Key Points: Chloride channels are important for proper hydration of the airway surface. TMEM16A protein is an important component of calcium‐activated chloride channels. Interleukin‐4, a cytokine that induces mucous cell metaplasia, also upregulates calcium‐dependent chloride secretion in human bronchial epithelial cells. In bronchial epithelial cells treated with interleukin‐4, we found that TMEM16A protein becomes highly expressed in goblet but not in ciliated cells. Upregulation of TMEM16A by interleukin‐4 may be important for secretion and proper expansion of mucins. Abstract  The TMEM16A protein has a potential role as a Ca²⁺‐activated Cl⁻ channel (CaCC) in airway epithelia where it may be important in the homeostasis of the airway surface fluid. We investigated the function and expression of TMEM16A in primary human bronchial epithelial cells and in a bronchial cell line (CFBE41o–). Under resting conditions, TMEM16A protein expression was relatively low. However, TMEM16A silencing with short‐interfering RNAs caused a marked inhibition of CaCC activity, thus demonstrating that a low TMEM16A expression is sufficient to support Ca²⁺‐dependent Cl⁻ transport. Following treatment for 24–72 h with interleukin‐4 (IL‐4), a cytokine that induces mucous cell metaplasia, TMEM16A protein expression was strongly increased in approximately 50% of primary bronchial epithelial cells, with a specific localization in the apical membrane. IL‐4 treatment also increased the percentage of cells expressing MUC5AC, a marker of goblet cells. Interestingly, MUC5AC was detected specifically in cells expressing TMEM16A. In particular, MUC5AC was found in 15 and 60% of TMEM16A‐positive cells when epithelia were treated with IL‐4 for 24 or 72 h, respectively. In contrast, ciliated cells showed expression of the cystic fibrosis transmembrane conductance regulator Cl⁻ channel but not of TMEM16A. Our results indicate that TMEM16A protein is responsible for CaCC activity in airway epithelial cells, particularly in cells treated with IL‐4, and that TMEM16A upregulation by IL‐4 appears as an early event of goblet cell differentiation. These findings suggest that TMEM16A expression is particularly required under conditions of mucus hypersecretion to ensure adequate secretion of electrolytes and water.

To evaluate type of surgery, long-term survival and factors influencing outcome in pulmonary carcinoid tumors. We reviewed data of 252 patients who underwent surgery for carcinoid tumor in 1968-1989 (Group A) and in 1990-2005 (Group B). All cases were reviewed and classified as typical (TC) or atypical carcinoid (AC) according to WHO criteria (1999). There were 174 (69%) patients with TC (167 N0, 6 N1 and 1 N2) and 78 (31%) with AC (56 N0, 13 N1, 9 N2). Surgery consisted of 163 (64.7%) formal lung resections (121 lobectomies, 18 bilobectomies, 14 segmentectomies, 10 pneumonectomies), 76 (30.1%) sleeve or bronchoplastic resections and 13 (5.2%) wedge resections. No perioperative mortality occurred, 17 (6.7%) patients experienced complications. Overall 5, 10 and 15-year survival rate was 90%, 83% and 77%. TC showed a more favourable prognosis than AC (10-year survival rate 93% and 64%; p=0.00001) as well as N0 patients in comparison with N1-2 patients (10-year survival rate 87% and 50%; p=0.00005). Group A received lymph-node sampling, Group B received a systematic lymphadenectomy. No difference was found between Group A and B in detection of nodal metastases (10.9% versus 11.9%; p=0.79), but in Group A we observed 2 lymph-node relapses. In Group B number of sleeve resections significantly increased (2.7% versus 20.4%; p=0.0001) and number of pneumonectomies showed a significant reduction (7.2% versus 1.4%; p=0.01). Typical histology and N0 status were important prognostic factors in carcinoid tumors. Parenchyma-sparing procedures must be considered the treatment of choice with systematic lymphadenectomy.

STEM CELLS, a peer reviewed journal published monthly, provides a forum for prompt publication of original investigative papers and concise reviews. STEM CELLS is read and written by clinical and basic scientists whose expertise encompasses the rapidly expanding fields of stem and progenitor cell biology. STEM CELLS welcomes original articles and concise reviews describing basic laboratory investigations of stem cells and the translation of their clinical aspects of characterization and manipulation from the bench to patient care. The journal covers all aspects of stem cells embryonic stem cells/induced pluripotent stem cells; tissue-specific stem cells; stem cell technology: epigenetics, genomics, proteomics, and metabonomics; cancer stem cells; translational and clinical research; and regenerative medicine.

Amiodarone interferes with the endocytic pathway, inhibits proteolysis, and causes the formation of vacuoles, but uptake and intracellular distribution of the drug, origin of vacuoles, and functional consequences of amiodarone accumulation remain unclear. Our objective was to study amiodarone uptake, clarify the origin of vacuoles, and investigate the effect of amiodarone on the life cycle of the coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS), which, to enter cells, relies on the proteolytic cleavage of a viral spike protein by the endosomal proteinase cathepsin L. Using alveolar macrophages, we studied uptake of 125I-amiodarone and 125I-B2, an analog lacking the lateral group diethylamino-β-ethoxy, and analyzed the effects of amiodarone on the distribution of endosomal markers and on the uptake of an acidotropic dye. Furthermore, using Vero cells, we tested the impact of amiodarone on the in vitro spreading of the SARS coronavirus. We found that (1) amiodarone associates with different cell membranes and accumulates in acidic organelles; (2) the diethylamino-β-ethoxy group is an important determinant of uptake; (3) vacuoles forming upon exposure to amiodarone are enlarged late endosomes; (4) amiodarone inhibits the spreading in vitro of SARS coronavirus; and (5) trypsin cleavage of the viral spike protein before infection, which permits virus entry through the plasma membrane, does not impair amiodarone antiviral activity. We conclude that amiodarone alters late compartments of the endocytic pathway and inhibits SARS coronavirus infection by acting after the transit of the virus through endosomes.