EHMT2/G9a Inhibits Aortic Smooth Muscle Cell Death by Suppressing Autophagy Activation.

Although EHMT2 (also known as G9a) plays a critical role in several kinds of cancers and cardiac remodeling, its function in vascular smooth muscle cells (VSMCs) remains unknown. In the present study, we revealed a novel function of EHMT2 in regulating autophagic cell death (ACD) of VSMC. Inhibition of EHMT2 by BIX01294 or knockdown of EHMT2 resulted in reduced VSMC numbers which were independent of proliferation and apoptosis. Interestingly, EHMT2 protein levels were significantly decreased in VSMCs treated with autophagic inducers. Moreover, more autophagic vacuoles and accumulated LC3II were detected in VSMCs treated with BIX01294 or lenti-shEHMT2 than their counterparts. Furthermore, we found that EHMT2 inhibited the ACD of VSMCs by suppressing autophagosome formation. Mechanistically, the pro-autophagic effect elicited by EHMT2 inhibition was associated with SQSTM1 and BECN1 overexpression. Moreover, these detrimental effects were largely nullified by SQSTM1 or BECN1 knockdown. More importantly, similar results were observed in primary human aortic VSMCs. Overall, these findings suggest that EHMT2 functions as a crucial negative regulator of ACD via decreasing SQSTM1 or BECN1 expression and that EHMT2 could be a potent therapeutic target for cardiovascular diseases (e.g., aortic dissection).

Is Retzius-sparing robot-assisted radical prostatectomy associated with better functional and oncological outcomes? Literature review and meta-analysis.

OBJECTIVE: To evaluate the efficiency, safety and clinical outcomes of Retzius-sparing robot-assisted radical prostatectomy (RS-RARP) in comparison with the standard RARP. METHODS: A systematic search from Web of Science, PubMed, EMBase, Cochrane Library and Google Scholar was performed using the terms "Retzius-sparing", "Bocciardi approach" and "robot-assisted radical prostatectomy". Video articles and abstract papers for academic conferences were excluded. Meta-analysis of interested outcomes such as positive surgical margins (PSMs) and continence recovery was undertaken. A comprehensive literature review of all studies regarding Retzius-sparing (RS) approach was conducted and summarized. RESULTS: From 2010 to 2017, 11 original articles about RS-RARP approach were retrieved. Of that, only four studies comparing the RS-RARP approach to the conventional RARP were comparable for meta-analysis. Faster overall continence recovery within 1 month after the surgery was noted in the RS group (61% vs. 43%; p = 0.004). PSMs of pT2 and pT3 stages were not significantly different between the groups (10.0% vs. 7.4%; p = 0.39 and 13.1% vs. 9.5%, p = 0.56, respectively). Of all the studies, only one reported sexual recovery outcomes after RS treatment in which 40% of the participants achieved sexual intercourse within the first month. CONCLUSION: Though more technically demanding than the conventional RARP, the RS technique is a safe and feasible approach. This meta-analysis and literature review indicates that RS technique, as opposed to the conventional approach, is associated with a faster continence recovery while PSMs were comparable between the two groups. The limitations of observational studies and the small data in our meta-analysis may prevent an ultimate conclusion. Future well-designed RCTs are needed to validate and confirm our findings.

Melatonin protects circulatory death heart from ischemia/reperfusion injury via the JAK2/STAT3 signalling pathway.

AIMS: The shortage of donor hearts could be alleviated with the use of the allografts from donation after circulatory death (DCD). Here, we evaluated the protective effect of melatonin on myocardial ischemia/reperfusion (MI/R) injury in a DCD heart model after ex vivo perfusion. MAIN METHODS: Donor hearts were harvested from DCD model rats pre-treated with or without melatonin and subjected to 30 min of ex vivo perfusion, followed by transplantation. Tissue samples were obtained at 3, 12, and 24 h after heart transplantation. Myocardial oedema was evaluated based on the water content and wet/dry ratio, while inflammation was examined with hematoxylin & eosin staining. The expression levels of matrix metalloproteinase-9, interleukin-6, and tumour necrosis factor-α were evaluated. Oxidative stress level was determined from the content of malondialdehyde, activities of superoxide dismutase and glutathione peroxidase, and expression of Nrf2, NQO1 and cytochrome-C. Myocardial apoptosis was detected with TUNEL assay and measurement of the expression levels of Bax, Bcl-2, caspase-3, and cleaved caspase-3. The activation of the JAK2/STAT3 signalling pathway was evaluated by determining the levels of p-JAK2 and p-STAT3. KEY FINDINGS: Melatonin pre-treatment protected the heart from MI/R by reducing myocardial oedema and inflammation, attenuating oxidative stress, and decreasing myocardial apoptosis. Furthermore, the JAK2/STAT3 signalling pathway was activated after melatonin treatment during MI/R. The protective effects of melatonin were abolished by AG490. SIGNIFICANCE: Melatonin pre-treatment protected the heart from MI/R in a DCD heart model after ex vivo perfusion. Melatonin exerted cardioprotective effects through the activation of the JAK2/STAT3 signalling pathway.

Trop2 Guarantees Cardioprotective Effects of Cortical Bone-Derived Stem Cells on Myocardial Ischemia/Reperfusion Injury.

Stem cell transplantation represents a promising therapeutic approach for myocardial ischemia/reperfusion (I/R) injury, where cortical bone-derived stem cells (CBSCs) stand out and hold superior cardioprotective effects on myocardial infarction than other types of stem cells. However, the molecular mechanism underlying CBSCs function on myocardial I/R injury is poorly understood. In a previous study, we reported that Trop2 (trophoblast cell-surface antigen 2) is expressed exclusively on the CBSCs membrane, and is involved in regulation of proliferation and differentiation of CBSCs. In this study, we found that the Trop2 is essential for the ameliorative effects of CBSCs on myocardial I/R-induced heart damage via promoting angiogenesis and inhibiting cardiomyocytes apoptosis in a paracrine manner. Trop2 is required for the colonization of CBSCs in recipient hearts. When Trop2 was knocked out, CBSCs largely lost their functions in lowering myocardial infarction size, improving heart function, enhancing capillary density, and suppressing myocardial cell death. Mechanistically, activating the AKT/GSK3ß/ß-Catenin signaling axis contributes to the essential role of Trop2 in CBSCs-rendered cardioprotective effects on myocardial I/R injury. In conclusion, maintaining the expression and/or activation of Trop2 in CBSCs might be a promising strategy for treating myocardial infarction, I/R injury, and other related heart diseases.

EZH2 inhibits autophagic cell death of aortic vascular smooth muscle cells to affect aortic dissection.

Enhancer of zeste homolog 2 (EZH2), a methyltransferase that di- and tri-methylates lysine-27 of histone H3, largely functions as a transcriptional repressor, and plays a critical role in various kinds of cancers. Here we report a novel function of EZH2 in regulating autophagic cell death (ACD) of vascular smooth muscle cells (VSMCs) that affect aortic dissection (AD). Inhibition of EZH2 activity by UNC1999 or knockdown EZH2 resulted in VSMC loss, while overexpression of EZH2 facilitated VSMC growth, and these effects of EZH2 on VSMCs were independent of proliferation and apoptosis. Interestingly, more autophagic vacuoles and increased LC3II protein levels were identified in VSMCs with EZH2 inhibition or deficiency. Moreover, when compared with counterparts, chloroquine alone, or chloroquine with rapamycin treatment led to more LC3II accumulation in EZH2 inhibited or knockdown VSMCs, which indicated that EZH2 negatively regulated autophagosome formation. In conjunction to this, ATG5 and ATG7 protein levels were remarkably increased in EZH2 inhibited or deficient VSMCs, and ATG5 or ATG7 knockdown virtually rescued VSMC loss induced by EZH2 inhibition or knockdown. In addition, we found that the MEK-ERK1/2 signaling pathway, but not AMPKα, mTOR, or AKT pathway, is responsible for the impact of EZH2 on ACD of VSMCs. Additionally, the adverse effects of EZH2 inhibition or knockdown on VSMCs were largely reversed by PD98059, an inhibitor of MEK1. More importantly, decreased EZH2 expression levels in the aortic wall of patients with AD indicated its contribution to VSMC loss and AD occurrence. Overall, these findings revealed that EZH2 affects ACD of VSMCs and the pathologic process of AD via regulating ATG5 and ATG7 expression and MEK-ERK1/2 signaling. Our hitherto unrecognized findings indicate that EZH2 activation has therapeutic or preventive potential for AD.

CDKN1C (P57): one of the determinants of human endometrial stromal cell decidualization.

Decidualization is regulated by crosstalk of progesterone and the cAMP pathway. It involves extensive reprogramming of gene expression and includes a wide range of functions. To investigate how cell cycle regulatory genes drive the human endometrial stromal cell (ESC) exit cell cycle and enter differentiation, primary cultured ESC was treated with 8-Br-cAMP and MPA and cell cycle distribution was investigated by flow cytometry. High-throughput cell cycle regulatory gene expression was also studied by microarray. To validate the results of microarray chip, immunohistochemistry and semi-quantitative method of optical density were used to analyze the expression of cell cycle regulator proteins in proliferative phase of endometrium (n = 6) and early pregnancy decidua (n = 6). In addition, we selected cyclin-dependent kinase inhibitor 1c (CDKN1C, also known as P57) and cyclin-dependent kinase inhibitor 2b (CDKN2B, also known as P15) in order to study their role in the process of decidualization by the RNAi method. ESC was arrested at G0/G1 checkpoints during decidualization. Cell cycle regulatory genes P57 and P15 were upregulated, while cyclin D1 (CCND1), cyclin-dependent kinase 2 (CDK2), and cell division cycle protein 2 homolog (CDC2) were downregulated during ESC differentiation both in vitro and vivo. P57 siRNA impaired ESC decidualization and caused different morphological and ultrastructural changes as well as a relatively low secretion of prolactin, but P15 siRNA had no effects. We concluded that P15, CCND1, CDK2, and CDC2 may participate in ESC withdraw from the cell cycle and go into differentiation both in vitro and in vivo. P57 is one of the key determinants of ESC differentiation due to its effect on the cell cycle distribution, but its association with the decidua-specific transcription factor needs further investigation.