Pendrin Research Articles

Expression and relationship of pendrin and MUC5AC in patients with chronic rhinosinusitis

To explore the expression of pendrin in sinonasal mucosal tissue of patients with chronic rhinosinusitis (CRS) and examine its relationship with mucin5AC (MUC5AC). Thirty mucosal tissue (located on anterior wall of maxillary sinus ostium and close to uncinate process) of patients with CRS with or without nasal polyps and 10 normal sinonasal mucosal tissue located at the same sites as CRS were collected. Histological changes of sinonasal mucosa were examined by hematoxylin and eosin (HE) staining. The expression of total mucins was evaluated by periodic acid Schiff staining (PAS). And the expressions of pendrin and MUC5AC in sinonasal mucosa were determined by immunohistochemistry (IHC), quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. The tissue samples demonstrated mucosal thickening, goblet cell hyperplasia and metaplasia, epithelial cilia partial deletion, glandular hyperplasia and a dense infiltration of inflammatory cells in CRS with or without nasal polyps. IHC revealed that positive pendrin was expressed dominantly at apical membrane of epithelial cells and sparsely in submucosal glandular cells, there was a positive expression rate of CRS with nasal polyps and CRS without nasal polyps; MUC5AC was expressed abundantly in goblet cells and pseudostratified ciliated columnar epithelium cells and weakly in submucosal glandular cells in CRS. There were significant increases in positive expression rate of total mucins production, pendrin and MUC5AC in patients of CRS with nasal polyps or without nasal polyps than those in control (86.7% and 80.0% vs 20.0%, 73.3% and 70.0% vs 10.0%, 83.3% and 76.7% vs 20.0%, all P<0.05); the relative expression levels of mRNA and protein expression of pendrin were significantly greater in patients of CRS with or without nasal polyps than those in controls (1.685±0.111 and 1.537±0.262 vs 1.012±0.167, 2.066±0.188 and 1.996±0.153 vs 1.000±0.169, all P<0.05). The relative expression levels of mRNA expression of MUC5AC were significantly greater in patients of CRS with or without nasal polyps than in controls (1.861±0.718 and 1.562±0.428 vs 1.004±0.094, P<0.05). And the expression level of pendrin mRNA was positively correlated with that of MUC5AC mRNA in patients with CRS (r=0.670, P=0.006 and r=0.713, P=0.003). An up-regulation of pendrin is correlated with an over-expression of MUC5AC in patients with CRS. And pendrin is an important cause of mucus hypersecretion in CRS.

Branchial osmoregulation in the euryhaline bull shark, Carcharhinus leucas: a molecular analysis of ion transporters

Bull sharks, Carcharhinus leucas, are one of only a few species of elasmobranchs that live in both marine and freshwater environments. Osmoregulation in euryhaline elasmobranchs is achieved through the control and integration of various organs (kidney, rectal gland and liver) in response to changes in environmental salinity. However, little is known regarding the mechanisms of ion transport in the gills of euryhaline elasmobranchs and how they are affected by osmoregulatory challenges. This study was conducted to gain insight into the branchial ion and acid-base regulatory mechanisms of C. leucas by identifying putative ion transporters and determining whether their expression is influenced by environmental salinity. We hypothesised that expression levels of the Na(+)/K(+)-ATPase (NKA) pump, Na(+)/H(+) exchanger 3 (NHE3), vacuolar-type H(+)-ATPase (VHA) and anion exchanger pendrin (PDN) would be upregulated in freshwater (FW) C. leucas. Immunohistochemistry was used to localise all four ion transporters in gills of bull sharks captured in both FW and estuarine/seawater (EST/SW) environments. NHE3 immunoreactivity occurred in the apical region of cells with basolateral NKA expression whereas PDN was apically expressed in cells that also exhibited basolateral VHA immunoreactivity. In accordance with our hypotheses, quantitative real-time PCR showed that the mRNA expression of NHE3 and NKA was significantly upregulated in gills of FW-captured C. leucas relative to EST/SW-captured animals. These data suggest that NHE3 and NKA together may be important in mediating branchial Na(+) uptake in freshwater environments, whereas PDN and VHA might contribute to Cl(-)/HCO(3)(-) transport in marine and freshwater bull shark gills.