miR-26b-5p regulates hypoxia-induced phenotypic switching of vascular smooth muscle cells via the TGF-β/Smad4 signaling pathway

Endothelin-1 potentiated constriction in preeclampsia placental veins: Role of ETAR/ETBR/CaV1.2/CALD1

BACKGROUND

Placenta plays a vital role in preeclampsia. The present study investigated the role of endothelin-1 (ET-1) and its receptors in preeclampsia placenta.

METHOD

Placenta samples were collected from normal and preeclampsia pregnancies, with one single fetus. Placental chorionic plate vessel tone was measured with DMT using vasoactive agents with or without antagonists. Role of L-type voltage-dependent calcium channels (CaV1.2) in single smooth muscle cell was detected using whole-cell patch clamp. PCR, Western blot, and ELISA was used to detect molecule expressions. Placental vessel explants and human umbilical vein smooth muscle cell (HUVSMC) were exposed to ET-1 treatment with or without antagonists. Human umbilical vein endothelial cell (HUVEC) and pregnant sheep was exposed to hypoxic condition, simulating preeclampsia.

RESULTS

ET-1 and IRL1620 mediated stronger contractions in preeclampsia placental veins, despite unchanged ETAR and decreased ETBR expression. Comparing with control, there was higher ET-1 in umbilical plasma, maternal plasma, and placental vessels from preeclampsia. In utero hypoxia increased plasma ET-1 in fetal lambs and ewes. Hypoxia promoted ET-1 production in HUVEC. Role and expression of CaV1.2 was decreased in preeclampsia placental vessels, while high-molecular-weight caldesmon (CALD1), the marker of contractile phenotype of smooth muscle cells, was significantly increased. ET-1 treatment increased CALD1 in placental explants and in HUVSMC via ETAR/ETBR.

CONCLUSION

The present study firstly demonstrated ET-1 induced greater contraction in preeclampsia placental chorionic plate veins via ETAR/ETBR, instead of via weaker CaV1.2. In utero hypoxia promoted plasma ET-1 in fetal lambs and ewe, similar to that in preeclampsia. ET-1, binding with ETAR/ETBR increased CALD1, which was associated with stronger contraction in preeclampsia. The data provided important information in preeclampsia onset.

Pharmacological and molecular mechanisms of miRNA-based therapies for targeting cardiovascular dysfunction

Advances in understanding gene expression regulation through epigenetic mechanisms have contributed to elucidating the regulatory mechanisms of noncoding RNAs as pharmacological targets in several diseases. MicroRNAs (miRs) are a class of evolutionarily conserved, short, noncoding RNAs regulating in a concerted manner gene expression at the post-transcriptional level by targeting specific sequences of the 3'-untranslated region of mRNA. Conversely, mechanisms of cardiovascular disease (CVD) remain largely elusive due to their life-course origins, multifactorial pathophysiology, and co-morbidities. In this regard, CVD treatment with conventional medications results in therapeutic failure due to progressive resistance to monotherapy, which overlooks the multiple factors involved, and reduced adherence to poly-pharmacology approaches. Consequently, considering its role in regulating complete gene pathways, miR-based drugs have appreciably progressed into preclinical and clinical testing. This review summarizes the current knowledge about the mechanisms of miRs in cardiovascular disease, focusing specifically on describing how clinical chemistry and physics have improved the stability of the miR molecule. In addition, a comprehensive review of the main miRs involved in cardiovascular disease and the clinical trials in which these molecules are used as active pharmacological molecules is provided.

GATA2‑miR‑374a axis promotes vascular smooth muscle cells proliferation, migration via targeting circTADA2A/RORA axis

Evidence has shown that microRNAs (miRNAs/miRs) play key roles in biological functions of vascular smooth muscle cells (VSMCs). However, the role of miR-374a in VSMCs remains to be elucidated. The present study aimed to explore the influence of miR-374a on VSMCs and its molecular mechanism. The expression level of miR-374a was measured by reverse transcription-quantitative (RT-q) PCR. MTT and Transwell assay were employed to assess the role of miR-374a in proliferation and migration of VSMCs. To order to determine miR-374a targets, a dual-luciferase reporter assay was conducted, which was further verified by rescue experiments. Chromatin Immunoprecipitation Assay and JASPAR databases were applied to explore the regulatory association between GATA binding protein 2 (GATA2) and miR-374a. Western blotting or RT-qPCR were employed to detect the protein expression levels of GATA2 or RAR-related orphan receptor A (RORA). The present study found that miR-374a was elevated in VSMCs following treatment with platelet-derived growth factor-BB (PDGF-BB) compared with that in control group. In addition, the results demonstrated that a higher expression of a miR-374a could promote proliferation and migration of VSMCs while miR-374a inhibitor suppressed the PDGF-BB-induced proliferation and migration of VSMCs in vitro. Furthermore, circTADA2A bound to miR-374a and then upregulated RORA expression, which resulted in inhibition in VSMCs proliferation and migration. On the other hand, the result indicated that GATA2 overexpression could augment the proliferation, migration of PDGF-bb-induced VSMCs, which could be rescued by miR-374a inhibitor. The findings suggested that the GATA2/circTADA2A-miR-374a axis promoted the proliferation and migration of VSMCs by targeting RORA, which were closely related to atherosclerosis (AS). Thus the results might offer a new therapeutic target for AS.

Study on the Regulatory Mechanism of the PDK1-Mediated TGF-β/Smad Signaling Pathway in Hypoxia-Induced Yak Lungs

The aim of this study was to investigate the effects of hypoxia-induced phenotype, glucose metabolism, ROS levels, and the PDK1-mediated regulation of TGF-β/Smad signaling in yellow cattles, yaks, and those overexpressing PDK1 PASMCs using growth curves, flow cytometry, scratch experiments, glucose and lactic acid assays, RT-qPCR, and Western blotting. The results showed that hypoxia significantly promoted proliferation, migration, antiapoptosis, ROS levels, glucose consumption, and lactate production in yellow cattle PASMCs (p < 0.05), and the cells were dedifferentiated from the contractile phenotype; conversely, hypoxia had no significant effect on yak PASMCs (p > 0.05). PDK1 overexpression significantly promoted proliferation, antiapoptosis, glucose consumption, and lactate production in yak PASMCs under normoxia and hypoxia (p < 0.05), decreased their migration levels under hypoxia (p < 0.05), and dedifferentiated the contractile phenotype of the cells. Overexpression of PDK1 in yak PASMCs is detrimental to their adaptation to hypoxic environments. Yak PASMCs adapted to the effects of hypoxia on lung tissue by downregulating the expression of genes related to the PDK1 and TGF-β/Smad signaling pathways. Taken together, the regulation of PDK1-mediated TGF-β/Smad signaling may be involved in the process of yaks' adaptation to the hypoxic environment of the plateau, reflecting the good adaptive ability of yaks. The present study provides basic information to further elucidate the mechanism of PDK1-mediated TGF-β/Smad signaling induced by hypoxia in the lungs of yaks, as well as target genes for the treatment of plateau diseases in humans and animals.

LXRα Promotes Abdominal Aortic Aneurysm Formation Through UHRF1 Epigenetic Modification of miR-26b-3p

BACKGROUND

Abdominal aortic aneurysm (AAA) is a severe aortic disease without effective pharmacological approaches. The nuclear hormone receptor LXRα (liver X receptor α), encoded by the NR1H3 gene, serves as a critical transcriptional mediator linked to several vascular pathologies, but its role in AAA remains elusive.

METHODS

Through integrated analyses of human and murine AAA gene expression microarray data sets, we identified NR1H3 as a candidate gene regulating AAA formation. To investigate the role of LXRα in AAA formation, we used global Nr1h3-knockout and vascular smooth muscle cell-specific Nr1h3-knockout mice in 2 AAA mouse models induced with angiotensin II (1000 ng·kg·min; 28 days) or calcium chloride (CaCl2; 0.5 mol/L; 42 days).

RESULTS

Upregulated LXRα was observed in the aortas of patients with AAA and in angiotensin II- or CaCl2-treated mice. Global or vascular smooth muscle cell-specific Nr1h3 knockout inhibited AAA formation in 2 mouse models. Loss of LXRα function prevented extracellular matrix degeneration, inflammation, and vascular smooth muscle cell phenotypic switching. Uhrf1, an epigenetic master regulator, was identified as a direct target gene of LXRα by integrated analysis of transcriptome sequencing and chromatin immunoprecipitation sequencing. Susceptibility to AAA development was consistently enhanced by UHRF1 (ubiquitin-like containing PHD and RING finger domains 1) in both angiotensin II- and CaCl2-induced mouse models. We then determined the CpG methylation status and promoter accessibility of UHRF1-mediated genes using CUT&Tag (cleavage under targets and tagmentation), RRBS (reduced representation bisulfite sequencing), and ATAC-seq (assay for transposase-accessible chromatin with sequencing) in vascular smooth muscle cells, which revealed that the recruitment of UHRF1 to the promoter of miR-26b led to DNA hypermethylation accompanied by relatively closed chromatin states, and caused downregulation of miR-26b expression in AAA. Regarding clinical significance, we found that underexpression of miR-26b-3p correlated with high risk in patients with AAA. Maintaining miR-26b-3p expression prevented AAA progression and alleviated the overall pathological process.

CONCLUSIONS

Our study reveals a pivotal role of the LXRα/UHRF1/miR-26b-3p axis in AAA and provides potential biomarkers and therapeutic targets for AAA.

Multi-omics in thoracic aortic aneurysm: the complex road to the simplification

BACKGROUND

Thoracic aortic aneurysm (TAA) is a serious condition that affects the aorta, characterized by the dilation of its first segment. The causes of TAA (e.g., age, hypertension, genetic syndromes) are heterogeneous and contribute to the weakening of the aortic wall. This complexity makes treating this life-threatening aortopathy challenging, as there are currently no etiological therapy available, and pharmacological strategies, aimed at avoiding surgical aortic replacement, are merely palliative. Recent studies on novel therapies for TAA have focused on identifying biological targets and etiological mechanisms of the disease by using advanced -omics techniques, including epigenomics, transcriptomics, proteomics, and metabolomics approaches.

METHODS

This review presents the latest findings from -omics approaches and underscores the importance of integrating multi-omics data to gain more comprehensive understanding of TAA.

RESULTS

Literature suggests that the alterations in TAA mediators frequently involve members of pro-fibrotic process (i.e., TGF-β signaling pathways) or proteins associated with cell/extracellular structures (e.g., aggrecans). Further analyses often reported the importance in TAA of processes as inflammation (PCR, CD3, leukotriene compounds), oxidative stress (chromatin OXPHOS, fatty acids), mitochondrial respiration and glycolysis/gluconeogenesis (e.g., PPARs and HIF1a). Of note, more recent metabolomics studies added novel molecular markers to the list of TAA-specific detrimental mediators (proteoglycans).

CONCLUSION

It is increasingly clear that integrating data from different -omics branches, along with clinical data, is essential as well as complicated both to reveal hidden relevant information and to address complex diseases such as TAA. Importantly, recent progresses in metabolomics highlighted novel potential and unprecedented marks in TAA diagnosis and therapy.

METTL14/YTHDF1 axis-modified UCHL5 aggravates atherosclerosis by activating the NLRP3 inflammasome

BACKGROUND

Vascular smooth muscle cell (VSMC) phenotypic switching contributes to VSMC proliferation and migration in atherosclerosis (AS). Nevertheless, the regulatory mechanism of VSMC phenotypic switching during AS progression is unclear. Here, the role and regulatory mechanism of UCHL5 in VSMC phenotypic switching during AS progression were investigated.

METHODS

ApoE^-/- mice were fed with high fat diet to establish AS model in vivo. VSMCs stimulated by ox-LDL were used as AS cellular model. VSMC proliferation and migration were examined by CCK8 assay and transwell assay, respectively. The levels of pro-inflammatory cytokines were assessed using ELISA. The interactions between METTL14/YTHDF1, UCHL5 and NLRP3 were analyzed using RIP and/or dual-luciferase reporter gene and/or Co-IP assays. NLRP3 ubiquitination was analyzed by ubiquitination analysis.

RESULTS

UCHL5 was significantly upregulated in AS patients and ox-LDL-treated VSMCs. UCHL5 silencing ameliorated plaque formation and vascular remodeling in vivo and suppressed ox-LDL-induced VSMC proliferation, migration, inflammation and phenotypic switching in vitro. Moreover, METTL14 could increase UCHL5 mRNA m⁶A level and promoted UCHL5 expression by recruiting YTHDF1. Moreover, UCHL5 overexpression enhanced protein stability by deubiquitinating NLRP3. Rescue studies revealed that NLRP3 overexpression abrogated UCHL5 silencing-mediated biological effects in ox-LDL-treated VSMCs.

CONCLUSION

UCHL5 modified by METTL14/YTHDF1 axis could facilitate the inflammation and vascular remodeling in atherosclerosis by activating the NLRP3 inflammasome.

circHECTD1 Promotes the Proliferation and Migration of Human Brain Vascular Smooth Muscle Cells via Interacting with KHDRBS3 to Stabilize EZH2 mRNA Expression

Purpose

The objective of this paper is to explore the role of circHECTD1 in vascular smooth muscle cells (VSMCs) and atherosclerosis (AS).

Methods

VSMCs were treated with platelet-derived growth factor-BB (PDGF-BB) in vitro, and the level of circHECTD1 was determined using qRT-PCR. Cell proliferation, migration, and invasion were analyzed using CCK8 and transwell assays. Cell apoptosis and cell cycle were analyzed using flow cytometry. The binding interaction between circHECTD1 and KHDRBS3 or EZH2 was investigated using the RIP, RNA pull-down.

Results

CircHECTD1 was upregulated in PDGF-BB-induced VSMCs with a dose-dependent and time-dependent manner. Knockdown of circHECTD1 suppressed VSMCsproliferation and migration and enhanced cell apoptosis in VSMCs, while circHECTD1 overexpression yielded opposite effects. Mechanistically, circHECTD1 could interact with KHDRBS3, thus enhanced the stability of EZH2 mRNA and increased EZH2 protein level. In addition, silencing EZH2 in VSMCs reversed the proliferation-enhancing effect of circHECTD1 overexpression.

Conclusion

Our findings provided providing a potential prognostic and therapy biomarker for AS.

Research progress on the mechanism of phenotypic transformation of pulmonary artery smooth muscle cells induced by hypoxia

Phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) is a key factor in pulmonary vascular remodeling. Inhibiting or reversing phenotypic transformation can inhibit pulmonary vascular remodeling and control the progression of hypoxic pulmonary hypertension. Recent studies have shown that hypoxia causes intracellular peroxide metabolism to induce oxidative stress, induces multi-pathway signal transduction, including those related to autophagy, endoplasmic reticulum stress and mitochondrial dysfunction, and also induces non-coding RNA regulation of cell marker protein expression, resulting in PASMCs phenotypic transformation. This article reviews recent research progress on mechanisms of hypoxia-induced phenotypic transformation of PASMCs, which may be helpful for finding targets to inhibit phenotypic transformation and to improve pulmonary vascular remodeling diseases such as hypoxia-induced pulmonary hypertension.

Mechanism of Hypoxia-Mediated Smooth Muscle Cell Proliferation Leading to Vascular Remodeling

Vascular remodeling refers to changes in the size, contraction, distribution, and flow rate of blood vessels and even changes in vascular function. Vascular remodeling can cause cardiovascular and cerebrovascular diseases. It can also lead to other systemic diseases, such as pulmonary hypertension, pulmonary atherosclerosis, chronic obstructive pulmonary disease, stroke, and ascites of broilers. Hypoxia is one of the main causes of vascular remodeling. Prolonged hypoxia or intermittent hypoxia can lead to loss of lung ventilation, causing respiratory depression, irregular respiratory rhythms, and central respiratory failure. Animals that are unable to adapt to the highland environment are also prone to sustained constriction of the small pulmonary arteries, increased resistance to pulmonary circulation, and impaired blood circulation, leading to pulmonary hypertension and right heart failure if they live in a highland environment for long periods of time. However, limited studies have been found on the relationship between hypoxia and vascular remodeling. Therefore, this review will explore the relationship between hypoxia and vascular remodeling from the aspects of endoplasmic reticulum stress, mitochondrial dysfunction, abnormal calcium channel, disordered cellular metabolism, abnormal expression of miRNA, and other factors. This will help to understand the detailed mechanism of hypoxia-mediated smooth muscle cell proliferation and vascular remodeling for the better treatment and management of diseases due to vascular remodeling.

MicroRNA-26b-5p alleviates cerebral ischemia-reperfusion injury in rats via inhibiting the N-myc/PTEN axis by downregulating KLF10 expression

MicroRNAs plays important role in cerebral ischemia-reperfusion (CIR). However, the role of miR-26b-5p in CIR injury remains unclear. PC12 cells were treated with oxygen-glucose deprivation (OGD) for 0 h, 2 h, 4 h, 6 h, and then reoxygenated for 24 h to construct an in vitro I/R model. Then, miR-26b-5p mimic, small interfering RNA of KLF10 and KLF10 overexpression plasmid were transfected into cells respectively for mechanism study. Our results showed that miR-26b-5p was downregulated in OGD/R-induced PC12 cells. After overexpression of miR-26b-5p, cell proliferation ability was enhanced, apoptosis, ROS and inflammatory mediators were inhibited. Bioinformatics analysis indicated that miR-26b-5p was directly bound to the 3' UTR of KLF10, and downregulated the expression of KLF10. KLF10 was upregulated in OGD/R cells, and transfection with si-KLF10 promoted cell proliferation and reduced apoptosis, NO concentration and inflammatory factor secretion. Moreover, pcDNA-KLF10 reversed the inhibitory effects of miR-26b-5p mimic on apoptosis, NO content and inflammatory factor secretion, as well as the downregulation of N-myc and PTEN expression. Meanwhile, I/R rat models were constructed and divided into sham operation group (femoral artery isolation only), model group (middle cerebral artery occlusion model of rats was prepared by thread embolization), treatment group (200 µL of miR-26b-5p mimic was injected into the brain of model rats). We observed that the infarct size of brain tissue was reduced, KLF10 expression was downregulated, and apoptosis and inflammatory response were reduced. These results suggest that miR-26b-5p had protective effects on CIRI and it may be a potential treatment target.

Comparison of Cardiac miRNA Transcriptomes Induced by Diabetes and Rapamycin Treatment and Identification of a Rapamycin-Associated Cardiac MicroRNA Signature

Rapamycin (Rap), an inhibitor of mTORC1, reduces obesity and improves lifespan in mice. However, hyperglycemia and lipid disorders are adverse side effects in patients receiving Rap treatment. We previously reported that diabetes induces pansuppression of cardiac cytokines in Zucker obese rats (ZO-C). Rap treatment (750 μg/kg/day for 12 weeks) reduced their obesity and cardiac fibrosis significantly; however, it increased their hyperglycemia and did not improve their cardiac diastolic parameters. Moreover, Rap treatment of healthy Zucker lean rats (ZL-C) induced cardiac fibrosis. Rap-induced changes in ZL-C's cardiac cytokine profile shared similarities with that of diabetes-induced ZO-C. Therefore, we hypothesized that the cardiac microRNA transcriptome induced by diabetes and Rap treatment could share similarities. Here, we compared the cardiac miRNA transcriptome of ZL-C to ZO-C, Rap-treated ZL (ZL-Rap), and ZO (ZO-Rap). We report that 80% of diabetes-induced miRNA transcriptome (40 differentially expressed miRNAs by minimum 1.5-fold in ZO-C versus ZL-C; p ≤ 0.05) is similar to 47% of Rap-induced miRNA transcriptome in ZL (68 differentially expressed miRNAs by minimum 1.5-fold in ZL-Rap versus ZL-C; p ≤ 0.05). This remarkable similarity between diabetes-induced and Rap-induced cardiac microRNA transcriptome underscores the role of miRNAs in Rap-induced insulin resistance. We also show that Rap treatment altered the expression of the same 17 miRNAs in ZL and ZO hearts indicating that these 17 miRNAs comprise a unique Rap-induced cardiac miRNA signature. Interestingly, only four miRNAs were significantly differentially expressed between ZO-C and ZO-Rap, indicating that, unlike the nondiabetic heart, Rap did not substantially change the miRNA transcriptome in the diabetic heart. In silico analyses showed that (a) mRNA-miRNA interactions exist between differentially expressed cardiac cytokines and miRNAs, (b) human orthologs of rat miRNAs that are strongly correlated with cardiac fibrosis may modulate profibrotic TGF-β signaling, and (c) changes in miRNA transcriptome caused by diabetes or Rap treatment include cardioprotective miRNAs indicating a concurrent activation of an adaptive mechanism to protect the heart in conditions that exacerbate diabetes.

Antioxidant Activity Mediates Pirfenidone Antifibrotic Effects in Human Pulmonary Vascular Smooth Muscle Cells Exposed to Sera of Idiopathic Pulmonary Fibrosis Patients

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by an exacerbated fibrotic response. Although molecular and cellular determinants involved in the onset and progression of this devastating disease are largely unknown, an aberrant remodeling of the pulmonary vasculature appears to have implications in IPF pathogenesis. Here, we demonstrated for the first time that an increase of reactive oxygen species (ROS) generation induced by sera from IPF patients drives both collagen type I deposition and proliferation of primary human pulmonary artery smooth muscle cells (HPASMCs). IPF sera-induced cellular effects were significantly blunted in cells exposed to the NADPH oxidase inhibitor diphenyleneiodonium (DPI) proving the causative role of ROS and suggesting their potential cellular source. Contrary to IPF naive patients, sera from Pirfenidone-treated IPF patients failed to significantly induce both ROS generation and collagen synthesis in HPASMCs, mechanistically implicating antioxidant properties as the basis for the in vivo effect of this drug.