Role for Runt-related Transcription Factor 2 in Proliferative and Calcified Vascular Lesions in Pulmonary Arterial Hypertension

Roxadustat increases markers of calcification in patients with end-stage kidney disease: prospective cohort study

To determine the effects of roxadustat on calcification when treating renal anemia in end-stage kidney disease (ESKD) patients. A prospective cohort study enrolled participants with ESKD that either received roxadustat or no roxadustat treatment. The primary outcome was the change in the degree of hydroxyapatite (HAP) crystals deposition. The secondary outcome was calcification propensity, a measure of calcification, allowing an evaluation of the conversion process from primary to secondary calciprotein particles. A total of 205 patients were enrolled, and 187 (91.2%) completed follow-up for inclusion in the analysis and were divided into the roxadustat group (n = 92) and the control group (n = 95) based on whether or not they were taking roxadustat regularly over a 6-mo period. After roxadustat administration for 6 mo, patients exhibited increases in total RBC counts, hematocrit, hemoglobin, calcium, total ferritin binding, intact fibroblast growth factor 23 (iFGF23), secreted phosphoprotein 24 (SPP24), and calcification propensity relative to pre-treatment levels. No significant differences were observed in patients who were not treated with roxadustat. The deposition degree of HAP crystals increased by 5% and 0.01% following treatment with roxadustat in the roxadustat group and control group, respectively. Linear regression analysis found that the use of roxadustat was an independent risk factor for calcification propensity and changes in the degree of HAP crystals deposition. Roxadustat treatment may increase iFGF23, SPP24, and calcification propensity in patients with ESKD when treating these patients for renal anemia. Therefore, the clinicians should aware of this risk when treating patients with prolyl hydroxylase domain inhibitors.

MicroRNA in pediatric pulmonary hypertension microRNA profiling to inform disease classification, severity, and treatment response in pediatric pulmonary hypertension

Pediatric pulmonary hypertension is a heterogeneous disease associated with significant morbidity and mortality. MicroRNAs have been implicated as both pathologic drivers of disease and potential therapeutic targets in pediatric pulmonary hypertension. We sought to characterize the circulating microRNA profiles of a diverse array of pediatric patients with pulmonary hypertension using high-throughput sequencing technology. Peripheral blood samples were drawn from patients recruited at the time of a clinically indicated cardiac catheterization, and microRNA sequencing followed by differential expression and target/pathway enrichment analyses were performed. Among 63 pediatric patients with pulmonary hypertension, we identified specific microRNA signatures that uniquely classified patients by disease subtype, correlated with indicators of disease severity including invasive hemodynamic metrics, and changed over the course of treatment for pulmonary hypertension. These microRNA profiles include a number of specific microRNA molecules known to function in signaling pathways critical to pulmonary vascular biology and disease, including transforming growth factor-β (TGF-β), VEGF, PI3K/Akt, cGMP-PKG, and HIF-1 signaling. Circulating levels of miR-122-5p, miR-124-3p, miR-204-5p, and miR-9-5p decreased over the course of treatment in a subset of patients who had multiple samples drawn during the study period. Our findings support the further investigation of specific microRNAs as mechanistic mediators, biomarkers, and therapeutic targets in pulmonary hypertension.NEW & NOTEWORTHY We present novel insight into the circulating microRNA profiles of pediatric patients with pulmonary hypertension. Our findings support the utility of microRNAs as both useful biomarkers of disease severity and potential therapeutic targets in pediatric pulmonary hypertension.

RUNX2 is stabilised by TAZ and drives pulmonary artery calcification and lung vascular remodelling in pulmonary hypertension due to left heart disease

BACKGROUND

Calcification is common in chronic vascular disease, yet its role in pulmonary hypertension due to left heart disease is unknown. Here, we probed for the role of runt-related transcription factor-2 (RUNX2), a master transcription factor in osteogenesis, and its regulation by the HIPPO pathway transcriptional coactivator with PDZ-binding motif (TAZ) in the osteogenic reprogramming of pulmonary artery smooth muscle cells and vascular calcification in patients with pulmonary hypertension due to left heart disease. We similarly examined its role using an established rat model of pulmonary hypertension due to left heart disease induced by supracoronary aortic banding.

METHODS

Pulmonary artery samples were collected from patients and rats with pulmonary hypertension due to left heart disease. Genome-wide RNA sequencing was performed, and pulmonary artery calcification assessed. Osteogenic signalling via TAZ and RUNX2 was delineated by protein biochemistry. In vivo, the therapeutic potential of RUNX2 or TAZ inhibition by CADD522 or verteporfin was tested in the rat model.

RESULTS

Gene ontology term analysis identified significant enrichment in ossification and osteoblast differentiation genes, including RUNX2, in pulmonary arteries of patients and lungs of rats with pulmonary hypertension due to left heart disease. Pulmonary artery calcification was evident in both patients and rats. Both TAZ and RUNX2 were upregulated and activated in pulmonary artery smooth muscle cells of patients and rats. Co-immunoprecipitation revealed a direct interaction of RUNX2 with TAZ in pulmonary artery smooth muscle cells. TAZ inhibition or knockdown decreased RUNX2 abundance due to accelerated RUNX2 protein degradation rather than reduced de novo synthesis. Inhibition of either TAZ or RUNX2 attenuated pulmonary artery calcification, distal lung vascular remodelling and pulmonary hypertension development in the rat model.

CONCLUSION

Pulmonary hypertension due to left heart disease is associated with pulmonary artery calcification that is driven by TAZ-dependent stabilisation of RUNX2, causing osteogenic reprogramming of pulmonary artery smooth muscle cells. The TAZ-RUNX2 axis may present a therapeutic target in pulmonary hypertension due to left heart disease.

Identification and Validation of the miR/RAS/RUNX2 Autophagy Regulatory Network in AngII-Induced Hypertensive Nephropathy in MPC5 Cells Treated with Hydrogen Sulfide Donors

The balanced crosstalk between miRNAs and autophagy is essential in hypertensive nephropathy. Hydrogen sulfide donors have been reported to attenuate renal injury, but the mechanism is unclear. We aimed to identify and verify the miRNAs and autophagy regulatory networks in hypertensive nephropathy treated with hydrogen sulfide donors through bioinformatics analysis and experimental verification. From the miRNA dataset, autophagy was considerably enriched in mice kidney after angiotensin II (AngII) and combined hydrogen sulfide treatment (H2S_AngII), among which there were 109 differentially expressed miRNAs (DEMs) and 21 hub ADEGs (autophagy-related differentially expressed genes) in the AngII group and 70 DEMs and 13 ADEGs in the H2S_AngII group. A miRNA-mRNA-transcription factors (TFs) autophagy regulatory network was then constructed and verified in human hypertensive nephropathy samples and podocyte models. In the network, two DEMs (miR-98-5p, miR-669b-5p), some hub ADEGs (KRAS, NRAS), and one TF (RUNX2) were altered, accompanied by a reduction in autophagy flux. However, significant recovery occurred after treatment with endogenous or exogenous H2S donors, as well as an overexpression of miR-98-5p and miR-669b-5p. The miR/RAS/RUNX2 autophagy network driven by H2S donors was related to hypertensive nephropathy. H2S donors or miRNAs increased autophagic flux and reduced renal cell injury, which could be a potentially effective medical therapy.

Exosomes enriched by miR-429-3p derived from ITGB1 modified Telocytes alleviates hypoxia-induced pulmonary arterial hypertension through regulating Rac1 expression

BACKGROUND

Recent studies have emphasized the critical role of Telocytes (TCs)-derived exosomes in organ tissue injury and repair. Our previous research showed a significant increase in ITGB1 within TCs. Pulmonary Arterial Hypertension (PAH) is marked by a loss of microvessel regeneration and progressive vascular remodeling. This study aims to investigate whether exosomes derived from ITGB1-modified TCs (ITGB1-Exo) could mitigate PAH.

METHODS

We analyzed differentially expressed microRNAs (DEmiRs) in TCs using Affymetrix Genechip miRNA 4.0 arrays. Exosomes isolated from TC culture supernatants were verified through transmission electron microscopy and Nanoparticle Tracking Analysis. The impact of miR-429-3p-enriched exosomes (Exo-ITGB1) on hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs) was evaluated using CCK-8, transwell assay, and inflammatory factor analysis. A four-week hypoxia-induced mouse model of PAH was constructed, and H&E staining, along with Immunofluorescence staining, were employed to assess PAH progression.

RESULTS

Forty-five miRNAs exhibited significant differential expression in TCs following ITGB1 knockdown. Mus-miR-429-3p, significantly upregulated in ITGB1-overexpressing TCs and in ITGB1-modified TC-derived exosomes, was selected for further investigation. Exo-ITGB1 notably inhibited the migration, proliferation, and inflammation of PASMCs by targeting Rac1. Overexpressing Rac1 partly counteracted Exo-ITGB1's effects. In vivo administration of Exo-ITGB1 effectively reduced pulmonary vascular remodeling and inflammation.

CONCLUSIONS

Our findings reveal that ITGB1-modified TC-derived exosomes exert anti-inflammatory effects and reverse vascular remodeling through the miR-429-3p/Rac1 axis. This provides potential therapeutic strategies for PAH treatment.

Activation of CaMKII/HDAC4 by SDF1 contributes to pulmonary arterial hypertension via stabilization Runx2

Stromal derived factor 1 (SDF1) has been shown to be involved in the pathogenesis of pulmonary artery hypertension (PAH). However, the detailed molecular mechanisms remain unclear. To address this, we utilized primary cultured rat pulmonary artery smooth muscle cells (PASMCs) and monocrotaline (MCT)-induced PAH rat models to investigate the mechanisms of SDF1 driving PASMCs proliferation and pulmonary arterial remodeling. SDF1 increased runt-related transcription factor 2 (Runx2) acetylation by Calmodulin (CaM)-dependent protein kinase II (CaMKII)-dependent HDAC4 cytoplasmic translocation, elevation of Runx2 acetylation conferred its resistance to proteasome-mediated degradation. The accumulation of Runx2 further upregulated osteopontin (OPN) expression, finally leading to PASMCs proliferation. Blocking SDF1, suppression of CaMKII, inhibition the nuclear export of HDAC4 or silencing Runx2 attenuated pulmonary arterial remodeling and prevented PAH development in MCT-induced PAH rat models. Our study provides novel sights for SDF1 induction of PASMCs proliferation and suggests that targeting SDF1/CaMKII/HDAC4/Runx2 axis has potential value in the management of PAH.

Roxadustat ameliorates vascular calcification in CKD rats by regulating HIF-2α/HIF-1α

Vascular calcification (VC) is a common complication of chronic kidney disease (CKD). VC is a gene-regulated process similar to osteogenic differentiation. There are still no convincing schemes to prevent and reduce the development of VC. It has been reported that hypoxia-inducing factor 1α (HIF-1α) and endothelin-1(ET-1) are related to VC. In this study, we found that the expression of ET-1 and HIF-1α was enhanced after VC, the interaction between HIF-1α and ET-1 was confirmed by CO-IP and luciferase experiments. We found that ET-1 was an upregulated differential gene of calcified vascular smooth muscle cells (VSMCs) through gene sequencing. However, hypoxia-inducing factor 2α (HIF-2α) and HIF-1α have antagonistic effects on each other. HIF-1α is a pro-inflammatory cytokine, and HIF-2α can improve inflammation and fibrosis. Roxadustat, as a selective PHD3 inhibitor, preferentially activates HIF-2α. It is still unclear whether roxadustat improves VC in CKD by regulating the expression of HIF-2α/HIF-1α. Alizarin red staining and western blot as well as immunohistochemical results showed that roxadustat could significantly reduce the degree of vascular and VSMCs calcification in CKD rats. Serum HIF-1α and ET-1 were significantly decreased after roxadustat treatment. In addition, western blot results showed that roxadustat could decrease the expression of HIF-1α and ET-1 in vascular tissues and calcified VSMC, but HIF-2α expression significantly increased. Interestingly, our study confirmed that activation of HIF-1α or inhibition of HIF-2α reversed the ameliorating effect of roxadustat on VC, proving that the effect mediated by roxadustat is HIF-2α/HIF-1α dependent. We have demonstrated for the first time that roxadustat improves VC in CKD rats by regulating HIF-2α/HIF-1α, thus providing a new idea for the application of roxadustat in VC of CKD.

Induced pluripotent stem cell-derived exosomes attenuate vascular remodelling in pulmonary arterial hypertension by targeting HIF-1α and Runx2

AIMS

Pulmonary arterial hypertension (PAH) is characterized by extensive pulmonary arterial remodelling. Although mesenchymal stem cell (MSC)-derived exosomes provide protective effects in PAH, MSCs exhibit limited senescence during in vitro expansion compared with the induced pluripotent stem cells (iPSCs). Moreover, the exact mechanism is not known.

METHODS AND RESULTS

In this study, we used murine iPSCs generated from mouse embryonic fibroblasts with triple factor (Oct4, Klf4, and Sox2) transduction to determine the efficacy and action mechanism of iPSC-derived exosomes (iPSC-Exo) in attenuating PAH in rats with monocrotaline (MCT)-induced pulmonary hypertension. Both early and late iPSC-Exo treatment effectively prevented the wall thickening and muscularization of pulmonary arterioles, improved the right ventricular systolic pressure, and alleviated the right ventricular hypertrophy in MCT-induced PAH rats. Pulmonary artery smooth muscle cells (PASMC) derived from MCT-treated rats (MCT-PASMC) developed more proliferative and pro-migratory phenotypes, which were attenuated by the iPSC-Exo treatment. Moreover, the proliferation and migration of MCT-PASMC were reduced by iPSC-Exo with suppression of PCNA, cyclin D1, MMP-1, and MMP-10, which are mediated via the HIF-1α and P21-activated kinase 1/AKT/Runx2 pathways.

CONCLUSION

IPSC-Exo are effective at reversing pulmonary hypertension by reducing pulmonary vascular remodelling and may provide an iPSC-free therapy for the treatment of PAH.

Functions of RNA-Binding Proteins in Cardiovascular Disease

Gene expression is under tight regulation from the chromatin structure that regulates gene accessibility by the transcription machinery to protein degradation. At the transcript level, this regulation falls on RNA-binding proteins (RBPs). RBPs are a large and diverse class of proteins involved in all aspects of a transcript's lifecycle: splicing and maturation, localization, stability, and translation. In the past few years, our understanding of the role of RBPs in cardiovascular diseases has expanded. Here, we discuss the general structure and function of RBPs and the latest discoveries of their role in pulmonary and systemic cardiovascular diseases.

Targeting IL-11 system as a treatment of pulmonary arterial hypertension

IL-11 is linked to fibrotic diseases, but its role in pulmonary hypertension is unclear. We examined IL-11's involvement in idiopathic pulmonary arterial hypertension (iPAH). Using samples from control (n = 20) and iPAH (n = 6) subjects, we assessed IL-11 and IL-11Rα expression and localization through RT-qPCR, ELISA, immunohistochemistry, and immunofluorescence. A monocrotaline-induced PAH model helped evaluate the impact of siRNA-IL-11 on pulmonary artery remodeling and PH. The effects of recombinant human IL-11 and IL-11Rα on human pulmonary artery smooth muscle cell (HPASMC) proliferation, pulmonary artery endothelial cell (HPAEC) mesenchymal transition, monocyte interactions, endothelial tube formation, and precision cut lung slice (PCLS) pulmonary artery remodeling and contraction were evaluated. IL-11 and IL-11Rα were over-expressed in pulmonary arteries (3.2-fold and 75-fold respectively) and serum (1.5-fold and 2-fold respectively) of patients with iPAH. Therapeutic transient transfection with siRNA targeting IL-11 resulted in a significant reduction in pulmonary artery remodeling (by 98%), right heart hypertrophy (by 66%), and pulmonary hypertension (by 58%) in rats exposed to monocrotaline treatment. rhIL-11 and soluble rhIL-11Rα induce HPASMC proliferation and HPAEC to monocyte interactions, mesenchymal transition, and tube formation. Neutralizing monoclonal IL-11 and IL-11Rα antibodies inhibited TGFβ1 and EDN-1 induced HPAEC to mesenchymal transition and HPASMC proliferation. In 3D PCLS, rhIL-11 and soluble rhIL-11Rα do not promote pulmonary artery contraction but sensitize PCLS pulmonary artery contraction induced by EDN-1. In summary, IL-11 and IL-11Rα are more highly expressed in the pulmonary arteries of iPAH patients and contribute to pulmonary artery remodeling and the development of PH.

Hypoxia and panvascular diseases: exploring the role of hypoxia-inducible factors in vascular smooth muscle cells under panvascular pathologies

As an emerging discipline, panvascular diseases are a set of vascular diseases with atherosclerosis as the common pathogenic hallmark, which mostly affect vital organs like the heart, brain, kidney, and limbs. As the major responser to the most common stressor in the vasculature (hypoxia)-hypoxia-inducible factors (HIFs), and the primary regulator of pressure and oxygen delivery in the vasculature-vascular smooth muscle cells (VSMCs), their own multifaceted nature and their interactions with each other are fascinating. Abnormally active VSMCs (e.g., atherosclerosis, pulmonary hypertension) or abnormally dysfunctional VSMCs (e.g., aneurysms, vascular calcification) are associated with HIFs. These widespread systemic diseases also reflect the interdisciplinary nature of panvascular medicine. Moreover, given the comparable proliferative characteristics exhibited by VSMCs and cancer cells, and the delicate equilibrium between angiogenesis and cancer progression, there is a pressing need for more accurate modulation targets or combination approaches to bolster the effectiveness of HIF targeting therapies. Based on the aforementioned content, this review primarily focused on the significance of integrating the overall and local perspectives, as well as temporal and spatial balance, in the context of the HIF signaling pathway in VSMC-related panvascular diseases. Furthermore, the review discussed the implications of HIF-targeting drugs on panvascular disorders, while considering the trade-offs involved.

Epigenetic Reader Bromodomain-Containing Protein 4 in Aging-Related Vascular Pathologies and Diseases: Molecular Basis, Functional Relevance, and Clinical Potential

Aging is a key independent risk factor of various vascular diseases, for which the regulatory mechanisms remain largely unknown. Bromodomain-containing protein 4 (BRD4) is a member of the Bromodomain and Extra-Terminal domain (BET) family and is an epigenetic reader playing diverse roles in regulating transcriptional elongation, chromatin remodeling, DNA damage response, and alternative splicing in various cells and tissues. While BRD4 was initially recognized for its involvement in cancer progression, recent studies have revealed that the aberrant expression and impaired function of BRD4 were highly associated with aging-related vascular pathology, affecting multiple key biological processes in the vascular cells and tissues, providing new insights into the understanding of vascular pathophysiology and pathogenesis of vascular diseases. This review summarizes the recent advances in BRD4 biological function, and the progression of the studies related to BRD4 in aging-associated vascular pathologies and diseases, including atherosclerosis, aortic aneurism vascular neointima formation, pulmonary hypertension, and essential hypertension, providing updated information to advance our understanding of the epigenetic mechanisms in vascular diseases during aging and paving the way for future research and therapeutic approaches.

Critical miRNAs in regulating pulmonary hypertension: A focus on Signaling pathways and therapeutic Targets

Pulmonary hypertension (PH) is complex disease as a result of obstructive pulmonary arterial remodeling, which in turn results in elevated pulmonary arterial pressure (PAP) and subsequent right ventricular heart failure, eventually leading to premature death. However, there is still a lack of a diagnostic blood-based biomarker and therapeutic target for PH. Because of the difficulty of diagnosis, new and more easily accessible prevention and treatment strategy are being explored. New target and diagnosis biomarkers should also allow for early diagnosis. In biology, miRNAs are short endogenous RNA molecules that are not coding. It is known that miRNAs can regulate gene expression and affect a variety of biological processes. Besides, miRNAs have been proven to be a crucial factor in PH pathogenesis. miRNAs have various effects on pulmonary vascular remodeling and are expressed differentially in various pulmonary vascular cells. Nowadays, it has been shown to be critical in the functions of different miRNAs in the pathogenesis of PH. Therefore, clarifying the mechanism of miRNAs regulating pulmonary vascular remodeling is of great importance to explore new therapeutic targets of PH and improve the survival qualify and time of patients. This review is focused on the role, mechanism, and potential therapeutic targets of miRNAs in PH and puts forward possible clinical treatment strategies.

Transcription factors and potential therapeutic targets for pulmonary hypertension

Pulmonary hypertension (PH) is a refractory and fatal disease characterized by excessive pulmonary arterial cell remodeling. Uncontrolled proliferation and hypertrophy of pulmonary arterial smooth muscle cells (PASMCs), dysfunction of pulmonary arterial endothelial cells (PAECs), and abnormal perivascular infiltration of immune cells result in pulmonary arterial remodeling, followed by increased pulmonary vascular resistance and pulmonary pressure. Although various drugs targeting nitric oxide, endothelin-1 and prostacyclin pathways have been used in clinical settings, the mortality of pulmonary hypertension remains high. Multiple molecular abnormalities have been implicated in pulmonary hypertension, changes in numerous transcription factors have been identified as key regulators in pulmonary hypertension, and a role for pulmonary vascular remodeling has been highlighted. This review consolidates evidence linking transcription factors and their molecular mechanisms, from pulmonary vascular intima PAECs, vascular media PASMCs, and pulmonary arterial adventitia fibroblasts to pulmonary inflammatory cells. These findings will improve the understanding of particularly interactions between transcription factor-mediated cellular signaling pathways and identify novel therapies for pulmonary hypertension.

Transcription factors in the pathogenesis of pulmonary arterial hypertension-Current knowledge and therapeutic potential

Pulmonary arterial hypertension (PAH) is a disease characterized by elevated pulmonary vascular resistance and pulmonary artery pressure. Mortality remains high in severe cases despite significant advances in management and pharmacotherapy. Since currently approved PAH therapies are unable to significantly reverse pathological vessel remodeling, novel disease-modifying, targeted therapeutics are needed. Pathogenetically, PAH is characterized by vessel wall cell dysfunction with consecutive remodeling of the pulmonary vasculature and the right heart. Transcription factors (TFs) regulate the process of transcribing DNA into RNA and, in the pulmonary circulation, control the response of pulmonary vascular cells to macro- and microenvironmental stimuli. Often, TFs form complex protein interaction networks with other TFs or co-factors to allow for fine-tuning of gene expression. Therefore, identification of the underlying molecular mechanisms of TF (dys-)function is essential to develop tailored modulation strategies in PAH. This current review provides a compendium-style overview of TFs and TF complexes associated with PAH pathogenesis and highlights their potential as targets for vasculoregenerative or reverse remodeling therapies.

Updates in the Pharmacotherapy of Pulmonary Hypertension in Patients with Heart Failure with Preserved Ejection Fraction

Pulmonary hypertension (PH) associated with left heart disease (LHD) is a complex cardiopulmonary condition where a variable degree of pulmonary congestion, arterial vasoconstriction and vascular remodeling can lead to PH and right heart strain. Right heart dysfunction has a significant prognostic impact on these patients. Therefore, preserving right ventricular (RV) function is an important treatment goal. However, the treatment of PH in patients with left heart disease has produced conflicting evidence. The transition from pure LHD to LHD with PH is a continuum and clinically challenging. The heart failure with preserved ejection fraction (HFpEF) patient population is heterogeneous when it comes to PH and RV function. Appropriate clinical and hemodynamic phenotyping of patients with HFpEF and concomitant PH is paramount to making the appropriate treatment decision. This manuscript will summarize the current evidence for the use of pulmonary arterial vasodilators in patients with HFpEF.

Cysteine and glycine rich protein 2 exacerbates vascular fibrosis in pulmonary hypertension through the nuclear translocation of yes-associated protein and transcriptional coactivator with PDZ-binding motif

Pulmonary hypertension (PH) is a serious cardiovascular disease with a poor prognosis and high mortality. The pathogenesis of PH is complex, and the main pathological changes in PH are abnormal hypertrophy and vessel stiffness. Cysteine and glycine rich protein 2 (Csrp2), a member of the LIM-only family plays a key role in the response to vascular injury. However, its roles in vascular fibrosis and PH have not been clarified. Therefore, this study aimed to investigate whether Csrp2 can promote vascular fibrosis and to further explore the possible mechanisms. Csrp2 expression was increased in both the pulmonary vasculature of rats with PH and hypoxic pulmonary vascular smooth muscle cells (PASMCs). Hypoxia activated TGF-β1 and its downstream effector, SP1. Additionally, hypoxia activated the ROCK pathway and inhibited KLF4 expression. Silencing SP1 and overexpressing KLF4 reversed the hypoxia-induced increase in Csrp2 expression. Csrp2 knockdown decreased the expression of extracellular matrix (ECM) proteins and inhibited the nuclear translocation and expression of YAP/TAZ in hypoxic PASMCs. These results indicate that hypoxia induces Csrp2 expression through the TGF-β1/SP1 and ROCK/KLF4 pathways. Elevated Csrp2 promoted the nuclear translocation and expression of YAP/TAZ, leading to vascular fibrosis and the development of PH.

Nebulization of extracellular vesicles: A promising small RNA delivery approach for lung diseases

Small extracellular vesicles (sEVs) are a group of cell-secreted nanovesicles with a diameter up to 200 nm. A growing number of studies have indicated that sEVs can reflect the pathogenesis of human diseases and mediate intercellular communications. Recently, sEV research has drastically increased due to their drug delivery property. However, a comprehensive method of delivering exogenous small RNAs-loaded sEVs through nebulization has not been reported. The methodology is complicated by uncertainty regarding the integrity of sEVs after nebulization, the delivery efficiency of aerosolized sEVs, their deposition in the lungs/cells, etc. This study demonstrates that sEVs can be delivered to murine lungs through a vibrating mesh nebulizer (VMN). In vivo sEV tracking indicated that inhaled sEVs were distributed exclusively in the lung and localized primarily in lung macrophages and airway epithelial cells. Additionally, sEVs loaded with small RNAs were successfully delivered into the lungs. The administration of siMyd88-loaded sEVs through inhalation reduced lipopolysaccharide (LPS)-induced lung injury in mice, supporting an application of this nebulization methodology to deliver functional small RNAs. Collectively, our study proposes a novel method of sEVs-mediated small RNA delivery into the murine lung through nebulization and presents a potential sEV-based therapeutic strategy for human lung diseases.

Hypoxia-inducible factor signaling in vascular calcification in chronic kidney disease patients

Chronic kidney disease (CKD) affects approximately 15% of the adult population in high-income countries and is associated with significant comorbidities, including increased vascular calcifications which is associated with a higher risk for cardiovascular events. Even though the underlying pathophysiology is unclear, hypoxia-inducible factor (HIF) signaling appears to play a central role in inflammation, angiogenesis, fibrosis, cellular proliferation, apoptosis and vascular calcifications which is influenced by multiple variables such as iron deficiency anemia, serum phosphorus and calcium levels, fibroblast growth factor-23 (FGF-23) and Klotho. Along with the growing understanding of the pathology, potential therapeutic alternatives have emerged including HIF stabilizers and SGLT-2 inhibitors. The aim of this review is to discuss the role of HIF signaling in the pathophysiology of vascular calcification in CKD patients and to identify potential therapeutic approaches.

IL-11 system participates in pulmonary artery remodeling and hypertension in pulmonary fibrosis

Background

Pulmonary hypertension (PH) associated to idiopathic pulmonary fibrosis (IPF) portends a poor prognosis. IL-11 has been implicated in fibrotic diseases, but their role on pulmonary vessels is unknown. Here we analyzed the contribution of IL-11 to PH in patients with IPF and the potential mechanism implicated.

Methods

Pulmonary arteries, lung tissue and serum of control subjects (n = 20), IPF (n = 20) and PH associated to IPF (n = 20) were used to study the expression and localization of IL-11 and IL-11Rα. Two models of IL-11 and bleomycin-induced lung fibrosis associated to PH were used in Tie2-GFP transgenic mice to evaluate the contribution of IL-11 and endothelial cells to pulmonary artery remodeling. The effect of IL-11 and soluble IL-11Rα on human pulmonary artery endothelial cells and smooth muscle cell transformations and proliferation were analyzed.

Results

IL-11 and IL-11Rα were over-expressed in pulmonary arteries and serum of patients with PH associated to IPF vs IPF patients without PH. Recombinant mice (rm)IL-11 induced lung fibrosis and PH in Tie2-GFP mice, activating in vivo EnMT as a contributor of pulmonary artery remodeling and lung fibrosis. Transient transfection of siRNA-IL-11 reduced lung fibrosis and PH in Tie2-GFP bleomycin model. Human (h)rIL-11 and soluble hrIL-11Rα induced endothelial to mesenchymal transition (EnMT) and pulmonary artery smooth muscle cell to myofibroblast-like transformation, cell proliferation and senescence in vitro.

Conclusions

IL-11 and IL-11Rα are overexpressed in pulmonary arteries of PH associated to IPF patients, and contributes to pulmonary artery remodeling and PH.

Pathogenesis of Pulmonary Calcification and Homologies with Biomineralization in Other Tissues

Lungs often present tissue calcifications and even ossifications, both in the context of high or normal serum calcium levels. Precise mechanisms governing lung calcifications have not been explored. Herein, we emphasize recent advances about calcification processes in other tissues (especially vascular and bone calcifications) and discuss potential sources of calcium precipitates in the lungs, involvement of mineralization promoters and crystallization inhibitors, as well as specific cytokine milieu and cellular phenotypes characteristic for lung diseases, which may be involved in pulmonary calcifications. Further studies are necessary to demonstrate the exact mechanisms underlying calcifications in the lungs, document homologies in biomineralization processes between various tissues in physiological and pathologic conditions, and unravel any locally specific characteristics of mineralization processes that may be targeted to reduce or prevent functionally relevant lung calcifications without negatively affecting the skeleton.

HNRNPA2B1: RNA-Binding Protein That Orchestrates Smooth Muscle Cell Phenotype in Pulmonary Arterial Hypertension

BACKGROUND

RNA-binding proteins are master orchestrators of gene expression regulation. They regulate hundreds of transcripts at once by recognizing specific motifs. Thus, characterizing RNA-binding proteins targets is critical to harvest their full therapeutic potential. However, such investigation has often been restricted to a few RNA-binding protein targets, limiting our understanding of their function. In cancer, the RNA-binding protein HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2B1; A2B1) promotes the pro-proliferative/anti-apoptotic phenotype. The same phenotype in pulmonary arterial smooth muscle cells (PASMCs) is responsible for the development of pulmonary arterial hypertension (PAH). However, A2B1 function has never been investigated in PAH.

METHOD

Through the integration of computational and experimental biology, the authors investigated the role of A2B1 in human PAH-PASMC. Bioinformatics and RNA sequencing allowed them to investigate the transcriptome-wide function of A2B1, and RNA immunoprecipitation and A2B1 silencing experiments allowed them to decipher the intricate molecular mechanism at play. In addition, they performed a preclinical trial in the monocrotaline-induced pulmonary hypertension rat model to investigate the relevance of A2B1 inhibition in mitigating pulmonary hypertension severity.

RESULTS

They found that A2B1 expression and its nuclear localization are increased in human PAH-PASMC. Using bioinformatics, they identified 3 known motifs of A2B1 and all mRNAs carrying them. In PAH-PASMC, they demonstrated the complementary nonredundant function of A2B1 motifs because all motifs are implicated in different aspects of the cell cycle. In addition, they showed that in PAH-PASMC, A2B1 promotes the expression of its targets. A2B1 silencing in PAH-PASMC led to a decrease of all tested mRNAs carrying an A2B1 motif and a concomitant decrease in proliferation and resistance to apoptosis. Last, in vivo A2B1 inhibition in the lungs rescued pulmonary hypertension in rats.

CONCLUSIONS

Through the integration of computational and experimental biology, the study revealed the role of A2B1 as a master orchestrator of the PAH-PASMC phenotype and its relevance as a therapeutic target in PAH.

Role of prolyl hydroxylase/HIF-1 signaling in vascular calcification

Morbidity and mortality of chronic kidney disease (CKD) patients are largely associated with vascular calcification, an actively regulated process in which vascular smooth muscle cells (VSMCs) change into cells similar to osteocytes/chondrocytes, known as trans-differentiation. Cellular and systemic response to low oxygen (hypoxia) is regulated by the prolyl hydroxylase/hypoxia-inducible factor (HIF)-1 pathway. Recent studies highlighted that hypoxia-mediated activation of HIF-1 induces trans-differentiation of VSMCs into bone-forming type through an increase in osteo-/chondrogenic genes. Inhibition of the HIF-1 pathway abolished osteochondrogenic differentiation of VSMCs. Hypoxia strongly enhanced elevated phosphate-induced VSMC osteogenic trans-differentiation and calcification. HIF-1 was shown to be essential for phosphate enhanced VSMC calcification. O₂-dependent degradation HIF-1 is triggered by the prolyl hydroxylase domain proteins (PHD). Prolyl hydroxylase inhibitors, daprodustat and roxadustat, increase high phosphate-induced VC in VSMCs, stabilizing HIF-1α and activating the HIF-1 pathway in these cells. Whether the use of these PHD inhibitors to treat anemia in CKD patients will favor the development and progression of vascular calcification remains to be explored.

Pulmonary hypertension: Linking inflammation and pulmonary arterial stiffening

Pulmonary hypertension (PH) is a progressive disease that arises from multiple etiologies and ultimately leads to right heart failure as the predominant cause of morbidity and mortality. In patients, distinct inflammatory responses are a prominent feature in different types of PH, and various immunomodulatory interventions have been shown to modulate disease development and progression in animal models. Specifically, PH-associated inflammation comprises infiltration of both innate and adaptive immune cells into the vascular wall of the pulmonary vasculature—specifically in pulmonary vascular lesions—as well as increased levels of cytokines and chemokines in circulating blood and in the perivascular tissue of pulmonary arteries (PAs). Previous studies suggest that altered hemodynamic forces cause lung endothelial dysfunction and, in turn, adherence of immune cells and release of inflammatory mediators, while the resulting perivascular inflammation, in turn, promotes vascular remodeling and the progression of PH. As such, a vicious cycle of endothelial activation, inflammation, and vascular remodeling may develop and drive the disease process. PA stiffening constitutes an emerging research area in PH, with relevance in PH diagnostics, prognostics, and as a therapeutic target. With respect to its prognostic value, PA stiffness rivals the well-established measurement of pulmonary vascular resistance as a predictor of disease outcome. Vascular remodeling of the arterial extracellular matrix (ECM) as well as vascular calcification, smooth muscle cell stiffening, vascular wall thickening, and tissue fibrosis contribute to PA stiffening. While associations between inflammation and vascular stiffening are well-established in systemic vascular diseases such as atherosclerosis or the vascular manifestations of systemic sclerosis, a similar connection between inflammatory processes and PA stiffening has so far not been addressed in the context of PH. In this review, we discuss potential links between inflammation and PA stiffening with a specific focus on vascular calcification and ECM remodeling in PH.

Attenuating effect of magnesium on pulmonary arterial calcification in rodent models of pulmonary hypertension

OBJECTIVE

Vascular calcification has been considered as a potential therapeutic target in pulmonary hypertension. Mg2+ has a protective role against calcification. This study aimed to investigate whether Mg2+ could alleviate pulmonary hypertension by reducing medial calcification of pulmonary arteries.

METHODS

Monocrotaline (MCT)-induced and chronic hypoxia-induced pulmonary hypertension rats were given an oral administration of 10% MgSO4 (10 ml/kg per day). Additionally, we administered Mg2+ in calcified pulmonary artery smooth muscle cells (PASMCs) after incubating with β-glycerophosphate (β-GP, 10 mmol/l).

RESULTS

In vivo, MCT-induced and chronic hypoxia-induced pulmonary hypertension indexes, including right ventricular systolic pressure, right ventricular mass index, and arterial wall thickness, as well as Alizarin Red S (ARS) staining-visualized calcium deposition, high calcium levels, and osteochondrogenic differentiation in pulmonary arteries, were mitigated by dietary Mg2+ intake. In vitro, β-GP-induced calcium-rich deposits stained by ARS, calcium content, as well as the detrimental effects of calcification to proliferation, migration, and resistance to apoptosis of PASMCs were alleviated by high Mg2+ but exacerbated by low Mg2+. Expression levels of mRNA and protein of β-GP-induced osteochondrogenic markers, RUNX Family Transcription Factor 2, and Msh Homeobox 2 were decreased by high Mg2+ but increased by low Mg2+; however, Mg2+ did not affect β-GP-induced expression of SRY-Box Transcription Factor 9. Moreover, mRNA expression and protein levels of β-GP-reduced calcification inhibitor, Matrix GLA protein was increased by high Mg2+ but decreased by low Mg2+.

CONCLUSION

Mg2+ supplement is a powerful strategy to treat pulmonary hypertension by mitigating pulmonary arterial calcification as the calcification triggered physiological and pathological changes to PASMCs.

Salusin-β, a TOR2A gene product, promotes proliferation, migration, fibrosis, and calcification of smooth muscle cells and accelerates the imbalance of vasomotor function and vascular remodeling in monocrotaline-induced pulmonary hypertensive rats

Purpose: The hyper-proliferation, promoted migration, fibrosis, and calcification of pulmonary arterial smooth muscle cells (PASMCs) play critical roles in pulmonary artery (PA) continuous contraction and vascular remodeling, leading to elevated pulmonary arterial resistance and pulmonary hypertension (PH). In this study, we sought to ascertain the effects of a TOR2A gene product, salusin-β, on PASMCs’ proliferation, migration, fibrosis, calcification, and the imbalance of vasomotor function as well as pulmonary vascular remodeling in monocrotaline (MCT)-induced PH rats and their underlying mechanisms.

Methods: Knockdown or overexpression of salusin-β in rats or PASMCs was performed through tail vein injection or cell transfection of virus. The right ventricular systolic pressure (RVSP) of the rat was measured by right ventricle catheterization. Sodium nitroprusside (SNP) or acetylcholine (ACh)-induced dose-dependent relaxation was used to evaluate the vasodilatation function. Primary PASMCs were isolated from the PAs of control and PH rats.

Results: The salusin-β protein expressions were significantly increased in PAs and PASMCs isolated from PH rats compared with control rats. Knockdown of salusin-β in rats decreased high K⁺ solution-induced contraction, RVSP and RV hypertrophy index, improved SNP or ACh-induced vascular relaxation of PAs, and relieved vascular remodeling and calcification of PAs from PH rats. Silencing salusin-β in PASMCs isolated from PH rats alleviated the proliferation, migration, fibrosis, and calcification, as well as the NAD(P)H oxidase activity and reactive oxygen species (ROS) level. Overexpression of salusin-β exerted the opposite effects on vasomotor function and vascular remodeling, and PASMCs proliferation, migration, fibrosis and calcification.

Conclusion: Increased salusin-β activity in PAs from PH rats contributes to PASMCs proliferation, migration, fibrosis, and calcification, leading to the imbalance of vascular contraction and relaxation and vascular remodeling through stimulating the production of NAD(P)H oxidase derived ROS.

MicroRNA-212-5p, an anti-proliferative miRNA, attenuates hypoxia and sugen/hypoxia-induced pulmonary hypertension in rodents

MicroRNAs (miRNA, miR-) play important roles in disease development. In this study, we identified an anti-proliferative miRNA, miR-212-5p, that is induced in pulmonary artery smooth muscle cells (PASMCs) and lungs of pulmonary hypertension (PH) patients and rodents with experimental PH. We found that smooth muscle cell (SMC)-specific knockout of miR-212-5p exacerbated hypoxia-induced pulmonary vascular remodeling and PH in mice, suggesting that miR-212-5p may be upregulated in PASMCs to act as an endogenous inhibitor of PH, possibly by suppressing PASMC proliferation. Extracellular vesicles (EVs) have been shown recently to be promising drug delivery tools for disease treatment. We generated endothelium-derived EVs with an enriched miR-212-5p load, 212-eEVs, and found that they significantly attenuated hypoxia-induced PH in mice and Sugen/hypoxia-induced severe PH in rats, providing proof of concept that engineered endothelium-derived EVs can be used to deliver miRNA into lungs for treatment of severe PH.

Extracellular Matrix Stiffness in Lung Health and Disease

The extracellular matrix (ECM) provides structural support and imparts a wide variety of environmental cues to cells. In the past decade, a growing body of work revealed that the mechanical properties of the ECM, commonly known as matrix stiffness, regulate the fundamental cellular processes of the lung. There is growing appreciation that mechanical interplays between cells and associated ECM are essential to maintain lung homeostasis. Dysregulation of ECM-derived mechanical signaling via altered mechanosensing and mechanotransduction pathways is associated with many common lung diseases. Matrix stiffening is a hallmark of lung fibrosis. The stiffened ECM is not merely a sequelae of lung fibrosis but can actively drive the progression of fibrotic lung disease. In this article, we provide a comprehensive view on the role of matrix stiffness in lung health and disease. We begin by summarizing the effects of matrix stiffness on the function and behavior of various lung cell types and on regulation of biomolecule activity and key physiological processes, including host immune response and cellular metabolism. We discuss the potential mechanisms by which cells probe matrix stiffness and convert mechanical signals to regulate gene expression. We highlight the factors that govern matrix stiffness and outline the role of matrix stiffness in lung development and the pathogenesis of pulmonary fibrosis, pulmonary hypertension, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. We envision targeting of deleterious matrix mechanical cues for treatment of fibrotic lung disease. Advances in technologies for matrix stiffness measurements and design of stiffness-tunable matrix substrates are also explored. © 2022 American Physiological Society. Compr Physiol 12:3523-3558, 2022.

The role of hypoxia-inducible factors in cardiovascular diseases

Cardiovascular diseases are the leading cause of death worldwide. During the development of cardiovascular diseases, hypoxia plays a crucial role. Hypoxia-inducible factors (HIFs) are the key transcription factors for adaptive hypoxic responses, which orchestrate the transcription of numerous genes involved in angiogenesis, erythropoiesis, glycolytic metabolism, inflammation, and so on. Recent studies have dissected the precise role of cell-specific HIFs in the pathogenesis of hypertension, atherosclerosis, aortic aneurysms, pulmonary arterial hypertension, and heart failure using tissue-specific HIF-knockout or -overexpressing animal models. More importantly, several compounds developed as HIF inhibitors or activators have been in clinical trials for the treatment of renal cancer or anemia; however, little is known on the therapeutic potential of these inhibitors for cardiovascular diseases. The purpose of this review is to summarize the recent advances on HIFs in the pathogenesis and pathophysiology of cardiovascular diseases and to provide evidence of potential clinical therapeutic targets.

miR-424/322 protects against abdominal aortic aneurysm formation by modulating the Smad2/3/runt-related transcription factor 2 axis

Rupture of abdominal aortic aneurysms (AAAs) is one of the leading causes of sudden death in the elderly population. The osteogenic transcription factor runt-related gene (RUNX) encodes multifunctional mediators of intracellular signal transduction pathways in vascular remodeling and inflammation. We aimed to evaluate the roles of RUNX2 and its putative downstream target miR-424/322 in the modulation of several AAA progression-related key molecules, such as matrix metalloproteinases and vascular endothelial growth factor. In the GEO database, we found that male patients with AAAs had higher RUNX2 expression than did control patients. Several risk factors for aneurysm induced the overexpression of MMPs through RUNX2 transactivation, and this was dependent on Smad2/3 upregulation in human aortic smooth muscle cells. miR-424 was overexpressed through RUNX2 after angiotensin II (AngII) challenge. The administration of siRUNX2 and miR-424 mimics attenuated the activation of the Smad/RUNX2 axis and the overexpression of several AAA progression-related molecules in vitro. Compared to their littermates, miR-322 KO mice were susceptible to AngII-induced AAA, whereas the silencing of RUNX2 and the administration of exogenous miR-322 mimics ameliorated the AngII-induced AAA in ApoE KO mice. Overall, we established the roles of the Smad/RUNX2/miR-424/322 axis in AAA pathogenesis. We demonstrated the therapeutic potentials of miR-424/322 mimics and RUNX2 inhibitor for AAA progression.

Non-Coding RNA Networks in Pulmonary Hypertension

Non-coding RNAs (ncRNAs) are involved in various cellular processes. There are several ncRNA classes, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The detailed roles of these molecules in pulmonary hypertension (PH) remain unclear. We systematically collected and reviewed reports describing the functions of ncRNAs (miRNAs, lncRNAs, and circRNAs) in PH through database retrieval and manual literature reading. The characteristics of identified articles, especially the experimental methods, were carefully reviewed. Furthermore, regulatory networks were constructed using ncRNAs and their interacting RNAs or genes. These data were extracted from studies on pulmonary arterial smooth muscle cells, pulmonary artery endothelial cells, and pulmonary artery fibroblasts. We included 14 lncRNAs, 1 circRNA, 74 miRNAs, and 110 mRNAs in the constructed networks. Using these networks, herein, we describe the current knowledge on the role of ncRNAs in PH. Moreover, these networks actively provide an improved understanding of the roles of ncRNAs in PH. The results of this study are crucial for the clinical application of ncRNAs.

Impaired endothelium-dependent and endothelium-independent systemic vasodilatory reserve in pulmonary hypertension regardless the clinical group: A generalized dysfunction beyond the pulmonary arteries?

OBJECTIVE

Endothelium-dependent (ED) and endothelium-independent (EI) flow-mediated vasodilatation (FMD) have been used as measures of systemic arterial vasodilatory reserve. In this study, we aimed to assess both ED-FMD and EI-FMD in different groups with pulmonary hypertension (PH), and to investigate the relationship of these measures with clinical, echocardiographic, and invasive parameters of diseases severity and targeted treatment status.

METHODS

Our study population comprised 41 patients with PH [28 (68.2%) women, age 46.3±19.6 years] including idiopathic pulmonary arterial hypertension, Eisenmenger syndrome, and chronic thromboembolic PH in whom diagnosis were confirmed in accordance with current guidelines and 17 age and sex-matched healthy controls. The brachial artery (BA) was used for assessment of FMD with Duplex ultrasound, and serial changes in diameter were recorded at baseline, 1, and 3 minutes after termination of 2-minute external occlusive compression for ED-FMD, and after sublingual intake of glycerol trinitrate for EI-FMD, respectively.

RESULTS

Compared with controls, overall the PH group showed significantly lower ED-FMD (0.65±0.21 vs. 0.30±0.23 and 0.65±0.18 vs. 0.24±0.21) and EI-FMD (0.67±0.15 vs. 0.37±0.25 and 0.75±0.20 vs. 0.32±0.24) responses at 1st and 3rd min (p<0.001 for all). All these changes in the values of ED-FMD and EI-FMD were comparable among the PH subgroups. Neither ED-FMD nor EI-FMD were correlated with measures of PH severity and targeted therapy (TT) status (p>0.05).

CONCLUSION

Our results suggest an impaired BA vasodilatory reserve in patients with PH regardless of the clinical subgroup. Although these findings seem to be consistent with systemic dysfunction, acute FMD may not reflect the severity of PH and cannot be used as a potential surrogate for outcome in this setting.

Impaired endothelium-dependent and endothelium-independent systemic vasodilatory reserve in pulmonary hypertension regardless the clinical group: A generalized dysfunction beyond the pulmonary arteries?

OBJECTIVE

Endothelium-dependent (ED) and endothelium-independent (EI) flow-mediated vasodilatation (FMD) have been used as measures of systemic arterial vasodilatory reserve. In this study, we aimed to assess both ED-FMD and EI-FMD in different groups with pulmonary hypertension (PH), and to investigate the relationship of these measures with clinical, echocardiographic, and invasive parameters of diseases severity and targeted treatment status.

METHODS

Our study population comprised 41 patients with PH [28 (68.2%) women, age 46.3±19.6 years] including idiopathic pulmonary arterial hypertension, Eisenmenger syndrome, and chronic thromboembolic PH in whom diagnosis were confirmed in accordance with current guidelines and 17 age and sex-matched healthy controls. The brachial artery (BA) was used for assessment of FMD with Duplex ultrasound, and serial changes in diameter were recorded at baseline, 1, and 3 minutes after termination of 2-minute external occlusive compression for ED-FMD, and after sublingual intake of glycerol trinitrate for EI-FMD, respectively.

RESULTS

Compared with controls, overall the PH group showed significantly lower ED-FMD (0.65±0.21 vs. 0.30±0.23 and 0.65±0.18 vs. 0.24±0.21) and EI-FMD (0.67±0.15 vs. 0.37±0.25 and 0.75±0.20 vs. 0.32±0.24) responses at 1st and 3rd min (p<0.001 for all). All these changes in the values of ED-FMD and EI-FMD were comparable among the PH subgroups. Neither ED-FMD nor EI-FMD were correlated with measures of PH severity and targeted therapy (TT) status (p>0.05).

CONCLUSION

Our results suggest an impaired BA vasodilatory reserve in patients with PH regardless of the clinical subgroup. Although these findings seem to be consistent with systemic dysfunction, acute FMD may not reflect the severity of PH and cannot be used as a potential surrogate for outcome in this setting.

Pulmonary Artery 18F-Fluorodeoxyglucose Uptake by PET/CMR as a Marker of Pulmonary Hypertension in Sarcoidosis

OBJECTIVES

This study investigated whether pulmonary artery (PA) ¹⁸F-FDG uptake is associated with hypertension, and if it correlates to elevated pulmonary pressures.

BACKGROUND

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with computed tomography or cardiac magnetic resonance (CMR) has been used to assess inflammation mostly in large arteries of the systemic circulation. Much less is known about inflammation of the vasculature of the pulmonary system and its relationship to pulmonary hypertension (PH).

METHODS

In a single-center cohort of 175 patients with suspected cardiac sarcoidosis, who underwent hybrid thoracic PET/CMR, ¹⁸F-FDG uptake in the PA was quantified according to maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) and compared with available results from right heart catheterization (RHC) or transthoracic echocardiography (TTE).

RESULTS

Thirty-three subjects demonstrated clear ¹⁸F-FDG uptake in the PA wall. In the subgroup of patients who underwent RHC (n = 10), the mean PA pressure was significantly higher in the group with PA ¹⁸F-FDG uptake compared with the group without uptake (34.4 ± 7.2 mm Hg vs 25.6 ± 9.3 mm Hg; P = 0.003), and 9 (90%) patients with PA ¹⁸F-FDG uptake had PH when a mean PA pressure cutoff of 25 mm Hg was used compared with 18 (45%) in the nonuptake group (P < 0.05). In the subgroup that underwent TTE, signs of PH were present in a significantly higher number of patients with PA ¹⁸F-FDG uptake (14 [51.9%] vs 37 [29.8%]; P < 0.05). Qualitative assessment of ¹⁸F-FDG uptake in the PA wall showed a sensitivity of 33% and specificity of 96% for separating patients with PH based on RHC-derived PA pressures. SUVmax and TBR in the PA wall correlated with PA pressure derived from RHC and/or TTE.

CONCLUSIONS

We demonstrate that ¹⁸F-FDG uptake by PET/CMR in the PA is associated with PH and that its intensity correlates with PA pressure.

Angiopoietin-like proteins in atherosclerosis

Atherosclerosis, as a chronic inflammatory disease within the arterial wall, is a leading cause of morbidity and mortality worldwide due to its role in myocardial infarction, stroke and peripheral artery disease. Additional evidence is emerging that the angiopoietin-like (ANGPTL) family of proteins participate in the pathology of this disease process via endothelial dysfunction, inflammation, dyslipidemia, calcification, foam cell formation and platelet activation. This review summarizes current knowledge on the ANGPTL family of proteins in atherosclerosis related pathological processes. Moreover, the potential value of ANGPTL family proteins as predictive biomarkers in atherosclerosis is discussed. Given the attractive role of ANGPTL3, ANGPTL4, ANGPTL8 in atherosclerotic dyslipidemia via regulation of lipoprotein lipase (LPL), antisense oligonucleotide or/and monoclonal antibody-based inactivation of these proteins represent potential atherosclerotic therapies.

Novel molecular insights and public omics data in pulmonary hypertension

Pulmonary hypertension is a rare disease with high morbidity and mortality which mainly affects women of reproductive age. Despite recent advances in understanding the pathogenesis of pulmonary hypertension, the high heterogeneity in the presentation of the disease among different patients makes it difficult to make an accurate diagnosis and to apply this knowledge to effective treatments. Therefore, new studies are required to focus on translational and personalized medicine to overcome the lack of specificity and efficacy of current management. Here, we review the majority of public databases storing 'omics' data of pulmonary hypertension studies, from animal models to human patients. Moreover, we review some of the new molecular mechanisms involved in the pathogenesis of pulmonary hypertension, including non-coding RNAs and the application of 'omics' data to understand this pathology, hoping that these new approaches will provide insights to guide the way to personalized diagnosis and treatment.

The isobaric pulmonary arterial compliance in pulmonary hypertension

Pulmonary hypertension is associated with stiffening of pulmonary arteries which increases right ventricular pulsatile loading. High pulmonary artery wedge pressure (PAWP) in postcapillary pulmonary hypertension (Pc-PH) further decreases pulmonary arterial compliance (PAC) at a given pulmonary vascular resistance (PVR) compared with precapillary pulmonary hypertension, thus responsible for a higher total arterial load. In all other vascular beds, arterial compliance is considered as mainly determined by the distending pressure, due to non-linear stress-strain behaviour of arteries. We tested the applicability, advantages and drawbacks of two comparison methods of PAC depending on the level of mean pulmonary arterial pressure (mPAP; isobaric PAC) or PVR. Right heart catheterisation data including PAC (stroke volume/pulse pressure) were obtained in 112 Pc-PH (of whom 61 had combined postcapillary and precapillary pulmonary hypertension) and 719 idiopathic pulmonary arterial hypertension (iPAH). PAC could be compared over the same mPAP range (25-66 mmHg) in 792 (95.3%) out of 831 patients and over the same PVR range (3-10.7 WU) in only 520 (62.6%) out of 831 patients. The main assumption underlying comparisons at a given PVR was not verified as the PVR×PAC product (RC-time) was not constant but on the contrary more variable than mPAP. In the 788/831 (94.8%) patients studied over the same PAC range (0.62-6.5 mL·mmHg-1), PVR and thus total arterial load tended to be higher in iPAH. Our study favours comparing PAC at fixed mPAP level (isobaric PAC) rather than at fixed PVR. A reappraisal of the effects of PAWP on the pulsatile and total arterial load put on the right heart is needed, and this point deserves further studies.

Interferon regulatory factor 7 inhibits rat vascular smooth muscle cell proliferation and inflammation in monocrotaline-induced pulmonary hypertension

AIMS

Although interferon regulatory factor 7 (IRF7) has known roles in regulating the inflammatory response, vascular smooth muscle cell proliferation, and apoptosis, its role in the pathogenesis of pulmonary hypertension (PH) is unclear. We hypothesized that IRF7 overexpression could inhibit pulmonary vascular remodeling and slow the progression of PH.

MAIN METHODS

IRF7 mRNA and protein levels in the lung samples and pulmonary artery smooth muscle cells (PASMCs) isolated from monocrotaline (MCT)-induced PH rats were assessed. We evaluated the effects of IRF7 on inflammation, proliferation, and apoptosis using an in vivo MCT-induced PH rat model and in vitro methods.

KEY FINDINGS

We noted decreased IRF7 mRNA and protein levels in the pulmonary vasculature of MCT-induced PH rats. IRF7 upregulation attenuated pulmonary vascular remodeling, decreased the pulmonary artery systolic pressure, and improved the right ventricular (RV) structure and function. Our findings suggest that nuclear factor kappa-Bp65 (NF-κBp65) deactivation could confer pulmonary vasculature protection, reduce proinflammatory cytokine (tumor necrosis factor-α, interleukin 6) release, and decrease PASMC proliferation and resistance to apoptosis via deactivating transcription factor 3 (ATF3) signaling. ATF3 deactivation induced the downregulation of the proliferation-dependent genes proliferating cell nuclear antigen (PCNA), cyclin D1, and survivin, coupled with increased levels of B cell lymphoma-2-associated X protein (Bax)/B cell lymphoma-2 (Bcl2) ratio, and cleaved caspase-3 in PASMCs.

SIGNIFICANCE

Our findings showed that IRF7 downregulation could initiate inflammation via NF-κBp65 signaling, causing PASMC proliferation via ATF3 signaling pathway activation. Therefore, IRF7 could be a potential molecular target for PH therapy.

Resveratrol: Mechanistic and therapeutic perspectives in pulmonary arterial hypertension

Resveratrol, trans 3,5,4'-trihydroxystilbene, is a stilbenoid polyphenol with a wide range of properties including antioxidant, neuroprotective, cardioprotective, anti-inflammatory and anticancer activities. It is found in the skins of grape (50-100 μg/mL), red wine, peanuts, bilberries, blueberries and cranberries. The most important effects of resveratrol have been found in cardiovascular disease, with pulmonary arterial hypertension (PAH) being a major severe and progressive component. Many factors are involved in the pathogenesis of PAH, including enzymes, transcription factors, proteins, chemokines, cytokines, hypoxia, oxidative stress and others. Resveratrol treats PAH through its actions on various signaling pathways. These signaling pathways are mainly suppressed SphK1-mediated NF-κB activation, BMP/SMAD signaling pathway, miR-638 and NR4A3/cyclin D1 pathway, SIRT1 pathway, Nrf-2, HIF-1 α expression, MAPK/ERK1 and PI3K/AKT pathways, and RhoA-ROCK signaling pathway. Resveratrol efficiently inhibits the proliferation of pulmonary arterial smooth muscle cells and right ventricular remodeling, which are underlying processes leading to enhanced PAH. While supportive evidence from randomized controlled trials is yet to be available, current in vitro and in vivo studies seem to be convincing and suggest a therapeutic promise for the use of resveratrol in PAH.

Bromodomain-containing protein 4 and its role in cardiovascular diseases

Bromodomain-containing protein 4 (BRD4), a chromatin-binding protein, is involved in the development of various tumors. Recent evidence suggests that BRD4 also plays a significant role in cardiovascular diseases, such as ischemic heart disease, hypertension, and cardiac hypertrophy. This review summarizes the roles of BRD4 as a potential regulator of various pathophysiological processes in cardiovascular diseases, implicating that BRD4 may be a new therapeutic target for cardiovascular diseases in the future.

Experimental Rodent Models of Cardiovascular Diseases

Cardiovascular diseases, as the most common non-communicable disease in the world, cause a high mortality rate today and bring a serious medical burden to countries worldwide, especially in low- and middle-income countries. Experimental rodent models are widely used for cardiovascular diseases researches due to the effective simulation of human cardiovascular diseases, strong reproductive ability, and easy detection. Herein, we will summarize the pathological manifestations of common cardiovascular diseases and illustrate the establishment of corresponding experimental rodent models in detail.

Micro-RNA Analysis in Pulmonary Arterial Hypertension: Current Knowledge and Challenges

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The role of miRNAs in PAH is fast expanding, and it is increasingly difficult to identify which molecules have the highest translational potential.

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This review discusses the challenges in miRNA analysis and interpretation in PAH and highlights 4 promising miRNAs in this field.

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Additional pre-clinical studies and clinical trials are urgently needed to bring miRNAs from the bench to the bedside soon.

Pulmonary arterial hypertension (PAH) is a rare, chronic disease of the pulmonary vasculature that is associated with poor outcomes. Its pathogenesis is multifactorial and includes micro-RNA (miRNA) deregulation. The understanding of the role of miRNAs in PAH is expanding quickly, and it is increasingly difficult to identify which miRNAs have the highest translational potential. This review summarizes the current knowledge of miRNA expression in PAH, discusses the challenges in miRNA analysis and interpretation, and highlights 4 promising miRNAs in this field (miR-29, miR-124, miR-140, and miR-204).

Pulmonary hypertension secondary to pulmonary fibrosis: clinical data, histopathology and molecular insights

Pulmonary hypertension (PH) developing secondarily in pulmonary fibrosis (PF) patients (PF-PH) is a frequent co-morbidity. The high prevalence of PH in PF patients is very concerning since the presence of PH is a strong predictor of mortality in PF patients. Until recently, PH was thought to arise solely from fibrotic destruction of the lung parenchyma, leading to hypoxic vasoconstriction and loss of vascular bed density. Thus, potential cellular and molecular dysregulation of vascular remodeling as a driver of PF-PH has been under-investigated. The recent demonstrations that there is no correlation between the severity of the fibrosis and development of PH, along with the finding that significant vascular histological and molecular differences exist between patients with and without PH have shifted the etiological paradigm of PF-PH. This review aims to provide a comprehensive translational overview of PH in PF patients from clinical diagnosis and outcome to the latest understanding of the histology and molecular pathophysiology of PF-PH.

Regulation of Vascular Calcification by Reactive Oxygen Species

Vascular calcification is the deposition of hydroxyapatite crystals in the medial or intimal layers of arteries that is usually associated with other pathological conditions including but not limited to chronic kidney disease, atherosclerosis and diabetes. Calcification is an active, cell-regulated process involving the phenotype transition of vascular smooth muscle cells (VSMCs) from contractile to osteoblast/chondrocyte-like cells. Diverse triggers and signal transduction pathways have been identified behind vascular calcification. In this review, we focus on the role of reactive oxygen species (ROS) in the osteochondrogenic phenotype switch of VSMCs and subsequent calcification. Vascular calcification is associated with elevated ROS production. Excessive ROS contribute to the activation of certain osteochondrogenic signal transduction pathways, thereby accelerating osteochondrogenic transdifferentiation of VSMCs. Inhibition of ROS production and ROS scavengers and activation of endogenous protective mechanisms are promising therapeutic approaches in the prevention of osteochondrogenic transdifferentiation of VSMCs and subsequent vascular calcification. The present review discusses the formation and actions of excess ROS in different experimental models of calcification, and the potential of ROS-lowering strategies in the prevention of this deleterious condition.

CD248 as a novel therapeutic target in pulmonary arterial hypertension

Pulmonary vascular remodeling is the most important pathological characteristic of pulmonary arterial hypertension (PAH). No effective treatment for PAH is currently available because the mechanism underlying vascular remodeling is not completely clear. CD248, also known as endosialin, is a transmembrane protein that is highly expressed in pericytes and fibroblasts. Here, we evaluated the role of CD248 in pulmonary vascular remodeling and the processes of PAH pathogenesis. Activation of CD248 in pulmonary artery smooth muscle cells (PASMCs) was found to be proportional to the severity of PAH. CD248 contributed to platelet-derived growth factor-BB (PDGF-BB)-induced PASMC proliferation and migration along with the shift to more synthetic phenotypes. In contrast, treatment with Cd248 siRNA or the anti-CD248 therapeutic antibody (ontuxizumab) significantly inhibited the PDGF signaling pathway, obstructed NF-κB p65-mediated transcription of Nox4, and decreased reactive oxygen species production induced by PDGF-BB in PAMSCs. In addition, knockdown of CD248 alleviated pulmonary vascular remodeling in rat PAH models. This study provides novel insights into the dysfunction of PASMCs leading to pulmonary vascular remodeling, and provides evidence for anti-remodeling treatment for PAH via the immediate targeting of CD248.

Oral 15-Hydroxyeicosatetraenoic Acid Induces Pulmonary Hypertension in Mice by Triggering T Cell-Dependent Endothelial Cell Apoptosis

Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased mean pulmonary arterial pressure. Elevated plasma and lung concentrations of oxidized lipids, including 15-hydroxyeicosatetraenoic acid (15-HETE), have been demonstrated in patients with PAH and animal models. We previously demonstrated that feeding mice with 15-HETE is sufficient to induce pulmonary hypertension, but the mechanisms remain unknown. RNA sequencing data from the mouse lungs on 15-HETE diet revealed significant activation of pathways involved in both antigen processing and presentation and T cell-mediated cytotoxicity. Analysis of human microarray from patients with PAH also identified activation of identical pathways compared with controls. We show that in both 15-HETE-fed mice and patients with PAH, expression of the immunoproteasome subunit 5 is significantly increased, which was concomitant with an increase in the number of CD8/CD69 (cluster of differentiation 8 / cluster of differentiation 69) double-positive cells, as well as pulmonary arterial endothelial cell apoptosis in mice. Human pulmonary arterial endothelial cells cultured with 15-HETE were more prone to apoptosis when exposed to CD8 cells. Cultured intestinal epithelial cells secreted more oxidized lipids in response to 15-HETE, which is consistent with accumulation of circulating oxidized lipids in 15-HETE-fed mice. Administration of an apoA-I (apolipoprotein A-I) mimetic peptide, Tg6F (transgenic 6F), which is known to prevent accumulation of circulating oxidized lipids, not only inhibited pulmonary arterial endothelial cell apoptosis but also prevented and rescued 15-HETE-induced pulmonary hypertension in mice. In conclusion, our results suggest that (1) 15-HETE diet induces pulmonary hypertension by a mechanism that involves oxidized lipid-mediated T cell-dependent pulmonary arterial endothelial cell apoptosis and (2) Tg6F administration may be a novel therapy for treating PAH.

Increased Levels of Runt-Related Transcription Factor 2 Are Associated With Poor Survival of Patients With Idiopathic Pulmonary Arterial Hypertension

Runt-related transcription factor 2 (RUNX2) plays a pivotal role in the pathogenesis of pulmonary arterial hypertension (PAH); yet, whether circulating levels of RUNX2 can predict survival of patients with idiopathic PAH (IPAH) is still unclear. The present study aimed to investigate the correlation between circulating levels of RUNX2 and survival of patients with IPAH. Blood samples were collected from 46 incident patients with IPAH and 30 healthy controls in Shanghai Pulmonary Hospital. Levels of RUNX2 were measured using ELISA. Linear regression and cox proportional hazards analysis were performed to assess the prognostic value of RUNX2 levels in predicting survival using the Kaplan-Meier method. Nonsurvivors had significantly shorter 6MWD, higher levels of NT-proBNP, increased mRAP, mPAP, mPAWP, PVR, and decreased CO as well as CI, compared with survivors (p < .05). Plasma levels of RUNX2 were significantly higher in nonsurvival and survival patients with IPAH compared with controls (p ≤ .001), and higher in nonsurvivors than in survivors (p = .001). RUNX2 levels served as an independent predictor of survival in these patients (p < .001). RUNX2 levels ≥41.5 ng/ml had a sensitivity of 80.0% and a specificity of 74.2% by ROC analysis. Patients with a RUNX2 level <41.5 ng/ml and/or mRAP <3.5 mmHg had a significantly better prognosis than those with a higher RUNX2 level in all subjects as well as in male or female patients (p < .05). The level of circulating RUNX2 is an independent predictor for survival and it is correlated with the clinical severity of IPAH.

The Role of Mitochondria in Vascular Calcification

Vascular calcification (VC) was defined as the ectopic deposition of calcium-phosphorus complexes on the blood vessel walls. It was a process involving multiple factors and mechanisms, covering the phenotype transition of vascular smooth muscle cells (VSMCs) and release of microvesicles. It was a common end-stage alteration of chronic diseases such as cardiovascular disease and chronic kidney disease. Increasing evidence indicates that mitochondria were involved in the development of VC. Mitochondria provided energy to cells, maintained the stability of cell functions, and participated in a variety of biological behavior. Oxidative stress, autophagy, apoptosis, and mitochondrial DNA (mtDNA) damage could affect the development of VSMCs calcification by alteration of mitochondrial function. This article reviewed the mechanism of calcification and the role of mitochondria in VC, aiming to raise a novel insight into drug development and clinical treatment.

Beyond the Lungs: Systemic Manifestations of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease characterized by progressive loss and remodeling of the pulmonary arteries, resulting in right heart failure and death. Until recently, PAH was seen as a disease restricted to the pulmonary circulation. However, there is growing evidence that patients with PAH also exhibit systemic vascular dysfunction, as evidenced by impaired brachial artery flow-mediated dilation, abnormal cerebral blood flow, skeletal myopathy, and intrinsic kidney disease. Although some of these anomalies are partially due to right ventricular insufficiency, recent data support a mechanistic link to the genetic and molecular events behind PAH pathogenesis. This review serves as an introduction to the major systemic findings in PAH and the evidence that supports a common mechanistic link with PAH pathophysiology. In addition, it discusses recent studies describing morphological changes in systemic vessels and the possible role of bronchopulmonary anastomoses in the development of plexogenic arteriopathy. On the basis of available evidence, we propose a paradigm in which metabolic abnormalities, genetic injury, and systemic vascular dysfunction contribute to systemic manifestations in PAH. This concept not only opens exciting research possibilities but also encourages clinicians to consider extrapulmonary manifestations in their management of patients with PAH.