Vascular endothelial growth factor receptor 1 expression in nasal polyp tissue

Relevance of the GH-VEGFB/VEGFA axis in liver grafts from brain-dead donors with alcohol-associated liver disease

Introduction

Grafts with alcohol-associated liver disease (ALD) subjected to prolonged cold ischaemia from donors after brain death (DBD) are typically unsuitable for transplantation. Here, we investigated the role of growth hormone (GH) in livers with ALD from DBDs and its relationship with vascular endothelial growth factor A (VEGFA) and VEGFB.

Methods

Livers from rats fed ethanol for 6 weeks and with brain death (BD) were cold stored for 24 h and subjected to ex vivo reperfusion. Hepatic damage and proliferative and inflammatory parameters were analysed after BD, before graft retrieval, and after reperfusion. Survival was monitored using an in vivo transplantation model.

Results

In DBDs, the administration of GH, which increased the levels in the intestine but not in the liver, induced the generation of both VEGFA and VEGFB in the intestine and protected against hepatic damage caused by BD before retrieving liver grafts from donors. However, VEGFA was the only factor that protected against damage after cold ischemia and reperfusion, which also increased the survival of the recipients.

Discussion

In conclusion, the signalling pathway and beneficial properties of the GH-VEGFA/VEGFB pathway, in which the intestine-liver axis plays a key role, were disrupted when grafts with ALD from DBDs were retrieved from donors and subjected to cold ischemia and reperfusion.

Staphylococcus aureus lysate induces an IgE response via memory B cells in nasal polyps

BACKGROUND

Locally increased IgE levels plays a pathologic role in chronic rhinosinusitis with nasal polyps (CRSwNP).

OBJECTIVE

This study aimed to investigate whether Staphylococcus aureus could induce aberrant IgE synthesis in CRSwNP and the potential mechanisms involved.

METHODS

Total IgE, IL-4, IL-5, and IL-13 concentrations in the supernatants of the cultures stimulated with S aureus lysate were assessed by ELISA. S aureus-induced cellular responses were investigated by single-cell RNA sequencing. Flow cytometry and quantitative reverse transcription PCR were used to analyze B-cell subsets and stimulated cell ε-germline transcript expression, respectively. IgE-positive B-cell and germinal center localization were assessed by immunohistochemistry and immunofluorescence.

RESULTS

S aureus lysate induced IgE production in the supernatants of nasal polyp (NP) tissues but not in those of healthy nasal mucosa. Moreover, IgE levels increased from days 2 to 4 after stimulation, paralleling the enhanced ε-germline transcript, IL-5, and IL-13 expression. Single-cell RNA sequencing revealed that there were increased IL-5 and IL-13 in group 2 innate lymphoid cells and identified a clonal overlap between unstimulated memory B cells and S aureus-stimulated plasma cells. The enriched IgE within NPs was mainly produced by IgE-negative memory B cells. Cellular evidence indicated that the IgE memory response to S aureus might also exist in the peripheral blood of CRSwNP patients. The S aureus-induced IgE memory response was associated with elevated IgE levels in NPs, asthma, and postoperative CRSwNP recurrence.

CONCLUSIONS

S aureus induced an IgE response via IgE-negative memory B cells in CRSwNP patients, possibly contributing to CRSwNP development.

Pericyte loss leads to microvessel remodeling and nasal polyp formation

BACKGROUND

Chronic rhinosinusitis (CRS) may be caused by increased vascular permeability and inflammatory cell leakage in the subepithelial tissue.

AIMS/OBJECTIVES

The aim of this study is to clarify the role of pericytes in tissue edema, microvessel dysfunction and vascular remodeling mechanisms in patients of CRS with nasal polyps (CRSwNP).

MATERIAL AND METHODS

A total of 63 tissue samples were collected, including 42 CRSwNP samples (22 eosinophilic CRSwNP (eCRSwNP) and 20 non-eosinophilic CRSwNP (non-eCRSwNP) samples) and 21 samples of CRS without nasal polyps (CRSsNP). The samples were stained by immunofluorescence to measure microvessel density (MVD) and microvessel pericyte coverage index (MPI).

RESULTS

We found that the albumin expression in the eCRSwNP group was significantly increased (p < .05). The MPI was significantly decreased (p <.05). There was a significant negative correlation between the MPI and the plasma albumin level (r=-0.82, p < .05). The MPI was negatively correlated with eosinophilic count (r=-0.77, p < .05). In the eCRSwNP group, the expressions of IL-4, Ang-1 and Ang-2 were increased compared with those in the control group.

CONCLUSIONS AND SIGNIFICANCE

Pericyte loss may induce microvessel dysfunction, affect the development of interstitial edema and eosinophilic exosmosis in eCRSwNP, and contribute to the formation and maintenance of nasal polyps.

The Effect of Bevacizumab and Propranolol on Nasal Polyposis

OBJECTIVE

This study aims to evaluate the effects of bevacizumab and propranolol from the point of view of a possible antiangiogenic effect in a model of primary nasal polyp (NP) tissue culture.

METHODS

NP samples of 21 patients and normal healthy nasal mucosa samples of 7 patients were cultured. Samples were divided into four groups as follows (healthy nasal mucosa, NP without any treatment, NP treated with propranolol, NP treated with bevacizumab). Cultured tissues were formalin fixed and paraffin embedded. Tissue sections and immunohistochemical VEGF-A, angiopoietin-1 (Ang-1), and angiopoietin-2 (Ang-2) expressions were evaluated. ELISA was also performed for each one of them.

RESULTS

Both propranolol and bevacizumab significantly decreased the expressions of VEGF-A and Ang-1, and they significantly increased the expression of Ang-2 in comparison to the control NP group. In the healthy nasal mucosa group, no significant expression of VEGF-A was seen, a slight (+) Ang-1 expression, and a high (+++) Ang-2 expression were observed.

CONCLUSION

Bevacizumab and propranolol exert an antiangiogenic effect on NP tissues, mainly by decreasing VEGF-A and Ang-1 expression, increasing Ang-2 expression.

Exosomal miR-22-3p Derived from Chronic Rhinosinusitis with Nasal Polyps Regulates Vascular Permeability by Targeting VE-Cadherin

Background

The abnormal vascular permeability is associated with the formation of chronic rhinosinusitis with nasal polyps (CRSwNP). Previously, our study demonstrated that the nasal lavage fluid- (NLF-) derived exosomes from CRSwNP can promote the vascular permeability of human umbilical vein endothelial cells (HUVECs). miR-22-3p, a specific differentiated miRNA, is reported to regulate microvessels in some diseases. This study is purposed to explore the impact of exosomal miR-22-3p derived from CRSwNP on vascular permeability and identify the underlying targets.

Methods

Exosomes were extracted from NLF of 26 CRSwNP patients and 10 control patients. Quantitative real-time PCR (qRT- PCR) was applied to evaluate the relative level of exosomal miR-22-3p. The impact of exosomal miR-22-3p on HUVECs was assessed by permeability assays in vitro. The potential molecular targets of miR-22-3p were investigated by applying such technologies as dual-luciferase reporter assay and western blot.

Results

miR-22-3p was upregulated in NLF-derived exosomes from CRSwNP. Exosomal miR-22-3p derived from CRSwNP enhanced the tubule permeability of HUVECs. Vascular endothelial- (VE-) cadherin (CDH5) was identified as a direct target of miR-22-3p. miR-22-3p regulated the vascular permeability by targeting VE-cadherin in HUVECs.

Conclusions

Exosomal miR-22-3p derived from NLF of CRSwNP plays an important role in regulating vascular permeability by targeting VE-cadherin.

Identification of rare variants of allergic rhinitis based on whole genome sequencing and gene expression profiling: A preliminary investigation in four families

Background

Despite the success of genome-wide association studies for allergic rhinitis (AR), no definitive causal variants have been identified, and a substantial portion of the heritability of the disease is yet to be discovered.

Methods

Four families, each with at least 1 parent and one child suffering from dust mite (DM) AR, were recruited, and whole-genome sequencing was performed on samples from 9 eligible individuals from these families. Conjoint analysis was performed for existing gene expression profiling data in the literature and the whole genome sequencing data obtained for these individuals; for presence of family-specific variants segregating with AR and the pathways involved. Similar analyses were also performed with data obtained for 96 sporadic house dust mite (HDM) AR patients and 96 healthy controls.

Results

Three rare variants in three genes (FLT1_c.603A ​> ​T; VEGFB_c.322A ​> ​C; and ITGA2_c.502+1G ​> ​A), which are involved in Focal Adhesion pathway, were identified in affected, but not unaffected, subjects in two families. VEGFB_c.322A ​> ​C and/or ITGA2_c.502+1G ​> ​A were further detected in all DM AR patients but not in any healthy individuals in 1 family; which was further investigated for members. The 3 identified variants were not found in any of the sporadic DM AR patients or healthy controls.

Conclusion

Despite the relatively small sample size, this study has identified several potentially functional rare variants in AR candidate genes, and it provides a platform for future work in larger numbers of families and sporadic individuals for a better understanding of the genetic basis of AR.

Identification of key genes and pathways in chronic rhinosinusitis with nasal polyps using bioinformatics analysis

PURPOSE

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a prevalent inflammatory disease of yet unknown etiology. The purpose of this study was to uncover key genes and pathways related to the pathogenesis of CRSwNP via bioinformatics approaches.

MATERIALS AND METHODS

The gene expression profile of GSE36830 extracted from Gene Expression Omnibus database was used to screen differentially expressed genes (DEGs) between nasal polyp samples and control samples. Furthermore, functional and pathway enrichment analysis was performed using the clusterProfiler package in R language. In addition, protein-protein interaction (PPI) network was constructed by STRING database and functional modules were detected using Molecular Complex Detection algorithm.

RESULTS

A total of 538 DEGs (326 up-regulated and 212 down-regulated) were identified. The most significantly enriched pathways for up-regulated and down-regulated genes were hematopoietic cell lineage and salivary secretion, respectively. Moreover, twenty hub genes with high connectivity degrees were selected from the PPI network, such as TYRO protein tyrosine kinase binding protein (TYROBP), G protein subunit gamma 2 (GNG2), CCR7, and CCR3. Besides, six important modules were obtained, which were highly associated with chemokine signaling pathway, Th1 and Th2 cell differentiation, complement and coagulation cascades, cell cycle, systemic lupus erythematosus, and Staphylococcus aureus infection.

CONCLUSIONS

The results of this study may provide new insights into potential molecular mechanisms of CRSwNP. Nevertheless, further experiments are needed to confirm these findings.

Cigarette smoke extract increases vascular endothelial growth factor production via TLR4/ROS/MAPKs/NF-kappaB pathway in nasal fibroblast

PURPOSE

Cigarette smoke is a complex mixture of various chemical compounds, including free radicals and highly toxic compounds. Cigarette smoke exposure has been shown to be associated with chronic rhinosinusitis and tissue remodeling in upper airway. Vascular endothelial growth factor (VEGF) is one of the cytokines with a crucial role in tissue remodeling of airway. The aims of this study were to determine the effects of cigarette smoke extract (CSE) on VEGF expression and to investigate the underlying molecular mechanisms of CSE in nasal fibroblasts.

METHODS

Nasal fibroblasts were stimulated with CSE. Cytotoxicity was evaluated by 3-(4,5- dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. The expression level of VEGF was measured using reverse transcription-polymerase chain reaction (RT-PCR), and enzyme-linked immunosorbent assay. Messenger RNA (mRNA) expression level of TLR4 were determined by RT-PCR. Small interfering RNA (siRNA) for TLR4 was transfected to suppress TLR4 expression. Activation of reactive oxygen species (ROS) was analyzed by using dichloro-dihydro-fluorescein diacetate assay. Mitogen-activated protein kinase (MAPK) and NF-kappaB activations were determined by using western blot and/or luciferase assay.

RESULTS

CSE had no significant cytotoxic effect in nasal fibroblast up to 5%. CSE significantly increased both VEGF mRNA and protein expression dose-dependently. The down-regulation of TLR4 transcription by siRNA treatment suppressed CSE-induced expressions of both TLR4 and VEGF. Pretreatment with ROS scavengers, specific inhibitors of each MAPK, and NF-kappaB inhibitor significantly decreased CSE-induced VEGF expression.

CONCLUSIONS

CSE has a stimulatory effect on VEGF expression through the TLR4, ROS, MAPK, and NF-kappaB signaling pathway in nasal fibroblasts.

The Role of Periostin in the Occurrence and Progression of Eosinophilic Chronic Sinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a highly heterogeneous disease with different host defence responses. However, whether periostin and vascular endothelial growth factor (VEGF) are similarly impaired in patients with eosinophilic CRSwNP (ENP) and those with non-eosinophilic CRSwNP (nENP) remains unclear. We sought to evaluate the expression and possible modulation of periostin and VEGF, regulated on activation normal T expressed and secreted (RANTES) and eotaxin-2 in the polyp tissues from 30 patients with ENP and from 36 patients with nENP and in middle turbinate tissues from 12 control subjects. We found that ENP tissues exhibited a significantly increased expression of periostin and VEGF compared with tissues from patients with nENP and control subjects (P < 0.05, respectively). Accordingly, the expression of VEGF, RANTES, and eotaxin-2 in ENP fibroblasts was significantly up-regulated after stimulation with up-regulated periostin in vitro, but the expression of VEGF and RANTES was significantly inhibited by stimulation with down-regulated periostin. Our findings suggest that periostin might play an important role in the occurrence and progression of ENP and might be a potential therapeutic target.

Transcriptome Analysis Reveals Distinct Gene Expression Profiles in Eosinophilic and Noneosinophilic Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP), one of the most prevalent chronic diseases, is characterized by persistent inflammation of sinonasal mucosa. However, the pathogenesis of CRSwNP remains unclear. Here, we performed next-generation RNA sequencing and a comprehensive bioinformatics analyses to characterize the transcriptome profiles, including mRNAs and long noncoding RNAs (lncRNAs), in patients with eosinophilic and noneosinophilic CRSwNP. A total of 1917 novel lncRNAs and 280 known lncRNAs were identified. We showed eosinophilic CRSwNP (ECRSwNP) and noneosinophilic CRSwNP (non-ECRSwNP) display distinct transcriptome profiles. We identified crucial pathways, including inflammatory, immune response and extracellular microenvironment, connected to the pathogenetic mechanism of CRSwNP. We also discovered key lncRNAs differentially expressed, including lncRNA XLOC_010280, which regulates CCL18 and eosinophilic inflammation. The qRT-PCR and in situ RNA hybridization results verified the key differentially expressed genes. The feature of distinct transcriptomes between ECRSwNP and non-ECRSwNP suggests the necessity to develop specific biomarkers and personalized therapeutic strategies. Our findings lay a solid foundation for subsequent functional studies of mRNAs and lncRNAs as diagnostic and therapeutic targets in CRSwNP by providing a candidate reservoir.

Clinical and biological markers of difficult-to-treat severe chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the upper airways of which two major phenotypes exist, CRS without nasal polyps (CRSsNP) and CRS with nasal polyps (CRSwNP). Some patients with CRS have suboptimal response to current guideline treatments. These patients remain severe and uncontrolled by treatment and have a poor quality of life. It is highly important to identify both clinical and biological markers, so-called biomarkers, in this subset of patients. The presence of nasal polyps and comorbidity with asthma and with aspirin-exacerbated respiratory disease (AERD) are the most common clinical traits that have been associated to difficult-to-treat severe CRS. In addition to clinical traits, numerous biological markers, with known etiopathogenic roles in CRS, have been associated to difficult-to-treat or recalcitrant CRS. This review summarizes the existing knowledge of the clinical and biological markers associated to difficult-to-treat or uncontrolled severe CRS.

Corticosteroid treatment regulates mucosal remodeling in chronic rhinosinusitis with nasal polyps

OBJECTIVES/HYPOTHESIS

To investigate the effect of oral plus intranasal corticosteroid (CS) treatment on nasal polyp (NP) mucosa remodeling from patients with severe chronic rhinosinusitis with nasal polyps (CRSwNP).

STUDY DESIGN

Case series, retrospective study.

METHODS

Patients (n = 18) with severe CRSwNP were treated with oral prednisone for 2 weeks and intranasal budesonide for 12 weeks. NP biopsies were obtained from patients biopsies before (w0) and after 2 weeks (w2) and 12 weeks (w12) of CS treatment. Matrix metalloprotease 1 (MMP-1), MMP-2, MMP-7, MMP-9, and tissue inhibitor of metalloprotease type 1 (TIMP-1) expression was evaluated by immunohistochemistry in cell and tissue structures. Epithelial damage, eosinophil infiltration, and collagen content were also examined in NP tissues before and after CS treatment.

RESULTS

Compared to w0: 1) oral plus intranasal CS significantly (P < .01) increased presence of submucosal glands at w2, decreased epithelial cell hyperplasia at w12, and decreased tissue eosinophilia at w2 and w12; 2) CS treatment significantly (P < .05) increased immunoreactivity for MMP-1 and MMP-2 in the epithelium at w2, but decreased immunoreactivity for MMP-9 in the epithelium at w2 and w12; 3) at w12, CS significantly (P < .05) reduced MMP-9 immunoreactive positivity and intensity in the extracellular matrix, while increasing total collagen amount in the extracellular matrix; and 4) CS treatment significantly (P < .01) reduced the number of eosinophils and their MMP and TIMP-1 immunoreactive expression.

CONCLUSIONS

CS treatment modulates NP mucosa remodeling, particularly by promoting epithelial repair, regulating tissue remodeling markers, increasing total collagen content, and reducing tissue eosinophil infiltration.

LEVEL OF EVIDENCE

4

Deprived TLR9 expression in apparently healthy nasal mucosa might trigger polyp-growth in chronic rhinosinusitis patients

Background

The origin of nasal polyps in chronic rhinosinusitis is unknown, but the role of viral infections in polyp growth is clinically well established. Toll-like receptors (TLRs) have recently emerged as key players in our local airway defense against microbes. Among these, TLR9 has gained special interest in viral diseases. Many studies on chronic rhinosinusitis with nasal polyps (CRSwNP) compare polyp tissue with nasal mucosa from polyp-free individuals. Knowledge about changes in the turbinate tissue bordering the polyp tissue is limited.

Objectives

To analyse the role of TLR9 mediated microbial defense in tissue bordering the polyp.

Methods

Nasal polyps and turbinate tissue from 11 patients with CRSwNP and turbinate tissue from 11 healthy controls in total were used. Five biopsies from either group were analysed immediately with flow cytometry regarding receptor expression and 6 biopsies were used for in vitro stimulation with a TLR9 agonist, CpG. Cytokine release was analysed using Luminex. Eight patients with CRSwNP in total were intranasally challenged with CpG/placebo 24 hours before surgery and the biopsies were collected and analysed as above.

Results

TLR9 expression was detected on turbinate epithelial cells from healthy controls and polyp epithelial cells from patients, whereas TLR9 was absent in turbinate epithelial cells from patients. CpG stimulation increased the percentage cells expressing TLR9 and decreased percentage cells expressing VEGFR2 in turbinate tissue from patients. After CpG stimulation the elevated levels of IL-6, G-CSF and MIP-1β in the turbinate tissue from patients were reduced towards the levels demonstrated in healthy controls.

Conclusion

Defects in the TLR9 mediated microbial defense in the mucosa adjacent to the anatomic origin of the polyp might explain virus induced polyp growth. CpG stimulation decreased VEGFR2, suggesting a role for CpG in polyp formation. The focus on turbinate tissue in patients with CRSwNP opens new perspectives in CRSwNP-research.