MeCP2 promotes endothelial-to-mesenchymal transition in human endothelial cells by downregulating BMP7 expression.

Endothelial-to-mesenchymal transition (EndMT) plays a pivotal role in the development of organ fibrosis and can be induced by TGF-ß. It is characterized by the loss of endothelial cell markers and the acquisition of mesenchymal markers. In this study, we found that methyl-CpG binding protein 2 (MeCP2) was increased in TGF-ß-induced EndMT, and silencing of MeCP2 inhibited EndMT induction. Viral overexpression of MeCP2 in vitro promoted EndMT and suppressed the expression of bone morphogenic protein-7 (BMP7). The methylation of CpG islands in BMP7 promoter was increased in MeCP2-overexpressing endothelial cells and Chromatin immunoprecipitation assay showed the direct binding of MeCP2 at the BMP7 promoter. In summary, our results suggest that MeCP2 promotes EndMT by epigenetically silencing BMP7 in endothelial cells and MeCP2 may be a target for diseases driven by EndMT.

SIRT1 inhibits TGF-ß-induced endothelial-mesenchymal transition in human endothelial cells with Smad4 deacetylation.

Endothelial-mesenchymal transition (EndMT) plays a pivotal role in organ fibrosis. This study examined the effect of SIRT1 on transforming growth factor beta (TGF-ß)-induced EndMT in human endothelial cells (ECs) and its probable molecular mechanism. We assessed EndMT by immunofluorescence staining, quantitative real-time polymerase chain reaction, Western blotting, and migration and invasion assays. Adenovirus was used to overexpress or knockdown SIRT1 in ECs. The regulatory relationship between SIRT1 and Smad4 was analyzed by coimmunoprecipitation assay. We found that SIRT1 was decreased in TGF-ß-induced EndMT, and SIRT1 inhibited TGF-ß-induced EndMT through deacetylating Smad4. Our findings suggest that SIRT1 has an important role in inhibiting EndMT by regulating the TGF-ß/Smad4 pathway in human ECs and, thus, protecting against fibrosis.

Local structural modelling and local pair distribution function analysis for Zr-Pt metallic glass.

In disordered glass structures, the structural modelling and analyses based on local experimental data are not yet established. Here we investigate the icosahedral short-range order (SRO) in a Zr-Pt metallic glass using local structural modelling, which is a reverse Monte Carlo simulation dedicated to two-dimensional angstrom-beam electron diffraction (ABED) patterns, and local pair distribution function (PDF) analysis. The local structural modelling invariably leads to the icosahedral SRO atomic configurations that are similarly distorted by starting from some different initial configurations. Furthermore, the SRO configurations with 11-13 coordination numbers reproduce almost identical ABED patterns, indicating that these SRO structures are similar to each other. Further local PDF analysis explicitly indicates the presence of the wide distribution of atomic bond distances, which is comparable to the global PDF profile, even at the SRO level. The SRO models based on the conventional MD simulation can be strengthened by comparison with those obtained by the present local structural modelling and local PDF analysis based on the ABED data.

Topical Simvastatin Improves Lesions of Diffuse Normolipemic Plane Xanthoma by Inhibiting Foam Cell Pyroptosis.

Xanthoma pathogenesis is speculated to be associated with oxidized low-density lipoprotein (ox-LDL) deposition, although this remains unclear. Most patients with diffuse plane xanthomas present elevated blood lipid levels, and they benefit from treatment with oral lipid-lowering agents. However, there is no available treatment for diffuse normolipemic plane xanthoma (DNPX). In this study, for the first time, we used a topical simvastatin ointment to treat DNPX in three pediatric patients and observed favorable results. Immunofluorescence staining showed that the pyroptotic pathway was significantly attenuated after topical simvastatin application on the skin lesions of the patients. As ox-LDL deposition was observed in the lesions, we used ox-LDL to build a foam cell model in vitro. In the ox-LDL-induced foam cell formation, simvastatin consistently inhibited pyroptotic activation and inflammation in the macrophages. Additionally, the overexpression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) or 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase (HMGCR), the known target of statins, reversed the effects of simvastatin. Moreover, gasdermin D (GSDMD) or HMGCR knockdown inhibited ox-LDL-induced pyroptosis. Furthermore, the immunoprecipitation results confirmed the interaction between NLRP3 and HMGCR, and this interaction was inhibited by simvastatin. In conclusion, we demonstrated that topical application of simvastatin ointment might be a promising treatment for DNPX skin lesions and that this therapeutic effect may be related to pyroptosis inhibition via HMGCR inhibition in foam cells. Moreover, xanthoma pathogenesis might be associated with ox-LDL deposition and inflammation.

MeCP2 inhibits cell functionality through FoxO3a and autophagy in endothelial progenitor cells.

OBJECTIVES: Autophagy is an evolutionarily conserved intracellular degradation mechanism in which cell constituents are phagocytosed to maintain cellular homeostasis. Forkhead box O 3a (FoxO3a) promotes autophagy to protect cells from environmental stress. Methylated CpG binding protein 2 (MeCP2) is a nuclear protein that binds DNA and represses transcription. However, the mechanism and interplay between FoxO3a and MeCP2 underlying endothelial progenitor cell (EPC) function are not fully understood. RESULTS: In EPCs, MeCP2 overexpression attenuated autophagy and cell functionality, which were reversed by the autophagy activator rapamycin or co-transfection with FoxO3a. FoxO3a promoted cell function, which was reversed by the autophagy inhibitor chloroquine. Following MeCP2 overexpression, MeCP2 was found enriched on the FoxO3a promoter, resulting in promoter hypermethylation and enhanced H3K9 histone modification in nucleosomes of the FoxO3a promoter. CONCLUSIONS: MeCP2 attenuated cell functionality via DNA hypermethylation and histone modification of the FoxO3a promoter to inhibit FoxO3a transcription and autophagy. MATERIALS AND METHODS: EPCs were isolated from human umbilical cord blood and treated with adenoviral vectors containing interference sequences. The effects and mechanism of MeCP2 and FoxO3a were analyzed by utilizing western blotting, cell counting kit-8, transwell plates, Matrigel, matrix adhesion, transmission electron microscopy, and chromatin immunoprecipitation.

PJ34, a PARP1 inhibitor, promotes endothelial repair in a rabbit model of high fat diet-induced atherosclerosis.

Objective: Atherosclerosis involves endothelial injury caused by oxidative stress. Endothelial progenitor cells (EPCs) play important roles in preventing the early stages of atherosclerosis. Meanwhile, poly (ADP-ribose) polymerase 1 (PARP1) utilizes nicotinamide adenine dinucleotide (NAD+) to repair DNA damage. PARP1 overactivation results in excessive NAD+ consumption in the presence of pathological DNA damage. PJ34 is a PARP1 inhibitor that attenuates cellular NAD+ depletion and can prevent endothelial dysfunction. However, few studies have been conducted on its effects on EPCs. In this study, we tried to elucidate the action of PJ34 in rabbit EPCs and tested its effectiveness in rabbit atherosclerosis. Methods: We analyzed the effect of PJ34 supplementation by inducing oxidative damage by H2O2in vitro and using a rabbit atherosclerosis model induced by a high-fat-diet in vivo. Transwell, immunofluorescence, Matrigel, and western blot analyses, as well as adenoviral vector transfection were used to quantify the levels of reactive oxygen species, proteins, and NAD+. Results: The effects of PJ34 were dependent on SIRT1 levels. In vitro results showed that when oxidative damage attenuated cellular function, PJ34 treatment restored partial functionality. In vivo results confirmed that PJ34 can prevent atherosclerosis in a rabbit model.

Correction to: PARP1 inhibitor (PJ34) improves the function of aging-induced endothelial progenitor cells by preserving intracellular NAD+ levels and increasing SIRT1 activity.

The original article [1] contains an error regarding the erroneous inclusion of 3 µl as a parameter in the x-axis of Fig. 2c; the correct version of Fig. 2c can instead be seen below.

PARP1 inhibitor (PJ34) improves the function of aging-induced endothelial progenitor cells by preserving intracellular NAD+ levels and increasing SIRT1 activity.

BACKGROUND: Nicotinamide adenine dinucleotide (NAD+) is a critical molecule involved in various biological functions. Poly (ADP-ribose) polymerase 1 (PARP1) and sirtuin 1 (SIRT1) affect cellular NAD+ levels and play essential roles in regulating metabolism. However, there has been little research on the effects of PARP1 and SIRT1 crosstalk during senescence. METHODS: We isolated endothelial progenitor cells (EPCs) from human umbilical cord blood and treated them with a PARP1 inhibitor (PJ34). RESULTS: Using a stress-induced premature aging model built by H2O2, transfection with adenoviral vectors, and Western blot analysis, we observed that PJ34 treatment preserved intracellular NAD+ levels, increased SIRT1 activity, decreased p53 acetylation, and improved the function of stress-induced premature aging EPCs. CONCLUSIONS: Our results suggest that PJ34 improves the function of aging-induced EPCs and may contribute to cellular therapies for atherosclerosis.