Qiuwang Zhang

Atherosclerosis, a chronic inflammatory disease of the arteries, is the primary cause of ischemic heart disease and stroke, which are the leading drivers of global mortality and major contributors to disability. Important risk factors for atherosclerosis include insulin resistance (IR), hypertension and hyperlipidemia. IR-induced endothelial dysfunction, inflammation, dyslipidemia, vascular remodeling, and prothrombotic effects represent central mechanistic links between IR and atherosclerosis. In this review, these mechanisms are summarized and discussed by incorporating emerging mechanistic insights into IR-induced trained immunity, tissue-selective IR, and mitochondrial dysfunction, with an emphasis on their contributions to atherosclerosis. Furthermore, emerging therapeutic strategies using mesenchymal stem cells (MSCs) and their exosomes to improve IR are discussed, with a focus on their underlying mechanisms, as well as current challenges and outstanding issues in the field. While the current literature shows promising effects of MSCs and their exosomes in improving IR in cellular and animal models, clinical evidence remains limited. To harness the potential therapeutic benefits of MSCs and their exosomes, standardized manufacturing protocols and optimal routes of administration and dosing need to be determined.

An emerging field in cardiovascular research is the translational investigation of transfer RNA-derived small RNAs (tsRNAs). TsRNAs, a class of small non-coding RNA molecules, have been shown to modulate cellular functions by regulating gene expression post-transcriptionally. They are implicated in diverse pathological conditions, including cancer, cardiovascular disease (CVD), infectious disease, diabetes, neurological disease, and metabolic disorder. Accumulating evidence suggests tsRNAs as important players and biomarkers in CVD. Dysregulated tsRNAs are identified in atherosclerosis, heart failure, hypertension and other types of CVD. Bioinformatics and in vitro experimental analyses reveal that tsRNAs may participate in the regulation of endothelial and inflammatory cell interactions, endothelial cell and vascular smooth muscle cell proliferation and migration, and cardiac metabolism, mitophagy and remodeling, contributing to the pathogenesis of CVD. In addition, altered tsRNAs possess great diagnostic and prognostic potential in CVD. Nevertheless, there are currently no in vivo mechanistic studies using animal models, and the small sizes of reported clinical studies that examined tsRNAs limit their diagnostic and prognostic value. Although of promise, further research is needed to address the utility of tsRNAs in cardiovascular care. Keywords: transfer RNA-derived small RNAs gene regulation cardiovascular disease pathogenesis biomarker

Endothelin-1 (ET-1) plays a critical role in diabetic vasculopathy. Although clinical trials have shown promise for ET-1 receptor antagonists in treating diabetic nephropathy, their clinical use remains limited by adverse effects. MiR-454-3p targets ET-1. This study aimed to investigate the role of miR-454-3p in modulating ET-1 expression and related molecular changes in endothelial cells (ECs) under high glucose conditions using both bioinformatics and experimental approaches. Bioinformatics analysis identified 10 miR-454-3p target genes expressed in ECs previously implicated in diabetic vascular complications: ET-1, GJA1, IRF1, PIK3CB, TRPC3, SLMAP, ESR1, ITGB8, MAPK1, and PPARG. With the exception of PPARG, which protects ECs from hyperglycemia-induced damage, all have been reported to exacerbate endothelial dysfunction. Western blotting showed that high glucose increased ET-1 expression in human umbilical vein ECs (HUVECs) and human dermal microvascular endothelial cells (HDMECs), while miR-454-3p overexpression significantly suppressed this effect in both cell types. Conditioned medium (CM) from HUVECs transfected with miR-454-3p mimics enhanced eNOS expression in recipient cells, compared to control CM. Pre-treatment of HUVEC control CM with an anti-ET-1 antibody also increased eNOS expression, supporting that miR-454-3p promotes NOS production partly via ET-1 suppression. MiR-454-3p overexpression in HUVECs did not affect PPARG expression or cell proliferation. In conclusion, miR-454-3p overexpression inhibits high glucose-induced ET-1 expression in HUVECs and HDMECs, and promotes eNOS production without affecting PPARG expression in HUVECs. Our findings suggest that miR-454-3p modulates ET-1 expression under hyperglycemic conditions in vitro, which may provide a foundation for future studies exploring its potential application in managing diabetic vasculopathy.

MicroRNAs, a class of small non-coding RNA molecules that regulate gene expression post-transcriptionally, are implicated in various pathological conditions including diabetes mellitus (DM). DM has been increasingly recognized as an inflammatory disease and monocytes play a key role in propagating inflammation under hyperglycemic conditions. We hypothesize that high glucose dysregulates microRNAs to promote monocyte inflammatory activity, which may contribute to the pathogenesis of DM. THP-1 monocytes were cultured in normal (5 mM) and high (25 mM) glucose conditions. RT-qPCR and Western blotting were performed to assay microRNAs and proteins, respectively. Monocytes were transfected with microRNA mimics using Lipofectamine RNAiMAX reagent. THP-1 monocyte growth was assessed using Calcein-AM dye and a Boyden chamber assay was applied to measure monocyte migration. The results showed that high glucose downregulated miR-139-5p associated with increased protein expression of CXCR4, an experimentally validated target of miR-139-5p. Correspondingly, treatment with high glucose resulted in a significant increase in THP-1 cell migration towards SDF-1, a cognate ligand for CXCR4. MiR-139-5p overexpression inhibited high glucose-induced CXCR4 expression, leading to reduced cell migration towards SDF-1. High glucose did not affect THP-1 monocyte growth. In conclusion, the miR-139-5p-CXCR4 axis may play a role in high glucose-induced inflammation by regulating monocyte migration.

Background: Thrombosis is a common cause of vascular prosthesis failure. Antibody coating of prostheses to capture circulating endothelial progenitor cells to aid endothelialization on the device surface appears a promising solution to prevent thrombus formation. Compared with random antibody immobilization, oriented antibody coating (OAC) increases antibody-antigen binding capacity and reduces antibody immunogenicity in vivo. Currently, few OAC methods have been documented, with none possessing clinical application potential. Results: Dopamine and the linker amino-PEG8-hydrazide-t-boc were successfully deposited on the surface of cobalt chromium (CC) discs, CC stents and expanded polytetrafluoroethylene (ePTFE) grafts under a slightly basic condition. CD34 antibodies were immobilized through the reaction between aldehydes in the Fc region created by oxidation and hydrazides in the linker after t-boc removal. CD34 antibody-coated surfaces were integral and smooth as shown by scanning electron microscopy (SEM), had significantly reduced or no substrate-specific signals as revealed by X-ray photoelectron spectroscopy, were hospitable for HUVEC growth as demonstrated by cell proliferation assay, and specifically bound CD34 + cells as shown by cell binding testing. CD34 antibody coating turned hydrophobic property of ePTFE grafts to hydrophilic. In a porcine carotid artery interposition model, a confluent monolayer of cobblestone-shaped CD31 + endothelial cells on the luminal surface of the CD34 antibody coated ePTFE graft were observed. In contrast, thrombi and fibrin fibers on the bare graft, and sporadic cells on the graft coated by chemicals without antibodies were seen. Conclusion: A universal, OAC method was developed. Our in vitro and in vivo data suggest that the method can be potentially translated into clinical application, e.g., modifying ePTFE grafts to mitigate their thrombotic propensity and possibly provide for improved long-term patency for small-diameter grafts.

Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disease characterized by aberrant angiogenesis and vascular malformations. Mutations in the transforming growth factor beta co-receptor, endoglin (ENG), account for approximately half of known HHT cases and cause abnormal angiogenic activity in endothelial cells (ECs). To date, how ENG deficiency contributes to EC dysfunction remains to be fully understood. MicroRNAs (miRNAs) regulate virtually every cellular process. We hypothesized that ENG depletion results in miRNA dysregulation that plays an important role in mediating EC dysfunction. Our goal was to test the hypothesis by identifying dysregulated miRNAs in ENG-knockdown human umbilical vein endothelial cells (HUVECs) and characterizing their potential role in EC function. We identified 32 potentially downregulated miRNAs in ENG-knockdown HUVECs with a TaqMan miRNA microarray. MiRs-139-5p and -454-3p were found to be significantly downregulated after RT-qPCR validation. While the inhibition of miR-139-5p or miR-454-3p had no effect on HUVEC viability, proliferation or apoptosis, angiogenic capacity was significantly compromised as determined by a tube formation assay. Most notably, the overexpression of miRs-139-5p and -454-3p rescued impaired tube formation in HUVECs with ENG knockdown. To our knowledge, we are the first to demonstrate miRNA alterations after the knockdown of ENG in HUVECs. Our results indicate a potential role of miRs-139-5p and -454-3p in ENG-deficiency-induced angiogenic dysfunction in ECs. Further study to examine the involvement of miRs-139-5p and -454-3p in HHT pathogenesis is warranted.

Editorial: Anti-inflammatory immunopharmacology in the prevention and treatment of major chronic diseases

Endothelial cell (EC) dysfunction has been implicated in a variety of pathological conditions. The collection of ECs from patients is typically conducted postmortem or through invasive procedures, such as surgery and interventional procedures, hampering efforts to clarify the role of ECs in disease onset and progression. In contrast, endothelial colony-forming cells (ECFCs), also termed late endothelial progenitor cells, late outgrowth endothelial cells, blood outgrowth endothelial cells, or endothelial outgrowth cells, are obtained in a minimally invasive manner, namely, by the culture of human peripheral blood mononuclear cells in endothelial growth medium. ECFCs resemble mature ECs phenotypically, genetically, and functionally, making them excellent surrogates for ECs. Numerous studies have been performed that examined ECFC function in conditions such as coronary artery disease, diabetes mellitus, hereditary hemorrhagic telangiectasia, congenital bicuspid aortic valve disease, pulmonary arterial hypertension, venous thromboembolic disease, and von Willebrand disease. Here, we provide an updated review of studies using ECFCs that were performed to better understand the pathophysiology of disease. We also discuss the potential of ECFCs as disease biomarkers and the standardized methods to culture, quantify, and evaluate ECFCs and suggest the future direction of research in this field.

Background. Hereditary hemorrhagic telangiectasia (HHT) is a rare, autosomal dominant genetic disorder characterized by life-threatening vascular dysplasia. Myeloid angiogenic cells (MACs), alternatively called early endothelial progenitor cells or circulating angiogenic cells, do not directly incorporate into developing blood vessels, but augment angiogenesis in a paracrine manner. MAC dysfunction has been reported in HHT. MicroRNAs (miRNAs) regulate cellular function by modulating gene expression post-transcriptionally. To date, the role of miRNAs in HHT MAC dysfunction has not been documented. Objective. The goal of this study was to comparatively profile miRNAs in HHT patient and control MACs to identify dysregulated miRNAs that may be responsible for the observed MAC dysfunction in HHT. Methodology/Results. Twenty-three dysregulated miRNAs (twenty-one upregulated and two downregulated) in HHT MACs were identified with a TaqMan miRNA microarray. Pathway enrichment analysis showed that the dysregulated miRNAs were significantly enriched in pathways involved in HHT pathogenesis, such as the transforming growth factor β (TGFβ), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Hippo signalling pathways. Furthermore, miR-132-3p was determined to be significantly reduced in HHT MACs compared with controls by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Bioinformatic analysis revealed that miR-132-3p is significantly enriched in the TGFβ and PI3K/AKT signalling pathways, targeting SMAD4, an effector of the TGFβ signalling pathway and RASA1, a negative regulator of the PI3K/AKT signalling pathway, respectively. Conclusion. MiRNA dysregulation, specifically reduced expression of miR-132-3p, in HHT MACs was identified. The dysregulated miRNAs are significantly enriched in the TGFβ, PI3K/AKT, and Hippo signalling pathways. These data suggest that alteration in miRNA expression may impair these pathways and contribute to MAC dysfunction in HHT.

Non-coding RNAs (ncRNAs) are functional ribonucleic acid (RNA) species that include microRNAs (miRs), a class of short non-coding RNAs (∼21–25 nucleotides), and long non-coding RNAs (lncRNAs) consisting of more than 200 nucleotides. They regulate gene expression post-transcriptionally and are involved in a wide range of pathophysiological processes. Hereditary hemorrhagic telangiectasia (HHT) is a rare disorder inherited in an autosomal dominant fashion characterized by vascular dysplasia. Patients can develop life-threatening vascular malformations and experience severe hemorrhaging. Effective pharmacological therapies are limited. The study of ncRNAs in HHT is an emerging field with great promise. This review will explore the current literature on the involvement of ncRNAs in HHT as diagnostic and pathogenic factors.