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.

KIT as a therapeutic target for non-oncological diseases.

KIT is a receptor tyrosine kinase that after binding to its ligand stem cell factor activates signaling cascades linked to biological processes such as proliferation, differentiation, migration and cell survival. Based on studies performed on SCF and/or KIT mutant animals that presented anemia, sterility, and/or pigmentation disorders, KIT signaling was mainly considered to be involved in the regulation of hematopoiesis, gametogenesis, and melanogenesis. More recently, novel animal models and ameliorated cellular and molecular techniques have led to the discovery of a widen repertoire of tissue compartments and functions that are being modulated by KIT. This is the case for the lung, heart, nervous system, gastrointestinal tract, pancreas, kidney, liver, and bone. For this reason, the tyrosine kinase inhibitors that were originally developed for the treatment of hemato-oncological diseases are being currently investigated for the treatment of non-oncological disorders such as asthma, rheumatoid arthritis, and alzheimer's disease, among others. The beneficial effects of some of these tyrosine kinase inhibitors have been proven to depend on KIT inhibition. This review will focus on KIT expression and regulation in healthy and pathologic conditions other than cancer. Moreover, advances in the development of anti-KIT therapies, including tyrosine kinase inhibitors, and their application will be discussed.

Human bronchial epithelium orchestrates dendritic cell activation in severe asthma.

The innate immune response is impaired in asthma, with increased epithelial release of C-X-C motif chemokine ligand (CXCL)8, interleukin (IL)-33 and thymic stromal lymphopoietin (TSLP). We hypothesised that dendritic cells might modulate the hyperresponsive epithelium in severe asthma.For this purpose, we investigated epithelial-dendritic crosstalk in normal and diseased conditions, and because ultrafine particulate matter may affect asthmatic airways, we investigated its impact on this crosstalk. Air-liquid interface cultures of human bronchial epithelial cells (HBEC) of control subjects (cHBEC) or severe asthma patients (saHBEC) were co-cultured with monocyte-derived dendritic cells (moDC).Increased release of CXCL8, TSLP and IL-33 from saHBEC contrasted with cHBEC producing CXCL10 and CCL2. Regarding moDC activation, saHBEC co-cultures induced only upregulation of CD86 expression, while cHBEC yielded full moDC maturation with HLA-DR, CD80, CD86 and CD40 upregulation. Particulate matter stimulation of HBEC had no effect on cHBEC but stimulated CXCL8 and IL-33 release in saHBEC. Particulate matter impaired epithelium signalling (TSLP, IL-33 and CXCL8) in saHBEC co-cultures despite C-C chemokine ligand 2 induction.Crosstalk between HBEC and moDC can be established in vitro, driving a T1-type response with cHBEC and a T2-type response with saHBEC. Normal or asthmatic status of HBEC differentially shapes the epithelial-dendritic responses. We conclude that control moDC cannot rescue the hyperresponsive airway epithelium of severe asthmatics.

Prostaglandin E2 Inhibits NLRP3 Inflammasome Activation through EP4 Receptor and Intracellular Cyclic AMP in Human Macrophages.

PGE2 is a potent lipid mediator involved in maintaining homeostasis but also promotion of acute inflammation or immune suppression in chronic inflammation and cancer. Nucleotide-binding domain, leucine-rich repeat-containing protein (NLR)P3 inflammasome plays an important role in host defense. Uncontrolled activation of the NLRP3 inflammasome, owing to mutations in the NLRP3 gene, causes cryopyrin-associated periodic syndromes. In this study, we showed that NLRP3 inflammasome activation is inhibited by PGE2 in human primary monocyte-derived macrophages. This effect was mediated through PGE2 receptor subtype 4 (EP4) and an increase in intracellular cAMP, independently of protein kinase A or exchange protein directly activated by cAMP. A specific agonist of EP4 mimicked, whereas its antagonist or EP4 knockdown reversed, PGE2-mediated NLRP3 inhibition. PGE2 caused an increase in intracellular cAMP. Blockade of adenylate cyclase by its inhibitor reversed PGE2-mediated NLRP3 inhibition. Increase of intracellular cAMP by an activator of adenylate cyclase or an analog of cAMP, or a blockade of cAMP degradation by phosphodiesterase inhibitor decreased NLRP3 activation. Protein kinase A or exchange protein directly activated by cAMP agonists did not mimic, and their antagonists did not reverse, PGE2-mediated NLRP3 inhibition. Additionally, constitutive IL-1ß secretion from LPS-primed PBMCs of cryopyrin-associated periodic fever syndromes patients was substantially reduced by high doses of PGE2. Moreover, blocking cytosolic phospholipase A2α by its inhibitor or small interfering RNA or inhibiting cyclooxygenase 2, resulting in inhibition of endogenous PGE2 production, caused an increase in NLRP3 inflammasome activation. Our results suggest that PGE2 might play a role in maintaining homeostasis during the resolution phase of inflammation and might serve as an autocrine and paracrine regulator.

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

Reconstituted human upper airway epithelium as 3-d in vitro model for nasal polyposis.

BACKGROUND: Primary human airway epithelial cells cultured in an air-liquid interface (ALI) develop a well-differentiated epithelium. However, neither characterization of mucociliar differentiation overtime nor the inflammatory function of reconstituted nasal polyp (NP) epithelia have been described. OBJECTIVES: 1st) To develop and characterize the mucociliar differentiation overtime of human epithelial cells of chronic rhinosinusitis with nasal polyps (CRSwNP) in ALI culture system; 2nd) To corroborate that 3D in vitro model of NP reconstituted epithelium maintains, compared to control nasal mucosa (NM), an inflammatory function. METHODS: Epithelial cells were obtained from 9 NP and 7 control NM, and differentiated in ALI culture for 28 days. Mucociliary differentiation was characterized at different times (0, 7, 14, 21, and 28 days) using ultrastructure analysis by electron microscopy; ΔNp63 (basal stem/progenitor cell), ß-tubulin IV (cilia), and MUC5AC (goblet cell) expression by immunocytochemistry; and mucous (MUC5AC, MUC5B) and serous (Lactoferrin) secretion by ELISA. Inflammatory function of ALI cultures (at days 0, 14, and 28) through cytokine (IL-8, IL-1ß, IL-6, IL-10, TNF-α, and IL-12p70) and chemokine (RANTES, MIG, MCP-1, IP-10, eotaxin-1, and GM-CSF) production was analysed by CBA (Cytometric Bead Array). RESULTS: In both NP and control NM ALI cultures, pseudostratified epithelium with ciliated, mucus-secreting, and basal cells were observed by electron microscopy at days 14 and 28. Displaying epithelial cell re-differentation, ß-tubulin IV and MUC5AC positive cells increased, while ΔNp63 positive cells decreased overtime. No significant differences were found overtime in MUC5AC, MUC5B, and lactoferrin secretions between both ALI cultures. IL-8 and GM-CSF were significantly increased in NP compared to control NM regenerated epithelia. CONCLUSION: Reconstituted epithelia from human NP epithelial cells cultured in ALI system provides a 3D in vitro model that could be useful both for studying the role of epithelium in CRSwNP while developing new therapeutic strategies, including cell therapy, for CRSwNP.

The fish oil ingredient, docosahexaenoic acid, activates cytosolic phospholipase A2 via GPR120 receptor to produce prostaglandin E2 and plays an anti-inflammatory role in macrophages.

Docosahexaenoic acid (DHA) is one of the major ingredients of fish oil and has been reported to have anti-inflammatory properties mediated through the GPR120 receptor. Whether cytosolic phospholipase A2 (cPLA2 ) and lipid mediators produced from cPLA2 activation are involved in the anti-inflammatory role of DHA in macrophages has not been reported. We report here that DHA and the GPR120 agonist, GW9508, activate cPLA2 and cyclooxygenase 2 (COX-2), and cause prostaglandin E2 (PGE2) release in a murine macrophage cell line RAW264.7 and in human primary monocyte-derived macrophages. DHA and GW9508 activate cPLA2 via GPR120 receptor, G protein Gαq and scaffold protein ß-arrestin 2. Extracellular signal-regulated kinase 1/2 activation is involved in DHA- and GW9508-induced cPLA2 activation, but not p38 mitogen-activated protein kinase. The anti-inflammatory role of DHA and GW9508 is in part via activation of cPLA2 , COX-2 and production of PGE2 as a cPLA2 inhibitor or a COX-2 inhibitor partially reverses the DHA- and GW9508-induced inhibition of lipopolysaccharide-induced interleukin-6 secretion. The cPLA2 product arachidonic acid and PGE2 also play an anti-inflammatory role. This effect of PGE2 is partially through inhibition of the nuclear factor-κB signalling pathway and through the EP4 receptor of PGE2 because an EP4 inhibitor or knock-down of EP4 partially reverses DHA inhibition of lipopolysaccharide-induced interleukin-6 secretion. Hence, DHA has an anti-inflammatory effect partially through induction of PGE2.

Low molecular weight hyaluronan activates cytosolic phospholipase A2α and eicosanoid production in monocytes and macrophages.

Hyaluronan (HA) is the major glycosaminoglycan in the extracellular matrix. During inflammation, there is an increased breakdown of HA, resulting in the accumulation of low molecular weight (LMW) HA and activation of monocytes and macrophages. Eicosanoids, derived from the cytosolic phospholipase A2 group IVA (cPLA2α) activation, are potent lipid mediators also attributed to acute and chronic inflammation. The aim of this study was to determine the effect of LMW HA on cPLA2α activation, arachidonic acid (AA) release, and subsequent eicosanoid production and to examine the receptors and downstream mechanisms involved in these processes in monocytes and differently polarized macrophages. LMW HA was a potent stimulant of AA release in a time- and dose-dependent manner, induced cPLA2α, ERK1/2, p38, and JNK phosphorylation, as well as activated COX2 expression and prostaglandin (PG) E2 production in primary human monocytes, murine RAW 264.7, and wild-type bone marrow-derived macrophages. Specific cPLA2α inhibitor blocked HA-induced AA release and PGE2 production in all of these cells. Using CD44, TLR4, TLR2, MYD88, RHAMM or STAB2 siRNA-transfected macrophages and monocytes, we found that AA release, cPLA2α, ERK1/2, p38, and JNK phosphorylation, COX2 expression, and PGE2 production were activated by LMW HA through a TLR4/MYD88 pathway. Likewise, PGE2 production and COX2 expression were blocked in Tlr4(-/-) and Myd88(-/-) mice, but not in Cd44(-/-) mice, after LMW HA stimulation. Moreover, we demonstrated that LMW HA activated the M1 macrophage phenotype with the unique cPLA2α/COX2(high) and COX1/ALOX15/ALOX5/LTA4H(low) gene and PGE2/PGD2/15-HETE(high) and LXA4(low) eicosanoid profile. These findings reveal a novel link between HA-mediated inflammation and lipid metabolism.

Differential expression of remodeling markers by tissue structure in nasal polyposis.

BACKGROUND: Data on the expression and role of matrix metalloproteinases (MMPs) and their tissue inhibitors (tissue inhibitor of metalloproteinases [TIMPs]) in chronic rhinosinusitis with nasal polyps (CRSwNPs) are contradictory, partly because or the use of different techniques of tissue analysis. The aim of this study was to establish a qualitative/semiquantitative method of analysis on the expression of these remodeling markers in different tissue structures and eosinophils in both NPs and nasal mucosa (NM). METHODS: NP tissues were obtained from patients undergoing endoscopic sinus surgery for severe CRSwNPs (n = 33) and NM tissues from patients undergoing nasal corrective surgery (n = 12). MMPs (MMP-1, MMP-2, MMP-7, and MMP-9) and TIMP type 1 (TIMP-1) expression were evaluated by immunohistochemistry in tissue structures (epithelium, glands, vessels, and extracellular matrix [ECM]) and eosinophils. Tissue eosinophilia was also analyzed in NP tissues. RESULTS: MMPs and TIMP-1 expression were found in the epithelium, glands, vessels, and ECM (in both NM and NP) and in eosinophils (only in NP). Significant (p < 0.01) findings were observed in NP compared with NM: increase in MMP-1 in ECM; decrease in MMP-2 in glands, vessels, and epithelium; decrease in MMP-7 in all tissue structures; increase in MMP-9 in ECM and decrease in epithelium and glands; and no differences in TIMP-1. NP tissues showed a clear eosinophilic inflammation compared with NM (p < 0.01). CONCLUSION: These findings suggest that (1) metalloproteases (MMP-1, MMP-2, MMP-7, and MMP-9) may play an important role in the remodeling of NPs and/or in NP formation and (2) a differential analysis of tissue structures and inflammatory cells should be performed when studying remodeling marker expression and regulation in the upper airways.

Changes in microRNA and mRNA expression with differentiation of human bronchial epithelial cells.

We studied the changes in expression of microRNAs (miRNAs or miRs) and mRNA in normal human bronchial epithelial cells as they differentiate from an undifferentiated monolayer to a differentiated pseudostratified epithelium after 28 days of air-liquid interface (ALI) culture. After 28 days in ALI, the epithelial cells differentially expressed basal, ciliated, and goblet cell markers. Using Affymetrix microarrays, 20 human miRNAs were found to be up-regulated, whereas 35 miRNAs were found to be down-regulated in differentiated cells compared with undifferentiated cells. An analysis of changes in global mRNA expression revealed that 1,201 probe sets demonstrated an 8-fold change (FC) or greater at Day 28 of ALI culture. Of these, 816 were up-regulated and 385 were down-regulated. With differentiation, miR-449a increased (FC, 38.15), and was related to changes in mRNA for cell division cycle 25 homolog A (FC, 0.11). MiR-455 decreased (FC, 0.12) and was related to changes in mRNA for the epithelial cell marker, mucin 1 (FC, 136). Transfection with anti-miR-449 or miR-455-3p resulted in changes in target protein expression (cell division cycle 25 homolog A and mucin 1, respectively), whereas transfection with reporter genes with 3'-untranslated regions of these targets confirmed control of expression through that structure. Therefore, changes in specific miRNAs during human airway epithelial cell differentiation control gene and protein expression important for differentiation.

Mucin gene expression in rhinitis syndromes.

Rhinitis and rhinosinusitis are often associated with airway diseases such as asthma, cystic fibrosis, and nasal polyposis. In these diseases, the alteration of both the quantity and quality of mucus results in an impaired mucociliary clearance, and this produces, in extreme cases, the airway obstruction. Mucins are the major component in mucus and are responsible for its viscoelastic properties. Mucin expression patterns have been shown to be altered in rhinitis-associated diseases. It has been proposed that this is one of the causes of hyperviscid mucus plugs in these pathologies. For this reason, the study of mucin expression and regulation in upper- and lower-airway diseases, such as asthma, cystic fibrosis, and nasal polyposis, may be crucial for the development of new therapies against mucus hypersecretion. In this review, we report major findings regarding mucin expression and regulation in rhinitis syndromes.