Deqin Lu

Background: High fat diet (HFD)‐induced increases in free fatty acids in the blood increase the risk of cardiovascular diseases by compromising vascular function. We reported that palmitic acid decreases eNOS (endothelial nitric oxide synthase) phosphorylation at serine 633 by reducing the expression of the PP4R2 (protein phosphatase 4 regulatory subunit 2) protein and activating PP4, leading to endothelial dysfunction. This study aimed to elucidate the underlying mechanisms. Methods: Studies were performed using C57BL/6J male mice fed an HFD or a normal fat diet for 12 weeks. PP4R2 protein expression was upregulated or PP4C protein expression was downregulated in the aorta by injecting Ppp4r2 overexpression (OE‐ Ppp4r2 ) or Ppp4c knockdown (sh Ppp4c ) lentiviral vectors into the tail vein, respectively. Mouse aortic endothelial cells were transfected with LV‐sh Ppp4c or LV‐OE‐ Ppp4r2 and then treated with palmitic acid. Results: Decreases in PP4R2 protein levels increased PP4 activity and decreased phosphorylated‐eNOS Ser633 and NO levels in the aortas of HFD‐fed mice and palmitic acid‐treated mouse aortic endothelial cells. Either Ppp4r2 overexpression or Ppp4c knockdown inhibited PP4 activity, improved eNOS/NO function in the aorta and endothelial cells, and ameliorated HFD‐induced pathological changes in the aorta. Palmitic acid activated PP4 in mouse aortic endothelial cells by increasing degradation of the PP4R2 protein and enhancing the interactions between PP4R2 and PP4C. Ginkgolide B, a potential ligand of PP4R2 identified with an in silico virtual screen, promoted PP4R2 inhibition of PP4 and partially reversed eNOS/NO dysfunction. Conclusions: The endothelial PP4R2 protein is essential for maintaining eNOS/NO function and vascular homeostasis. Boosting PP4R2 inhibitory effect on PP4 activity, like using ginkgolide B, offers a potential strategy for combating HFD‐induced vascular damage.

Endometrial cancer ranks among the most prevalent tumours in women, with approximately 80-85% classified as endometrioid type. Evidence has suggested a significant link between obesity and the development of endometrial endometrioid cancer (EEC). We analysed RNA sequencing data encompassing 407 EEC samples and 35 normal endometrial tissue samples sourced from TCGA, and created a risk score model built on differentially expressed genes related to fatty acid metabolism within the tumour microenvironment (TME). Patients categorised as high-risk scores exhibited a higher prevalence of dMMR and TP53 mutations, fewer mutations in KRAS and PTEN, and worse prognostic outcomes. Further investigation indicated that the two patient subgroups showed varying sensitivities to different chemotherapeutic agents. Additionally, the composition of immune cell infiltration in the TME diverged between these subgroups. Tumour Immune Dysfunction and Exclusion analysis suggested that individuals with high-risk scores are not suited for immunotherapeutic intervention. Based on bioinformatic analyses, this research offers a novel framework for the classification and therapeutic direction of EEC.

Early spontaneous abortion (ESA) is recognized as the most common complication during pregnancy and is often linked to dysfunction in the trophoblast and placenta. Studies suggest that downregulation of trophoblast oestrogen-related receptor gamma (ESRRG) may play a significant role in the impairment of placental function. In light of these findings, we evaluated the impact of ESRRG on trophoblast and placental function in ESAs, aiming to uncover new targets for diagnosis and treatment. Bioinformatics methods were used to analyse differentially expressed genes in the trophoblast of ESA patients and normal controls. ESA Patients and controls were recruited and the villus tissues were collected. Protein and mRNA levels were determined by western blot and qRT-PCR, respectively. Mitochondrial morphological changes in trophoblasts were observed via transmission electron microscopy. CCK8 and Transwell assays were conducted with ESRRG-knockdown HTR-8/SVneo cells. MitoSOX staining, JC-1 assays and ATP quantification were used to assess mitochondrial function in vitro. In addition, Esrrg was overexpressed in ICR female mice, and the number of embryos in the uterus was determined. The expression of ESRRG was significantly decreased in the placental villous tissue of ESA patients, accompanied by abnormal mitochondrial morphology and decreased ATP levels in trophoblast cells. Impaired proliferation, invasion, migration and tube formation abilities were observed in ESRRG-downregulated HTR-8/SVneo cells, as well as impaired mitochondrial function. ESRRG overexpression was associated with improved trophoblast functionality in a lipopolysaccharide-induced abortion model in ICR mice, leading to an increased number of retained embryos in the uterus. In summary, this study revealed that ESRRG downregulation plays an important role in ESA, providing new targets for diagnosis and treatment.

Cell division cycle associated 7 (CDCA7) plays a role in various malignancies, especially pancreatic cancer (PC). However, its expression pattern and functional significance in PC require further research. Therefore, this study aimed to investigate CDCA7 expression levels and biological functions in PC using in vitro and in vivo experiments. Western blotting, immunohistochemistry, and real-time polymerase chain reaction were performed to detect CDCA7 expression in PC cells and tissues. Additionally, the biological functions of CDCA7 were assessed using cell proliferation, wound healing, and Transwell assays. CDCA7 overexpression promoted PC cell proliferation, migration, and invasion, and increased resistance to the chemotherapy drug gemcitabine, possibly through enhanced aerobic glycolysis. Additionally, immunoprecipitation assay showed that CDCA7 interacted with STAT3 protein and affected the transcriptional regulation of hexokinase 2. Conclusively, targeting CDCA7 might be a promising therapeutic strategy to increase gemcitabine sensitivity by inhibiting glycolysis in PC cells.

Introduction: Myocardial ischemia-reperfusion injury (MIRI) is a prevalent complication in patients with myocardial infarction. The pathological mechanism of MIRI remains elusive. Ferroptosis plays a critical role in MIRI. This study aimed to investigate the role of spermidine/spermine N1-acetyltransferase 1 (Sat1) in MIRI by regulation of ferroptosis.Methods: Rats and H9C2 cells were used to perform MIRI model. The extent of myocardial damage and associated pathological changes were evaluated. Protein expression was detected by western blot. Then we observed the mitochondrial morphology and measured cell viability and damage. The levels of lipid peroxide and glutathione were measured, and lipid reactive oxygen species (ROS) was quantified. Differentially expressed genes (DEGs) in MIRI were analyzed. Moreover, to explore the role of Sat1 in MIRI, this study utilized adeno-associated virus 9 and lentiviral transduction to modulate Sat1 expression in rats and H9C2 cells, respectively. The transcription factor that regulates Sat1 expression was predicated. Luciferase reporter gene experiment was conducted to reveal the potential sites of Sox2 binding to Sat1.Results: This study revealed that ferroptosis was involved in MIRI. Through bioinformatic analysis, Sat1 was identified as a significant gene in MIRI, which has been reported as an inducer of ferroptosis. Our results showed that Sat1 expression was significantly increased in MIRI. Next, the study showed that inhibition of Sat1 alleviated MIRI by suppressing ferroptosis in vivo and in vitro, and over-expression of Sat1 promoted MIRI via activation of ferroptosis. Furthermore, Sat1 and its interacting genes were enriched in several signaling pathways, including ferroptosis and the MAPK signaling pathway. The results showed that Sat1 regulated MIRI through ferroptosis via MAPK/ERK pathway. Moreover, it is found that Sox2 can suppress Sat1 expression at the transcriptional level. The potential binding site was TAACAAAGGAA.Conclusion: In sum, this study demonstrated Sat1 expression was increased in MIRI, inhibition of Sat1 can alleviate MIRI by regulating ferroptosis via MAPK/ERK pathway, and Sat1 was negatively regulated by Sox2. These findings suggested that Sat1 may serve as a potential therapeutic target for the treatment of MIRI.

Increasing evidences demonstrate that chlorogenic acid (CGA), a polyphenol with multiple effects such as anti-inflammatory and anti-oxidation, protects against myocardial ischemia–reperfusion injury (MIRI) in vitro and in vivo. But its detailed cardiac protection mechanism is still unclear. The MIRI mice model was established by ligating the left anterior descending branch (LAD) of the left coronary artery in C57BL/6 mice. Sixty C57BL/6 mice were randomly divided into four groups. CGA group and CGA + I/R group (each group n = 15) were gavaged with 30 mg/kg/day CGA for 4 weeks. Sham group and I/R group mice (each group n = 15) were administered equal volumes of saline. In vitro MIRI model was constructed by hypoxia and reoxygenation of HL-1 cardiomyocytes. The results showed that CGA pretreatment reduced myocardial infarction size and cTnT contents in serum, simultaneously reduced the levels of Lnc Neat1 expression and attenuated NLRP3 inflammasome-mediated pyroptosis in myocardial tissue. Consistent with in vivo results, the pretreatment of 0.2 μM and 2 μM CGA for 12 h in HL-1 cardiomyocytes depressed hypoxia/reoxygenation-induced Lnc Neat1 expression, NLRP3 inflammasome activation and pyroptosis. Lnc Neat1 shRNA transfection mediated by lentivirus in HL-1 cardiomyocytes significantly reduced activation of NLRP3 inflammasome and pyroptosis. Our findings suggest that CGA protects against MIRI by depressing Lnc Neat1 expression and NLRP3 inflammasome-mediated pyrotosis. Inhibiting the levels of Lnc Neat1 expression may be a therapeutic strategy for MIRI.

Increasing evidences suggest that angiotensin (Ang) II participates in the pathogenesis of endothelial dysfunction (ED) through multiple signaling pathways, including angiotensin type 1 receptor (AT₁R) mediated NADPH oxidase (Nox)/reactive oxygen species (ROS) signal transduction. However, the detailed mechanism is not completely understood. In this study, we reported that AngII/AT₁R-mediated activated protein phosphatase 2A (PP2A) downregulated endothelial nitric oxide synthase (eNOS) phosphorylation via Nox/ROS pathway. AngII treatment reduced the levels of phosphorylation of eNOS Ser1177 and nitric oxide (NO) content along with phosphorylation of PP2Ac (PP2A catalytic subunit) Tyr307, meanwhile increased the PP2A activity and ROS production in human umbilical vein endothelial cells (HUVECs). These changes could be impeded by AT₁R antagonist candesartan (CAN). The pretreatment of 10⁻⁸ M PP2A inhibitor okadaic acid (OA) reversed the levels of eNOS Ser1177 and NO content. Similar effects of AngII on PP2A and eNOS were also observed in the mesenteric arteries of Sprague-Dawley rats subjected to AngII infusion via osmotic minipumps for 2 weeks. We found that the PP2A activity was increased, but the levels of PP2Ac Tyr307 and eNOS Ser1177 as well as NO content were decreased in the mesenteric arteries. The pretreatments of antioxidant N-acetylcysteine (NAC) and apocynin (APO) abolished the drop of the levels of PP2Ac Tyr307 and eNOS Ser1177 induced by AngII in HUVECs. The knockdown of p22phox by small interfering RNA (siRNA) gave rise to decrement of ROS production and increment of the levels of PP2Ac Tyr307 and eNOS Ser1177. These results indicated that AngII/AT₁R pathway activated PP2A by downregulating its catalytic subunit Tyr307 phosphorylation, which relies on the Nox activation and ROS production. In summary, our findings indicate that AngII downregulates PP2A catalytic subunit Tyr307 phosphorylation to activate PP2A via AT₁R-mediated Nox/ROS signaling pathway. The activated PP2A further decreases levels of eNOS Ser1177 phosphorylation and NO content leading to endothelial dysfunction.

Objective To investigate the roles of protein phosphatase 2C (PP2C) activated by palmitic acid (PA) in the phosphorylation modulation of endothelial nitric oxide (eNOS) at the site of serine 1177 (eNOS Ser1177) in human umbilical vein endothelial cells (HUVECs). Methods HUVECs were randomly divided into control group, PA group, specific PP2C inhibitor sanguinarine (San) combined with PA group and PP2Cα specific small interference RNA (siRNA) transfection group. The protein expression of total eNOS, phosphorylated eNOS Ser1177 and PP2Cα were detected by Western blotting. The intracellular NO content was measured by DAF-FM DA. The co-localization of eNOS protein and PP2C protein was observed by co-immunoprecipitation. Results Compared with the control group, the phosphorylation levels of eNOS Ser1177 and NO content decreased significantly in the PA group. The PP2C inhibitor sanguinarine reversed PA-induced decrease of eNOS Ser1177 phosphorylation level and NO content. The phosphorylation levels of eNOS Ser1177 were enhanced dramatically after PP2Cα protein was knocked down by specific siRNA. The eNOS protein and PP2C protein co-localized in endothelial cells. Conclusion PA reduces the phosphorylation level of endothelial eNOS Ser1177 in HUVECs by activating PP2C.