Respiratory syncytial virus (RSV) is the major viral cause of severe pulmonary disease in young infants worldwide. However, the mechanisms by which RSV causes disease in humans remain poorly understood. To help bridge this gap, we developed an ex vivo/in vitro model of RSV infection based on well-differentiated primary pediatric bronchial epithelial cells (WD-PBECs), the primary targets of RSV infection in vivo. Our RSV/WD-PBEC model demonstrated remarkable similarities to hallmarks of RSV infection in infant lungs. These hallmarks included restriction of infection to noncontiguous or small clumps of apical ciliated and occasional nonciliated epithelial cells, apoptosis and sloughing of apical epithelial cells, occasional syncytium formation, goblet cell hyperplasia/metaplasia, and mucus hypersecretion. RSV was shed exclusively from the apical surface at titers consistent with those in airway aspirates from hospitalized infants. Furthermore, secretion of proinflammatory chemokines such as CXCL10, CCL5, IL-6, and CXCL8 reflected those chemokines present in airway aspirates. Interestingly, a recent RSV clinical isolate induced more cytopathogenesis than the prototypic A2 strain. Our findings indicate that this RSV/WD-PBEC model provides an authentic surrogate for RSV infection of airway epithelium in vivo. As such, this model may provide insights into RSV pathogenesis in humans that ultimately lead to successful RSV vaccines or therapeutics.

There is a need for reproducible and effective models of pediatric bronchial epithelium to study disease states such as asthma. We aimed to develop, characterize, and differentiate an effective, an efficient, and a reliable three-dimensional model of pediatric bronchial epithelium to test the hypothesis that children with asthma differ in their epithelial morphologic phenotype when compared with nonasthmatic children. Primary cell cultures from both asthmatic and nonasthmatic children were grown and differentiated at the air-liquid interface for 28 d. Tight junction formation, MUC5AC secretion, IL-8, IL-6, prostaglandin E2 production, and the percentage of goblet and ciliated cells in culture were assessed. Well-differentiated, multilayered, columnar epithelium containing both ciliated and goblet cells from asthmatic and nonasthmatic subjects were generated. All cultures demonstrated tight junction formation at the apical surface and exhibited mucus production and secretion. Asthmatic and nonasthmatic cultures secreted similar quantities of IL-8, IL-6, and prostaglandin E2. Cultures developed from asthmatic children contained considerably more goblet cells and fewer ciliated cells compared with those from nonasthmatic children. A well-differentiated model of pediatric epithelium has been developed that will be useful for more in vivo like study of the mechanisms at play during asthma. (Pediatr Res 67: 17-22, 2010)

The incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is rapidly degraded in the circulation by dipeptidyl peptidase IV forming the N-terminally truncated peptide GIP(3-42). The present study examined the biological activity of this abundant circulating fragment peptide to establish its possible role in GIP action. Human GIP and GIP(3-42) were synthesised by Fmoc solid-phase peptide synthesis, purified by HPLC and characterised by electrospray ionisation-mass spectrometry. In GIP receptor-transfected Chinese hamster lung fibroblasts, GIP(3-42) dose dependently inhibited GIP-stimulated (10 7 M) cAMP production (up to 75·4 5·4%; P<0·001). In BRIN-BD11 cells, GIP(3-42) was significantly less potent at stimulating insulin secretion (1·9-to 3·2-fold; P<0·001), compared with native GIP and significantly inhibited GIP-stimulated (10 7 M) insulin secretion with maximal inhibition (48·8 6·2%; P<0·001) observed at 10 7 M. In (ob/ob) mice, administration of GIP(3-42) significantly inhibited GIPstimulated insulin release (2·1-fold decrease; P<0·001) and exaggerated the glycaemic excursion (1·4-fold; P<0·001) induced by a conjoint glucose load. These data indicate that the N-terminally truncated GIP(3-42) fragment acts as a GIP receptor antagonist, moderating the insulin secreting and metabolic actions of GIP in vivo.

Aims/hypothesis. This study examined the plasma stability, biological activity and antidiabetic potential of two novel N-terminally modified analogues of gastric inhibitory polypeptide (GIP). Methods. Degradation studies were carried out on GIP, N-acetyl-GIP (Ac-GIP) and N-pyroglutamyl-GIP (pGlu-GIP) in vitro following incubation with either dipeptidylpeptidase IV or human plasma. Cyclic adenosine 3′5′ monophosphate (cAMP) production was assessed in Chinese hamster lung fibroblast cells transfected with the human GIP receptor. Insulin-releasing ability was assessed in vitro in BRIN-BD11 cells and in obese diabetic (ob/ob) mice. Results. GIP was rapidly degraded by dipeptidylpeptidase IV and plasma (t 1/2 2.3 and 6.2 h, respectively) whereas Ac-GIP and pGlu-GIP remained intact even after 24 h. Both Ac-GIP and pGlu-GIP were extremely potent (p<0.001) at stimulating cAMP production (EC 50 values 1.9 and 2.7 nmol/l, respectively), almost a tenfold increase compared to native GIP (18.2 nmol/l). Both Ac-GIP and pGlu-GIP (10 -13 -10 -8 mmol/l) were more potent at stimulating insulin release compared to the native GIP (p<0.001), with 1.3-fold and 1.2-fold increases observed at 10 -8 mol/l, respectively. Administration of GIP analogues (25 nmol/kg body weight, i.p.) together with glucose (18 mmol/kg) in (ob/ob) mice lowered (p<0.001) individual glucose values at 60 min together with the areas under the curve for glucose compared to native GIP. This antihyperglycaemic effect was coupled to a raised (p<0.001) and more prolonged insulin response after administration of Ac-GIP and pGlu-GIP (AUC, 644±54 and 576±51 ng·ml -1 ·min, respectively) compared with native GIP (AUC, 257±29 ng·ml -1 ·min). Conclusion/interpretation. Ac-GIP and pGlu-GIP, show resistance to plasma dipeptidylpeptidase IV degradation, resulting in enhanced biological activity and improved antidiabetic potential in vivo, raising the possibility of their use in therapy of Type II (non-insulin-dependent) diabetes mellitus. [Diabetologia (2002[Diabetologia ( ) 45:1281[Diabetologia ( -1291 Keywords GIP analogues, antihyperglycaemic effects, insulin secretion, DPP IV stability, BRIN-BD11 cells, obese hyperglycaemic (ob/ob) mice. Corresponding author: Dr. F. P. M. O'Harte, School of Biomedical Sciences, University of Ulster, Coleraine, N. Ireland, UK, BT52 1SA, E-mail: fpm.oharte@ulst.ac.uk Abbreviations: cAMP, Cyclic adenosine 3′ 5′ monophosphate; DPP IV, Dipeptidylpeptidase IV; GIP, gastric inhibitory polypeptide; GLP-1, glucagon-like peptide-1(7-36)amide; TFA, trifluoroacetic acid; ESI-MS, electrospray ionisation mass spectrometry; pGlu, N-pyroglutamyl; Ac, N-acetyl; Fmoc, 9-fluorenylmethoxycarbonyl; CHL, Chinese hamster lung fibroblast; DPA, diprotin A; FSK, forskolin; IBMX, isobutylmethylxanthine Diabetologia (2002) 45:1281-1291 DOI 10.1007 Improved stability, insulin-releasing activity and antidiabetic potential of two novel N-terminal analogues of gastric inhibitory polypeptide: N-acetyl-GIP and pGlu-GIP Type II (non-insulin-dependent) diabetes me...

Goblet cell hyperplasia (GCH) and decreased ciliated cells are characteristic of asthma. We examined the effects of IL-13 (2 and 20 ng/mL) on in vitro mucociliary differentiation in pediatric bronchial epithelial cells (