Methylation-mediated silencing of PTPRD induces pulmonary hypertension by promoting pulmonary arterial smooth muscle cell migration via the PDGFRB/PLCγ1 axis

Genome-wide characterization of circular RNAs in three rat models of pulmonary hypertension reveals distinct pathological patterns

BACKGROUND

Pulmonary hypertension (PH) is a devastating disease marked by elevated pulmonary artery pressure, resulting in right ventricular (RV) failure and mortality. Despite the identification of several dysregulated genes in PH, the involvement of circular RNAs (circRNAs), a subset of long noncoding RNAs, remains largely unknown.

METHODS

In this study, high-throughput RNA sequencing was performed to analyze the genome-wide expression patterns of circRNAs in pulmonary arteries from three models of PH rats induced by hypoxia (Hyp), hypoxia/Sugen5416 (HySu), and monocrotaline (MCT). Differentially expressed circRNAs (DEcircRNAs) were identified, and a weighted gene coexpression network was constructed to explore circRNA networks associated with PH pathogenesis. A circRNA-miRNA-mRNA regulatory network was built, and the functional significance of targeted mRNAs was evaluated. Single-cell RNA sequencing provided insights into the distribution of cell type-specific circRNAs across PH progression.

RESULTS

Our analysis revealed 45 circRNAs exhibiting significant changes across all three PH rat models, with their host genes participating in the calcium signaling and muscle contraction. We identified 372 PH-related circRNA-miRNA-mRNA interactions, shedding light on the regulatory networks during PH development. Furthermore, we uncovered 186, 195 and 311 Hyp-, Hysu- and MCT-specific circRNAs, respectively. These circRNAs were enriched in distinct biological processes, emphasizing their unique regulatory roles. Single-cell spatial distribution analysis of these circRNAs in the pulmonary arteries of PH patients revealed that Hyp-specific circRNA predominantly appeared in the pulmonary vascular structural cells, while HySu- and MCT-specific circRNAs exhibited broader distribution, including significant enrichment in immune-related cells.

CONCLUSION

Our study presents the first comprehensive view of circRNA regulatory networks in the pulmonary arteries of three PH rat models. We provide insights into PH-associated circRNAs, particularly their involvement in calcium signaling and muscle contraction.

A novel PDGFR inhibitor WQ-C-401 prevents pulmonary vascular remodeling in rats with monocrotaline-induced pulmonary arterial hypertension

Platelet-derived growth factor (PDGF) is one of the most important cytokines associated with pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). PDGF receptor (PDGFR) inhibition exerted therapeutic effects on PAH in clinical trials, but serious side effects warrant the withdrawal of existing drugs. In this study, a novel highly selective PDGFR inhibitor WQ-C-401 was developed, and its effects on PDGFR signaling pathway and pulmonary vascular remodeling in PAH were investigated. Cell proliferation assays and Western blot analysis of PDGFRα/β phosphorylation showed that WQ-C-401 inhibited PDGFR-mediated cell proliferation assay and suppressed PDGFR phosphorylation in a concentration-dependent manner. DiscoverX's KinomeScanTM technology confirmed the good kinome selectivity of WQ-C-401 (S score (1) of PDGFR = (0.01)). In monocrotaline (MCT)-induced PAH rats, intragastric administration of WQ-C-401 (25, 50, 100 mg/kg/d) or imatinib (50 mg/kg/d, positive control) significantly decreased right ventricular systolic pressure (RVSP). Histological analysis demonstrated that WQ-C-401 inhibited pulmonary vascular remodeling by reducing muscularization and fibrosis, as well as alleviated right ventricular hypertrophy in MCT-treated rats. In addition, WQ-C-401 suppressed MCT-induced cell hyperproliferation and CD68+ macrophage infiltration around the pulmonary artery. In vitro, WQ-C-401 inhibited PDGF-BB-induced proliferation and migration of human pulmonary arterial smooth muscle cells (PASMCs). Moreover, Western blot analysis showed that WQ-C-401 concertration-dependently inhibited PDGF-BB-induced phosphorylation of ERK1/2 and PDGFRβ Y751, decreased collagen Ⅰ synthesis and increased alpha smooth muscle actin (α-SMA) expression in PASMCs. Collectively, our results suggest that WQ-C-401 is a selective and potent PDGFR inhibitor which could be a promising drug for the therapeutics of PAH by preventing pulmonary vascular remodeling.

Genomic structural variation contributes to evolved changes in gene expression in high-altitude Tibetan sheep

Tibetan sheep were introduced to the Qinghai Tibet plateau roughly 3,000 B.P., making this species a good model for investigating genetic mechanisms of high-altitude adaptation over a relatively short timescale. Here, we characterize genomic structural variants (SVs) that distinguish Tibetan sheep from closely related, low-altitude Hu sheep, and we examine associated changes in tissue-specific gene expression. We document differentiation between the two sheep breeds in frequencies of SVs associated with genes involved in cardiac function and circulation. In Tibetan sheep, we identified high-frequency SVs in a total of 462 genes, including EPAS1, PAPSS2, and PTPRD. Single-cell RNA-Seq data and luciferase reporter assays revealed that the SVs had cis-acting effects on the expression levels of these three genes in specific tissues and cell types. In Tibetan sheep, we identified a high-frequency chromosomal inversion that exhibited modified chromatin architectures relative to the noninverted allele that predominates in Hu sheep. The inversion harbors several genes with altered expression patterns related to heart protection, brown adipocyte proliferation, angiogenesis, and DNA repair. These findings indicate that SVs represent an important source of genetic variation in gene expression and may have contributed to high-altitude adaptation in Tibetan sheep.

Unwinding circular RNA's role in inflammatory pulmonary diseases

Circular RNAs (circRNAs) have emerged as pivotal regulators of gene expression and cellular processes in various physiological and pathological conditions. In recent years, there has been a growing interest in investigating the role of circRNAs in inflammatory lung diseases, owing to their potential to modulate inflammation-associated pathways and contribute to disease pathogenesis. Inflammatory lung diseases, like asthma, chronic obstructive pulmonary disease (COPD), and COVID-19, pose significant global health challenges. The dysregulation of inflammatory responses demonstrates a pivotal function in advancing these diseases. CircRNAs have been identified as important players in regulating inflammation by functioning as miRNA sponges, engaging with RNA-binding proteins, and participating in intricate ceRNA networks. These interactions enable circRNAs to regulate the manifestation of key inflammatory genes and signaling pathways. Furthermore, emerging evidence suggests that specific circRNAs are differentially expressed in response to inflammatory stimuli and exhibit distinct patterns in various lung diseases. Their involvement in immune cell activation, cytokine production, and tissue remodeling processes underscores their possible capabilities as therapeutic targets and diagnostic biomarkers. Harnessing the knowledge of circRNA-mediated regulation in inflammatory lung diseases could lead to the development of innovative strategies for disease management and intervention. This review summarizes the current understanding of the role of circRNAs in inflammatory lung diseases, focusing on their regulatory mechanisms and functional implications.

In Silico and In Vitro Mapping of Receptor-Type Protein Tyrosine Phosphatase Receptor Type D in Health and Disease: Implications for Asprosin Signalling in Endometrial Cancer and Neuroblastoma

BACKGROUND

Protein Tyrosine Phosphatase Receptor Type D (PTPRD) is involved in the regulation of cell growth, differentiation, and oncogenic transformation, as well as in brain development. PTPRD also mediates the effects of asprosin, which is a glucogenic hormone/adipokine derived following the cleavage of the C-terminal of fibrillin 1. Since the asprosin circulating levels are elevated in certain cancers, research is now focused on the potential role of this adipokine and its receptors in cancer. As such, in this study, we investigated the expression of PTPRD in endometrial cancer (EC) and the placenta, as well as in glioblastoma (GBM).

METHODS

An array of in silico tools, in vitro models, tissue microarrays (TMAs), and liquid biopsies were employed to determine the gene and protein expression of PTPRD in healthy tissues/organs and in patients with EC and GBM.

RESULTS

PTPRD exhibits high expression in the occipital lobe, parietal lobe, globus pallidus, ventral thalamus, and white matter, whereas in the human placenta, it is primarily localised around the tertiary villi. PTPRD is significantly upregulated at the mRNA and protein levels in patients with EC and GBM compared to healthy controls. In patients with EC, PTPRD is significantly downregulated with obesity, whilst it is also expressed in the peripheral leukocytes. The EC TMAs revealed abundant PTPRD expression in both low- and high-grade tumours. Asprosin treatment upregulated the expression of PTPRD only in syncytialised placental cells.

CONCLUSIONS

Our data indicate that PTPRD may have potential as a biomarker for malignancies such as EC and GBM, further implicating asprosin as a potential metabolic regulator in these cancers. Future studies are needed to explore the potential molecular mechanisms/signalling pathways that link PTPRD and asprosin in cancer.

Fatty Oil of Descurainia Sophia Nanoparticles Improve Monocrotaline-Induced Pulmonary Hypertension in Rats Through PLC/IP3R/Ca2+ Signaling Pathway

Purpose

Fatty oil of Descurainia Sophia (OIL) has poor stability and low solubility, which limits its pharmacological effects. We hypothesized that fatty oil nanoparticles (OIL-NPs) could overcome this limitation. The protective effect of OIL-NPs against monocrotaline-induced lung injury in rats was studied.

Methods

We prepared OIL-NPs by wrapping fatty oil with polylactic-polyglycolide nanoparticles (PLGA-NPs) and conducted in vivo and in vitro experiments to explore its anti-pulmonary hypertension (PH) effect. In vitro, we induced malignant proliferation of pulmonary artery smooth muscle cells (RPASMC) using anoxic chambers, and studied the effects of OIL-NPs on the malignant proliferation of RPASMC cells and phospholipase C (PLC)/inositol triphosphate receptor (IP3R)/Ca2+ signal pathways. In vivo, we used small animal echocardiography, flow cytometry, immunohistochemistry, western blotting (WB), polymerase chain reaction (PCR) and metabolomics to explore the effects of OIL-NPs on the heart and lung pathological damage and PLC/IP3R/Ca2+ signal pathway of pulmonary hypertension rats.

Results

We prepared fatty into OIL-NPs. In vitro, OIL-NPs could improve the mitochondrial function and inhibit the malignant proliferation of RPASMC cells by inhibiting the PLC/IP3R/Ca2+signal pathway. In vivo, OIL-NPs could reduce the pulmonary artery pressure of rats and alleviate the pathological injury and inflammatory reaction of heart and lung by inhibiting the PLC/IP3R/Ca2+ signal pathway.

Conclusion

OIL-NPs have anti-pulmonary hypertension effect, and the mechanism may be related to the inhibition of PLC/IP3R/Ca2+signal pathway.

Proteome Profiling of Brain Vessels in a Mouse Model of Cerebrovascular Pathology

Cerebrovascular pathology that involves altered protein levels (or signaling) of the transforming growth factor beta (TGFβ) family has been associated with various forms of age-related dementias, including Alzheimer disease (AD) and vascular cognitive impairment and dementia (VCID). Transgenic mice overexpressing TGFβ1 in the brain (TGF mice) recapitulate VCID-associated cerebrovascular pathology and develop cognitive deficits in old age or when submitted to comorbid cardiovascular risk factors for dementia. We characterized the cerebrovascular proteome of TGF mice using mass spectrometry (MS)-based quantitative proteomics. Cerebral arteries were surgically removed from 6-month-old-TGF and wild-type mice, and proteins were extracted and analyzed by gel-free nanoLC-MS/MS. We identified 3602 proteins in brain vessels, with 20 demonstrating significantly altered levels in TGF mice. For total and/or differentially expressed proteins (p ≤ 0.01, ≥ 2-fold change), using multiple databases, we (a) performed protein characterization, (b) demonstrated the presence of their RNA transcripts in both mouse and human cerebrovascular cells, and (c) demonstrated that several of these proteins were present in human extracellular vesicles (EVs) circulating in blood. Finally, using human plasma, we demonstrated the presence of several of these proteins in plasma and plasma EVs. Dysregulated proteins point to perturbed brain vessel vasomotricity, remodeling, and inflammation. Given that blood-isolated EVs are novel, attractive, and a minimally invasive biomarker discovery platform for age-related dementias, several proteins identified in this study can potentially serve as VCID markers in humans.

Betulinaldehyde inhibits vascular remodeling by regulating the microenvironment through the PLCγ1/Ca2+/MMP9 pathway

BACKGROUND

Vascular remodeling plays a crucial role in the pathogenesis of several cardiovascular diseases (CVDs). Unfortunately, current drug therapies offer limited relief for vascular remodeling. Therefore, the development of innovative therapeutic strategies or drugs that target vascular remodeling is imperative. Betulinaldehyde (BA) is a triterpenoid with diverse biological activities, but its effects on vascular remodeling remain unclear.

OBJECTIVE

This study aimed to investigate the role of BA in vascular remodeling and its mechanism of action, providing valuable information for future applications of BA in the treatment of CVDs.

METHODS

Network pharmacology was used to predict the key targets of BA in vascular remodeling. The effect of BA on vascular remodeling was assessed in a rat model of balloon injury using hematoxylin and eosin staining, Masson staining, immunohistochemistry staining, and Western blotting. A phenotypic transformation model of vascular smooth muscle cells (VSMCs) was induced by platelet-derived growth factor-BB, and the functional impacts of BA on VSMCs were assessed via CCK-8, EdU, Wound healing, Transwell, and Western blotting. Finally, after manipulation of phospholipase C gamma1 (PLCγ1) expression, Western blotting and Ca²⁺ levels determination were performed to investigate the potential mechanism of action of BA.

RESULTS

The most key target of BA in vascular remodeling, matrix metalloproteinase 9 (MMP9), was identified through network pharmacology screening. Vascular remodeling was alleviated by BA in vivo and its effects were associated with decreased MMP9 expression. In vitro studies indicated that BA inhibited VSMC proliferation, migration, phenotypic transformation, and downregulated MMP9 expression. Additionally, BA decreased PLCγ1 expression and Ca²⁺ levels in VSMCs. However, after pretreatment with a phospholipase C agonist, BA's effects on down-regulating the expression of PLCγ1 and Ca²⁺ levels were inhibited, while the expression of MMP9 increased compared to that in the BA treatment group.

CONCLUSION

This study demonstrated the critical role of BA in vascular remodeling. These findings revealed a novel mechanism whereby BA mediates its protective effects through MMP9 regulation by inhibiting the PLCγ1/Ca²⁺/MMP9 signaling pathway. Overall, BA may potentially be developed into a novel medication for CVDs and may serve as a promising therapeutic strategy for improving recovery from CVDs by targeting MMP9.

[Effect of platelet-derived growth factor-BB on pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension and its mechanism]

OBJECTIVES

To study the effect of platelet-derived growth factor-BB (PDGF-BB) on pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension (HPH).

METHODS

A total of 128 neonatal rats were randomly divided into four groups: PDGF-BB+HPH, HPH, PDGF-BB+normal oxygen, and normal oxygen (n=32 each). The rats in the PDGF-BB+HPH and PDGF-BB+normal oxygen groups were given an injection of 13 μL 6×1010 PFU/mL adenovirus with PDGF-BB genevia the caudal vein. After 24 hours of adenovirus transfection, the rats in the HPH and PDGF-BB+HPH groups were used to establish a neonatal rat model of HPH. Right ventricular systolic pressure (RVSP) was measured on days 3, 7, 14, and 21 of hypoxia. Hematoxylin-eosin staining was used to observe pulmonary vascular morphological changes under an optical microscope, and vascular remodeling parameters (MA% and MT%) were also measured. Immunohistochemistry was used to measure the expression levels of PDGF-BB and proliferating cell nuclear antigen (PCNA) in lung tissue.

RESULTS

The rats in the PDGF-BB+HPH and HPH groups had a significantly higher RVSP than those of the same age in the normal oxygen group at each time point (P<0.05). The rats in the PDGF-BB+HPH group showed vascular remodeling on day 3 of hypoxia, while those in the HPH showed vascular remodeling on day 7 of hypoxia. On day 3 of hypoxia, the PDGF-BB+HPH group had significantly higher MA% and MT% than the HPH, PDGF-BB+normal oxygen, and normal oxygen groups (P<0.05). On days 7, 14, and 21 of hypoxia, the PDGF-BB+HPH and HPH groups had significantly higher MA% and MT% than the PDGF-BB+normal oxygen and normal oxygen groups (P<0.05). The PDGF-BB+HPH and HPH groups had significantly higher expression levels of PDGF-BB and PCNA than the normal oxygen group at all time points (P<0.05). On days 3, 7, and 14 of hypoxia, the PDGF-BB+HPH group had significantly higher expression levels of PDGF-BB and PCNA than the HPH group (P<0.05), while the PDGF-BB+normal oxygen group had significantly higher expression levels of PDGF-BB and PCNA than the normal oxygen group (P<0.05).

CONCLUSIONS

Exogenous administration of PDGF-BB in neonatal rats with HPH may upregulate the expression of PCNA, promote pulmonary vascular remodeling, and increase pulmonary artery pressure.

PTPN1 Deficiency Modulates BMPR2 Signaling and Induces Endothelial Dysfunction in Pulmonary Arterial Hypertension

Bone morphogenic protein receptor 2 (BMPR2) expression and signaling are impaired in pulmonary arterial hypertension (PAH). How BMPR2 signaling is decreased in PAH is poorly understood. Protein tyrosine phosphatases (PTPs) play important roles in vascular remodeling in PAH. To identify whether PTPs modify BMPR2 signaling, we used a siRNA-mediated high-throughput screening of 22,124 murine genes in mouse myoblastoma reporter cells using ID1 expression as readout for BMPR2 signaling. We further experimentally validated the top hit, PTPN1 (PTP1B), in healthy human pulmonary arterial endothelial cells (PAECs) either silenced by siRNA or exposed to hypoxia and confirmed its relevance to PAH by measuring PTPN1 levels in blood and PAECs collected from PAH patients. We identified PTPN1 as a novel regulator of BMPR2 signaling in PAECs, which is downregulated in the blood of PAH patients, and documented that downregulation of PTPN1 is linked to endothelial dysfunction in PAECs. These findings point to a potential involvement for PTPN1 in PAH and will aid in our understanding of the molecular mechanisms involved in the disease.