Some ABCA3 mutations elevate ER stress and initiate apoptosis of lung epithelial cells
Open Access
- 1 December 2011
- journal article
- Published by Springer Science and Business Media LLC in Respiratory Research
- Vol. 12 (1), 4
- https://doi.org/10.1186/1465-9921-12-4
Abstract
ABCA3 transporter (ATP-binding cassette transporter of the A subfamily) is localized to the limiting membrane of lamellar bodies, organelles for assembly and storage of pulmonary surfactant in alveolar epithelial type II cells (AECII). It transports surfactant phospholipids into lamellar bodies and absence of ABCA3 function disrupts lamellar body biogenesis. Mutations of the ABCA3 gene lead to fatal neonatal surfactant deficiency and chronic interstitial lung disease (ILD) of children. ABCA3 mutations can result in either functional defects of the correctly localized ABCA3 or trafficking/folding defects where mutated ABCA3 remains in the endoplasmic reticulum (ER). Human alveolar epithelial A549 cells were transfected with vectors expressing wild-type ABCA3 or one of the three ABCA3 mutant forms, R43L, R280C and L101P, C-terminally tagged with YFP or hemagglutinin-tag. Localization/trafficking properties were analyzed by immunofluorescence and ABCA3 deglycosylation. Uptake of fluorescent NBD-labeled lipids into lamellar bodies was used as a functional assay. ER stress and apoptotic signaling were examined through RT-PCR based analyses of XBP1 splicing, immunoblotting or FACS analyses of stress/apoptosis proteins, Annexin V surface staining and determination of the intracellular glutathion level. We demonstrate that two ABCA3 mutations, which affect ABCA3 protein trafficking/folding and lead to partial (R280C) or complete (L101P) retention of ABCA3 in the ER compartment, can elevate ER stress and susceptibility to it and induce apoptotic markers in the cultured lung epithelial A549 cells. R43L mutation, resulting in a functional defect of the properly localized ABCA3, had no effect on intracellular stress and apoptotic signaling. Our data suggest that expression of partially or completely ER localized ABCA3 mutant proteins can increase the apoptotic cell death of the affected cells, which are factors that might contribute to the pathogenesis of genetic ILD.Keywords
This publication has 45 references indexed in Scilit:
- Genetic Disorders of Surfactant DysfunctionPediatric and Developmental Pathology, 2009
- Epithelial Endoplasmic Reticulum Stress and Apoptosis in Sporadic Idiopathic Pulmonary FibrosisAmerican Journal of Respiratory and Critical Care Medicine, 2008
- Activation of the Unfolded Protein Response by ΔF508 CFTRAmerican Journal of Respiratory Cell and Molecular Biology, 2008
- Cigarette smoke induces endoplasmic reticulum stress and the unfolded protein response in normal and malignant human lung cellsBMC Cancer, 2008
- Effects of cystic fibrosis transmembrane conductance regulator and ΔF508CFTR on inflammatory response, ER stress, and Ca2+of airway epitheliaAmerican Journal of Physiology-Lung Cellular and Molecular Physiology, 2007
- The endoplasmic reticulum and the unfolded protein responseSeminars in Cell & Developmental Biology, 2007
- The activities and function of molecular chaperones in the endoplasmic reticulumSeminars in Cell & Developmental Biology, 2007
- Endoplasmic reticulum stress: cell life and death decisionsJCI Insight, 2005
- Human ABCA3, a product of a responsible gene for abca3 for fatal surfactant deficiency in newborns, exhibits unique ATP hydrolysis activity and generates intracellular multilamellar vesiclesBiochemical and Biophysical Research Communications, 2004
- XBP1 mRNA Is Induced by ATF6 and Spliced by IRE1 in Response to ER Stress to Produce a Highly Active Transcription FactorCell, 2001