Loss of Endothelium-Derived Wnt5a Is Associated With Reduced Pericyte Recruitment and Small Vessel Loss in Pulmonary Arterial Hypertension

o8G Site-Specifically Modified tRF-1-AspGTC: A Novel Therapeutic Target and Biomarker for Pulmonary Hypertension

BACKGROUND

Hypoxia and oxidative stress contribute to the development of pulmonary hypertension (PH). tRNA-derived fragments play important roles in RNA interference and cell proliferation, but their epitranscriptional roles in PH development have not been investigated. We aimed to gain insight into the mechanistic contribution of oxidative stress-induced 8-oxoguanine in pulmonary vascular remodeling.

METHODS

Through small RNA modification array analysis and quantitative polymerase chain reaction, a significant upregulation of the 8-oxoguanine -modified tRF-1-AspGTC was found in the lung tissues and the serum of patients with PH.

RESULTS

This modification occurs at the position 5 of the tRF-1-AspGTC (5o8G tRF). Inhibition of the 5o8G tRF reversed hypoxia-induced proliferation and apoptosis resistance in pulmonary artery smooth muscle cells. Further investigation unveiled that the 5o8G tRF retargeted mRNA of WNT5A (Wingless-type MMTV integration site family, member 5A) and CASP3 (Caspase3) and inhibited their expression. Ultimately, BMPR2 (Bone morphogenetic protein receptor 2) -reactive oxygen species/5o8G tRF/WNT5A signaling pathway exacerbated the progression of PH.

CONCLUSIONS

Our study highlights the role of site-specific 8-oxoguanine-modified tRF in promoting the development of PH. Our findings present a promising therapeutic avenue for managing PH and propose 5o8G tRF as a potential innovative marker for diagnosing this disease.

C-type natriuretic peptide/cGMP/FoxO3 signaling attenuates hyperproliferation of pericytes from patients with pulmonary arterial hypertension

Pericyte dysfunction, with excessive migration, hyperproliferation, and differentiation into smooth muscle-like cells contributes to vascular remodeling in Pulmonary Arterial Hypertension (PAH). Augmented expression and action of growth factors trigger these pathological changes. Endogenous factors opposing such alterations are barely known. Here, we examine whether and how the endothelial hormone C-type natriuretic peptide (CNP), signaling through the cyclic guanosine monophosphate (cGMP) -producing guanylyl cyclase B (GC-B) receptor, attenuates the pericyte dysfunction observed in PAH. The results demonstrate that CNP/GC-B/cGMP signaling is preserved in lung pericytes from patients with PAH and prevents their growth factor-induced proliferation, migration, and transdifferentiation. The anti-proliferative effect of CNP is mediated by cGMP-dependent protein kinase I and inhibition of the Phosphoinositide 3-kinase (PI3K)/AKT pathway, ultimately leading to the nuclear stabilization and activation of the Forkhead Box O 3 (FoxO3) transcription factor. Augmentation of the CNP/GC-B/cGMP/FoxO3 signaling pathway might be a target for novel therapeutics in the field of PAH.

Increased endothelial sclerostin caused by elevated DSCAM mediates multiple trisomy 21 phenotypes

Trisomy 21 (T21), a recurrent aneuploidy occurring in 1:800 births, predisposes to congenital heart disease (CHD) and multiple extracardiac phenotypes. Despite a definitive genetic etiology, the mechanisms by which T21 perturbs development and homeostasis remain poorly understood. We compared the transcriptome of CHD tissues from 49 patients with T21 and 226 with euploid CHD (eCHD). We resolved cell lineages that misexpressed T21 transcripts by cardiac single-nucleus RNA sequencing and RNA in situ hybridization. Compared with eCHD samples, T21 samples had increased chr21 gene expression; 11-fold-greater levels (P = 1.2 × 10-8) of SOST (chr17), encoding the Wnt inhibitor sclerostin; and 1.4-fold-higher levels (P = 8.7 × 10-8) of the SOST transcriptional activator ZNF467 (chr7). Euploid and T21 cardiac endothelial cells coexpressed SOST and ZNF467; however, T21 endothelial cells expressed 6.9-fold more SOST than euploid endothelial cells (P = 2.7 × 10-27). Wnt pathway genes were downregulated in T21 endothelial cells. Expression of DSCAM, residing within the chr21 CHD critical region, correlated with SOST (P = 1.9 × 10-5) and ZNF467 (P = 2.9 × 10-4). Deletion of DSCAM from T21 endothelial cells derived from human induced pluripotent stem cells diminished sclerostin secretion. As Wnt signaling is critical for atrioventricular canal formation, bone health, and pulmonary vascular homeostasis, we concluded that T21-mediated increased sclerostin levels would inappropriately inhibit Wnt activities and promote Down syndrome phenotypes. These findings imply therapeutic potential for anti-sclerostin antibodies in T21.

Efficient EVs separation and detection by an alumina-nanochannel-array-membrane integrated microfluidic chip and an antibody barcode biochip

BACKGROUND

Small endosome-derived lipid nanovesicles (30-200 nm) are actively secreted by living cells and serve as pivotal biomarkers for early cancer diagnosis. However, the study of extracellular vesicles (EVs) requires isolation and purification from various body fluids. Although traditional EVs isolation and detection technologies are mature, they usually require large amount of sample, consumes long-time, and have relatively low-throughput. How to efficiently isolate, purify and detect these structurally specific EVs from body fluids with high-throughput remains a great challenge in in vitro diagnostics and clinical research.

RESULTS

Herein, we suggest a nanosized microfluidic device for efficient and economical EVs filtration based on an alumina nanochannel array membrane. We evaluated the filtration device performance of alumina membranes with different diameters and found that an optimized chamber array with a hydrophilic-treated channel diameter of 90 nm could realize a filtration efficiency of up to 82% without any assistance from chemical or physical separation methods. Importantly, by integrating meticulously designed multichannel microfluidic biochips, EVs can be captured in-situ and monitored by antibody barcode biochip. The proposed filtration chip together with the high-throughput detection chip were capable of filtration of a few tens of μL samples and recognition of different phonotypes. The practical filtration and detection of EVs from clinical samples demonstrated the high performance of the device.

SIGNIFICANT

Overall, this work provides a cost-effective, highly efficient and automated EVs filtration chip and detection dual-function integrated chip platform, which can directly separate EVs from serum or cerebrospinal fluid with an efficiency of 82% and conduct in-situ detection. This small fluidic device can provide a powerful tool for highly efficient identifying and analyzing EVs, presenting great application potential in clinical detection.

Ddx5 Targeted Epigenetic Modification of Pericytes in Pulmonary Hypertension After Intrauterine Growth Restriction

Newborns with intrauterine growth restriction (IUGR) have a higher likelihood of developing pulmonary arterial hypertension (PAH) in adulthood. Although there is increasing evidence suggesting that pericytes play a role in regulating myofibroblast transdifferentiation and angiogenesis in malignant and cardiovascular diseases, their involvement in the pathogenesis of IUGR-related pulmonary hypertension and the underlying mechanisms remain incompletely understood. To address this issue, a study was conducted using a Sprague-Dawley rat model of IUGR-related pulmonary hypertension. Our investigation revealed increased proliferation and migration of pulmonary microvascular pericytes in IUGR-related pulmonary hypertension, accompanied by weakened endothelial-pericyte interactions. Through whole-transcriptome sequencing, Ddx5 (DEAD-box protein 5) was identified as one of the hub genes in pericytes. DDX5, a member of the RNA helicase family, plays a role in the regulation of ATP-dependent RNA helicase activities and cellular function. MicroRNAs have been implicated in the pathogenesis of PAH, and microRNA-205 (miR-205) regulates cell proliferation, migration, and angiogenesis. The results of dual-luciferase reporter assays confirmed the specific binding of miR-205 to Ddx5. Mechanistically, miR-205 negatively regulates Ddx5, leading to the degradation of β-catenin by inhibiting the phosphorylation of Gsk3β at serine 9. In vitro experiments showed the addition of miR-205 effectively ameliorated pericyte dysfunction. Furthermore, in vivo experiments demonstrated that miR-205 agomir could ameliorate pulmonary hypertension. Our findings indicated that the downregulation of miR-205 expression mediates pericyte dysfunction through the activation of Ddx5. Therefore, targeting the miR-205/Ddx5/p-Gsk3β/β-catenin axis could be a promising therapeutic approach for IUGR-related pulmonary hypertension.

Overexpression of Wnt5a promoted the protective effect of mesenchymal stem cells on Lipopolysaccharide-induced endothelial cell injury via activating PI3K/AKT signaling pathway

BACKGROUND

Lung endothelial barrier injury plays an important role in the pathophysiology of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Mesenchymal stem cells (MSCs) therapy has shown promise in ARDS treatment and restoration of the impaired barrier function. It has been reported that Wnt5a shows protective effects on endothelial cells. Therefore, the study aimed to investigate whether overexpression of Wnt5a could promote the protective effects of MSCs on Lipopolysaccharide (LPS)-induced endothelial cell injury.

METHODS

To evaluate the protective effects of MSCs overexpressing Wnt5a, we assessed the migration, proliferation, apoptosis, and angiogenic ability of endothelial cells. We assessed the transcription of protective cellular factors using qPCR and determined the molecular mechanism using Western blot analysis.

RESULTS

Overexpression of Wnt5a upregulated the transcription of protective cellular factors in MSCs. Co-culture of MSCWnt5a promoted endothelial migration, proliferation and angiogenesis, and inhibited endothelial cell apoptosis through the PI3K/AKT pathway.

CONCLUSIONS

Overexpression of Wnt5a promoted the therapeutic effect of MSCs on endothelial cell injury through the PI3K/AKT signaling. Our study provides a novel approach for utilizing genetically modified MSCs in the transplantation therapy for ARDS.

Extrapulmonary manifestations of pulmonary arterial hypertension

INTRODUCTION

Extrapulmonary manifestations of pulmonary arterial hypertension (PAH) may play a critical pathobiological role and a deeper understanding will advance insight into mechanisms and novel therapeutic targets. This manuscript reviews our understanding of extrapulmonary manifestations of PAH.

AREAS COVERED

A group of experts was assembled and a complimentary PubMed search performed (October 2023 - March 2024). Inflammation is observed throughout the central nervous system and attempts at manipulation are an encouraging step toward novel therapeutics. Retinal vascular imaging holds promise as a noninvasive method of detecting early disease and monitoring treatment responses. PAH patients have gut flora alterations and dysbiosis likely plays a role in systemic inflammation. Despite inconsistent observations, the roles of obesity, insulin resistance and dysregulated metabolism may be illuminated by deep phenotyping of body composition. Skeletal muscle dysfunction is perpetuated by metabolic dysfunction, inflammation, and hypoperfusion, but exercise training shows benefit. Renal, hepatic, and bone marrow abnormalities are observed in PAH and may represent both end-organ damage and disease modifiers.

EXPERT OPINION

Insights into systemic manifestations of PAH will illuminate disease mechanisms and novel therapeutic targets. Additional study is needed to understand whether extrapulmonary manifestations are a cause or effect of PAH and how manipulation may affect outcomes.

Deciphering the impacts of modulating the Wnt-planar cell polarity (PCP) pathway on alveolar repair

Many adult lung diseases involve dysregulated lung repair. Deciphering the molecular and cellular mechanisms that govern intrinsic lung repair is essential to develop new treatments to repair/regenerate the lungs. Aberrant Wnt signalling is associated with lung diseases including emphysema, idiopathic pulmonary fibrosis and pulmonary arterial hypertension but how Wnt signalling contributes to these diseases is still unclear. There are several alternative pathways that can be stimulated upon Wnt ligand binding, one of these is the Planar Cell Polarity (PCP) pathway which induces actin cytoskeleton remodelling. Wnt5a is known to stimulate the PCP pathway and this ligand is of particular interest in regenerative lung biology because of its association with lung diseases and its role in the alveolar stem cell niche. To decipher the cellular mechanisms through which Wnt5a and the PCP pathway affect alveolar repair we utilised a 3-D ex-vivo model of lung injury and repair, the AIR model. Our results show that Wnt5a specifically enhances the alveolar epithelial progenitor cell population following injury and surprisingly, this function is attenuated but not abolished in Looptail (Lp) mouse lungs in which the PCP pathway is dysfunctional. However, Lp tracheal epithelial cells show reduced stiffness and Lp alveolar epithelial cells are less migratory than wildtype (WT), indicating that Lp lung epithelial cells have a reduced capacity for repair. These findings provide important mechanistic insight into how Wnt5a and the PCP pathway contribute to lung repair and indicate that these components of Wnt signalling may be viable targets for the development of pro-repair treatments.

The TGFβ1/SMADs/Snail1 signaling axis mediates pericyte-derived fibrous scar formation after spinal cord injury

AIMS

The deposition of fibrous scars after spinal cord injury (SCI) affects axon regeneration and the recovery of sensorimotor function. It has been reported that microvascular pericytes in the neurovascular unit are the main source of myofibroblasts after SCI, but the specific molecular targets that regulate pericyte participation in the formation of fibrous scars remain to be clarified.

METHODS

In this study, a rat model of spinal cord dorsal hemisection injury was used. After SCI, epigallocatechin gallate (EGCG) was intraperitoneally injected to block the TGFβ1 signaling pathway or LV-Snail1-shRNA was immediately injected near the core of the injury using a microsyringe to silence Snail1 expression. Western blotting and RT-qPCR were used to analyze protein expression and transcription levels in tissues. Nissl staining and immunofluorescence analysis were used to analyze neuronal cell viability, scar tissue, and axon regeneration after SCI. Finally, the recovery of hind limb function after SCI was evaluated.

RESULTS

The results showed that targeted inhibition of Snail1 could block TGFβ1-induced pericyte-myofibroblast differentiation in vitro. In vivo experiments showed that timely blockade of Snail1 could reduce fibrous scar deposition after SCI, promote axon regeneration, improve neuronal survival, and facilitate the recovery of lower limb motor function.

CONCLUSION

In summary, Snail1 promotes the deposition of fibrous scars and inhibits axonal regeneration after SCI by inducing the differentiation of pericytes into myofibroblasts. Snail1 may be a promising therapeutic target for SCI.

Pericytes contribute to pulmonary vascular remodeling via HIF2α signaling

Vascular remodeling is the process of structural alteration and cell rearrangement of blood vessels in response to injury and is the cause of many of the world's most afflicted cardiovascular conditions, including pulmonary arterial hypertension (PAH). Many studies have focused on the effects of vascular endothelial cells and smooth muscle cells (SMCs) during vascular remodeling, but pericytes, an indispensable cell population residing largely in capillaries, are ignored in this maladaptive process. Here, we report that hypoxia-inducible factor 2α (HIF2α) expression is increased in the lung tissues of PAH patients, and HIF2α overexpressed pericytes result in greater contractility and an impaired endothelial-pericyte interaction. Using single-cell RNAseq and hypoxia-induced pulmonary hypertension (PH) models, we show that HIF2α is a major molecular regulator for the transformation of pericytes into SMC-like cells. Pericyte-selective HIF2α overexpression in mice exacerbates PH and right ventricular hypertrophy. Temporal cellular lineage tracing shows that HIF2α overexpressing reporter NG2+ cells (pericyte-selective) relocate from capillaries to arterioles and co-express SMA. This novel insight into the crucial role of NG2+ pericytes in pulmonary vascular remodeling via HIF2α signaling suggests a potential drug target for PH.

MiR-122-5p as a potential regulator of pulmonary vascular wall cell in idiopathic pulmonary arterial hypertension

MicroRNAs (miRNAs) are versatile regulators of pulmonary arterial remodeling in idiopathic pulmonary arterial hypertension (IPAH). We herein aimed to characterize miRNAs in peripheral blood mononuclear cell (PBMC) and plasma exosomes, and investigate specific miRNA expression in pulmonary artery cells and lung tissues in IPAH. A co-dysregulated miRNA was identified from the miRNA expression profiles of PBMC and plasma exosomes in IPAH. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed the potential function of differentially expressed miRNAs. Real-time quantitative reverse transcription polymerase chain reaction was used to validate the expression of specific miRNAs in hypoxia-induced pulmonary microvascular endothelial cells (PMECs), pulmonary artery smooth muscle cells (PASMCs), pericyte cells (PCs), and lung tissues of patients with IPAH and rats. Finally, the miRNA-mRNA mechanisms of miR-122-5p were predicted. MiR-122-5p was the only co-upregulated miRNA in PBMC and plasma exosomes in patients with IPAH. Functional analysis of differentially expressed miRNAs revealed associations with the GO terms "transcription, DNA-templated," "cytoplasm," and "metal ion binding" in both PBMC and plasma exosomes, KEGG pathway MAPK signaling in PBMC, and KEGG-pathway human papillomavirus infection in plasma exosomes. Hypoxic PMECs and PCs, lung tissue of patients with IPAH, and rats showed increased expression of miR-122-5p, but hypoxic PASMCs showed decreased expression. And miR-122-5p mimics and inhibitor affected cell proliferation. Finally, miR-122-5p was found to potentially target DLAT (in lung tissue) and RIMS1 (in PMECs) in IPAH. According to the dual-luciferase assay, miR-122-5p bound to DLAT or RIMS1. In studies, DLAT imbalance was associated with cell proliferation and migration, RIMS1 is differentially expressed in cancer and correlated with cancer prognosis. Our findings suggest that the miR-122-5p is involved in various biological functions in the adjacent vascular wall cells in IPAH.

RGS5 as a Biomarker of Pericytes, Involvement in Vascular Remodeling and Pulmonary Arterial Hypertension

Introduction

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by a sustained rise in mean pulmonary artery pressure. Pulmonary vascular remodeling serves an important role in PAH. Identifying a key driver gene to regulate vascular remodeling of the pulmonary microvasculature is critical for PAH management.

Methods

Differentially expressed genes were identified using the Gene Expression Omnibus (GEO) GSE117261, GSE48149, GSE113439, GSE53408 and GSE16947 datasets. A co-expression network was constructed using weighted gene co-expression network analysis. Novel and key signatures of PAH were screened using four algorithms, including weighted gene co-expression network analysis, GEO2R analysis, support vector machines recursive feature elimination and robust rank aggregation rank analysis. Regulator of G-protein signaling 5 (RGS5), a pro-apoptotic/anti-proliferative protein, which regulate arterial tone and blood pressure in vascular smooth muscle cells. The expression of RGS5 was determined using reverse transcription-quantitative PCR (RT-qPCR) in PAH and normal mice. The location of RGS5 and pericytes was detected using immunofluorescence.

Results

Compared with that in the normal group, RGS5 expression was upregulated in the PAH group based on GEO and RT-qPCR analyses. RGS5 expression in single cells was enriched in pericytes in single-cell RNA sequencing analysis. RGS5 co-localization with pericytes was detected in the pulmonary microvasculature of PAH.

Conclusion

RGS5 regulates vascular remodeling of the pulmonary microvasculature and the occurrence of PAH through pericytes, which has provided novel ideas and strategies regarding the occurrence and innovative treatment of PAH.

Extracellular Vesicles in Pulmonary Hypertension: A Dangerous Liaison?

The term pulmonary hypertension (PH) refers to different conditions, all characterized by increased pressure and resistance in the pulmonary arterial bed. PH has a wide range of causes (essentially, cardiovascular, pulmonary, or connective tissue disorders); however, idiopathic (i.e., without a clear cause) PH exists. This chronic, progressive, and sometimes devastating disease can finally lead to right heart failure and eventually death, through pulmonary vascular remodeling and dysfunction. The exact nature of PH pathophysiology is sometimes still unclear. Extracellular vesicles (EVs), previously known as apoptotic bodies, microvesicles, and exosomes, are small membrane-bound vesicles that are generated by almost all cell types and can be detected in a variety of physiological fluids. EVs are involved in intercellular communication, thus influencing immunological response, inflammation, embryogenesis, aging, and regenerative processes. Indeed, they transport chemokines, cytokines, lipids, RNA and miRNA, and other biologically active molecules. Although the precise functions of EVs are still not fully known, there is mounting evidence that they can play a significant role in the pathophysiology of PH. In this review, after briefly recapping the key stages of PH pathogenesis, we discuss the current evidence on the functions of EVs both as PH biomarkers and potential participants in the distinct pathways of disease progression.

Biology and function of pericytes in the vascular microcirculation

Pericytes are the main cellular components of tiny arteries and capillaries. Studies have found that pericytes can undergo morphological contraction or relaxation under stimulation by cytokines, thus affecting the contraction and relaxation of microvessels and playing an essential role in regulating vascular microcirculation. Moreover, due to the characteristics of stem cells, pericytes can differentiate into a variety of inflammatory cell phenotypes, which then affect the immune function. Additionally, pericytes can also participate in angiogenesis and wound healing by interacting with endothelial cells in vascular microcirculation disorders. Here we review the origin, biological phenotype and function of pericytes, and discuss the potential mechanisms of pericytes in vascular microcirculation disorders, especially in pulmonary hypertension, so as to provide a sound basis and direction for the prevention and treatment of vascular microcirculation diseases.

Wnt7a deficit is associated with dysfunctional angiogenesis in pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is characterised by loss of microvessels. The Wnt pathways control pulmonary angiogenesis but their role in PAH is incompletely understood. We hypothesised that Wnt activation in pulmonary microvascular endothelial cells (PMVECs) is required for pulmonary angiogenesis, and its loss contributes to PAH.

METHODS

Lung tissue and PMVECs from healthy and PAH patients were screened for Wnt production. Global and endothelial-specific Wnt7a -/- mice were generated and exposed to chronic hypoxia and Sugen-hypoxia (SuHx).

RESULTS

Healthy PMVECs demonstrated >6-fold Wnt7a expression during angiogenesis that was absent in PAH PMVECs and lungs. Wnt7a expression correlated with the formation of tip cells, a migratory endothelial phenotype critical for angiogenesis. PAH PMVECs demonstrated reduced vascular endothelial growth factor (VEGF)-induced tip cell formation as evidenced by reduced filopodia formation and motility, which was partially rescued by recombinant Wnt7a. We discovered that Wnt7a promotes VEGF signalling by facilitating Y1175 tyrosine phosphorylation in vascular endothelial growth factor receptor 2 (VEGFR2) through receptor tyrosine kinase-like orphan receptor 2 (ROR2), a Wnt-specific receptor. We found that ROR2 knockdown mimics Wnt7a insufficiency and prevents recovery of tip cell formation with Wnt7a stimulation. While there was no difference between wild-type and endothelial-specific Wnt7a -/- mice under either chronic hypoxia or SuHx, global Wnt7a +/- mice in hypoxia demonstrated higher pulmonary pressures and severe right ventricular and lung vascular remodelling. Similar to PAH, Wnt7a +/- PMVECs exhibited an insufficient angiogenic response to VEGF-A that improved with Wnt7a.

CONCLUSIONS

Wnt7a promotes VEGF signalling in lung PMVECs and its loss is associated with an insufficient VEGF-A angiogenic response. We propose that Wnt7a deficiency contributes to progressive small vessel loss in PAH.

Vascular pathobiology of pulmonary hypertension

Pulmonary hypertension (PH), increased blood pressure in the pulmonary arteries, is a morbid and lethal disease. PH is classified into several groups based on etiology, but pathological remodeling of the pulmonary vasculature is a common feature. Endothelial cell dysfunction and excess smooth muscle cell proliferation and migration are central to the vascular pathogenesis. In addition, other cell types, including fibroblasts, pericytes, inflammatory cells and platelets contribute as well. Herein, we briefly note most of the main cell types active in PH and for each cell type, highlight select signaling pathway(s) highly implicated in that cell type in this disease. Among others, the role of hypoxia-inducible factors, growth factors (e.g., vascular endothelial growth factor, platelet-derived growth factor, transforming growth factor-β and bone morphogenetic protein), vasoactive molecules, NOTCH3, Kruppel-like factor 4 and forkhead box proteins are discussed. Additionally, deregulated processes of endothelial-to-mesenchymal transition, extracellular matrix remodeling and intercellular crosstalk are noted. This brief review touches upon select critical facets of PH pathobiology and aims to incite further investigation that will result in discoveries with much-needed clinical impact for this devastating disease.

Endotyping COPD: hypoxia-inducible factor-2 as a molecular "switch" between the vascular and airway phenotypes?

COPD is a heterogeneous disease with multiple clinical phenotypes. COPD endotypes can be determined by different expressions of hypoxia-inducible factors (HIFs), which, in combination with individual susceptibility and environmental factors, may cause predominant airway or vascular changes in the lung. The pulmonary vascular phenotype is relatively rare among COPD patients and characterised by out-of-proportion pulmonary hypertension (PH) and low diffusing capacity of the lung for carbon monoxide, but only mild-to-moderate airway obstruction. Its histologic feature, severe remodelling of the small pulmonary arteries, can be mediated by HIF-2 overexpression in experimental PH models. HIF-2 is not only involved in the vascular remodelling but also in the parenchyma destruction. Endothelial cells from human emphysema lungs express reduced HIF-2α levels, and the deletion of pulmonary endothelial Hif-2α leads to emphysema in mice. This means that both upregulation and downregulation of HIF-2 have adverse effects and that HIF-2 may represent a molecular "switch" between the development of the vascular and airway phenotypes in COPD. The mechanisms of HIF-2 dysregulation in the lung are only partly understood. HIF-2 levels may be controlled by NAD(P)H oxidases via iron- and redox-dependent mechanisms. A better understanding of these mechanisms may lead to the development of new therapeutic targets.

Animal Disease Models and Patient-iPS-Cell-Derived In Vitro Disease Models for Cardiovascular Biology-How Close to Disease?

Currently, zebrafish, rodents, canines, and pigs are the primary disease models used in cardiovascular research. In general, larger animals have more physiological similarities to humans, making better disease models. However, they can have restricted or limited use because they are difficult to handle and maintain. Moreover, animal welfare laws regulate the use of experimental animals. Different species have different mechanisms of disease onset. Organs in each animal species have different characteristics depending on their evolutionary history and living environment. For example, mice have higher heart rates than humans. Nonetheless, preclinical studies have used animals to evaluate the safety and efficacy of human drugs because no other complementary method exists. Hence, we need to evaluate the similarities and differences in disease mechanisms between humans and experimental animals. The translation of animal data to humans contributes to eliminating the gap between these two. In vitro disease models have been used as another alternative for human disease models since the discovery of induced pluripotent stem cells (iPSCs). Human cardiomyocytes have been generated from patient-derived iPSCs, which are genetically identical to the derived patients. Researchers have attempted to develop in vivo mimicking 3D culture systems. In this review, we explore the possible uses of animal disease models, iPSC-derived in vitro disease models, humanized animals, and the recent challenges of machine learning. The combination of these methods will make disease models more similar to human disease.

Label-Free Identification of Exosomes using Raman Spectroscopy and Machine Learning

Exosomes, nano-sized extracellular vesicles (EVs) secreted from cells, carry various cargo molecules reflecting their cells of origin. As EV content, structure, and size are highly heterogeneous, their classification via cargo molecules by determining their origin is challenging. Here, a method is presented combining surface-enhanced Raman spectroscopy (SERS) with machine learning algorithms to employ the classification of EVs derived from five different cell lines to reveal their cellular origins. Using an artificial neural network algorithm, it is shown that the label-free Raman spectroscopy method's prediction ratio correlates with the ratio of HT-1080 exosomes in the mixture. This machine learning-assisted SERS method enables a new direction through label-free investigation of EV preparations by differentiating cancer cell-derived exosomes from those of healthy. This approach will potentially open up new avenues of research for early detection and monitoring of various diseases, including cancer.

Pulmonary Vascular Remodeling in Pulmonary Hypertension

Pulmonary vascular remodeling is the critical structural alteration and pathological feature in pulmonary hypertension (PH) and involves changes in the intima, media and adventitia. Pulmonary vascular remodeling consists of the proliferation and phenotypic transformation of pulmonary artery endothelial cells (PAECs) and pulmonary artery smooth muscle cells (PASMCs) of the middle membranous pulmonary artery, as well as complex interactions involving external layer pulmonary artery fibroblasts (PAFs) and extracellular matrix (ECM). Inflammatory mechanisms, apoptosis and other factors in the vascular wall are influenced by different mechanisms that likely act in concert to drive disease progression. This article reviews these pathological changes and highlights some pathogenetic mechanisms involved in the remodeling process.

Planar cell polarity regulators in asymmetric organogenesis during development and disease

The phenomenon of planar cell polarity is critically required for a myriad of morphogenetic processes in metazoan and is accurately controlled by several conserved modules. Six "core" proteins, including Frizzled, Flamingo (Celsr), Van Gogh (Vangl), Dishevelled, Prickle, and Diego (Ankrd6), are major components of the Wnt/planar cell polarity pathway. The Fat/Dchs protocadherins and the Scrib polarity complex also function to instruct cellular polarization. In vertebrates, all these pathways are essential for tissue and organ morphogenesis, such as neural tube closure, left-right symmetry breaking, heart and gut morphogenesis, lung and kidney branching, stereociliary bundle orientation, and proximal-distal limb elongation. Mutations in planar polarity genes are closely linked to various congenital diseases. Striking advances have been made in deciphering their contribution to the establishment of spatially oriented pattern in developing organs and the maintenance of tissue homeostasis. The challenge remains to clarify the complex interplay of different polarity pathways in organogenesis and the link of cell polarity to cell fate specification. Interdisciplinary approaches are also important to understand the roles of mechanical forces in coupling cellular polarization and differentiation. This review outlines current advances on planar polarity regulators in asymmetric organ formation, with the aim to identify questions that deserve further investigation.

Approaches for the isolation and long-term expansion of pericytes from human and animal tissues

Pericytes surround capillaries in every organ of the human body. They are also present around the vasa vasorum, the small blood vessels that supply the walls of larger arteries and veins. The clinical interest in pericytes is rapidly growing, with the recognition of their crucial roles in controlling vascular function and possible therapeutic applications in regenerative medicine. Nonetheless, discrepancies in methods used to define, isolate, and expand pericytes are common and may affect reproducibility. Separating pure pericyte preparations from the continuum of perivascular mesenchymal cells is challenging. Moreover, variations in functional behavior and antigenic phenotype in response to environmental stimuli make it difficult to formulate an unequivocal definition of bona fide pericytes. Very few attempts were made to develop pericytes as a clinical-grade product. Therefore, this review is devoted to appraising current methodologies' pros and cons and proposing standardization and harmonization improvements. We highlight the importance of developing upgraded protocols to create therapeutic pericyte products according to the regulatory guidelines for clinical manufacturing. Finally, we describe how integrating RNA-seq techniques with single-cell spatial analysis, and functional assays may help realize the full potential of pericytes in health, disease, and tissue repair.

Liposomes or Extracellular Vesicles: A Comprehensive Comparison of Both Lipid Bilayer Vesicles for Pulmonary Drug Delivery

The rapid and non-invasive pulmonary drug delivery (PDD) has attracted great attention compared to the other routes. However, nanoparticle platforms, like liposomes (LPs) and extracellular vesicles (EVs), require extensive reformulation to suit the requirements of PDD. LPs are artificial vesicles composed of lipid bilayers capable of encapsulating hydrophilic and hydrophobic substances, whereas EVs are natural vesicles secreted by cells. Additionally, novel LPs-EVs hybrid vesicles may confer the best of both. The preparation methods of EVs are distinguished from LPs since they rely mainly on extraction and purification, whereas the LPs are synthesized from their basic ingredients. Similarly, drug loading methods into/onto EVs are distinguished whereby they are cell- or non-cell-based, whereas LPs are loaded via passive or active approaches. This review discusses the progress in LPs and EVs as well as hybrid vesicles with a special focus on PDD. It also provides a perspective comparison between LPs and EVs from various aspects (composition, preparation/extraction, drug loading, and large-scale manufacturing) as well as the future prospects for inhaled therapeutics. In addition, it discusses the challenges that may be encountered in scaling up the production and presents our view regarding the clinical translation of the laboratory findings into commercial products.

Pathophysiology and new advances in pulmonary hypertension

Pulmonary hypertension is a progressive and often fatal cardiopulmonary condition characterised by increased pulmonary arterial pressure, structural changes in the pulmonary circulation, and the formation of vaso-occlusive lesions. These changes lead to increased right ventricular afterload, which often progresses to maladaptive right ventricular remodelling and eventually death. Pulmonary arterial hypertension represents one of the most severe and best studied types of pulmonary hypertension and is consistently targeted by drug treatments. The underlying molecular pathogenesis of pulmonary hypertension is a complex and multifactorial process, but can be characterised by several hallmarks: inflammation, impaired angiogenesis, metabolic alterations, genetic or epigenetic abnormalities, influence of sex and sex hormones, and abnormalities in the right ventricle. Current treatments for pulmonary arterial hypertension and some other types of pulmonary hypertension target pathways involved in the control of pulmonary vascular tone and proliferation; however, these treatments have limited efficacy on patient outcomes. This review describes key features of pulmonary hypertension, discusses current and emerging therapeutic interventions, and points to future directions for research and patient care. Because most progress in the specialty has been made in pulmonary arterial hypertension, this review focuses on this type of pulmonary hypertension. The review highlights key pathophysiological concepts and emerging therapeutic directions, targeting inflammation, cellular metabolism, genetics and epigenetics, sex hormone signalling, bone morphogenetic protein signalling, and inhibition of tyrosine kinase receptors.

Plasma exosomes confer hypoxic pulmonary hypertension by transferring LOX-1 cargo to trigger phenotypic switching of pulmonary artery smooth muscle cells

The pulmonary vascular remodeling (PVR), the pathological basis of pulmonary hypertension (PH), entails pulmonary artery smooth muscle cells (PASMCs) phenotypic switching, but appreciation of the underlying mechanisms is incomplete. Exosomes, a novel transfer machinery enabling delivery of its cargos to recipient cells, have been recently implicated in cardiovascular diseases including PH. The two critical questions of whether plasma-derived exosomes drive PASMCs phenotypic switching and what cargo the exosomes transport, however, remain unclear. Herein, by means of transmission electron microscopy and protein detection, we for the first time, characterized lectin like oxidized low-density lipoprotein receptor-1 (LOX-1) as a novel cargo of plasma-derived exosomes in PH. With LOX-1 knockout (Olr1^-/-) rats-derived exosomes, we demonstrated that exosomal LOX-1 could be transferred into PASMCs and thus elicited cell phenotypic switching. Of importance, Olr1^-/- rats exhibited no cell phenotypic switching and developed less severe PH, but administration of wild type rather than Olr1^-/- exosomes to Olr1^-/- rats recapitulated the phenotype of PH with robust PASMCs phenotypic switching. We also revealed that exosomal LOX-1 triggered PASMCs phenotypic switching, PVR and ultimately PH via ERK1/2-KLF4 signaling axis. This study has generated proof that plasma-derived exosomes confer PH by delivering LOX-1 into PASMCs. Hence, exosomal LOX-1 represents a novel exploitable target for PH prevention and treatment.

Renomedullary exosomes produce antihypertensive effects in reversible two-kidney one-clip renovascular hypertensive mice

The rapid fall in blood pressure following unclipping of the stenotic renal artery in the Goldblatt two-kidney one-clip (2K1C) model of renovascular hypertension is proposed to be due to release of renomedullary vasodepressor lipids, but the mechanism has remained unclear. In this study, we hypothesized that the hypotensive response to unclipping is mediated by exosomes released from the renal medulla. In male C57BL6/J mice made hypertensive by the 2K1C surgery, unclipping of the renal artery after 10 days decreased mean arterial pressure (MAP) by 23 mmHg one hr after unclipping. This effect was accompanied by a 556% increase in the concentration of exosomes in plasma as observed by nanoparticle tracking analysis. Immunohistochemical analysis of exosome markers, CD63 and AnnexinII, showed increased staining in interstitial cells of the inner medulla of stenotic but not contralateral control kidney of clipped 2K1C mice. Treatment with rapamycin, an inducer of exosome release, blunted the hypertensive response to clipping, whereas GW-4869, an exosome biosynthesis inhibitor, prevented both the clipping-induced increase in inner medullary exosome marker staining and the unclipping-induced fall in MAP. Plasma exosomes isolated from unclipped 2K1C mice showed elevated neutral lipid content compared to sham mouse exosomes by flow cytometric analysis after Nile red staining. Exosomes from 2K1C but not sham control mice exerted potent MAP-lowering and diuretic-natriuretic effects in both 2K1C and angiotensin II-infused hypertensive mice. These results are consistent with increased renomedullary synthesis and release of exosomes with elevated antihypertensive neutral lipids in response to increased renal perfusion pressure.

Bronchopulmonary dysplasia and wnt pathway-associated single nucleotide polymorphisms

AIM

Genetic variants contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to evaluate the association of 45 SNPs with BPD susceptibility in a Turkish premature infant cohort.

METHODS

Infants with gestational age <32 weeks were included. Patients were divided into BPD or no-BPD groups according to oxygen need at 28 days of life, and stratified according to the severity of BPD. We genotyped 45 SNPs, previously identified as BPD risk factors, in 192 infants.

RESULTS

A total of eight SNPs were associated with BPD risk at allele level, two of which (rs4883955 on KLF12 and rs9953270 on CHST9) were also associated at the genotype level. Functional relationship maps suggested an interaction between five of these genes, converging on WNT5A, a member of the WNT pathway known to be implicated in BPD pathogenesis. Dysfunctional CHST9 and KLF12 variants may contribute to BPD pathogenesis through an interaction with WNT5A.

CONCLUSIONS

We suggest investigating the role of SNPs on different genes which are in relation with the Wnt pathway in BPD pathogenesis. We identified eight SNPs as risk factors for BPD in this study. In-silico functional maps show an interaction of the genes harboring these SNPs with the WNT pathway, supporting its role in BPD pathogenesis.

TRIAL REGISTRATION

NCT03467828.

IMPACT

It is known that genetic factors may contribute to the development of BPD in preterm infants. Further studies are required to identify specific genes that play a role in the BPD pathway to evaluate them as a target for therapeutic interventions. Our study shows an association of BPD predisposition with certain polymorphisms on MBL2, NFKBIA, CEP170, MAGI2, and VEGFA genes at allele level and polymorphisms on CHST9 and KLF12 genes at both allele and genotype level. In-silico functional mapping shows a functional relationship of these five genes with WNT5A, suggesting that Wnt pathway disruption may play a role in BPD pathogenesis.

Wnt5a Promotes AT1 and Represses AT2 Lineage-Specific Gene Expression in a Cell-Context-Dependent Manner

Lung maturation is not limited to proper structural development but also includes differentiation and functionality of various highly specialized alveolar cell types. Alveolar type 1 (AT1s) cells occupy nearly 95% of the alveolar surface and are critical for establishing efficient gas exchange in the mature lung. AT1 cells arise from progenitors specified during the embryonic stage as well as alveolar epithelial progenitors expressing surfactant protein C (Sftpcpos cells) during postnatal and adult stages. Previously, we found that Wnt5a, a non-canonical Wnt ligand, is required for differentiation of AT1 cells during the saccular phase of lung development. To further investigate the role of Wnt5a in AT1 cell differentiation, we generated and characterized a conditional Wnt5a gain-of-function mouse model. Neonatal Wnt5a gain-of-function disrupted alveologenesis through inhibition of cell proliferation. In this setting Wnt5a downregulated β-catenin-dependent canonical Wnt signaling, repressed AT2 (anti-AT2) and promoted AT1 (pro-AT1) lineage-specific gene expression. In addition, we identified 2 subpopulations of Sftpchigh and Sftpclow alveolar epithelial cells. In Sftpclow cells, Wnt5a exhibits pro-AT1 and anti-AT2 effects, concurrent with inhibition of canonical Wnt signaling. Interestingly, in the Sftpchigh subpopulation, although increasing AT1 lineage-specific gene expression, Wnt5a gain-of-function did not change AT2 gene expression, nor inhibit canonical Wnt signaling. Using primary epithelial cells isolated from human fetal lungs, we demonstrate that this property of Wnt5a is evolutionarily conserved. Wnt5a therefore serves as a selective regulator that ensures proper AT1/AT2 balance in the developing lung.

Protective role of small extracellular vesicles derived from HUVECs treated with AGEs in diabetic vascular calcification

The pathogenesis of vascular calcification in diabetic patients remains elusive. As an effective information transmitter, small extracellular vesicles (sEVs) carry abundant microRNAs (miRNAs) that regulate the physiological and pathological states of recipient cells. In the present study, significant up-regulation of miR-126-5p was observed in sEVs isolated from human umbilical vein endothelial cells (HUVECs) stimulated with advanced glycation end-products (A-EC/sEVs). Intriguingly, these sEVs suppressed the osteogenic differentiation of vascular smooth muscle cells (VSMCs) by targeting BMPR1B, which encodes the receptor for BMP, thereby blocking the smad1/5/9 signalling pathway. In addition, knocking down miR-126-5p in HUVECs significantly diminished the anti-calcification effect of A-EC/sEVs in a mouse model of type 2 diabetes. Overall, miR-126-5p is highly enriched in sEVs derived from AGEs stimulated HUVECs and can target BMPR1B to negatively regulate the trans-differentiation of VSMCs both in vitro and in vivo.

Biomechanical regulation of planar cell polarity in endothelial cells

Cell polarity refers to the uneven distribution of certain cytoplasmic components in a cell with a spatial order. The planar cell polarity (PCP), the cell aligns perpendicular to the polar plane, in endothelial cells (ECs) has become a research hot spot. The planar polarity of ECs has a positive significance on the regulation of cardiovascular dysfunction, pathological angiogenesis, and ischemic stroke. The endothelial polarity is stimulated and regulated by biomechanical force. Mechanical stimuli promote endothelial polarization and make ECs produce PCP to maintain the normal physiological and biochemical functions. Here, we overview recent advances in understanding the interplay and mechanism between PCP and ECs function involved in mechanical forces, with a focus on PCP signaling pathways and organelles in regulating the polarity of ECs. And then showed the related diseases caused by ECs polarity dysfunction. This study provides new ideas and therapeutic targets for the treatment of endothelial PCP-related diseases.

Perinatal Hypoxia Aggravates Occlusive Pulmonary Vasculopathy In SU5416/Hypoxia-Treated Rats Later In Life

Pulmonary arterial hypertension (PAH) is a fatal disease, which is characterized by occlusive pulmonary vascular disease (PVD) in small pulmonary arteries. It remains unknown whether perinatal insults aggravate occlusive PVD later in life. We tested the hypothesis that perinatal hypoxia aggravates PVD and survival in rats. PVD was induced in rats with/without perinatal hypoxia (E14 to P3) by injecting SU5416 at 7 weeks of age and subsequent exposure to hypoxia for 3 weeks (SU5416/hypoxia). Hemodynamic and morphological analyses were performed in rats with/without perinatal hypoxia at 7 weeks of age (baseline rats, n=12) and at 15 weeks of age in 4 groups of rats: SU5416/hypoxia or control rats with/without perinatal hypoxia (n=40). Pulmonary artery smooth muscle cells (PASMCs) from the baseline rats with/without perinatal hypoxia were used to assess cell proliferation, inflammation and genomic DNA methylation profile. Although perinatal hypoxia alone did not affect survival, physiological or pathological parameters at baseline or at the end of the experimental period in controls, perinatal hypoxia decreased weight gain and survival rate, and increased right ventricular systolic pressure, right ventricular hypertrophy, and indices of PVD in SU5416/hypoxia rats. Perinatal hypoxia alone accelerated the proliferation and inflammation of cultured PASMCs from baseline rats, which was associated with DNA methylation. In conclusion, we established the first fatal animal model of PAH with worsening hemodynamics and occlusive PVD elicited by perinatal hypoxia, which was associated with hyperproliferative, pro-inflammatory, and epigenetic changes in cultured PASMCs. These findings provide insights into the treatment and prevention of occlusive PVD.

Lung Fibrosis and Fibrosis in the Lungs: Is It All about Myofibroblasts?

In the lungs, fibrosis is a growing clinical problem that results in shortness of breath and can end up in respiratory failure. Even though the main fibrotic disease affecting the lung is idiopathic pulmonary fibrosis (IPF), which affects the interstitial space, there are many fibrotic events that have high and dangerous consequences for the lungs. Asthma, chronic obstructive pulmonary disease (COPD), excessive allergies, clearance of infection or COVID-19, all are frequent diseases that show lung fibrosis. In this review, we describe the different kinds of fibrosis and analyse the main types of cells involved-myofibroblasts and other cells, like macrophages-and review the main fibrotic mechanisms. Finally, we analyse present treatments for fibrosis in the lungs and highlight potential targets for anti-fibrotic therapies.

TLR/WNT: A Novel Relationship in Immunomodulation of Lung Cancer

The most frequent cause of death by cancer worldwide is lung cancer, and the 5-year survival rate is still very poor for patients with advanced stage. Understanding the crosstalk between the signaling pathways that are involved in disease, especially in metastasis, is crucial to developing new targeted therapies. Toll-like receptors (TLRs) are master regulators of the immune responses, and their dysregulation in lung cancer is linked to immune escape and promotes tumor malignancy by facilitating angiogenesis and proliferation. On the other hand, over-activation of the WNT signaling pathway has been reported in lung cancer and is also associated with tumor metastasis via induction of Epithelial-to-mesenchymal-transition (EMT)-like processes. An interaction between both TLRs and the WNT pathway was discovered recently as it was found that the TLR pathway can be activated by WNT ligands in the tumor microenvironment; however, the implications of such interactions in the context of lung cancer have not been discussed yet. Here, we offer an overview of the interaction of TLR-WNT in the lung and its potential implications and role in the oncogenic process.

Extracellular vesicles in respiratory disease

Extracellular vesicles (EVs) are membranous nanoparticles secreted by nearly all cell types and play a critical role in cell-to-cell crosstalk. EVs can be categorized based on their size, surface markers, or the cell type from which they originate. EVs carry "cargo," including but not limited to, RNA, DNA, proteins, and small signaling molecules. To date, many methods have been developed to isolate EVs from biological fluids, such as blood plasma, urine, bronchoalveolar lavage fluid, and urine. Once isolated, EVs can be characterized by dynamic light scattering, nanotracking analysis, nanoscale flow cytometry, and transmission electron microscopy. Given the ability of EVs to transport cargo between cells, research has recently focused on understanding their role in various human diseases. As understanding of their significance to disease processes grows, insight into the mechanisms behind the physiological role of their cargo in target cells can facilitate the development of a new type of biomarker and therapeutic target for diseases in future. In addition, their ability to deliver their cargo selectively to target cells within the human body means that they could serve as therapeutic agents or methods of drug delivery. In this review, we will first introduce EVs and the cargo they carry, outline current methods for EV isolation and characterization, and discuss their potential use as biomarkers and therapeutic agents in the near future.

Molecular Insight into the Therapeutic Effects of Stem Cell-Derived Exosomes in Respiratory Diseases and the Potential for Pulmonary Delivery

Respiratory diseases are the cause of millions of deaths annually around the world. Despite the recent growth of our understanding of underlying mechanisms contributing to the pathogenesis of lung diseases, most therapeutic approaches are still limited to symptomatic treatments and therapies that only delay disease progression. Several clinical and preclinical studies have suggested stem cell (SC) therapy as a promising approach for treating various lung diseases. However, challenges such as the potential tumorigenicity, the low survival rate of the SCs in the recipient body, and difficulties in cell culturing and storage have limited the applicability of SC therapy. SC-derived extracellular vesicles (SC-EVs), particularly SC-derived exosomes (SC-Exos), exhibit most therapeutic properties of stem cells without their potential drawbacks. Similar to SCs, SC-Exos exhibit immunomodulatory, anti-inflammatory, and antifibrotic properties with the potential to be employed in the treatment of various inflammatory and chronic respiratory diseases. Furthermore, recent studies have demonstrated that the microRNA (miRNA) content of SC-Exos may play a crucial role in the therapeutic potential of these exosomes. Several studies have investigated the administration of SC-Exos via the pulmonary route, and techniques for SCs and SC-Exos delivery to the lungs by intratracheal instillation or inhalation have been developed. Here, we review the literature discussing the therapeutic effects of SC-Exos against respiratory diseases and advances in the pulmonary route of delivery of these exosomes to the damaged tissues.

Single Cell Transcriptomic Analysis Reveals Organ Specific Pericyte Markers and Identities

Pericytes are mesenchymal-derived mural cells that wrap around capillaries and directly contact endothelial cells. Present throughout the body, including the cardiovascular system, pericytes are proposed to have multipotent cell-like properties and are involved in numerous biological processes, including regulation of vascular development, maturation, permeability, and homeostasis. Despite their physiological importance, the functional heterogeneity, differentiation process, and pathological roles of pericytes are not yet clearly understood, in part due to the inability to reliably distinguish them from other mural cell populations. Our study focused on identifying pericyte-specific markers by analyzing single-cell RNA sequencing data from tissue-specific mouse pericyte populations generated by the Tabula Muris Senis. We identified the mural cell cluster in murine lung, heart, kidney, and bladder that expressed either of two known pericyte markers, Cspg4 or Pdgfrb. We further defined pericytes as those cells that co-expressed both markers within this cluster. Single-cell differential expression gene analysis compared this subset with other clusters that identified potential pericyte marker candidates, including Kcnk3 (in the lung); Rgs4 (in the heart); Myh11 and Kcna5 (in the kidney); Pcp4l1 (in the bladder); and Higd1b (in lung and heart). In addition, we identified novel markers of tissue-specific pericytes and signaling pathways that may be involved in maintaining their identity. Moreover, the identified markers were further validated in Human Lung Cell Atlas and human heart single-cell RNAseq databases. Intriguingly, we found that markers of heart and lung pericytes in mice were conserved in human heart and lung pericytes. In this study, we, for the first time, identified specific pericyte markers among lung, heart, kidney, and bladder and reveal differentially expressed genes and functional relationships between mural cells.

Upregulation of Endothelial DKK1 (Dickkopf 1) Promotes the Development of Pulmonary Hypertension Through the Sp1 (Specificity Protein 1)/SHMT2 (Serine Hydroxymethyltransferase 2) Pathway

BACKGROUND

Pulmonary hypertension (PH) is a cancer-like proliferative disease, which has no curative treatment options. The dysfunction of pulmonary artery endothelial cells plays a key role in PH. DKK1 (Dickkopf 1) is a secretory glycoprotein that exerts proproliferative effects on tumor cells. In the present study, we aimed to identify the role and underlying mechanism of DKK1 in the development of PH, which still remain unclear.

METHODS AND RESULTS

We found endothelial DKK1 expression was upregulated in serum and lung tissues obtained from patients with PH, mice with hypoxia-induced PH, and human pulmonary artery endothelial cells cultured under hypoxic conditions. Endothelium-specific DKK1-knockout (DKK1ECKO) mice significantly ameliorated hypoxia+Sugen5416 and hypoxia-induced PH. More importantly, neutralizing anti-DKK1 antibody treatment significantly attenuated established hypoxia+Sugen5416 PH. Results of proteome analysis of control and DKK1-knockdown human pulmonary artery endothelial cells identified a significantly differentially expressed protein, SHMT2 (serine hydroxymethyltransferase 2), a key metabolic enzyme in one-carbon metabolism, as a novel DKK1 target. DKK1 knockdown in human pulmonary artery endothelial cells cultured under hypoxic conditions decreased the cellular NADPH/NADP+ ratio, increased reactive oxygen species levels and the extent of mitochondrial DNA damage, and inhibited mitochondrial membrane hyperpolarization. In the context of this altered redox defense and mitochondrial disorder, DKK1 induced a proproliferative and antiapoptotic phenotype in endothelial cells. Furthermore, we confirmed that DKK1 regulated SHMT2 transcription through the AKT-Sp1 (specificity protein 1) signaling axis.

CONCLUSIONS

Our data provide robust evidence and molecular explanations for the associations between DKK1, redox defense, mitochondrial disorders, and PH and reveal a novel target for PH treatment.

Bone marrow mesenchymal stem cell-derived exosomal miR-34c-5p ameliorates RIF by inhibiting the core fucosylation of multiple proteins

Renal interstitial fibrosis (RIF) is an incurable pathological lesion in chronic kidney diseases. Pericyte activation is the major pathological characteristic of RIF. Fibroblast and macrophage activation are also involved in RIF. Studies have revealed that core fucosylation (CF), an important post-translational modification of proteins, plays a key role in pericyte activation and RIF by regulating multiple profibrotic signaling pathways as a hub-like target. Here, we reveal that mesenchymal stem cell (MSC)-derived exosomes reside specifically in the injured kidney and deliver microRNA (miR)-34c-5p to reduce cellular activation and RIF by inhibiting CF. Furthermore, we showed that the CD81-epidermal growth factor receptor (EGFR) ligand-receptor complex aids the entry of exosomal miR-34c-5p into pericytes, fibroblasts, and macrophages. Altogether, our findings reveal a novel role of MSC-derived exosomes in inhibiting multicellular activation via CF and provide a potential intervention strategy for renal fibrosis.

Roles of Wnt Signaling Pathway and ROR2 Receptor in Embryonic Development: An Update Review Article

The Wnt family is a large class of highly conserved cysteine-rich secretory glycoproteins that play a vital role in various cellular and physiological courses through different signaling pathways during embryogenesis and tissue homeostasis 3. Wnt5a is a secreted glycoprotein that belongs to the noncanonical Wnt family and is involved in a wide range of developmental and tissue homeostasis. A growing body of evidence suggests that Wnt5a affects embryonic development, signaling through various receptors, starting with the activation of β-catenin by Wnt5a. In addition to affecting planar cell polarity and Ca2+ pathways, β-catenin also includes multiple signaling cascades that regulate various cell functions. Secondly, Wnt5a can bind to Ror receptors to mediate noncanonical Wnt signaling and a significant ligand for Ror2 in vertebrates. Consistent with the multiple functions of Wnt5A/Ror2 signaling, Wnt5A knockout mice exhibited various phenotypic defects, including an inability to extend the anterior and posterior axes of the embryo. Numerous essential roles of Wnt5a/Ror2 in development have been demonstrated. Therefore, Ror signaling pathway become a necessary target for diagnosing and treating human diseases. The Wnt5a- Ror2 signaling pathway as a critical factor has attracted extensive attention.

Pulmonary Arterial Hypertension: Emerging Principles of Precision Medicine across Basic Science to Clinical Practice

Pulmonary arterial hypertension (PAH) is an enigmatic and deadly vascular disease with no known cure. Recent years have seen rapid advances in our understanding of the molecular underpinnings of PAH, with an expanding knowledge of the molecular, cellular, and systems-level drivers of disease that are being translated into novel therapeutic modalities. Simultaneous advances in clinical technology have led to a growing list of tools with potential application to diagnosis and phenotyping. Guided by fundamental biology, these developments hold the potential to usher in a new era of personalized medicine in PAH with broad implications for patient management and great promise for improved outcomes.

Cell-to-Cell Crosstalk: A New Insight into Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease with high pulmonary arterial pressure, pulmonary vasoconstriction, pulmonary vascular remodeling, and microthrombosis in complex plexiform lesions, but it has been unclear of the exact mechanism of PH. A new understanding of the pathogenesis of PH is occurred and focused on the role of crosstalk between the cells on pulmonary vessels and pulmonary alveoli. It was found that the crosstalks among the endothelial cells, smooth muscle cells, fibroblasts, pericytes, alveolar epithelial cells, and macrophages play important roles in cell proliferation, migration, inflammation, and so on. Therefore, the heterogeneity of multiple pulmonary blood vessels and alveolar cells and tracking the transmitters of cell communication could be conducive to the further insights into the pathogenesis of PH to discover the potential therapeutic targets for PH.

Potential long-term effects of SARS-CoV-2 infection on the pulmonary vasculature: a global perspective

The lungs are the primary target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, with severe hypoxia being the cause of death in the most critical cases. Coronavirus disease 2019 (COVID-19) is extremely heterogeneous in terms of severity, clinical phenotype and, importantly, global distribution. Although the majority of affected patients recover from the acute infection, many continue to suffer from late sequelae affecting various organs, including the lungs. The role of the pulmonary vascular system during the acute and chronic stages of COVID-19 has not been adequately studied. A thorough understanding of the origins and dynamic behaviour of the SARS-CoV-2 virus and the potential causes of heterogeneity in COVID-19 is essential for anticipating and treating the disease, in both the acute and the chronic stages, including the development of chronic pulmonary hypertension. Both COVID-19 and chronic pulmonary hypertension have assumed global dimensions, with potential complex interactions. In this Review, we present an update on the origins and behaviour of the SARS-CoV-2 virus and discuss the potential causes of the heterogeneity of COVID-19. In addition, we summarize the pathobiology of COVID-19, with an emphasis on the role of the pulmonary vasculature, both in the acute stage and in terms of the potential for developing chronic pulmonary hypertension. We hope that the information presented in this Review will help in the development of strategies for the prevention and treatment of the continuing COVID-19 pandemic.

In this Review, the authors discuss the potential causes of the heterogeneity of COVID-19 and summarize the pathobiology of the disease, with an emphasis on the role of the pulmonary vasculature in the acute stage and the potential for developing chronic pulmonary hypertension.

A thorough understanding of the dynamic behaviour of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential to understanding its heterogeneous effects on the pulmonary vasculature in patients with coronavirus disease 2019 (COVID-19).

The severity and clinical phenotype of COVID-19 are influenced by host factors, including socioeconomic factors and genetics.

Silent hypoxia is a major and independent cause of lung damage in COVID-19; the use of modern imaging techniques is proving to be very valuable in identifying silent hypoxia.

The pulmonary vascular system has a major role in the pathobiology of COVID-19.

Both COVID-19 and chronic pulmonary hypertension are global diseases with a complex interaction.

A Synopsis of Signaling Crosstalk of Pericytes and Endothelial Cells in Salivary Gland

The salivary gland (SG) microvasculature constitutes a dynamic cellular organization instrumental to preserving tissue stability and homeostasis. The interplay between pericytes (PCs) and endothelial cells (ECs) culminates as a key ingredient that coordinates the development, maturation, and integrity of vessel building blocks. PCs, as a variety of mesenchymal stem cells, enthrall in the field of regenerative medicine, supporting the notion of regeneration and repair. PC-EC interconnections are pivotal in the kinetic and intricate process of angiogenesis during both embryological and post-natal development. The disruption of this complex interlinkage corresponds to SG pathogenesis, including inflammation, autoimmune disorders (Sjögren’s syndrome), and tumorigenesis. Here, we provided a global portrayal of major signaling pathways between PCs and ECs that cooperate to enhance vascular steadiness through the synergistic interchange. Additionally, we delineated how the crosstalk among molecular networks affiliate to contribute to a malignant context. Additionally, within SG microarchitecture, telocytes and myoepithelial cells assemble a labyrinthine companionship, which together with PCs appear to synchronize the regenerative potential of parenchymal constituents. By underscoring the intricacy of signaling cascades within cellular latticework, this review sketched a perceptive basis for target-selective drugs to safeguard SG function.

A review of BMP and Wnt signaling pathway in the pathogenesis of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive elevation in mean pulmonary arterial pressure. This occurs due to abnormal remodeling of small peripheral lung vasculature resulting in progressive occlusion of the artery lumen that eventually causes right heart failure and death. Current therapeutic options for PAH are limited and focused mainly on reversal of pulmonary vasoconstriction and proliferation of vascular cells. Although these treatments can relieve disease symptoms, PAH remains a progressive lethal disease.Bone morphogenetic proteins (BMPs) and their receptors were required for PAH-induced right ventricular hypertrophy. Emerging data suggest that restoration of BMP type II receptor (BMPR2) signaling in PAH is a promising alternative that could prevent and reverse pulmonary vascular remodeling. BMPR2 mutations have been identified in >70% of familial and roughly 15% of sporadic PAH cases. Wingless (Wnt) are a family of secreted glycoproteins with varying expression patterns and a range of functions, Wnt signaling pathway is divided into canonical signaling pathway and non-canonical signaling pathway. A recent study reports that interaction between BMP and Wnt closely associated with lung development, those cascade coordination regulation stem cell fate which determine lung branching morphogenes. The promoting effect of BMPR2 on proliferation, survival, and motility of endothelial cells was through recruiting Wnts signaling pathway, the interaction between BMP and Wnt closely associated with lung development.Therefore, in this review, we outline the latest advances of BMP and Wnt signaling pathway in the pathogenesis of PAH and disease progression.

[Research progress of tissue engineering technology in promoting revascularization of necrotic femoral bone tissue]

Objective

To summarize the research progress of tissue engineering technology to promote bone tissue revascularization in osteonecrosis of the femoral head (ONFH).

Methods

The relevant domestic and foreign literature in recent years was extensively reviewed. The mechanism of femoral head vascularization and the application progress of tissue engineering technology in the promotion of ONFH bone tissue revascularization were summarized.

Results

Rebuilding or improving the blood supply of the femoral head is the key to the treatment of ONFH. Tissue engineering is a hot spot in current research. It mainly focuses on the three elements of seed cells, scaffold materials, and angiogenic growth factors, combined with three-dimensional printing technology and drug delivery systems to promote the revascularization of the femoral bone tissue.

Conclusion

The strategy of revascularization of the femoral head can improve the local blood supply and delay or even reverse the progression of ONFH disease.

The role and therapeutic potential of exosomes in ischemic stroke

Ischemic stroke is a disease caused by insufficient blood and oxygen supply to the brain, which is mainly due to intracranial arterial stenosis and middle cerebral artery occlusion. Exosomes play an important role in cerebral ischemia. Nucleic acid substances such as miRNA, circRNA, lncRNA in exosomes can play communication roles and improve cerebral ischemia by regulating the development and regeneration of the nervous system, remodeling of blood vessels and inhibiting neuroinflammation. Furthermore, exosomes modulate stroke through various mechanisms, including improving neural communication, promoting the development of neuronal cells and myelin synapses, neurovascular unit remodeling and maintaining homeostasis of the nervous system. At the same time, exosomes are also a good carrier of bioactive substances, which can be modified and targeted to the lesion site. Here, we review the roles of exosomes in cerebral ischemia, and discuss the possible mechanisms and potentials of modification of exosomes for targeting stroke, providing a new idea for the prevention and treatment of cerebral ischemia.

Exosome-mediated stable epigenetic repression of HIV-1

Human Immunodeficiency Virus (HIV-1) produces a persistent latent infection. Control of HIV-1 using combination antiretroviral therapy (cART) comes at the cost of life-shortening side effects and development of drug-resistant HIV-1. An ideal and safer therapy should be deliverable in vivo and target the stable epigenetic repression of the virus, inducing a stable "block and lock" of virus expression. Towards this goal, we developed an HIV-1 promoter-targeting Zinc Finger Protein (ZFP-362) fused to active domains of DNA methyltransferase 3 A to induce long-term stable epigenetic repression of HIV-1. Cells were engineered to produce exosomes packaged with RNAs encoding this HIV-1 repressor protein. We find here that the repressor loaded anti-HIV-1 exosomes suppress virus expression and that this suppression is mechanistically driven by DNA methylation of HIV-1 in humanized NSG mouse models. The observations presented here pave the way for an exosome-mediated systemic delivery platform of therapeutic cargo to epigenetically repress HIV-1 infection.

Endothelial cells in the pathogenesis of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease that involves pulmonary vasoconstriction, small vessel obliteration, large vessel thickening and obstruction, and development of plexiform lesions. PAH vasculopathy leads to progressive increases in pulmonary vascular resistance, right heart failure and, ultimately, premature death. Besides other cell types that are known to be involved in PAH pathogenesis (e.g. smooth muscle cells, fibroblasts and leukocytes), recent studies have demonstrated that endothelial cells (ECs) have a crucial role in the initiation and progression of PAH. The EC-specific role in PAH is multi-faceted and affects numerous pathophysiological processes, including vasoconstriction, inflammation, coagulation, metabolism and oxidative/nitrative stress, as well as cell viability, growth and differentiation. In this review, we describe how EC dysfunction and cell signalling regulate the pathogenesis of PAH. We also highlight areas of research that warrant attention in future studies, and discuss potential molecular signalling pathways in ECs that could be targeted therapeutically in the prevention and treatment of PAH.

Vanderpool R, Al Ghouleh I, Lai YC. Recent advancements in pulmonary arterial hypertension and right heart failure research: overview of selected abstracts from ATS2020 and emerging COVID-19 research

Each year the American Thoracic Society (ATS) Conference brings together scientists who conduct basic, translational and clinical research to present on the recent advances in the field of respirology. Due to the Coronavirus Disease of 2019 (COVID-19) pandemic, the ATS2020 Conference was held online in a series of virtual meetings. In this review, we focus on the breakthroughs in pulmonary hypertension research. We have selected 11 of the best basic science abstracts which were presented at the ATS2020 Assembly on Pulmonary Circulation mini-symposium "What's New in Pulmonary Arterial Hypertension (PAH) and Right Ventricular (RV) Signaling: Lessons from the Best Abstracts," reflecting the current state of the art and associated challenges in PH. Particular emphasis is placed on understanding the mechanisms underlying RV failure, the regulation of inflammation, and the novel therapeutic targets that emerged from preclinical research. The pathologic interactions between pulmonary hypertension, right ventricular function and COVID-19 are also discussed.