SMYD2-Methylated PPARγ Facilitates Hypoxia-Induced Pulmonary Hypertension by Activating Mitophagy.

BACKGROUND: Hyperproliferation of pulmonary arterial smooth muscle cells (PASMCs) and consequent pulmonary vascular remodeling are the crucial pathological features of pulmonary hypertension (PH). Protein methylation has been shown to be critically involved in PASMC proliferation and PH, but the underlying mechanism remains largely unknown. METHODS: PH animal models were generated by treating mice/rats with chronic hypoxia for 4 weeks. SMYD2-vTg mice (vascular smooth muscle cell-specific suppressor of variegation, enhancer of zeste, trithorax and myeloid Nervy DEAF-1 (deformed epidural auto-regulatory factor-1) domain-containing protein 2 transgenic) or wild-type rats and mice treated with LLY-507 (3-cyano-5-{2-[4-[2-(3-methylindol-1-yl)ethyl]piperazin-1-yl]-phenyl}-N-[(3-pyrrolidin-1-yl)propyl]benzamide) were used to investigate the function of SMYD2 (suppressor of variegation, enhancer of zeste, trithorax and myeloid Nervy DEAF-1 domain-containing protein 2) on PH development in vivo. Primary cultured rat PASMCs with SMYD2 knockdown or overexpression were used to explore the effects of SMYD2 on proliferation and to decipher the underlying mechanism. RESULTS: We demonstrated that the expression of the lysine methyltransferase SMYD2 was upregulated in the smooth muscle cells of pulmonary arteries from patients with PH and hypoxia-exposed rats/mice and in the cytoplasm of hypoxia-induced rat PASMCs. More importantly, targeted inhibition of SMYD2 by LLY-507 significantly attenuated hypoxia-induced pulmonary vascular remodeling and PH development in both male and female rats in vivo and reduced rat PASMC hyperproliferation in vitro. In contrast, SMYD2-vTg mice exhibited more severe PH phenotypes and related pathological changes than nontransgenic mice after 4 weeks of chronic hypoxia treatment. Furthermore, SMYD2 overexpression promoted, while SMYD2 knockdown suppressed, the proliferation of rat PASMCs by affecting the cell cycle checkpoint between S and G2 phases. Mechanistically, we revealed that SMYD2 directly interacted with and monomethylated PPARγ (peroxisome proliferator-activated receptor gamma) to inhibit the nuclear translocation and transcriptional activity of PPARγ, which further promoted mitophagy to facilitate PASMC proliferation and PH development. Furthermore, rosiglitazone, a PPARγ agonist, largely abolished the detrimental effects of SMYD2 overexpression on PASMC proliferation and PH. CONCLUSIONS: Our results demonstrated that SMYD2 monomethylates nonhistone PPARγ and inhibits its nuclear translocation and activation to accelerate PASMC proliferation and PH by triggering mitophagy, indicating that targeting SMYD2 or activating PPARγ are potential strategies for the prevention of PH.

Nuclear Paraspeckle Assembly Transcript 1 Enhances Hydrogen Peroxide-Induced Human Vascular Smooth Muscle Cell Injury by Regulating miR-30d-5p/A Disintegrin and Metalloprotease 10.

BACKGROUND: Nuclear paraspeckle assembly transcript 1 (NEAT1) has been reported to be involved in the progression of many cancers; however, the role and mechanisms underlying NEAT1 in abdominal aortic aneurysm (AAA) remain unclear.Methods and Results: The expression of NEAT1, miR-30d-5p and A disintegrin and metalloprotease 10 (ADAM10) was measured by qRT-PCR and western blot. Functional experiments were conducted by using a CCK-8 assay, EDU assay, flow cytometry, western blot, ELISA, and commercial kits. The target relation was confirmed by dual-luciferase reporter assay and the RIP assay. It was then found that NEAT1 was upregulated in peripheral blood of AAA patients ~3.46-fold, smooth muscle cells (SMCs) isolated from AAA tissues ~2.6-fold and in a hydrogen peroxide (H2O2)-induced injury model of human vascular SMC (HVSMCs) ~2.0- and 3.9-fold at 50 µmol/L and 200 µmol/L H2O2treatment, respectively. NEAT1 deletion attenuated H2O2-induced cell proliferation promotion (40.0% vs. 74.3%), apoptosis inhibition (25.0% vs. 13.5%), and reduction of inflammatory response and oxidative stress in HVSMCs. Mechanistically, NEAT1 targeted miR-30d-5p to prevent the degradation of its target, ADAM10, in HVSMCs. Further rescue experiments suggested miR-30d-5p inhibition mitigated the effects of NEAT1 deletion on H2O2-induced HVSMCs. Moreover, ADAM10 overexpression counteracted the inhibitory functions of miR-30d-5p on H2O2-evoked HVSMC injury. CONCLUSIONS: NEAT1 promoted H2O2-induced HVSMC injury by inducing cell apoptosis, inflammation and oxidative stress through miR-30d-5p/ADAM10 axis, indicating the possible involvement of NEAT1 in the pathogenesis of AAA.

Characterization of winter PM2.5 source contributions and impacts of meteorological conditions and anthropogenic emission changes in the Sichuan Basin, 2002-2020.

In this study, the Weather Research and Forecasting (WRF) model and Community Multiscale Air Quality-Integrated Source Apportionment Method (CMAQ-ISAM) were utilized, which were integrated with the Multiresolution Emission Inventory for China (MEIC) emission inventory, to simulate winter PM2.5 concentrations, regional transport, and changes in emission source contributions in the Sichuan basin (SCB) from 2002 to 2020, considering variations in meteorological conditions and anthropogenic emissions. The results indicated a gradual decrease in the basin's winter average PM2.5 concentration from 300 µg/m3 to 120 µg/m3, with the most significant decrease occurring after 2014, reflecting the actual impact of China's air pollution control measures. Spatially, the main pollution area shifted from Chongqing to Chengdu and the western basin. The sources of PM2.5 at the eastern and western margins of the basin have remained stable and have been dominated by local emissions for many years, while the sources of PM2.5 in the central part of the basin have evolved from a multiregional co-influenced source during the early period to a high proportion of local emissions; except for boundary condition sources, residential sources were the main PM2.5 sources in the basin (approximately 29.70 %), followed by industrial sources (approximately 14.11 %). Industrial sources exhibited higher contributions in Chengdu and Chongqing and gradually stabilized with residential sources over the years, while residential sources dominated in the eastern and western parts of the basin and exhibited a declining trend. Meteorological conditions exacerbated pollution in the whole basin from 2008 to 2014, especially in the west (21-40 µg/m3). The eastern basin and Chongqing exhibited more years with alleviated meteorological pollution, including a 40+ µg/m3 decrease in Chongqing from 2002 to 2005. Reduced anthropogenic emissions alleviated annual pollution levels, with a greater reduction (> -20 µg/m3) after 2011 due to pollution control measures.

Metallothionein 3 Potentiates Pulmonary Artery Smooth Muscle Cell Proliferation by Promoting Zinc-MTF1-ATG5 Axis-mediated Autophagosome Formation.

Abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is one of the critical pathological mechanisms of pulmonary hypertension (PH), and therefore is gradually being adopted as an important direction for the treatment of PH. Metallothioneins (MTs) have been reported to be associated with PH, but the underlying mechanisms are not fully understood. Here, we demonstrated that the expression level of metallothionein 3 (MT3) was significantly increased in pulmonary arterioles from PH patients and chronic hypoxia-induced rat and mouse PH models, as well as in hypoxia-treated human PASMCs. Knockdown of MT3 significantly inhibited the proliferation of human PASMCs by arresting the cell cycle in the G1 phase, while overexpression of MT3 had the opposite effect. Mechanistically, we found that MT3 increased the intracellular zinc (Zn2+) concentration to enhance the transcriptional activity of metal-regulated transcription factor 1 (MTF1), which promoted the expression of autophagy-related gene 5 (ATG5), facilitating autophagosome formation. More importantly, MT3-induced autophagy and proliferation of human PASMCs were largely prevented by knockdown of MTF1 and ATG5. Therefore, in this study, we identified MT3-Zinc-MTF1-ATG5 as a novel pathway that affects PASMC proliferation by regulating autophagosome formation, suggesting that MT3 may be a novel target for the treatment of PH.

Branching externalized guidewire to facilitate retrograde endograft deployment in the hybrid aortic repair with aortic valve replacement.

Background: The hybrid aortic repair consisting of root replacement and endovascular arch repair is an optimal alternative for patients unfit for circulatory arrest. However, an artificial aortic valve prosthesis might impede the endovascular procedure. This study aims to present our experience with the branching retrograde externalized guidewire (BREG) technique in such situations, and discuss its utility and efficiency. Methods: From January 2015 to June 2021, a total of 112 patients underwent aortic root/valve replacement combined with aortic arch repair. Among them, the BREG technique was adopted on 24 patients, and the traditional frozen elephant trunk (FET) technique was used for 88 patients. The indication of the BREG was as follows: high-risk patients not suitable for traditional open surgery; meanwhile, the aortic disease required extended repair, and the aortic valve needed to be replaced concomitantly. The data of the 2 groups were compared. Results: The cardiopulmonary bypass time (213.5 ± 73.6 min vs. 246.5 ± 46.2 min, P = 0.046) and cross-clamped time (109.0 ± 27.6 min vs. 139.0 ± 24.6 min, P < 0.001) were significantly shorter in the BREG group than that in the FET group. Less operative red blood cell consumption was achieved in the BREG group (6.6 ± 5.7 vs. 9.4 ± 8.0 U, P = 0.046). The 30-day mortality was similar between the 2 groups (8.3% BREG vs. 9.1% FET, P > 0.999). Conclusion: The BREG technique facilitated the advancement of endovascular stent graft, avoided impeding the aortic valve prosthesis in hybrid aortic surgery with aortic valve replacement, and may benefit high-risk patients.

Surgical treatment of pregnancy complicated with aortic dissection / 中国胸心血管外科临床杂志

@#Objective To summarize the characteristics and management of pregnancy complicated with aortic dissection, and to explore the reasonable diagnosis and treatment plan. Methods The clinical data of 10 patients of pregnancy complicated with aortic dissection in Wuhan Tongji Hospital from January 2011 to June 2017 were collected. Their age was 25.2 (21-29) years. Results In the 10 patients, the majority (8 patients) were primipara, and most of them were in the late stages of pregnancy (5 patients) and puerperal (4 patients). Among them, 1 patient had gestational hypertension, and the blood pressure of the left and right upper extremities was significantly abnormal (initial blood pressure: left upper limb blood pressure: 90/60 mm Hg, right upper limb blood pressure: 150/90 mm Hg). The major clinical manifestations were severe chest and back pain which happened suddenly, with D-dimmer and C-creative protein increased which may be associated with inflammatory reaction. All patients were diagnosed by thoracoabdominal aortic CTA, including 5 patients of Stanford type A dissection and 5 patients of Stanford type B dissection. In the 10 patients, 1 patient refused surgery and eventually died of aortic rupture with the death of fetus before birth. And the remaining 9 patients underwent surgical treatment, 3 patients of endovascular graft exclusion for thoracic aortic stent graft, 2 patients underwent Bentall operation, 1 patient with Bentall + total aortic arch replacement + vascular thoracic aortic stent graft, 1 patient with Bentall operation combined with endovascular graft exclusion for thoracic aortic stent graft, 1 patient with Bentall + coronary artery bypass grafting, 1 patient of thoracoabdominal aortic vascular replacement. Among them, 1 patient underwent endovascular graft exclusion for thoracic aortic stent graft died of severe postoperative infection, and the remaining 8 patients were discharged from hospital. Nine patients were single birth, among them 5 newborn patients had severe asphyxia, 4 patients had mild asphyxia. Finally, 3 neonates died of severe complications, and the remaining 6 survived. Conclusion The ratio of pregnancy with Stanford type A aortic dissection is far higher than in the general population, the possibility of fetal intrauterine asphyxia is larger, but through active and effective surgical and perioperative treatment, we can effectively save the life of mother and fetus.