR group), with 12 mice in each group. Pathological changes in renal tissues were evaluated in each group, and indicators of renal function, ferroptosis, and fibrosis were assessed. Another 24 mice were used to establish the IR injury model to analyze changes in Kcr modification levels and EP300 expression over the 14-day course of IR injury. The in vitro HK-2 cell experimental model was established and divided into control group, hypoxia/reoxygenation (H/R) group, and C646 + H/R group. Corresponding HK-2 cells were transfected with the ME1-K337R plasmid, in which lysine 337 (K) was mutated to arginine (R) to mimic the de-Kcr modification. Small interfering RNA was used to target EP300 and transfect the cells in order to obtain EP300 knockdown cells (siEP300). The expression of ferroptosis-related proteins and fibrosis phenotypes was detected. Results At 14 d after IR injury, the protein Kcr level and EP300 expression were increased in mice. Compared with the Sham group, the Vehi+IR group showed markedly disrupted renal tissue structure, extensive red collagen deposition in the renal interstitium, decreased expression levels of glutathione, reduced nicotinamide adenine dinucleotide phosphate (NADPH), and glutathione peroxidase 4 (GPX4, P＜0.01), increased malondialdehyde and serum creatinine levels (P＜0.01), decreased ME1 enzymatic activity (P＜0.001), and increased expression of fibronectin 1 and smooth muscle actin-α (P＜0.001). Compared with the Vehi+IR group, the C646+IR group showed alleviated renal pathological injury, improved renal function, and reduced ferroptosis and fibrosis (P＜0.05). Compared with the control group, HK-2 cells subjected to H/R treatment exhibited aggravated ferroptosis and fibrosis (P＜0.05); compared with the H/R group, the C646+H/R group showed reduced ferroptosis and fibrosis (P＜0.05). Transfection with the ME1-K337R plasmid and siEP300 showed reduced ME1 Kcr, ferroptosis, and fibrosis. Conclusions EP300 contributes to ferroptosis in renal tubular epithelial cells by mediating ME1 crotonylation, and inhibition of EP300 may help alleviate the chronic progression following IR injury.

BACKGROUND: The sirtuin family is well recognized for its crucial involvement in various cellular processes. Nevertheless, studies on its role in the human endometrium are limited. This study aimed to explore the expression and localization of the sirtuin family in the human endometrium, focusing on sirtuin 3 (SIRT3) and its potential role in the oxidative imbalance of the endometrium in polycystic ovary syndrome (PCOS). METHODS: Endometrial specimens were collected from both patients with PCOS and controls undergoing hysteroscopy at the Center for Reproductive Medicine, Peking University Third Hospital, from July to August 2015 and used for cell culture. The protective effects of SIRT3 were investigated, and the mechanism of SIRT3 in improving endometrial receptivity of patients with PCOS was determined using various techniques, including cellular bioenergetic analysis, small interfering ribonucleic acid (siRNA) silencing, real-time quantitative polymerase chain reaction, Western blot, immunofluorescence, immunohistochemistry, and flow cytometry analysis. RESULTS: The sirtuin family was widely expressed in the human endometrium, with SIRT3 showing a significant increase in expression in patients with PCOS compared with controls ( P <0.05), as confirmed by protein and gene assays. Concurrently, endometrial antioxidant levels were elevated, while mitochondrial respiratory capacity was reduced, in patients with PCOS ( P <0.05). An endometrial oxidative stress (OS) model revealed that the downregulation of SIRT3 impaired the growth and proliferation status of endometrial cells and reduced their receptivity to day 4 mouse embryos. The results suggested that SIRT3 might be crucial in maintaining normal cellular state by regulating antioxidants, cell proliferation, and apoptosis, thereby contributing to enhanced endometrial receptivity. CONCLUSIONS Our findings proposed a significant role of SIRT3 in improving endometrial receptivity in patients with PCOS by alleviating OS and regulating the balance between cell proliferation and apoptosis. Therefore, SIRT3 could be a promising target for predicting and improving endometrial receptivity in this patient population.
Humans ; Female ; Polycystic Ovary Syndrome/metabolism* ; Endometrium/metabolism* ; Sirtuin 3/genetics* ; Oxidative Stress/genetics* ; Adult ; Animals ; Mice ; Apoptosis/physiology* ; Immunohistochemistry ; Cell Proliferation/physiology*

Objective To investigate the effects of sex hormone-binding globulin (SHBG)gene in the apoptosis of human trophoblastic cells.Methods The siRNA specific-targeting SHBG gene was transfected into human trophoblastic cells and they were divided into six groups:trophoblasts without transfection in normal control groups(group Ⅰ);transfect liposome in blank control groups(group Ⅱ);transfect nonspecific siRNA in negative control groups(group Ⅲ);transfect SHBG siRNA-Ⅰ,SHBG siRNA-Ⅱ,SHBG siRNA-Ⅲ respectively in trans-fection group(group Ⅳ,Ⅴ,Ⅵ).Hoechst 33258 dying method was used to detect cell apoptosis.SHBG and Caspase-3 mRNA profiling and the level of SHBG and caspase-3 protein were detected by real-time PCR and Western blot.Results There was no statistical significant difference in the gene expression and protein level of SHBG and caspase-3 in group Ⅰ,Ⅱ and Ⅲ (P >0.05).In Ⅳ,Ⅴ and Ⅵ group,there was no statistical significant difference in the expression level of SHBG and caspase 3 (P >0.05).Compared with group Ⅰ,Ⅱ and Ⅲ,the a-mount of SHBG gene expression decreased obviously,the caspase-3 mRNA and protein level increased obviously and the trophoblast cell ap-optosis increased markedly (P <0.05).Conclusion Through siRNA interference technology can reduce SHBG gene expression in human trophoblastic cells,and it can lead to excessive apoptosis of human trophoblasts cells.