A possible role of stem cells in nasal polyposis

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.

The role of hypoxia in the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal cavity characterized by excessive nasal mucus secretion and nasal congestion. The development of CRS is related to pathological mechanisms induced by hypoxia. Under hypoxic conditions, the stable expression of both Hypoxia inducible factor-1 (HIF-1) α and HIF-2α are involved in the immune response and inflammatory pathways of CRS. The imbalance in the composition of nasal microbiota may affect the hypoxic state of CRS and perpetuate existing inflammation. Hypoxia affects the differentiation of nasal epithelial cells such as ciliated cells and goblet cells, induces fibroblast proliferation, and leads to epithelial-mesenchymal transition (EMT) and tissue remodeling. Hypoxia also affects the proliferation and differentiation of macrophages, eosinophils, basophils, and mast cells in sinonasal mucosa, and thus influences the inflammatory state of CRS by regulating T cells and B cells. Given the multifactorial nature in which HIF is linked to CRS, this study aims to elucidate the effect of hypoxia on the pathogenic mechanisms of CRS.

Managing Chronic Rhinosinusitis with Nasal Polyps in the Elderly: Challenges and Solutions

The proportion of the population over 65 years old continues to grow. Chronic rhinosinusitis is common in this population and causes a reduction in quality of life and an increase in health care utilization. Diagnosis of chronic rhinosinusitis with nasal polyps follows the same principles for elderly patients as in the general population, but the elderly population presents some diagnostic challenges worth considering. Presbynasalis, the anatomic and functional changes of the nose and paranasal sinuses associated with aging must be accounted for when caring for these patients. In addition, polypharmacy and other medical issues that can cause similar symptoms must be considered. Medical therapy is generally similar to the general population but with additional concerns given the propensity for geriatric patients to be on multiple medications and to suffer from multiple medical issues. Sinus surgery should be considered following the same indications as in the general population. While some authors have found higher complication rates in endoscopic sinus surgery, others have found higher rates of success. As always, the risks of surgery must be considered with the possible benefits on a patient-to-patient basis.

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.

Integrated mRNA and microRNA transcriptome profiling during differentiation of human nasal polyp epithelium reveals an altered ciliogenesis

BACKGROUND

Human adult basal stem/progenitor cells (BSCs) obtained from chronic rhinosinusitis with nasal polyps (CRSwNP) when differentiated in an air-liquid interface (ALI) usually provide a pseudostratified airway epithelium with similar abnormalities than original in vivo phenotype. However, the intrinsic mechanisms regulating this complex process are not well defined and their understanding could offer potential new therapies for CRSwNP (incurable disease).

METHODS

We performed a transcriptome-wide analysis during in vitro mucociliary differentiation of human adult BSCs from CRSwNP, compared to those isolated from control nasal mucosa (control-NM), in order to identify which key mRNA and microRNAs are regulating this complex process in pathological and healthy conditions.

RESULTS

A number of genes, miRs, biological processes, and pathways were identified during mucociliary differentiation of both CRSwNP and control-NM epithelia, and notably, we have demonstrated for the first time that genetic transcriptional program responsible of ciliogenesis and cilia function is significantly impaired in CRSwNP epithelium, presumably produced by an altered expression of microRNAs, particularly of those miRs belonging to mir-34 and mi-449 families.

CONCLUSIONS

This study provides for the first time a novel insight into the molecular basis of sinonasal mucociliary differentiation, demonstrating that transcriptome related to ciliogenesis and cilia function is significantly impaired during differentiation of CRSwNP epithelium due to an altered expression of microRNAs.

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

Chronic rhinosinusitis is a common inflammatory disease of paranasal sinuses, which causes rhinorrhea, nasal congestion, and hyposmia. The genetic predisposition or the exposure to irritants can sustain the inflammatory response and the development of nasal polyposis. Nasal polyps are benign and teardrop-shaped growths that project in the nasal cavities, and originate from the ethmoid sinuses. This inflammatory process is associated with high expression of IL-4, IL-5 and IL-13 and IgE. Antibodies targeting these cytokines or receptors represent a therapeutic strategy in the treatment of nasal polyposis in combination with corticosteroids. The molecular pathogenesis of nasal polyps in chronic rhinosinusitis (CRS) patients is associated with remodeling transition, a process in which epithelial cells lose their typical phenotype, acquiring a mesenchymal-like aspect. TGFβ/SMAD, ERK, and Wnt/β-catenin pathways are altered during the nasal tissue remodeling. miRNA and inhibitor molecules targeting these signaling pathways are able to interfere with the process; which could lead to alternative therapies. Nasal polyps are an alternative source of mesenchymal stem cells, which can be isolated from surgical biopsies. A molecular understanding of the biology of PO-MSCs will contribute to the delineating inflammatory process underlying the development of nasal polyps.

Long-term defects of nasal epithelium barrier functions in patients with nasopharyngeal carcinoma post chemo-radiotherapy

BACKGROUND AND PURPOSE

Chronic and recurrent upper respiratory tract infection and inflammation is common in patients with nasopharyngeal carcinoma (NPC) post chemo-radiotherapy (CRT). Whether it is due to intrinsic (e.g., host-defense mechanisms of the epithelium), epigenetic or extrinsic factors is not fully understood.

MATERIALS AND METHODS

Tissue biopsies of the middle turbinate (MT) and inferior turbinate (IT) from NPC patients after CRT (mean of 3 years, n = 39) were compared with the IT biopsies from healthy subjects (n = 44). The epithelial ultrastructure was examined by transmission electron microscope (TEM). mRNA and protein expressions of epithelial stem/progenitor cells markers, as well markers of cell proliferation and differentiation markers was analyzed.

RESULTS

Abnormal epithelial architecture was observed in all tissue samples of NPC patients. Significantly decreased expression levels of mRNA and protein levels for p63 (basal cells), Ki67 (cell proliferation), p63⁺/KRT5⁺ (epithelial stem/progenitor cells), MUC5AC and MUC5B (secretary proteins from goblet cells), alpha-tubulin, beta-tubulin and TAp73 (ciliated cells), DNAH5 and DNAI1 and RSPH4A (microtubule assemblies of motile cilia), FOXJ1 and CP110 (ciliogenesis-associated markers) were evident in MT and IT biopsies from NPC patients when compared to healthy controls.

CONCLUSION

CRT causes long-term defects of epithelial barrier functions and increases the susceptibility of these patients to upper respiratory tract infection and inflammation.

Novel findings in immunopathophysiology of chronic rhinosinusitis and their role in a model of precision medicine

Our understanding of the pathophysiology of chronic rhinosinusitis (CRS) is continuously evolving. The traditional description of CRS in terms of two phenotypes based on the presence or absence of nasal polyps belies the underlying intricate immunopathophysiological processes responsible for this condition. CRS is being increasingly recognized as a disease spectrum encompassing a range of inflammatory states in the sinonasal cavity, with non-type 2 inflammatory disease on one end, type 2 inflammatory, eosinophil-heavy disease on the other and an overlap of both in different proportions in between. Abundance in research on the immune mechanisms of CRS has revealed various new endotypes that hold promise as biomarkers for the development of targeted therapies in severe, uncontrolled CRS. The introduction of precision medicine to manage this chronic, complex condition is a step forward in providing individualized care for all patients with CRS. In this review, the latest research on the pathophysiology of CRS with a focus on potential novel biomarkers and treatment options over the last 2 years are summarized and integrated into a suggested model of precision medicine in CRS.

[Regulatory dysfunctions in nasal polyposis]

Chronic rhinosinusitis is a heterogeneous group of inflammatory diseases with significant annual costs for the health care system. To date, there is no distinct signaling pathway known that explains the entire process from the beginning to tissue transformation. Due to the diversity of chronic rhinosinusitis, no uniform treatment has yet been developed. With a focus on chronic rhinosinusitis with nasal polyps (CRSwNP), molecular biologic gene expression studies have been performed to identify specific characteristics of nasal polyps that might allow the development of new therapeutic procedures. Microarray analysis revealed alterations in cell adhesion and differentiation as well as blood vessels. Further examinations identified two mechanisms that could play an important role in the pathogenesis of nasal polyps. In the context of the underlying disease, i.e., Th2-mediated chronic inflammation with predominantly eosinophilic cell infiltration, these findings might explain the pathogenesis of nasal polyps and allow development of new therapeutic strategies.