Angela L. Nocera

P-glycoprotein functions as an immunomodulator in healthy human primary nasal epithelial cells.

P‐glycoprotein (P‐gp) is an adenosine triphosphate (ATP)‐dependent efflux pump that confers chemotherapeutic resistance in cancer cells. Recent studies suggest that P‐gp may also function as an immunomodulator through regulation of cytokine transport. Sinonasal epithelial cells have been recognized as drivers of local innate and adaptive immunity and are known to overexpress P‐gp in the setting of inflammation. The objective of this study is to therefore determine whether P‐gp participates in the regulation of cytokine secretion in sinonasal epithelial cells.

P‐glycoprotein promotes epithelial T helper 2–associated cytokine secretion in chronic sinusitis with nasal polyps

Sinonasal epithelial cells are recognized as drivers of inflammation in chronic sinusitis with nasal polyps (CRSwNP) through secretion of T helper 2 (Th2)‐promoting cytokines. P‐glycoprotein (P‐gp) is overexpressed in nasal polyps and modulates epithelial cytokine secretion in healthy mucosa. The objective of this study is to determine whether P‐gp overactivity promotes Th2‐associated cytokine secretion in CRSwNP.

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

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.

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

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.

Secreted P-glycoprotein is a noninvasive biomarker of chronic rhinosinusitis

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.

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.

The sinonasal microbiota, neural signaling, and depression in chronic rhinosinusitis: Microbiota and neural signaling in CRS

The complex relationships between the human microbiota, the immune system, and the brain play important roles in both health and disease, and have been of increasing interest in the study of chronic inflammatory mucosal conditions. We hypothesized that the sinonasal microbiota may act as a modifier of interkingdom neural signaling and, subsequently, mental health, in the upper respiratory inflammatory condition chronic rhinosinusitis (CRS). In this study we investigated associations between the sinonasal microbiota; local concentrations of the neurotransmitters serotonin, dopamine, and γ‐aminobutyric acid (GABA); and depression severity in a cohort of 14 CRS patients and 12 healthy controls.

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.

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.

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.