MSCs attenuate hypoxia induced pulmonary hypertension by activating P53 and NF-kB signaling pathway through TNFα secretion

NEK2 inhibition reverses vascular remodeling in pulmonary arterial hypertension associated with congenital heart disease

OBJECTIVE

Pulmonary arterial hypertension (PAH) is a serious consequence of congenital heart disease (CHD). PAH is characterized by a cancer-like pro-proliferative and anti-apoptotic phenotype of pulmonary artery smooth muscle cells (PASMCs). Never in mitosis a-related kinase 2 (NEK2) has recently been identified as a key factor in tumor cell proliferation and migration whlie the functional importance of NEK2 in PAH associated with CHD (CHD-PAH) has not been elucidated yet.

METHODS

NEK2 expression in the pulmonary arterioles of rats with CHD-PAH and shunt-related PAH was evaluated. For this purpose, human PASMCs (hPASMCs) were transfected with lentiviruses for NEK2 knockdown or overexpression, and changes in expression of phenotypic markers in hPASMCs were determined. The proliferation, migration and apoptosis abilities of hPASMCs were respectively detected. Changes in vascular remodeling following NEK2 suppression were also observed in the shunt-related PAH rat model.

RESULTS

NEK2 was found to be highly expressed both in the PASMCs of the middle pulmonary arterioles of patients with CHD-PAH and shunt-related PAH rats. Additionally, overexpression of NEK2 enhanced phenotypic switch, proliferation, migration, and apoptosis resistance of hPAMSCs by activating the nuclear factor kappa B pathway. Moreover, hemodynamic parameters and pulmonary vascular remodeling were both found to be improved considerably following suppression of NEK2 expression by intratracheal instillation of adeno-associated virus in shunt-related PAH rats.

CONCLUSION

We demonstrated for the first time that NEK2 is a potential regulator of PASMCs function. Targeting NEK2 may be an effective strategy for the treatment of CHD-PAH.

Gut microbiota modulates lung gene expression and metabolism to aid SD rats in adapting to low-pressure hypoxia

Hypoxia has long posed a serious threat to the health of both animals and humans, causing respiratory acidosis, metabolic disorders, systemic inflammation, oxidative stress damage, and other issues, thereby endangering life and limiting development in high-altitude areas. Gut microbiota plays a crucial role in life activities and hypoxia adaptation. We transplanted the gut microbiota from small mammals, plateau zokors (Myospalax baileyi), from the Qinghai-Tibetan plateau (3,500 m) to Sprague-Dawley (SD) rats housed in a hypobaric chamber (equivalent to 6,000 m altitude) for 30 days. The results showed that microbiota transplantation significantly reshaped the gut microbiota structure of the rats, notably increasing the abundance of short-chain fatty acid-producing bacteria Lachnospiraceae and Prevotellaceae, alleviating hypoxia and acidosis, reducing pulmonary hypertension and right ventricular hypertrophy, increasing the production of anti-inflammatory substances like indole-3-lactic acid, and reducing the generation of pro-inflammatory substances, such as histamine and uric acid. It also decreased the expression of inflammatory genes like lgE, TNFα, and IFN-γ in the lung. Fecal microbiota transplantation from plateau-specific species to low-altitude SD rats effectively altered metabolism, changed gene expression, decreased pulmonary artery pressure, and enhanced plateau adaptability. This study demonstrates the potential effectiveness of treating hypoxic pulmonary hypertension through microbiota transplantation and offers insights into improving hypoxia adaptation.

IMPORTANCE

We report the beneficial effects of FMT on respiratory capacity, lung metabolism, and lung gene expression in SD rats under hypoxic conditions. We revealed the inhibitory effects of gut microbiota on lung mast cells and histamine expression under hypoxic conditions. The study demonstrated the potential effectiveness of treating HPH through FMT and offers insights into improving hypoxia adaptation.

Mesenchymal stem/stromal cells: dedicator to maintain tumor homeostasis

Mesenchymal stem/stromal cells （MSCs） act as a factor in tumor recurrence after drug treatment with their involvement observed in various cancer types. As a constituent of the tumor microenvironment (TME), MSCs not only provide support to tumor growth but also establish connections with diverse cell populations within the TME, serving as mediators linking different tumor-associated components. MSCs play an important role in maintaining tumor progression due to their stem cell properties and remarkable differentiation capacity. Given the intensification of tumor research and the encouraging results achieved in recent years，the aim of this article is to investigate the supportive role of MSCs in tumor cells as well as in various cellular and non-cellular components of the tumor microenvironment. Furthermore, the article shows that MSCs do not have a specific anatomical ecological niche and describes the contribution of MSCs to the maintenance of tumor homeostasis on the basis of homing, plasticity and tumor-forming properties. By elucidating the critical roles of different components of TME, this study provides a comprehensive understanding of tumor therapy and may offer new insights into defeating cancer.

Advancements in engineered mesenchymal stem cell exosomes for chronic lung disease treatment

Chronic lung diseases include an array of conditions that impact airways and lung structures, leading to considerable societal burdens. Mesenchymal stem cells (MSCs) and their exosomes (MSC-exos) can be used for cell therapy and exhibit a diverse spectrum of anti-inflammatory, antifibrotic, and immunomodulatory properties. Engineered MSC-exos possesses enhanced capabilities for targeted drug delivery, resulting in more potent targeting effects. Through various engineering modifications, these exosomes can exert many biological effects, resulting in specific therapeutic outcomes for many diseases. Moreover, engineered stem cell exosomes may exhibit an increased capacity to traverse physiological barriers and infiltrate protected lesions, thereby exerting their therapeutic effects. These characteristics render them a promising therapeutic agent for chronic pulmonary diseases. This article discusses and reviews the strategies and mechanisms of engineered MSC-exos in the treatment of chronic respiratory diseases based on many studies to provide new solutions for these diseases.

Transcriptomic Study on the Lungs of Broilers with Ascites Syndrome

Although broiler ascites syndrome (AS) has been extensively studied, its pathogenesis remains unclear. The lack of cardiopulmonary function in broilers causes relative hypoxia in the body; hence, the lung is the main target organ of AS. However, the transcriptome of AS lung tissue in broilers has not been studied. In this study, an AS model was successfully constructed, and lung tissues of three AS broilers and three healthy broilers were obtained for RNA sequencing (RNA-seq) and pathological observation. The results showed that 614 genes were up-regulated and 828 genes were down-regulated in the AS group compared with the normal group. Gene Ontology (GO) functional annotation revealed the following up-regulated genes: FABP4, APLN, EIF2AK4, HMOX1, MMP9, THBS1, TLR4, BCL2; and down-regulated genes: APELA, FGF7, WNT5A, CDK6, IL7, IL7R, APLNR. These genes have attracted much attention in cardiovascular diseases such as pulmonary hypertension. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that multiple metabolic processes were enriched, indicating abnormal lung metabolism of AS in broilers. These findings elucidate the potential genes and signal pathways in the lungs of broilers with AS and provide a potential target for studying the pathogenesis and preventing AS.

[Role of myelin and lymphocyte protein in regulating pulmonary artery smooth muscle cell proliferation and apoptosis in pulmonary hypertension]

OBJECTIVE

To investigate the role of myelin and lymphocyte protein (MAL) in pulmonary hypertension (PAH).

METHODS

Blood samples were collected from 50 patients with PAH (PAH group) and 50 healthy individuals for detection of plasma MAL expression using ELISA.According to the echocardiographic findings, the patients were divided into moderate/severe group (n=18) and mild group (n=32), and the correlation between MAL protein level and the severity of PAH was analyzed.In a pulmonary artery smooth muscle cell model of PAH with hypoxia-induced abnormal proliferation, the effects of mal gene knockdown and overexpression on cell growth, proliferation and starvation-induced apoptosis were observed; the changes in NK-κB signaling pathway in the transfected cells were detected to explore the molecular mechanism by which MAL regulates PAMSC proliferation and apoptosis.

RESULTS

The plasma level of MAL was significantly higher in patients with PAH than in healthy individuals (P < 0.05), and the patients with moderate/severe PAH had significantly higher MAL level than those with mild PAH (P < 0.001).In PAMSCs, exposure to hypoxia significantly increased the mRNA and protein expression levels of MAL (P < 0.05), and MAL knockdown obviously inhibited hypoxia-induced proliferation and promoted starvation-induced apoptosis of the PAMSCs (P < 0.05).Knocking down mal significantly inhibited the activation of NK-κB signaling pathway that participated in regulation of PAMSC proliferation (P < 0.05).

CONCLUSION

The plasma level of MAL is elevated in PAH patients in positive correlation with the disease severity.MAL knockdown inhibits abnormal proliferation and promotes apoptosis of PAMSCs by targeted inhibition of the NF-κB signaling pathway to improve vascular remodeling in PAH.

Mesenchymal Stem Cell-derived Nanovesicles as a Credible Agent for Therapy of Pulmonary Hypertension

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have been evaluated in many studies as promising therapeutic agents for pulmonary hypertension (PH). However, low yields and heterogeneity are major barriers in the translational utility of EVs for clinical studies. To address these limitations, we fabricated MSC-derived nanovesicles (MSC-NVs) by serial extrusion through filters, resulting in MSC-NVs with characteristics similar to conventional EVs but with much higher production yields. Herein, we examined the therapeutic efficacy of MSC-NVs in preclinical models of PH in vitro and in vivo. Intervention with MSC-NVs improved the core pathologies of monocrotaline-induced PH in rats. Intravenous administration of MSC-NVs resulted in significant uptake within hypertensive lungs, pulmonary artery lesions, and especially pulmonary artery smooth muscle cells (PASMCs). In vitro, MSC-NVs inhibited PDGF-induced proliferation, migration, and phenotype switching of PASMCs. miRNA-sequencing analysis of the genetic cargo of MSC-NVs revealed that miR-125b-5p and miR-100-5p are highly abundant, suggesting that they might account for the therapeutic effects of MSC-NVs in PH. Depletion of miR-125b-5p and miR-100-5p in MSCs almost completely abolished the beneficial effects of MSC-NVs in protecting PASMCs from PDGF-stimulated changes in vitro and also diminished the protective effects of MSC-NVs in monocrotaline-induced PH in vivo. These data highlight the efficacy and advantages of MSC-NVs over MSC-EVs as a promising therapeutic strategy against PH.

Potential biomarkers and therapeutic targets of idiopathic pulmonary arterial hypertension

BACKGROUND

Peripheral blood mononuclear cells (PBMCs) play an important role in the pathogenesis of pulmonary arterial hypertension (PAH). However, the specific roles of PBMCs in the development and progression of idiopathic PAH (IPAH) have not been fully understood.

METHODS

Here, differentially expressed genes (DEGs) of PBMCs or lung tissues between IPAH patients and healthy controls were identified via bioinformatics analysis of Gene Expression Omnibus (GEO) datasets GSE33463 and GSE48149, respectively. Subsequently, extensive target prediction and network analysis were performed to assess protein-protein interaction (PPI) networks, Gene Ontology (GO) terms, and pathway enrichment for DEGs. Co-expressed DEGs between PBMCs and lung tissues coupled with corresponding predicted miRNAs involved in PAH were also assessed. We identified 251 DEGs in PBMCs and 151 DEGs in lung tissue samples from IPAH. PDK4, RBPMS2, and PDE5A expression were altered in both PBMCs and lung tissues from IPAH patients compared to healthy control.

RESULTS

CXCL8, JUN, TLR8, IL1B, and TLR7 could be implicated as the hub genes in PBMCs, whereas ENO1, STAT1, CXCL10, GPI, and IRF1 in lung tissues. Finally, co-expressed DEGs of PDK4, RBPMS2, and PDE5A coupled with corresponding predicted miRNAs, especially miR-103a-3p, miR-185-5p, and miR-515-5p, are significantly associated with IPAH.

CONCLUSION

Our findings collectively suggest that the expression levels of PDK4, RBPMS2, and PDE5A in PBMCs are associated with the expression of these genes in lung tissues. Thus, these molecules may serve as potential circulating biomarkers and/or possible therapeutic targets for IPAH.

Epigenetic Regulation of Endothelial Dysfunction and Inflammation in Pulmonary Arterial Hypertension

Once perceived as a disorder treated by vasodilation, pulmonary artery hypertension (PAH) has emerged as a pulmonary vascular disease with severe endothelial cell dysfunction. In the absence of a cure, many studies seek to understand the detailed mechanisms of EC regulation to potentially create more therapeutic options for PAH. Endothelial dysfunction is characterized by complex phenotypic changes including unchecked proliferation, apoptosis-resistance, enhanced inflammatory signaling and metabolic reprogramming. Recent studies have highlighted the role of epigenetic modifications leading to pro-inflammatory response pathways, endothelial dysfunction, and the progression of PAH. This review summarizes the existing literature on epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, which can lead to aberrant endothelial function. Our goal is to develop a conceptual framework for immune dysregulation and epigenetic changes in endothelial cells in the context of PAH. These studies as well as others may lead to advances in therapeutics to treat this devastating disease.

Recent trends of NFκB decoy oligodeoxynucleotide-based nanotherapeutics in lung diseases

Nuclear factor κB (NFκB) is a unique protein complex that plays a major role in lung inflammation and respiratory dysfunction. The NFκB signaling pathway, therefore becomes an avenue for the development of potential pharmacological interventions, especially in situations where chronic inflammation is often constitutively active and plays a key role in the pathogenesis and progression of the disease. NFκB decoy oligodeoxynucleotides (ODNs) are double-stranded and carry NFκB binding sequences. They prevent the formation of NFκB-mediated inflammatory cytokines and thus have been employed in the treatment of a variety of chronic inflammatory diseases. However, the systemic administration of naked decoy ODNs restricts their therapeutic effectiveness because of their poor pharmacokinetic profile, instability, degradation by cellular enzymes and their low cellular uptake. Both structural modification and nanotechnology have shown promising results in enhancing the pharmacokinetic profiles of potent therapeutic substances and have also shown great potential in the treatment of respiratory diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis. In this review, we examine the contribution of NFκB activation in respiratory diseases and recent advancements in the therapeutic use of decoy ODNs. In addition, we also highlight the limitations and challenges in use of decoy ODNs as therapeutic molecules, cellular uptake of decoy ODNs, and the current need for novel delivery systems to provide efficient delivery of decoy ODNs. Furthermore, this review provides a common platform for discussion on the existence of decoy ODNs, as well as outlining perspectives on the latest generation of delivery systems that encapsulate decoy ODNs and target NFκB in respiratory diseases.