Cold exposure impairs extracellular vesicle swarm-mediated nasal antiviral immunity.

BACKGROUND: The human upper respiratory tract is the first site of contact for inhaled respiratory viruses and elaborates an array of innate immune responses. Seasonal variation in respiratory viral infections and the importance of ambient temperature in modulating immune responses to infections have been well recognized; however, the underlying biological mechanisms remain understudied. OBJECTIVE: We investigated the role of nasal epithelium-derived extracellular vesicles (EVs) in innate Toll-like receptor 3 (TLR3)-dependent antiviral immunity. METHODS: We evaluated the secretion and composition of nasal epithelial EVs after TLR3 stimulation in human autologous cells and fresh human nasal mucosal surgical specimens. We also explored the antiviral activity and mechanisms of TLR3-stimulated EVs against respiratory viruses as well as the effect of cool ambient temperature on TLR3-dependent antiviral immunity. RESULTS: We found that polyinosinic:polycytidylic acid, aka poly(I:C), exposure induced a swarm-like increase in the secretion of nasal epithelial EVs via the TLR3 signaling. EVs participated in TLR3-dependent antiviral immunity, protecting the host from viral infections through both EV-mediated functional delivery of miR-17 and direct virion neutralization after binding to virus ligands via surface receptors, including LDLR and ICAM-1. These potent antiviral immune defense functions mediated by TLR3-stimulated EVs were impaired by cold exposure via a decrease in total EV secretion as well as diminished microRNA packaging and antiviral binding affinity of individual EV. CONCLUSION: TLR3-dependent nasal epithelial EVs exhibit multiple innate antiviral mechanisms to suppress respiratory viral infections. Furthermore, our study provides a direct quantitative mechanistic explanation for seasonal variation in upper respiratory tract infection prevalence.

Cystatin SN is a potent upstream initiator of epithelial-derived type 2 inflammation in chronic rhinosinusitis.

BACKGROUND: Cystatin SN (CST1) and cystatin SA (CST2) are cysteine protease inhibitors that protect against allergen, viral, and bacterial proteases. Cystatins are overexpressed in the setting of allergic rhinitis and chronic rhinosinusitis with nasal polyps (CRSwNP); however, their role in promoting type 2 inflammation remains poorly characterized. OBJECTIVE: The purpose of this study was to use integrated poly-omics and a murine exposure model to explore the link between cystatin overexpression in CRSwNP and type 2 inflammation. METHODS: In this institutional review board- and institutional animal care and use committee-approved study, we compared tissue, exosome, and mucus CST1 and CST2 between CRSwNP and controls (n = 10 per group) by using matched whole exome sequencing, transcriptomic, proteomic, posttranslational modification, histologic, functional, and bioinformatic analyses. C57/BL6 mice were dosed with 3.9 µg/mL of CST1 or PBS intranasally for 5 to 18 days in the presence or absence of epithelial ABCB1a knockdown. Inflammatory cytokines were quantified by using Quansys multiplex assays or ELISAs. RESULTS: Of the 1305 proteins quantified, CST1 and CST2 were among the most overexpressed protease inhibitors in tissue, exosome, and mucus samples; they were localized to the epithelial layer. Multiple posttranslational modifications were identified in the polyp tissue. Exosomal CST1 and CST2 were strongly and significantly correlated with eosinophils and Lund-Mackay scores. Murine type 2 cytokine secretion and TH2 cell infiltration increased in a time-dependent manner following CST1 exposure and was abrogated by epithelial knockdown of ABCB1a, a regulator of epithelial cytokine secretion. CONCLUSION: CST1 is a potent upstream initiator of epithelial-derived type 2 inflammation in CRSwNP. Therapeutic strategies targeting CST activity and its associated posttranslational modifications deserve further interrogation.

Exosome swarms eliminate airway pathogens and provide passive epithelial immunoprotection through nitric oxide.

BACKGROUND: Nasal mucosa-derived exosomes (NMDEs) harbor immunodefensive proteins and are capable of rapid interepithelial protein transfer. OBJECTIVES: We sought to determine whether mucosal exposure to inhaled pathogens stimulates a defensive swarm of microbiocidal exosomes, which also donate their antimicrobial cargo to adjacent epithelial cells. METHODS: We performed an institutional review board-approved study of healthy NMDE secretion after Toll-like receptor (TLR) 4 stimulation by LPS (12.5 µg/mL) in the presence of TLR4 inhibitors. Interepithelial transfer of exosomal nitric oxide (NO) synthase and nitric oxide was measured by using ELISAs and NO activity assays. Exosomal antimicrobial assays were performed with Pseudomonas aeruginosa. Proteomic analyses were performed by using SOMAscan. RESULTS: In vivo and in vitro LPS exposure induced a 2-fold increase in NMDE secretion along with a 2-fold increase in exosomal inducible nitric oxide synthase expression and function through TLR4 and inhibitor of nuclear factor κB kinase activation. LPS stimulation increased exosomal microbiocidal activity against P aeruginosa by almost 2 orders of magnitude. LPS-stimulated exosomes induced a 4-fold increase in NO production within autologous epithelial cells with protein transfer within 5 minutes of contact. Pathway analysis of the NMDE proteome revealed 44 additional proteins associated with NO signaling and innate immune function. CONCLUSIONS: We provide direct in vivo evidence for a novel exosome-mediated innate immunosurveillance and defense mechanism of the human upper airway. These findings have implications for lower airway innate immunity, delivery of airway therapeutics, and host microbiome regulation.

Exosome function in aerodigestive mucosa.

Exosomes are 30-150 nm membrane-bound vesicles which are secreted by virtually all cell types. Exosomes have been studied in a wide range of both normal and pathologic human tissues, most notably cancer. The role of exosomes in immune surveillance and in non-invasive biomarker sampling, and their potential to act as therapeutic carriers lend particular importance to mucosal barrier derived exosomes. This review focuses specifically on current knowledge regarding exosomes derived from aerodigestive membranes. Specific topics covered include: isolation and characterization techniques, physiological function, protein expression, function as biomarkers of disease, and potential therapeutic uses.

Technologies and Standardization in Research on Extracellular Vesicles.

Extracellular vesicles (EVs) are phospholipid bilayer membrane-enclosed structures containing RNAs, proteins, lipids, metabolites, and other molecules, secreted by various cells into physiological fluids. EV-mediated transfer of biomolecules is a critical component of a variety of physiological and pathological processes. Potential applications of EVs in novel diagnostic and therapeutic strategies have brought increasing attention. However, EV research remains highly challenging due to the inherently complex biogenesis of EVs and their vast heterogeneity in size, composition, and origin. There is a need for the establishment of standardized methods that address EV heterogeneity and sources of pre-analytical and analytical variability in EV studies. Here, we review technologies developed for EV isolation and characterization and discuss paths toward standardization in EV research.

Unexpected effects of systemic steroids on the CRSwNP proteome: is protein upregulation more important than inhibition?

BACKGROUND: Oral steroids, traditionally thought of as immunosuppressive agents that are broad in their immunomodulatory effects, are a mainstay of treatment to reduce disease burden in chronic rhinosinusitis with nasal polyps (CRSwNP). The purpose of this study was to determine how differentially expressed proteins in CRSwNP are affected by oral steroid therapy. METHODS: Matched exosomal proteomic arrays were quantified using aptamer-based methods in systemic steroid-naive CRSwNP patients before and after a standardized oral prednisone course (n = 12). Previously identified differentially expressed proteins in CRSwNP patients were compared to determine the effect of steroids on expression. Fisher's exact test and t test were applied to normalized protein expression profiles to determine significance. RESULTS: Of 18 proteins previously identified to be highly underexpressed in CRSwNP, 16 (89%) had an average increase after systemic steroid treatment (p < 0.05). Lactoperoxidase, initially present at 9-fold lower concentrations in CRSwNP subjects, increased by 209% after steroid treatment. A similar trend was observed with other proteins of interest, including platelet factor 4 and C-C motif ligand 28. The converse of this steroid effect was not true; of the 53 proteins that are highly overexpressed in CRSwNP, only 22 (42%) decreased in quantity with steroid use. CONCLUSION: Proteomic analysis of differentially expressed proteins in CRSwNP demonstrates that systemic steroids cause almost uniform upregulation of transcriptionally decreased proteins, whereas the effects of steroids on transcriptionally increased proteins are more heterogeneous. Thus, proteomic analysis may be an effective tool to understand specific therapeutic benefits of steroid use in polyp disease and to create more targeted treatments.

Significant polyomic and functional upregulation of the PAPP-A/IGFBP-4/5/IGF-1 axis in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with epithelial expansion and polyp survival. However, the molecular mechanism of this aberrant proliferation is unclear. The purpose of this study was to interrogate derangements of the pappalysin-A/insulin-like growth factor binding protein/insulin-like growth factor-1 (PAPP-A/IGFBP-4/5/IGF-1 axis) as a major contributing factor to polyp growth in CRSwNP. METHODS: Matched tissue and exosomal proteomic arrays including PAPP-A, IGFBP-4, IGFBP-5, and IGF-1 were quantified using aptamer-based methods/Western blots for proteomic analysis and whole-transcriptome sequencing/quantitative polymerase chain reaction (qPCR) for transcriptomic analysis in CRSwNP and control patients. Functional PAPP-A assays were then performed in both tissue and exosomes (set 1: n = 20 per group; validation set 2: n = 26 per group). RESULTS: Tissue and exosomal PAPP-A was significantly overexpressed in CRSwNP compared to controls on both a transcriptomic and proteomic level (p < 0.0001). Known inhibitors of PAPP-A (stanniocalcin-1/-2) were significantly downregulated (p < 0.0001) as were PAPP-A cleavage products (IGFBP-5 p < 0.0001). PAPP-A function was shown to be increased 5-fold to 6-fold in tissue and exosomes. CONCLUSION: Upregulated tissue and exosomal PAPP-A signaling is significantly associated with CRSwNP and may be an important factor in the promotion of epithelial proliferation and polyp growth. These data lend further support to the emerging concept of exosomal functional and polyomic analyses as a method to study sinonasal pathology.

Osteitis is associated with dysregulated pro-osteoblastic activity in patients with nasal polyps.

OBJECTIVES/HYPOTHESIS: The overlying inflammatory mucosa plays a crucial role in the initiation of osteitis; however, the molecular mechanism is unclear. The objective of this study was to explore the bone morphogenetic protein (BMP) pathway and to correlate the expression of key signaling molecules with the degree of osteitis in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). STUDY DESIGN: Prospective experimental analysis. METHODS: This was an institutional review board-approved study in which mucosal samples were obtained from sites of osteitis in CRSwNP and compared to nonosteitic healthy controls (n = 10/group). Protein expression of key BMP pathway was quantified by aptamer-based protein array and confirmed by a set of selected mRNA analyses. Degree of osteitis was assessed using both Kennedy Osteitis Score and Global Osteitis Score (GOS). RESULTS: Pro-osteoblastic expression of BMP7 (fold change [FC] = -1.18, P = .017) and BMP9 (FC = -1.32, P = .023), their receptors, BMP receptor type-1A (BMPR1A) (FC = -2.56, P = .005) and BMP receptor type-2 (FC = -1.28, P = .022), and two enhancers of BMP signaling pathway, the repulsive guidance molecule domain family member B (FC = -1.13, P = .008) and the chordin-like protein 1 (FC = -1.18, P = .027), were all significantly downregulated in CRSwNP. Conversely, the pro-osteoclastic factor, tartrate-resistant acid phosphatase type 5 (ACP5) (FC = 2.36, P = .001), was significantly increased in CRSwNP. GOS was inversely correlated with levels of BMP7 (r = -0.684, P = .005) and BMPR1A (r = -0.864, P = .005) and positively correlated with levels of ACP5 (r = 0.815, P = .004). The FCs among the proteins studied significantly and positively correlated with the FCs of their mRNA expression (r = 0.908, P = .002). CONCLUSIONS: Downregulated pro-osteoblastic mucosal BMP signaling is strongly and significantly associated with increased osteitis in CRSwNP. LEVEL OF EVIDENCE: NA Laryngoscope, 129:E102-E109, 2019.

Translating transcription: proteomics in chronic rhinosinusitis with nasal polyps reveals significant discordance with messenger RNA expression.

BACKGROUND: Much of the literature examining chronic rhinosinusitis with nasal polyps (CRSwNP) immunopathology has been predicated on messenger RNA (mRNA) analysis with the assumption that transcriptional changes would reflect end-effector protein expression. The purpose of this study was to test this hypothesis using matched transcriptomic and proteomic data sets. METHODS: Matched tissue proteomic and transcriptomic arrays were quantified in CRSwNP polyp tissue and control inferior turbinate tissue (n = 10/group). Mucus samples were additionally collected in 6 subjects from each group. Proteins were grouped into functional categories by bioinformatics and differential expression analyses. Log-log regression and Pearson correlations were performed to determine the level of agreement between data sets. RESULTS: Of the 1310 proteins examined, 393 were significantly differentially expressed in CRSwNP. On regression analysis, differences in protein expression were poorly predicted by differences in mRNA expression (R2 = 0.020, p < 0.05). Several genes canonically thought to be overexpressed in CRSwNP, including IL-5, IL-13, TSLP, CCL13, and CCL26, showed substantial increases in mRNA transcription, but had minimally or unchanged protein expression. Others, including IgE, periostin, CCL18, and CST1/2, were increased at both the transcriptomic and proteomic levels. Among differentially regulated proteins, tissue and mucus protein levels showed weak correlation (r = 0.26, p < 0.0001). CONCLUSION: Proteomic analysis in CRSwNP has revealed novel disease-associated proteins and pathways, yet correlates poorly with transcriptomic data. The increasing availability of proteomic arrays opens the door to new potential explanatory mechanisms in CRSwNP and suggests that mRNA based studies should be validated with protein analysis.

Discriminant analysis followed by unsupervised cluster analysis including exosomal cystatins predict presence of chronic rhinosinusitis, phenotype, and disease severity.

BACKGROUND: Cystatins are epithelial protease inhibitors that participate in sinonasal immunity and inflammation. Nasal mucus-derived exosomes (NMDEs) are small vesicles secreted by epithelial cells that carry protein cargo reflective of their host cell. NMDEs have been used as a noninvasive biomarker source to study chronic rhinosinusitis with nasal polyps (CRSwNP) proteomics with superior sensitivity to whole mucus. The purpose of this study was to noninvasively quantify exosomal cystatins in a heterogenous population to determine their utility in predicting phenotype and disease severity. METHODS: This was an Institutional Review Board-approved study in which NMDEs were purified from 105 patients undergoing sinonasal surgery by ultracentrifugation. Demographic and clinical variables were collected and phenotypes were assigned a priori. Linear discriminant analysis was executed based on normalized Cystatin values as phenotype predictor variables. Unsupervised cluster analysis was performed using Ward's linkage followed by Duda/Hart Je(2)/Je(1) index cluster stopping rules. Analysis of variance (ANOVA), Welch's test, and Fisher's exact tests were used for continuous and categorical variables. RESULTS: NMDE Cystatin-2 expression segregated by phenotype (mean ± standard error [SEM]): control (23.4 ± 4.2 pg/µg, n = 32); CRS without NP (CRSsNP) (56.6 ± 8.3 pg/µg, n = 33); and CRSwNP (130.5 ± 16.7 pg/µg, n = 40) (p < 0.0001). Seven clusters were identified among patients where the highest NMDE Cystatin-2 levels clustered with asthma, tissue eosinophilia, and aspirin-exacerbated respiratory disease (AERD). CONCLUSION: Cystatin levels in NMDEs predict CRS phenotype and disease severity. As a "liquid biopsy," noninvasive NMDE collection offers a promising opportunity to study disease pathophysiology, discriminate disease states, and potentially reveal novel therapeutic targets.

Noninvasive exosomal proteomic biosignatures, including cystatin SN, peroxiredoxin-5, and glycoprotein VI, accurately predict chronic rhinosinusitis with nasal polyps.

BACKGROUND: Exosomes are secreted epithelial-derived vesicles that contain a conserved protein array representative of their parent cell. Exosomes may be reproducibly and noninvasively purified from nasal mucus. The exosomal proteome can be quantified using SOMAscanTM , a highly multiplexed, aptamer-based proteomic platform. The purpose of this study was to determine whether chronic rhinosinusitis with nasal polyps (CRSwNP) has a unique predictive exosomal proteomic biosignature. METHODS: Exosomes were isolated from whole mucus sampled from control and CRSwNP patients (n = 20 per group) by differential ultracentrifugation. The SOMAscanTM platform was used to simultaneously quantify 1310 biologically relevant human proteins. Matched tissue and whole mucus proteomes were also analyzed. Differential protein expression and discriminatory power were calculated using the unweighted pair group method with arithmetic-mean and principal component analysis, respectively. Bioinformatic analysis was performed using Ingenuity Pathway, MetaCore, and GeneMANIA analyses. RESULTS: The exosomal proteome demonstrated 123 significantly (p < 0.05) differentially regulated proteins in CRSwNP relative to control. Eighty of these proteins overlapped with the matched CRSwNP tissue proteome as compared with only 4 among matched whole mucus samples. Forty-three significantly dysregulated pathway networks overlapped between the exosomal and tissue proteome in CRSwNP as compared with only 3 among matched whole mucus samples. The best-performing protein set (cystatin-SN, peroxiredoxin-5, and glycoprotein VI) achieved an area under the curve (AUC) value of up to 99%. CONCLUSION: Our data contribute a significant advance in the development of a reproducible, noninvasive, serial, and quantitative "liquid biopsy" for rhinosinusitis. The exosomal proteomic approach has revealed a unique biosignature associated with CRSwNP, which outperforms whole mucus sampling, and thus provides a method of noninvasive disease detection and proposes new potential therapeutic targets.

Highly multiplexed proteomic analysis reveals significant tissue and exosomal coagulation pathway derangement in chronic rhinosinusitis with nasal polyps.

BACKGROUND: The coagulation pathway has been previously implicated in the etiopathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) through analysis of individual proteins within the cascade. The purpose of this study was to: (1) apply a large-scale proteomic approach to confirm these previous findings; and (2) correlate the protein aberrations between tissue and exosomes to establish exosomal proteomics as a method to probe the pathophysiology of CRSwNP. METHODS: This investigation was an internal review board-approved study in which matched tissue and mucus exosomal proteomes were compared between control and CRSwNP (n = 10/group) using an aptamer-based proteomic array and confirmed using whole transcriptome sequencing. Protein expression and the correlation between samples were calculated using Student's t-test and Benjamini-Hochberg procedures followed by the application of Ingenuity Pathway and MetaCore™ bioinformatics analyses. RESULTS: Among all protein pathways, the coagulation cascade was the most significantly associated with CRSwNP (p = 2.85e-8). Among the 13 significantly altered coagulation-related tissue proteins, fibronectin and fibrinogen gamma chains were the most overexpressed in CRSwNP relative to control (fold change [FC], 2.59; p = 0.006; and FC, 2.38; p < 0.001, respectively), whereas von Willebrand factor was the most underexpressed (FC, -3.06; p < 0.001). The exosomal fibrinolysis and coagulation pathway proteomes exhibited strong inverse and significant correlations with the tissue findings (r = -0.86; p = 0.013; and r = -0.79; p = 0.007, respectively). CONCLUSION: Our proteomic analysis confirmed that the coagulation pathway is highly significantly deranged within nasal polyp tissue. The correlation between tissue- and mucus-derived exosomal fibrinolysis and coagulation protein alterations were strong, inverse, and highly significant. This lends further support to the emerging concept of exosomal proteomic analysis as a method to study chronic sinonasal inflammation.

Direct CNS delivery of proteins using thermosensitive liposome-in-gel carrier by heterotopic mucosal engrafting.

Delivering therapeutics across the blood-brain barrier (BBB) for treating central nervous system (CNS) diseases is one of the biggest challenges today as the BBB limits the uptake of molecules greater than 500 Da into the CNS. Here we describe a novel trans-nasal mucosal drug delivery as an alternative to the intranasal drug delivery to overcome its limitations and deliver high molecular weight (HMW) therapeutics efficiently to the brain. This approach is based on human endoscopic skull base surgical techniques in which a surgical defect is repaired by engrafting semipermeable nasal mucosa over a skull base defect. Based on endoscopic skull based surgeries, our groups has developed a trans-nasal mucosal rodent model where we have evaluated the permeability of ovalbumin (45 kDa) as a model protein through the implanted mucosal graft for delivering HMW therapeutics to the brain. A thermo sensitive liposome-in-gel (LiG) system was developed for creating a drug depot allowing for a sustained release from the site of delivery to the brain through the implanted nasal graft. We would like to report this as an exploratory pilot study where we are using this novel surgical model to show that the implanted nasal mucosal graft and the LiG delivery system result in an efficient and a sustained brain delivery of HMW proteins. Hence, this study demonstrates that the trans-nasal mucosal engrafting technique could overcome the limitations for intranasal drug delivery and enable the uptake of HMW protein therapeutics into the CNS for the treatment of a wide range of neurodegenerative diseases.

Axonal Guidance Signaling Pathway Is Suppressed in Human Nasal Polyps.

Background Dysfunctional innervation might contribute to the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP), but the state of the axonal outgrowth signaling in CRSwNP is unknown. The purpose of this study was to explore the axonal outgrowth pathway-related protein expression in CRSwNP. Methods Institutional review board approved study in which tissue proteomes were compared between control and CRSwNP patients (n = 10/group) using an aptamer-based proteomic array and confirmed by whole transcriptomic analysis. Results Compared with controls, proteins associated with axonal guidance signaling pathway such as beta-nerve growth factor, semaphorin 3A, Ras-related C3 botulinum toxin substrate 1, Bcl-2, protein kinase C delta type, and Fyn were significantly decreased in patients with CRSwNP (fold change [FC] = -1.17, P = .002; FC = -1.09, P < .001; FC = -1.33, P < .001; FC = -1.31, P < .001; FC = -1.31, P = .004; and FC = -1.20, P = 0.012, respectively). In contrast, reticulon-4 receptor, an inhibitory factor, was significantly increased in patients with CRSwNP (FC = 1.25, P < .001). Furthermore, neuronal growth-associated proteins such as ciliary neurotrophic factor receptor subunit alpha, neuronal growth regulator 1, neuronal cell adhesion molecule, neural cell adhesion molecule L1, platelet-derived growth factor subunit A, and netrin-4 were all significantly decreased in patients with CRSwNP (FC = -1.25, P < .001; FC = -1.27, P = .002; FC = -1.65, P = .013; FC = -4.20, P < .001; FC = -1.28, P < .001; and FC = -2.31, P < .001, respectively). In contrast, tissue eosinophil count ( P < .001) and allergic inflammation factors such as IgE, periostin, and galectin-10 were all significantly increased in patients with CRSwNP (FC = 12.28, P < .001; FC = 3.95, P < .001; and FC = 2.44, P < .001, respectively). Furthermore, the log FC of the studied proteins expression significantly and positively correlated with log FC of their mRNA expression ( P < .001, r = .88). Conclusions Axonal guidance signaling and neural growth factors pathways proteins are significantly suppressed in eosinophilic CRSwNP.

TREM-1 Neutrophil Activation Pathway Is Suppressed in Eosinophilic Nasal Polyps.

Background Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by type 2 helper T-cell-skewed immune profiles, but the state of the neutrophil activation signaling pathway in CRSwNP is unknown. The purpose of this study was to examine neutrophil activation pathways in the pathogenesis of CRSwNP. Methods Institutional review board approved the study in which tissue proteomes were compared between control (inferior turbinate) and CRSwNP (nasal polyps) (n = 10/group) using an aptamer-based proteomic array and confirmed by whole transcriptomic analysis. Protein expression was analyzed using Student's t test and Benjamini-Hochberg procedures followed by the application of Ingenuity Pathway, MetaCore, and Genemania bioinformatics analyses. Results All the patients with CRSwNP (n = 10) had eosinophilic nasal polyps. Compared with controls, proteins associated with the triggering receptor expressed on myeloid cells 1 (TREM-1) neutrophil activation signaling pathway such as Calcineurin B, zeta chain-associated protein kinase of 70 kD (ZAP70), 14-3-3 protein theta, 14-3-3 protein zeta/delta, protein kinase C delta type (PKC-D), Interleukin (IL)-17B, IL-17B receptor, IL-23, and IL-1B were significantly decreased in CRSwNP (fold change [FC] = -1.60, P = .003; FC = -1.85, P = .040; FC = -1.26, P < .001; FC = -1.05, P = .008; and FC = -1.31, P = .004; FC = -1.22, P < .001; FC = -1.09, P = .022; FC = -1.25, P < .001; and FC = -1.31, P = .014; respectively). In contrast, tissue eosinophil count ( P < .001) and eosinophil-associated proteins such as C-C motif chemokine 17, periostin, and galectin 10 were all significantly increased in CRSwNP (FC = 1.56, P = .009; FC = 3.95, P < .001; and FC = 2.44, P < .001; respectively). Furthermore, the FC of the studied proteins' expression significantly and positively correlated with FC of their mRNA expression ( P = .001, r = .75). Conclusions TREM-1-associated neutrophilic signaling pathway proteins are significantly suppressed in eosinophilic CRSwNP.

Exosomes mediate interepithelial transfer of functional P-glycoprotein in chronic rhinosinusitis with nasal polyps.

OBJECTIVE: P-glycoprotein (P-gp) drives type-2 helper T-cell inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) through unknown posttranslational mechanisms of overexpression. A recent randomized clinical trial demonstrated that inhibition of P-gp was as effective as oral steroids and biologics in treating CRSwNP. Exosomes are 30- to 150-nm vesicles capable of intercellular membrane protein transfer. The aims of this study were 1) to determine whether CRSwNP mucus exosomes are enriched with P-gp, and 2) whether exosomal P-gp can be functionally transferred to autologous epithelial cells as a putative mechanism for the proinflammatory overexpression of P-gp in CRSwNP. STUDY DESIGN: Institutional review board-approved study in CRSwNP and control patients (n = 10 per group). METHODS: P-gp content of purified mucus exosomes was characterized by transmission electron microscopy and enzyme-linked immunosorbent assay. Epithelial transfer of exosomal P-gp was determined by time-lapse fluorescent microscopy and calcein acetoxymethylester functional P-gp assay. RESULTS: CD63+/P-gp+ exosomes were detected in both groups. P-gp was significantly enriched in CRSwNP exosomes relative to control (median 198.5; interquartile range 123.6-270.5 vs. 74.4; 41.3-95.0 pcg P-gp/109 exosomes, P = 0.002). Exosomes were absorbed by epithelial cells within 10 minutes, resulting in a significant increase in P-gp activity in CRSwNP patients relative to control (P = 0.006). CONCLUSION: Here we demonstrate the presence and P-gp enrichment of mucus-derived exosomes, or rhinosomes, in CRSwNP. These rhinosomes are capable of rapid intercellular transfer of P-gp, leading to increased P-gp function within recipient cells. This represents a novel mechanism for maintaining P-gp overexpression in CRSwNP, and more generally for interepithelial transfer of other proteins between mucosal epithelial cells. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:E295-E300, 2017.

Secreted P-glycoprotein is a noninvasive biomarker of chronic rhinosinusitis.

OBJECTIVE: The discovery of noninvasive biomarkers of chronic rhinosinusitis (CRS) is critical to enable our ability to provide prognostic information and targeted medical therapy. Epithelial P-glycoprotein (P-gp) is overexpressed in CRS and exists in an extracellular, secreted form. The objective of this study was to determine whether secreted P-gp concentrations are elevated in CRS and can be used to predict disease severity. METHODS: Institutional review board-approved study examining mucus concentrations of P-gp in 36 patients (10 control, 16 CRS without nasal polyps [CRSsNP], and 10 CRS with nasal polyps [CRSwNP]). P-gp concentrations were determined by enzyme-linked immunosorbent assay and normalized to total protein (TP). Clinical indices of disease severity, including the Sino-Nasal Outcomes Test (SNOT-22) and Lund-Mackay score, were collected for all patients. RESULTS: Secreted P-gp concentration was significantly higher in CRS versus control patients (mean ± standard deviation; 247.8 ± 224.8 vs. 102.4 ± 81.7 pcg P-gp/µg TP, P = 0.022). A threshold value of 250 pcg/µg TP was used to differentiate low versus high secretors. High P-gp secretors with CRS (sNP and wNP, n = 9) demonstrated significantly higher SNOT-22 and Lund-Mackay scores (57.1 ± 7.9 and 13.9 ± 7.3) versus low secretors (38.3 ± 23.9 and 6.8 ± 7.3; P = 0.030 and P = 0.013, respectively) and had a significantly higher proportion of CRSwNP (66.7%) versus the low secretors (23.5%, n = 17, P = 0.046). CONCLUSION: P-gp secretion levels are significantly elevated in patients with CRS. High P-gp secretion is associated with a higher incidence of CRSwNP and confers worse subjective and objective measures of disease severity. The presence of elevated P-gp secretion may therefore represent a novel noninvasive biomarker of CRS and could be used to predict patients who may benefit from P-gp inhibitory therapeutic strategies. LEVEL OF EVIDENCE: NA Laryngoscope, 127:E1-E4, 2017.

P-glycoprotein regulates Staphylococcus aureus enterotoxin B-stimulated interleukin-5 and thymic stromal lymphopoietin secretion in organotypic mucosal explants.

BACKGROUND: T-helper 2 (Th2) inflammation is a hallmark of chronic rhinosinusitis with nasal polyps (CRSwNP) although the pathogenesis is poorly understood. P-glycoprotein (permeability glycoprotein, P-gp) is an efflux pump that is capable of regulating cytokine transport and is expressed within sinonasal mucosa. The purpose of this study was to examine if the oversecretion of interleukin 5 (IL-5) and thymic stromal lymphopoietin (TSLP) in CRSwNP could be explained through P-gp-mediated secretory pathways. METHODS: Fifteen ethmoid mucosal explants were harvested from patients with CRS (n = 10) and CRSwNP (n = 10) and stimulated with Staphylococcus aureus enterotoxin B (SEB). P-gp was inhibited using zosuquidar trihydrochloride (herein Zosuquidar). P-gp expression was measured using real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-5, IL-8, and TSLP secretion were quantified using ELISA. RESULTS: P-gp protein was overexpressed in CRSwNP (28.32 ± 25.94 ng/mL per mg explant) as compared to CRS (10.74 ± 8.61; p = 0.01, 2-tailed Mann-Whitney U test). There was no difference in messenger RNA (mRNA) expression. SEB induced a significant increase in IL-5 and TSLP but not IL-8 secretion relative to control in the CRSwNP explants only. Subsequent P-gp inhibition significantly reduced IL-5 and TSLP secretion (p = 0.04 for both, 2-tailed Student t test) to control levels. The concentration of IL-5 and TSLP secretion were strongly and significantly correlated to the concentration of P-gp within the same explant (IL-5: r = 0.791, p = 0.001; TSLP: r = 0.687, p = 0.003; 2-tailed Spearman's rank-order correlation). CONCLUSION: P-gp protein is expressed at higher concentrations in CRSwNP as compared to CRS. This overexpression directly contributes to the relative hypersecretion of IL-5 and TSLP. These findings suggest a novel mechanism for Th2 skewing in CRSwNP.

Heterotopic Mucosal Grafting Enables the Delivery of Therapeutic Neuropeptides Across the Blood Brain Barrier.

BACKGROUND: The blood-brain barrier represents a fundamental limitation in treating neurological disease because it prevents all neuropeptides from reaching the central nervous system (CNS). Currently, there is no efficient method to permanently bypass the blood-brain barrier. OBJECTIVE: To test the feasibility of using nasal mucosal graft reconstruction of arachnoid defects to deliver glial-derived neurotrophic factor (GDNF) for the treatment of Parkinson disease in a mouse model. METHODS: The Institutional Animal Care and Use Committee approved this study in an established murine 6-hydroxydopamine Parkinson disease model. A parietal craniotomy and arachnoid defect was repaired with a heterotopic donor mucosal graft. The therapeutic efficacy of GDNF (2 µg/mL) delivered through the mucosal graft was compared with direct intrastriatal GDNF injection (2 µg/mL) and saline control through the use of 2 behavioral assays (rotarod and apomorphine rotation). An immunohistological analysis was further used to compare the relative preservation of substantia nigra cell bodies between treatment groups. RESULTS: Transmucosal GDNF was equivalent to direct intrastriatal injection at preserving motor function at week 7 in both the rotarod and apomorphine rotation behavioral assays. Similarly, both transmucosal and intrastriatal GDNF demonstrated an equivalent ratio of preserved substantia nigra cell bodies (0.79 ± 0.14 and 0.78 ± 0.09, respectively, P = NS) compared with the contralateral control side, and both were significantly greater than saline control (0.53 ± 0.21; P = .01 and P = .03, respectively). CONCLUSION: Transmucosal delivery of GDNF is equivalent to direct intrastriatal injection at ameliorating the behavioral and immunohistological features of Parkinson disease in a murine model. Mucosal grafting of arachnoid defects is a technique commonly used for endoscopic skull base reconstruction and may represent a novel method to permanently bypass the blood-brain barrier.

Intact soluble P-glycoprotein is secreted by sinonasal epithelial cells.

BACKGROUND: P-glycoprotein (P-gp) is a 170 kDa transmembrane efflux pump, which is upregulated in chronic rhinosinusitis. Studies of leukemia demonstrated that P-gp may also be secreted in an intact soluble form. The purpose of this study was to explore whether sinonasal epithelial cells were capable of secreting soluble P-gp and whether P-gp has any functional role. METHODS: Soluble and cytoplasmic P-gp were quantified in vehicle and lipopolysaccharide exposed cultures by enzyme-linked immunosorbent assay. The molecular weight of the soluble P-gp was determined by Western blot. Naive cultures were exposed to recombinant human P-gp at 0-2000 ng/mL. The degree of membranous interpolation was determined by quantitative fluorescent immunocytochemistry and function was determined by a calcein acetoxymethyl ester assay. RESULTS: Soluble P-gp was secreted intact at 170 kDa. Mean (standard deviation) secretion was detected within vehicle wells at 55.43 ± 26.26 ng/mL, which significantly increased to 333.27 ± 305.98 ng/mL (p < 0.001) after lipopolysaccharide stimulation. Soluble P-gp strongly and significantly correlated with cytoplasmic P-gp (r = 0.57, p = 0.000001). Exposure to 2000 ng/mL of recombinant P-gp significantly increased corrected total cell fluorescence (1.34 ± 1.85) relative to vehicle control 0.29 ± 0.26 (p = 0.01) and significantly reduced calcein acetoxymethyl ester fluorescence (82.03 ± 43.69) relative to 100 ng/mL recombinant P-gp exposed cells (123.11 ± 42.16, p = 0.001). CONCLUSION: Cultured sinonasal epithelial cells were able to both secrete intact P-gp and could functionally interpolate soluble P-gp into their cell membrane. These in vitro findings indicated that soluble P-gp may be present in nasal mucus as a biomarker and could participate in the maintenance of P-gp overexpression in chronic rhinosinusitis and associated inflammation.