PIM1 (Moloney Murine Leukemia Provirus Integration Site) Inhibition Decreases the Nonhomologous End-Joining DNA Damage Repair Signaling Pathway in Pulmonary Hypertension

Pim Kinases: Important Regulators of Cardiovascular Disease

Pim Kinases; Pim-1, Pim-2, and Pim-3, are a family of constitutively active serine/threonine kinases, widely associated with cell survival, proliferation, and migration. Historically considered to be functionally redundant, independent roles for the individual isoforms have been described. Whilst most established for their role in cancer progression, there is increasing evidence for wider pathological roles of Pim kinases within the context of cardiovascular disease, including inflammation, thrombosis, and cardiac injury. The Pim kinase isoforms have widespread expression in cardiovascular tissues, including the heart, coronary artery, aorta, and blood, and have been demonstrated to be upregulated in several co-morbidities/risk factors for cardiovascular disease. Pim kinase inhibition may thus be a desirable therapeutic for a multi-targeted approach to treat cardiovascular disease and some of the associated risk factors. In this review, we discuss what is known about Pim kinase expression and activity in cells of the cardiovascular system, identify areas where the role of Pim kinase has yet to be fully explored and characterised and review the suitability of targeting Pim kinase for the prevention and treatment of cardiovascular events in high-risk individuals.

Identification of novel genetic variants, including PIM1 and LINC01491, with ICD-10 based diagnosis of pulmonary arterial hypertension in the UK Biobank cohort

Pulmonary arterial hypertension (PAH) is characterized by remodeling and narrowing of the pulmonary vasculature which results in elevations of pulmonary arterial pressures. Here, we conducted a genome-wide association study (GWAS) using the UK Biobank, analyzing the genomes of 493 individuals diagnosed with primary pulmonary hypertension, based on ICD-10 coding, compared to 24,650 age, sex, and ancestry-matched controls in a 1:50 case-control design. Genetic variants were analyzed by Plink’s firth logistic regression and assessed for association with primary pulmonary hypertension. We identified three linked variants in the PIM1 gene, which encodes a protooncogene that has been garnering interest as a potential therapeutic target for PAH, that were associated with PAH with genome wide significance, one (rs192449585) of which lies in the promoter region of the gene. We also identified 15 linked variants in the LINC01491 gene. These results provide genetic evidence supporting the role of PIM1 inhibitors as a potential therapeutic option for PAH.

DNA-PKcs participated in hypoxic pulmonary hypertension

BACKGROUND

Hypoxic pulmonary hypertension (HPH) is a common complication of chronic lung disease, which severely affects the survival and prognosis of patients. Several recent reports have shown that DNA damage and repair plays a crucial role in pathogenesis of pulmonary arterial hypertension. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) as a part of DNA-PK is a molecular sensor for DNA damage that enhances DSB repair. This study aimed to demonstrate the expression and potential mechanism of DNA-PKcs on the pathogenesis of HPH.

METHODS

Levels of DNA-PKcs and other proteins in explants of human and rats pulmonary artery from lung tissues and pulmonary artery smooth muscle cells (PASMC) were measured by immunohistochemistry and western blot analysis. The mRNA expression levels of DNA-PKcs and NOR1 in PASMCs were quantified with qRT-PCR. Meanwhile, the interaction among proteins were detected by Co-immunoprecipitation (Co-IP) assays. Cell proliferation and apoptosis was assessed by cell counting kit-8 assay(CCK-8), EdU incorporation and flow cytometry. Rat models of HPH were constructed to verify the role of DNA-PKcs in pulmonary vascular remodeling in vivo.

RESULTS

DNA-PKcs protein levels were both significantly up-regulated in explants of pulmonary artery from HPH models and lung tissues of patients with hypoxemia. In human PASMCs, hypoxia up-regulated DNA-PKcs in a time-dependent manner. Downregulation of DNA-PKcs by targeted siRNA or small-molecule inhibitor NU7026 both induced cell proliferation inhibition and cell cycle arrest. DNA-PKcs affected proliferation by regulating NOR1 protein synthesis followed by the expression of cyclin D1. Co-immunoprecipitation of NOR1 with DNA-PKcs was severely increased in hypoxia. Meanwhile, hypoxia promoted G2 + S phase, whereas the down-regulation of DNA-PKcs and NOR1 attenuated the effects of hypoxia. In vivo, inhibition of DNA-PKcs reverses hypoxic pulmonary vascular remodeling and prevented HPH.

CONCLUSIONS

Our study indicated the potential mechanism of DNA-PKcs in the development of HPH. It might provide insights into new therapeutic targets for pulmonary vascular remodeling and pulmonary hypertension.

Evaluating the therapeutic role of selected active compounds in Plumula Nelumbinis on pulmonary hypertension via network pharmacology and experimental analysis

Excessive proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) are critical factors leading to vascular remodeling in pulmonary hypertension (PH). This study aimed to explore the effect and potential mechanism of Plumula Nelumbinis on PH by using network pharmacology and experimental analysis. Network pharmacology and molecular docking results indicated that the potential active components of Plumula Nelumbinis against PH were mainly alkaloid compounds, including neferine, liensinine, and isoliensinine. Subsequently, by constructing a Su5416 plus hypoxia (SuHx)-induced PH rat model, we found that the total alkaloids of Plumula Nelumbinis (TAPN) can reduce the right ventricular systolic pressure, delay the process of pulmonary vascular and right ventricular remodeling, and improve the right heart function in PH rats. In addition, TAPN can effectively reverse the upregulation of collagen1, collagen3, MMP2, MMP9, PCNA, PIM1, and p-SRC protein expression in lung tissue of PH rats. Finally, by constructing a hypoxia-induced PASMCs proliferation and migration model, we further found that TAPN, neferine, liensinine, and isoliensinine could inhibit the proliferation and migration of PASMCs induced by hypoxia; reverse the upregulation of collagen1, collagen3, MMP2, MMP9, PCNA, PIM1 and p-SRC protein expression in PASMCs. Based on these observations, we conclude that the alkaloid compounds extracted from Plumula Nelumbinis (such as neferine, liensinine, and isoliensinine) can inhibit the abnormal proliferation and migration of PASMCs by regulating the expression of p-SRC and PIM1, thereby delaying the progression of PH.

Oxidative Stress and Antioxidative Therapy in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is clinically characterized by a progressive increase in pulmonary artery pressure, followed by right ventricular hypertrophy and subsequently right heart failure. The underlying mechanism of PAH includes endothelial dysfunction and intimal smooth muscle proliferation. Numerous studies have shown that oxidative stress is critical in the pathophysiology of PAH and involves changes in reactive oxygen species (ROS), reactive nitrogen (RNS), and nitric oxide (NO) signaling pathways. Disrupted ROS and NO signaling pathways cause the proliferation of pulmonary arterial endothelial cells (PAECs) and pulmonary vascular smooth muscle cells (PASMCs), resulting in DNA damage, metabolic abnormalities, and vascular remodeling. Antioxidant treatment has become a main area of research for the treatment of PAH. This review mainly introduces oxidative stress in the pathogenesis of PAH and antioxidative therapies and explains why targeting oxidative stress is a valid strategy for PAH treatment.

Comprehensive Review on Novel Targets and Emerging Therapeutic Modalities for Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is the progressive increase in mean pulmonary arterial pressure (mPAP) (≥ 20 mmHg at rest). Current treatment strategies include the drugs targeting at nitric oxide pathway, endothelin receptors, prostaglandin receptors, thromboxane receptors and phosphodiesterase inhibitors, which provides the symptomatic relief. Despite of these treatments, the mortality amongst the PAH patients remains high due to non-reversal of the condition. This review primarily covers the introduction of PAH and the current treatments of the disease. This is followed by the newer disease targets expressed in the pathobiology of the disease like Rho Kinase Pathway, Vasoactive Intestinal Peptide Pathway, Receptor Tyrosine Kinases, Serotonin signalling pathway, Voltage-gated potassium (Kv) channel pathway. Newer formulation strategies for targeting at these specific receptors were covered and includes nano formulations like liposomes, Micelles, Polymeric Nanoparticles, Solid Lipid Nanoparticles (SLN), Bioresorbable stents, NONOates, Cell-Based Therapies, miRNA therapy for PAH. Novel targets were identified for their role in the pathogenesis of the PAH and needs to be targeted with new molecules or existing molecules effectively. Nanosystems have shown their potential as alternative carriers on the virtue of their better performance than traditional drug delivery systems.

A systematic review on active sites and functions of PIM-1 protein

The Proviral Integration of Molony murine leukemia virus (PIM)-1 protein contributes to the solid cancers and hematologic malignancies, cell growth, proliferation, differentiation, migration, and other life activities. Many studies have related these functions to its molecular structure, subcellular localization and expression level. However, recognition of specific active sites and their effects on the activity of this constitutively active kinase is still a challenge. Based on the close relationship between its molecular structure and functional activity, this review covers the specific residues involved in the binding of ATP and different substrates in its catalytic domain. This review then elaborates on the relevant changes in protein conformation and cell functions after PIM-1 binds to different substrates. Therefore, this intensive study can improve the understanding of PIM-1-regulated signaling pathways by facilitating the discovery of its potential phosphorylation substrates.

Integrated Bioinformatics Analysis Reveals Marker Genes and Potential Therapeutic Targets for Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare cardiovascular disease with very high mortality rate. The currently available therapeutic strategies, which improve symptoms, cannot fundamentally reverse the condition. Thus, new therapeutic strategies need to be established. Our research analyzed three microarray datasets of lung tissues from human PAH samples retrieved from the Gene Expression Omnibus (GEO) database. We combined two datasets for subsequent analyses, with the batch effects removed. In the merged dataset, 542 DEGs were identified and the key module relevant to PAH was selected using WGCNA. GO and KEGG analyses of DEGs and the key module indicated that the pre-ribosome, ribosome biogenesis, centriole, ATPase activity, helicase activity, hypertrophic cardiomyopathy, melanoma, and dilated cardiomyopathy pathways are involved in PAH. With the filtering standard (|MM| > 0.95 and |GS| > 0.90), 70 hub genes were identified. Subsequently, five candidate marker genes (CDC5L, AP3B1, ZFYVE16, DDX46, and PHAX) in the key module were found through overlapping with the top thirty genes calculated by two different methods in CytoHubb. Two of them (CDC5L and DDX46) were found to be significantly upregulated both in the merged dataset and the validating dataset in PAH patients. Meanwhile, expression of the selected genes in lung from PAH chicken measured by qRT-PCR and the ROC curve analyses further verified the potential marker genes' predictive value for PAH. In conclusion, CDC5L and DDX46 may be marker genes and potential therapeutic targets for PAH.

Novel molecular insights and public omics data in pulmonary hypertension

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

The p53 pathway in vasculature revisited: A therapeutic target for pathological vascular remodeling?

Pathological vascular remodeling contributes to the development of restenosis following intraluminal interventions, transplant vasculopathy, and pulmonary arterial hypertension. Activation of the tumor suppressor p53 may counteract vascular remodeling by inhibiting aberrant proliferation of vascular smooth muscle cells and repressing vascular inflammation. In particular, the development of different lines of small-molecule p53 activators ignites the hope of treating remodeling-associated vascular diseases by targeting p53 pharmacologically. In this review, we discuss the relationships between p53 and pathological vascular remodeling, and summarize current experimental data suggesting that drugging the p53 pathway may represent a novel strategy to prevent the development of vascular remodeling.

Oxidized DNA Precursors Cleanup by NUDT1 Contributes to Vascular Remodeling in Pulmonary Arterial Hypertension

Rationale: Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by abnormally elevated pulmonary pressures and right ventricular failure. Excessive proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs) is one of the most important drivers of vascular remodeling in PAH, for which available treatments have limited effectiveness.Objectives: To gain insights into the mechanisms leading to the development of the disease and identify new actionable targets.Methods: Protein expression profiling was conducted by two-dimensional liquid chromatography coupled to tandem mass spectrometry in isolated PASMCs from controls and patients with PAH. Multiple molecular, biochemical, and pharmacologic approaches were used to decipher the role of NUDT1 (nudrix hyrolase 1) in PAH.Measurements and Main Results: Increased expression of the detoxifying DNA enzyme NUDT1 was detected in cells and tissues from patients with PAH and animal models. In vitro, molecular or pharmacological inhibition of NUDT1 in PAH-PASMCs induced accumulation of oxidized nucleotides in the DNA, irresolvable DNA damage (comet assay), disruption of cellular bioenergetics (Seahorse), and cell death (terminal deoxynucleotidyl transferase dUTP nick end labeling assay). In two animal models with established PAH (i.e., monocrotaline and Sugen/hypoxia-treated rats), pharmacological inhibition of NUDT1 using (S)-Crizotinib significantly decreased pulmonary vascular remodeling and improved hemodynamics and cardiac function.Conclusions: Our results indicate that, by overexpressing NUDT1, PAH-PASMCs hijack persistent oxidative stress in preventing incorporation of oxidized nucleotides into DNA, thus allowing the cell to escape apoptosis and proliferate. Given that NUDT1 inhibitors are under clinical investigation for cancer, they may represent a new therapeutic option for PAH.

The Third Man: DNA sensing as espionage in pulmonary vascular health and disease

For as long as nucleic acids have been utilized to vertically and horizontally transfer genetic material, living organisms have had to develop methods of recognizing cytosolic DNA as either pathogenic (microbial invasion) or physiologic (mitosis and cellular proliferation). Derangement in key signaling molecules involved in these pathways of DNA sensing result in a family of diseases labeled interferonopathies. An interferonopathy, characterized by constitutive expression of type I interferons, ultimately manifests as severe autoimmune disease at a young age. Afflicted patients present with a constellation of immune-mediated conditions, including primary lung manifestations such as pulmonary fibrosis and pulmonary hypertension. The latter condition is especially interesting in light of the known role that DNA damage plays in a variety of types of inherited and induced pulmonary hypertension, with free DNA detection elevated in the circulation of affected individuals. While little is known regarding the role of cytosolic DNA sensing in development of pulmonary vascular disease, exciting new research in the related fields of immunology and oncology potentially sheds light on future areas of fruitful exploration. As such, the goal of this review is to summarize the state of the field of nucleic acid sensing, extrapolating common shared pathways that parallel our knowledge of pulmonary hypertension, in a molecular and cell-specific manner. Principles of DNA sensing related to known pulmonary injury inducing stimuli are also evaluated, in addition to potential therapeutic targets. Finally, future directions in pulmonary hypertension research and treatments will be briefly discussed.

DNA Damage and Repair in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex multifactorial disease with both genetic and environmental dynamics contributing to disease progression. Over the last decade, several studies have demonstrated the presence of genomic instability and increased levels of DNA damage in PAH lung vascular cells, which contribute to their pathogenic apoptosis-resistant and proliferating characteristics. In addition, the dysregulated DNA damage response pathways have been indicated as causal factors for the presence of persistent DNA damage. To understand the significant implications of DNA damage and repair in PAH pathogenesis, the current review summarizes the recent advances made in this field. This includes an overview of the observed DNA damage in the nuclear and mitochondrial genome of PAH patients. Next, the irregularities observed in various DNA damage response pathways and their role in accumulating DNA damage, escaping apoptosis, and proliferation under a DNA damaging environment are discussed. Although the current literature establishes the pertinence of DNA damage in PAH, additional studies are required to understand the temporal sequence of the above-mentioned events. Further, an exploration of different types of DNA damage in conjunction with associated impaired DNA damage response in PAH will potentially stimulate early diagnosis of the disease and development of novel therapeutic strategies.

Magnesium lithospermate B ameliorates hypobaric hypoxia-induced pulmonary arterial hypertension by inhibiting endothelial-to-mesenchymal transition and its potential targets

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by vascular remodeling leading to elevation of pulmonary artery pressure, right ventricular hypertrophy, and death. Currently, there are no cure exists for PAH. Magnesium lithospermate B (MLB) is the major component of Salvia przewalskii water extracts with treating angina and cardiovascular damage, anti-inflammation, anti-oxidation and anti-apoptosis. However, the effects of MLB on PAH still unclear. This study we investigated the efficacy of MLB in the hypobaric hypoxia-induced rat model of PAH. The results showed that MLB relieved mean pulmonary arterial pressure (mPAP) and right ventricular hypertrophy index (RVHI). Meanwhile, MLB significantly reduced pulmonary vascular remodeling. Additionally, MLB inhibited hypobaric hypoxia-induced α-smooth muscle actin (α-SMA) expression, cell apoptosis, and α-SMA and von Willebrand factor (vWF) co-expression in lung, suggesting that MLB could inhibit hypobaric hypoxia-induced endothelial-to-mesenchymal transition (EndMT). Furthermore, after treatment with MLB, the expression of hypoxia inducible factor-1α (HIF-1α), nuclear factor-kappa B (NF-κB), monocyte chemoattractant protein-1 (MCP-1), proliferating cell nuclear antigen (PCNA), cyclin-dependent kinase 4 (CDK4), CyclinD1, RhoA, rho-associated protein kinase 1 (ROCK1) and ROCK2 was decreased. Further, CHK1, PIM1, STK6, LKHA4, PDE5A, BRAF1, PLK1, AKT1, PAK6, PAK7 and ELNE may be the potential targets of MLB. Taken together, our findings suggest that MLB ameliorates hypobaric hypoxia-induced PAH by inhibiting EndMT in rats, and has potential value in the preventment and treatment of PAH.