Nasal Polyposis: Insights in Epithelial-Mesenchymal Transition and Differentiation of Polyp Mesenchymal Stem Cells

MicroRNA-145-5p Regulates the Epithelial-Mesenchymal Transition in Nasal Polyps by Targeting Smad3

OBJECTIVES

The annual prevalence of chronic rhinosinusitis (CRS) is increasing, and the lack of effective treatments imposes a substantial burden on both patients and society. The formation of nasal polyps in patients with CRS is closely related to tissue remodeling, which is largely driven by the epithelial-mesenchymal transition (EMT). MicroRNA (miRNA) plays a pivotal role in the pathogenesis of numerous diseases through the miRNA-mRNA regulatory network; however, the specific mechanism of the miRNAs involved in the formation of nasal polyps remains unclear.

METHODS

The expression of EMT markers and Smad3 were detected using western blots, quantitative real-time polymerase chain reaction, and immunohistochemical and immunofluorescence staining. Differentially expressed genes in nasal polyps and normal tissues were screened through the Gene Expression Omnibus database. To predict the target genes of miR-145-5p, three different miRNA target prediction databases were used. The migratory ability of cells was evaluated using cell migration assay and wound healing assays.

RESULTS

miR-145-5p was associated with the EMT process and was significantly downregulated in nasal polyp tissues. In vitro experiments revealed that the downregulation of miR-145-5p promoted EMT. Conversely, increasing miR-145-5p levels reversed the EMT induced by transforming growth factor-β1. Bioinformatics analysis suggested that miR-145-5p targets Smad3. Subsequent experiments confirmed that miR-145-5p inhibits Smad3 expression.

CONCLUSION

Overall, miR-145-5p is a promising target to inhibit nasal polyp formation, and the findings of this study provide a theoretical basis for nanoparticle-mediated miR-145-5p delivery for the treatment of nasal polyps.

Single-cell RNA sequencing reveals the epithelial cell, fibroblast, and key gene alterations in chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the nasal mucosa, and epithelial-mesenchymal transition (EMT) is thought to be an essential process in the pathogenesis of CRSwNP. However, the mechanisms of epithelial and fibroblastic changes at the single-cell level are unclear. In this study, we investigated the epithelial cell, fibroblast, and key gene alterations in the development of CRSwNP. We revealed major cell types involved in CRSwNP and nasal mucosal inflammation formation, then mapped epithelial and fibroblast subpopulations. We showed that the apical and glandular epithelial cells and the ADGRB3+ and POSTN+ fibroblasts were the key cell subtypes in the progression of CRSwNP. Pseudotime and cell cycle analysis identified dynamic changes between epithelial cells and fibroblasts during its development. WFDC2 and CCL26 were identified as the key marker genes involved in the development of CRSwNP and were validated by IHC staining, which may provide a potential novel target for future CRSwNP therapy. ScRNA-seq data provided insights into the cellular landscape and the relationship between epithelial cells and fibroblasts in the progression of CRSwNP. WFDC2 and CCL26 were identified as the key genes involved in the development of CRSwNP and may be the potential markers for gene therapy.

Simple, low-cost, and well-performing method, the outgrowth technique, for the isolation of cells from nasal polyps

BACKGROUND

Epithelial cells are an important part of the pathomechanism in chronic rhinosinusitis with nasal polyps. It is therefore essential to establish a robust method for the isolation and culture of epithelial cells from nasal polyps to enable further research. In this study, the feasibility of the outgrowth technique for the isolation of the epithelial cells from the nasal polyps was evaluated.

RESULTS

Using the outgrowth technique, epithelial cells could be isolated from all tissue samples. Isolated epithelial cells showed a proliferation rate of approximately 7- to 23-fold every 6 days up to the 3rd passage. Over 97% of isolated cells were shown to be cytokeratin- and p63-positive, and over 86% of them were Ki-67-positive in flow cytometry. Interleukin-33 and periostin were detectable in the supernatant.

CONCLUSIONS

We introduce a simple, low-cost, and well-performing method for isolating epithelial cells from nasal polyps with the outgrowth technique.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Epithelial cell dysfunction in chronic rhinosinusitis: the epithelial-mesenchymal transition

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is a type of epithelial cell dysfunction, which is widely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS), especially CRS with nasal polyps, and contributes to pathogenesis of the disease. EMT is mediated via complex mechanisms associated with multiple signaling pathways.

AREAS COVERED

We have summarized the underlying mechanisms and signaling pathways promoting EMT in CRS. Strategies or drugs/agents targeting the genes and pathways related to the regulation of EMT are also discussed for their potential use in the treatment of CRS and asthma. A literature search of studies published in English from 2000 to 2023 was conducted using the PubMed database, employing CRS, EMT, signaling, mechanisms, targeting agents/drugs, as individual or combinations of search terms.

EXPERT OPINION

EMT in nasal epithelium not only leads to epithelial cell dysfunction but also plays an important role in nasal tissue remodeling in CRS. A comprehensive understanding of the mechanisms underlying EMT and the development of drugs/agents targeting these mechanisms may provide new treatment strategies for CRS.

LRIG1 Levels in Chronic Rhinosinusitis With Nasal Polyps

Purpose: Nasal polyps (NPs), usually occurring together with chronic rhinosinusitis (CRS), are benign masses of mucosal origin arising from inflammation. The transmembrane protein known as leucine-rich repeats and immunoglobulin-like domains 1 (Lrig1) is a member of the Lrig family. Lrig1 is frequently expressed in the respiratory tract and epithelial tissues and can inhibit several signaling pathways involved in cell proliferation. The aim of this study was to determine Lrig1 levels in NP tissues of patients with CRS. Material and Methods: This study included 36 patients with CRS and NPs and 15 patients who underwent rhinoplasty as the control group. The Lrig1 levels of all participants were measured by the ELISA method. Results: This study revealed that Lrig1 levels were significantly lower in NP tissues than in tissues of the control group. The mean level of Lrig1 of the NP tissues was 22.2 ng/ml, while the mean level of the control group was 28.5 ng/ml. According to the results of ROC analysis, Lrig1 levels have the power to distinguish polyp tissues from control tissues (AUC=0.794). Lrig1 levels were higher in tissues with scores of 4-8 than in tissues with scores of 16-20 based on the results of computed tomography scoring. According to endoscopic evaluations, Lrig1 levels of tissues with scores of 5-8 or 9-11 were relatively lower than those of tissues with scores of 2-4. Conclusion: Lrig1 levels were found to be decreased in NP tissues. Thus, Lrig1 may be used to confirm the presence of NPs. Lrig1 may also be helpful in NP grading. Increasing the Lrig1 levels in cases of NPs has the potential to become a targetable treatment modality.

IGFBP2 derived from PO-MSCs promote epithelial barrier destruction by activating FAK signaling in nasal polyps

The nasal polyps (NPs) microenvironment comprises multiple cell types, including mesenchymal stromal cells (MSCs). Insulin-like growth factor binding protein 2 (IGFBP2) plays crucial roles in cell proliferation, differentiation and more. However, the role of NPs-derived MSCs (PO-MSCs) and IGFBP2 in NPs pathogenesis remains poorly defined. Herein, primary human nasal epithelial cells (pHNECs) and MSCs were extracted and cultured. Extracellular vesicles (EVs) and soluble proteins were isolated to investigate the role of PO-MSCs on epithelial-mesenchymal transition (EMT) and epithelial barrier function in NPs. Our data showed that IGFBP2, but not EVs from PO-MSCs (PO-MSCs-EVs), exhibited a crucial role in EMT and barrier destruction. Moreover, focal adhesion kinase (FAK) signaling pathway is necessary for IGFBP2 to exert its functions in human and mice nasal epithelial mucosa. Altogether, these findings may improve the current understanding of the role of PO-MSCs in NPs microenvironment and ultimately contribute to the prevention and treatment of NPs.

Enhanced ZNF521 expression induces an aggressive phenotype in human ovarian carcinoma cell lines

Epithelial ovarian carcinoma (EOC) is the most lethal gynecological tumor, that almost inevitably relapses and develops chemo-resistance. A better understanding of molecular events underlying the biological behavior of this tumor, as well as identification of new biomarkers and therapeutic targets are the prerequisite to improve its clinical management. ZNF521 gene amplifications are present in >6% of OCs and its overexpression is associated with poor prognosis, suggesting that it may play an important role in OC. Increased ZNF521 expression resulted in an enhancement of OC HeyA8 and ES-2 cell growth and motility. Analysis of RNA isolated from transduced cells by RNA-Seq and qRT-PCR revealed that several genes involved in growth, proliferation, migration and tumor invasiveness are differentially expressed following increased ZNF521 expression. The data illustrate a novel biological role of ZNF521 in OC that, thanks to the early and easy detection by RNA-Seq, can be used as biomarker for identification and treatment of OC patients.

TIM-4 in macrophages contributes to nasal polyp formation through the TGF-β1–mediated epithelial to mesenchymal transition in nasal epithelial cells

Chronic rhinosinusitis with nasal polyps (CRSwNP) is caused by prolonged inflammation of the paranasal sinus mucosa. The epithelial to mesenchymal transition (EMT) is involved in the occurrence and development of CRSwNP. The T-cell immunoglobulin domain and the mucin domain 4 (TIM-4) is closely related to chronic inflammation, but its mechanism in CRSwNP is poorly understood. In our study, we found that TIM-4 was increased in the sinonasal mucosa of CRSwNP patients and, especially, in macrophages. TIM-4 was positively correlated with α-SMA but negatively correlated with E-cadherin in CRS. Moreover, we confirmed that TIM-4 was positively correlated with the clinical parameters of the Lund-Mackay and Lund-Kennedy scores. In the NP mouse model, administration of TIM-4 neutralizing antibody significantly reduced the polypoid lesions and inhibited the EMT process. TIM-4 activation by stimulating with tissue extracts of CRSwNP led to a significant increase of TGF-β1 expression in macrophages in vitro. Furthermore, coculture of macrophages and human nasal epithelial cells (hNECs) results suggested that the overexpression of TIM-4 in macrophages made a contribution to the EMT process in hNECs. Mechanistically, TIM-4 upregulated TGF-β1 expression in macrophages via the ROS/p38 MAPK/Egr-1 pathway. In conclusion, TIM-4 contributes to the EMT process and aggravates the development of CRSwNP by facilitating the production of TGF-β1 in macrophages. Inhibition of TIM-4 expression suppresses nasal polyp formation, which might provide a new therapeutic approach for CRSwNP.

In situ gelling nanosuspension as an advanced platform for fluticasone propionate nasal delivery

In this work we present the development of in situ gelling nanosuspension as advanced form for fluticasone propionate nasal delivery. Drug nanocrystals were prepared by wet milling technique. Incorporation of drug nanocrystals into polymeric in situ gelling system with pectin and sodium hyaluronate as constitutive polymers was fine-tuned attaining appropriate formulation surface tension, viscosity and gelling ability. Drug nanonisation improved the release profile and enhanced formulation mucoadhesive properties. QbD approach combining formulation and administration parameters resulted in optimised nasal deposition profile, with 51.8% of the dose deposited in the middle meatus, the critical region in the treatment of rhinosinusitis and nasal polyposis. Results obtained in biocompatibility and physico-chemical stability studies confirmed the leading formulation potential for safe and efficient nasal corticosteroid delivery.

DNMTs Are Involved in TGF-β1-Induced Epithelial-Mesenchymal Transitions in Airway Epithelial Cells

Chronic rhinosinusitis (CRS) pathogenesis is closely related to tissue remodeling, including epithelial–mesenchymal transition (EMT). Epigenetic mechanisms play key roles in EMT. DNA methylation, mediated by DNA methyltransferases (DNMTs), is an epigenetic marker that is critical to EMT. The goal of this study was to determine whether DNMTs were involved in TGF-β1-induced EMT and elucidate the underlying mechanisms in nasal epithelial cells and air–liquid interface cultures. Global DNA methylation and DNMT activity were quantified. DNMT expression was measured using real-time PCR (qRT–PCR) in human CRS tissues. mRNA and protein levels of DNMTs, E-cadherin, vimentin, α-SMA, and fibronectin were determined using RT–PCR and Western blotting, respectively. DNMT1, DNMT3A, and DNMT3B gene expression were knocked down using siRNA transfection. MAPK phosphorylation and EMT-related transcription factor levels were determined using Western blotting. Signaling pathways were analyzed using specific inhibitors of MAPK. We demonstrated these data in primary nasal epithelial cells and air–liquid interface cultures. Global DNA methylation, DNMT activity, and DNMT expression increased in CRS tissues. DNMT expression was positively correlated with Lund–McKay CT scores. TGF-β1 dose-dependently induced DNMT expression. Further, 5-Aza inhibited TGF-β1-induced DNMT, Snail, and Slug expression related to EMT, as well as p38 and JNK phosphorylation in A549 cells and TGF-β1-induced DNMT expression and EMT in primary nasal epithelial cells and air–liquid interface cultures. TGF-β1-induced DNMT expression leads to DNA methylation and EMT via p38, JNK, Snail, and Slug signaling pathways. Inhibition of DNMT suppressed the EMT process and therefore is potentially a CRS therapeutic strategy.

STAT1 mediates the PI3K/AKT pathway through promoting microRNA-18a in nasal polyps

BACKGROUND

Epithelial to mesenchymal transition (EMT) is linked to the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP). The involvement of STAT1 has been reported in CRSwNP. However, its specific role in regulating EMT in CRSwNP is not clear. We sought to evaluate the role of STAT1 in EMT in CRSwNP using clinical samples and a murine model.

METHODS

Comprehensive analysis of differentially expressed genes was performed in nasal polyps from the CRSwNP patients, followed by pathway enrichment analysis. After bioinformatics prediction, the relationships between microRNA-18a (miR-18a) and PTEN or STAT1 were examined using dual-luciferase and RIP assays, respectively. The expression of STAT1, PTEN, and miR-18a in nasal tissues was detected using RT-qPCR, immunohistochemistry, and in situ hybridization. After the alteration of gene expression in mice with CRSwNP, western blot, RT-qPCR, and HE staining were conducted to detect EMT-related proteins, inflammatory factor secretion, inflammatory cell infiltration, and the PI3K/AKT pathway activity in nasal tissues.

RESULTS

STAT1 and miR-18a were highly expressed, and PTEN was poorly expressed in the nasal polyp. STAT1 promoted transcription of miR-18a, which targeted PTEN. Downregulation of STAT1 and miR-18a inhibited the EMT and inflammatory cell infiltration, while depletion of PTEN promoted the EMT and inflammatory cell infiltration in the nasal polyp. The PI3K/AKT pathway was activated in the nasal polyp and regulated by the STAT1/miR-18a/PTEN axis.

CONCLUSIONS

STAT1 acts as a transcription factor to promote transcription of miR-18a, and miR-18a targets PTEN to exacerbate the inflammatory response and EMT in CRSwNP.

Transcription Factor Specificity Protein 1 Regulates Inflammation and Fibrin Deposition in Nasal Polyps Via the Regulation of microRNA-125b and the Wnt/β-catenin Signaling Pathway

Nasal polyps (NPs) are multifactorial soft growths inside the nasal passages and are associated with chronic inflammation that originate from the nasal and paranasal sinus mucosae. This study focused on the role of microRNA (miR)-125b and the molecules associated with NP development. Differentially expressed miRNAs between nasal tissues from patients with chronic rhinosinusitis (CRS) with NP (CRSwNP) and CRS without NP (CRSsNP) were screened using microarray analysis. A murine model of CRSwNP was established. The expression of miR-125b in murine tissues was examined using reverse transcription quantitative polymerase chain reaction. Candidate upstream regulators of miR-125b were predicted using bioinformatics tools, and the binding relationship between specificity protein 1 (Sp1) and miR-125b was validated using luciferase and chromatin immunoprecipitation assays. Altered expression of Sp1 and miR-125b was induced to evaluate their relevance to the progression of NPs. miR-125b expression was significantly upregulated in NP tissues from patients with CRSwNP. Sp1 was confirmed as an upstream regulator that promotes miR-125b transcription in NPs. Overexpression of Sp1 reduced levels of d-dimer (an indicator of fibrinogen degradation products) and tissue-type plasminogen activator (t-PA) but increased eosinophil cationic protein and peroxidase levels, as well as the levels of inflammatory factors interleukin-5 (IL-5) and IL-8 in murine NP tissues. However, these trends were reversed after miR-125b downregulation. Sp1 and miR-125b were found to activate the Wnt/β-catenin signaling pathway in NPs. This study demonstrated that Sp1, an upstream transcription factor of miR-125b, accumulates on the miR-125b promoter to activate its transcription, which induces inflammation and fibrin deposition in NP by activating the Wnt/β-catenin axis.

ZNF521 Enhances MLL-AF9-Dependent Hematopoietic Stem Cell Transformation in Acute Myeloid Leukemias by Altering the Gene Expression Landscape

Leukemias derived from the MLL-AF9 rearrangement rely on dysfunctional transcriptional networks. ZNF521, a transcription co-factor implicated in the control of hematopoiesis, has been proposed to sustain leukemic transformation in collaboration with other oncogenes. Here, we demonstrate that ZNF521 mRNA levels correlate with specific genetic aberrations: in particular, the highest expression is observed in AMLs bearing MLL rearrangements, while the lowest is detected in AMLs with FLT3-ITD, NPM1, or CEBPα double mutations. In cord blood-derived CD34⁺ cells, enforced expression of ZNF521 provides a significant proliferative advantage and enhances MLL-AF9 effects on the induction of proliferation and the expansion of leukemic progenitor cells. Transcriptome analysis of primary CD34⁺ cultures displayed subsets of genes up-regulated by MLL-AF9 or ZNF521 single transgene overexpression as well as in MLL-AF9/ZNF521 combinations, at either the early or late time points of an in vitro leukemogenesis model. The silencing of ZNF521 in the MLL-AF9 + THP-1 cell line coherently results in an impairment of growth and clonogenicity, recapitulating the effects observed in primary cells. Taken together, these results underscore a role for ZNF521 in sustaining the self-renewal of the immature AML compartment, most likely through the perturbation of the gene expression landscape, which ultimately favors the expansion of MLL-AF9-transformed leukemic clones.

Benralizumab Effectiveness in Severe Eosinophilic Asthma with and without Chronic Rhinosinusitis with Nasal Polyps: A Real-World Multicenter Study

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) affects around 60% of patients with severe eosinophilic asthma (SEA). Benralizumab was recently approved for SEA add-on treatment.

OBJECTIVE

To assess the real-world effectiveness of benralizumab in SEA with or without CRSwNP.

METHODS

We conducted a multicenter observational study, including patients with SEA treated with benralizumab for 24 weeks in 12 Italian specialized facilities. Asthma exacerbations, Asthma Control Test (ACT), lung function, oral corticosteroid (OCS) dosage, and eosinophil and basophil count in peripheral blood were recorded at baseline and after 4, 12, and 24 weeks. The 22-item Sino-Nasal Outcome Test (SNOT-22) and Lund-Mackay scores were assessed at baseline and after 24 weeks in SEA+CRSwNP.

RESULTS

A total of 137 patients with late-onset SEA were included; 57.7% (79 of 137) showed the copresence of CRSwNP. Overall, severe asthma exacerbations decreased from 4 (3-6) to 0 (0-2) (P < .0001) after 24 weeks of treatment, and significant improvements were observed as early as 4 weeks in ACT score, OCS dosage, forced expiratory volume in the 1st second (FEV₁)%, FEV₁ (L), forced vital capacity (FVC)%, FEV₁/FVC% (P < .0001), and forced expiratory flow between 25% and 75% of FVC (FEF_25-75)% (P = .0022). Eosinophils and basophils in peripheral blood were rapidly depleted. In patients with SEA+CRSwNP, SNOT-22 decreased from 46 (39.5-64.5) to 32 (19-46) (P < .0001). Furthermore, in comparison with SEA, they showed enhanced responses with regard to ACT minimal clinically important difference (P = .0387), FEV₁% (P = .017), FEV₁ (L) (P = .02), and FEF_25-75% (P = .0362).

CONCLUSIONS

These real-world data suggest that benralizumab can represent a valid add-on therapeutic option for patients with SEA, especially with comorbid CRSwNP.

Deficit in Adipose Differentiation in Mesenchymal Stem Cells Derived from Chronic Rhinosinusitis Nasal Polyps Compared to Nasal Mucosal Tissue

Chronic rhinosinusitis of the nasal mucosa is an inflammatory disease of paranasal sinuses, which causes rhinorrhea, nasal congestion, and hyposmia, and in some cases, it can result in the development of nasal polyposis. Nasal polyps are benign lobular-shaped growths that project in the nasal cavities; they originate from inflammation in the paranasal mucous membrane and are associated with a high expression of interleukins (IL)-4, IL-5, IL-13, and IgE. Polyps derive from the epithelial–mesenchymal transition of the nasal epithelium resulting in a nasal tissue remodeling. Nasal polyps from three patients with chronic rhinosinusitis as well as control non-polyp nasal mucosa were used to isolate and cultivate mesenchymal stem cells characterized as CD73⁺, CD90⁺, CD105⁺/CD14⁻, CD34⁻, and CD45⁻. Mesenchymal stem cells (MSCs) cultures were induced to differentiate toward adipocytes, where lipid droplets and adipocyte genes PPARγ2, ADIPO-Q, and FABP4 were observed in control non-polyp nasal mucosa-derived mesenchymal cells but were scarcely present in the cultures derived from the nasal polyps, where apoptosis was evident. The modulation of the response to adipogenic stimulus in polyps represents a change in the molecular response that controls the cascade required for differentiation as well as possible means to specifically target these cells, sparing the normal mucosa of the nasal sinuses.