Cystic Fibrosis Human Organs-on-a-Chip.

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene: the gene product responsible for transporting chloride and bicarbonate ions through the apical membrane of most epithelial cells. Major clinical features of CF include respiratory failure, pancreatic exocrine insufficiency, and intestinal disease. Many CF animal models have been generated, but some models fail to fully capture the phenotypic manifestations of human CF disease. Other models that better capture the key characteristics of the human CF phenotype are cost prohibitive or require special care to maintain. Important differences have been reported between the pathophysiology seen in human CF patients and in animal models. These limitations present significant limitations to translational research. This review outlines the study of CF using patient-derived organs-on-a-chip to overcome some of these limitations. Recently developed microfluidic-based organs-on-a-chip provide a human experimental model that allows researchers to manipulate environmental factors and mimic in vivo conditions. These chips may be scaled to support pharmaceutical studies and may also be used to study organ systems and human disease. The use of these chips in CF discovery science enables researchers to avoid the barriers inherent in animal models and promote the advancement of personalized medicine.

Patient personalized translational tools in cystic fibrosis to transform data from bench to bed-side and back.

Cystic fibrosis is a deadly multiorgan disorder caused by loss of function mutations in the gene that encodes for the cystic fibrosis transmembrane conductance regulator (CFTR) chloride/bicarbonate ion channel. More than 1,700 CFTR genetic variants exist that can cause CF, and majority of these are extremely rare. Because of genetic and environmental influences, CF patients exhibit large phenotypic variation. These factors make clinical trials difficult and largely impractical due to limited and heterogeneous patient pools. Also, the benefit of approved small-molecule CF modulators in a large number of rare mutation patients remains unknown. The goal of this study is to perform a comprehensive bench-side study using in vitro patient enteroids and in vivo mice implanted human intestinal organoids (HIOs) to test CF modulator-Ivacaftor response for a rare CF mutation patient. Based on the positive Ivacaftor response in the enteroids, the patient was enrolled in a (N = 1) clinical trial and showed improved clinical outcomes upon Ivacaftor treatment. HIO implantation model allowed in vivo modulator dosing and provided an elegant human organ-based demonstration of bench-to-bedside testing of modulator effects. Additionally, using the CF HIO model the role of CFTR function in the maturation of human intestine was reported for the first time. In all, we demonstrate that these models effectively serve to translate data from the lab to the clinic and back so that patient-specific therapies could be easily identified and disease-relevant developmental abnormalities in CF organs could be studied and addressed.NEW & NOTEWORTHY In this study, we report an example of laboratory models informing clinical care for rare CF mutation patient, with subsequent recapitulation of clinical benefit in a unique and disease relevant, human-derived in vivo model, effectively translating data from the lab to the clinic and back. This extensive work outlines a potential platform to identify patient-specific therapies and to understand relevant developmental abnormalities associated with CF disease.

Secreted Phospholipase A2 Group X Acts as an Adjuvant for Type 2 Inflammation, Leading to an Allergen-Specific Immune Response in the Lung.

Secreted phospholipase A2 (sPLA2) enzymes release free fatty acids, including arachidonic acid, and generate lysophospholipids from phospholipids, including membrane phospholipids from cells and bacteria and surfactant phospholipids. We have shown that an endogenous enzyme sPLA2 group X (sPLA2-X) is elevated in the airways of asthmatics and that mice lacking the sPLA2-X gene (Pla2g10) display attenuated airway hyperresponsiveness, innate and adaptive immune responses, and type 2 cytokine production in a model of airway sensitization and challenge using a complete allergen that induces endogenous adjuvant activity. This complete allergen also induces the expression of sPLA2-X/Pla2g10 In the periphery, an sPLA2 found in bee venom (bee venom PLA2) administered with the incomplete Ag OVA leads to an Ag-specific immune response. In this study, we demonstrate that both bee venom PLA2 and murine sPLA2-X have adjuvant activity, leading to a type 2 immune response in the lung with features of airway hyperresponsiveness and Ag-specific type 2 airway inflammation following peripheral sensitization and subsequent airway challenge with OVA. Further, the adjuvant effects of sPLA2-X that result in the type 2-biased OVA-specific adaptive immune response in the lung were dependent upon the catalytic activity of the enzyme, as a catalytically inactive mutant form of sPLA2-X does not elicit the adaptive component of the immune response, although other components of the immune response were induced by the inactive enzyme, suggesting receptor-mediated effects. Our results demonstrate that exogenous and endogenous sPLA2s play an important role in peripheral sensitization, resulting in airway responses to inhaled Ags.

Secreted PLA2 group X orchestrates innate and adaptive immune responses to inhaled allergen.

Phospholipase A2 (PLA2) enzymes regulate the formation of eicosanoids and lysophospholipids that contribute to allergic airway inflammation. Secreted PLA2 group X (sPLA2-X) was recently found to be increased in the airways of asthmatics and is highly expressed in airway epithelial cells and macrophages. In the current study, we show that allergen exposure increases sPLA2-X in humans and in mice, and that global deletion of Pla2g10 results in a marked reduction in airway hyperresponsiveness (AHR), eosinophil and T cell trafficking to the airways, airway occlusion, generation of type-2 cytokines by antigen-stimulated leukocytes, and antigen-specific immunoglobulins. Further, we found that Pla2g10-/- mice had reduced IL-33 levels in BALF, fewer type-2 innate lymphoid cells (ILC2s) in the lung, less IL-33-induced IL-13 expression in mast cells, and a marked reduction in both the number of newly recruited macrophages and the M2 polarization of these macrophages in the lung. These results indicate that sPLA2-X serves as a central regulator of both innate and adaptive immune response to proteolytic allergen.