The polarity of the conducting airway epithelium is responsible for its directional secretion. This is an essential characteristic of lung integrity and function that dictates interactions between the external environment (apical) and subepithelial structures (basolateral). Defining the directional secretomes in the in vitro human bronchial epithelial (HBE) differentiated model could bring valuable insights into lung biology and pulmonary diseases. Normal primary HBE cells (n = 3) were differentiated into respiratory tract epithelium. Apical and basolateral secretions (24 h) were processed for proteome profiling and pathway analysis. A total of 243 proteins were identified in secretions from all HBE cultures combined. Of these, 51% were classified as secreted proteins, including true secreted proteins (36%) and exosomal proteins (15%). Close examination revealed consistent secretion of 69 apical proteins and 13 basolateral proteins and differential secretion of 25 proteins across all donors. Expression of Annexin A4 in apical secretions and Desmoglein-2 in basolateral secretions was validated using Western blot or ELISA in triplicate independent experiments. To the best of our knowledge, this is the first study defining apical and basolateral secretomes in the in vitro differentiated HBE model. The data demonstrate that epithelial polarity directs protein secretion with different patterns of biological processes to the apical and basolateral surfaces that are consistent with normal bronchial epithelium homeostatic functions. Applying this in vitro directional secretome model to lung diseases may elucidate their molecular pathophysiology and help define potential therapeutic targets.

No abstract

BackgroundInvasive fungal infections are a leading cause of death in allo-HSCT (allogenic hematopoietic stem cell transplant) recipients. We describe the epidemiology of IFIs (invasive fungal infections) in allo-HSCT recipients at a single institution in Salt Lake City, Utah between 2006 and 2015.MethodsWe searched all encounters in the Intermountain Healthcare electronic medical record from 2006 to 2015 for clinical data associated with IFIs in allo-HSCT recipients. EORTC-MSG definitions were applied to categorize IFI as proven, probable, or possible. Linear regression was used to model the variation in incidence over time.Results326 unique allo-HSCT were performed; of these 114 episodes of IFI occurred in 105 patients. Mean incidence was 35.9 IFI per 100 transplants, and increased by 2.3 IFI cases/100 transplants per year. 25.4% of cases were classified as proven; 47.4% as probable and 19.3% as possible. Invasive Aspergillus represented the majority of cases (62.3%), followed by non-specified (in most cases positive imaging and a positive β-d-glucan, 18%), Candidiasis (10%), and Mucorales (3.5%). The median age was 50 years, range 22 to 73, with males representing 52.6% of cases. The most common non-hematologic comorbidities were chronic pulmonary disease (42.9%), chronic heart failure (32.4%), and hepatic disease (31.4%). 48.6% of patients received matched unrelated allo-HSCT, 34.3% received matched sibling donor allo-HSCT, 14.3% received haploidentical allo-HSCT, and 3% received cord allo-HSCT. 79% of transplants were myeloablative. Median time from transplant to onset of IFI was 145 days (95% CI 39–259). The median time to onset of Aspergillosis was 120 days (95% CI 34–241 days), Candidiasis was 130 days (95% CI 12–283 days), and Mucorales was 246 days (95% CI 126–338 days). Active GVHD was present in 60% of IFI cases. 63% of cases were on antifungal prophylaxis, most commonly an echinocandin. All-cause mortality was 30.5% at 42 days and 65.7% at 1 year. The median time to death from the onset of IFI was 68.5 days.ConclusionIFIs are common in allo-HSCT recipients and appear to be increasing in frequency. Further work is needed to risk-stratify patients, determine optimal prophylaxis and empiric treatment, and define resistance trends. Disclosures All authors: No reported disclosures.