ABCMdb

ABCA3 p.Arg280Cys

Predicted by SNAP2:	A: D (71%), C: D (71%), D: D (75%), E: D (75%), F: D (75%), G: D (75%), H: D (63%), I: D (71%), K: N (57%), L: D (71%), M: D (71%), N: D (53%), P: D (71%), Q: D (63%), S: D (63%), T: D (59%), V: D (71%), W: D (85%), Y: D (71%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: N, P: D, Q: N, S: D, T: D, V: D, W: D, Y: D,

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[hide] Ubiquitin-mediated proteasomal degradation of ABC ... J Pharm Sci. 2011 Sep;100(9):3602-19. doi: 10.1002/jps.22615. Epub 2011 May 12. Nakagawa H, Toyoda Y, Wakabayashi-Nakao K, Tamaki H, Osumi M, Ishikawa T
Ubiquitin-mediated proteasomal degradation of ABC transporters: a new aspect of genetic polymorphisms and clinical impacts.
J Pharm Sci. 2011 Sep;100(9):3602-19. doi: 10.1002/jps.22615. Epub 2011 May 12., [PMID:21567408]

Abstract [show]
The interindividual variation in the rate of drug metabolism and disposition has been known for many years. Pharmacogenomics dealing with heredity and response to drugs is a part of science that attempts to explain variability of drug responses and to search for the genetic basis of such variations or differences. Genetic polymorphisms of drug metabolizing enzymes and drug transporters have been found to play a significant role in the patients' responses to medication. Accumulating evidence demonstrates that certain nonsynonymous polymorphisms have great impacts on the protein stability and degradation, as well as the function of drug metabolizing enzymes and transporters. The aim of this review article is to address a new aspect of protein quality control in the endoplasmic reticulum and to present examples regarding the impact of nonsynonymous single-nucleotide polymorphisms on the protein stability of thiopurine S-methyltransferase as well as ATP-binding cassette (ABC) transporters including ABCC4, cystic fibrosis transmembrane conductance regulator (CFTR, ABCC7), ABCC11, and ABCG2. Furthermore, we will discuss the molecular mechanisms underlying posttranslational modifications (intramolecular and intermolecular disulfide bond formation and N-linked glycosylation) and ubiquitin-mediated proteasomal degradation of ABCG2, one of the major drug transporter proteins in humans.

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155 Effect of Mutations and Nonsynonymous SNPs on Protein Trafficking, Maturation, or ERAD of ABC Transporters Protein AA Mutation/SNP Effect on Protein Reference ABCA1 W590S Mutation Functional defect 115 R587W Mutation Impaired glycol processing 115 Q597R Mutation Impaired glycol processing, ERAD 115,116 Y1532C Mutation Altered protein trafficking 117 R1925Q Mutation Altered protein trafficking 118 ABCA3 R43L Mutation Altered protein trafficking 119 L101P Mutation Altered protein trafficking 119 R280C Mutation Altered protein trafficking 119 ABCA4 L541P Mutation Mislocalization 120 R602W Mutation Mislocalization 120 A1038V Mutation Mislocalization 120 C1490Y Mutation Mislocalization 120 ABCB1a G268V Mutation ERAD 121 G341C Mutation ERAD 121 I1196S Mutation Reduced glycosylation 122 ABCB4 I541F Mutation Accumulation in ER 123 ABCB11a E135K Mutation Reduced level of mature protein 124 L198P Mutation Reduced level of mature protein 124 E297G Mutation Reduced level of mature protein 124 L413W Mutation Reduced level of mature protein 124 R432T Mutation Reduced level of mature protein 124 D482G Mutation Immature protein in ER 124,125 N490D Mutation Reduced level of mature protein 124 A570T Mutation Reduced level of mature protein 124 T655I Mutation Reduced level of mature protein 124 Y818F SNP Moderate reduction of protein 124 G982R Mutation Retention in ER 125 R1153C Mutation ERAD 125 R1286Q Mutation Retention in ER 125 ABCC2a R768W Mutation Impaired protein trafficking 126 I1173F Mutation Impaired protein maturation 127 R1392 Mutation Impaired protein maturation 128 M1393 Mutation Impaired protein maturation 129 ABCC4a E757K SNP Altered protein trafficking 23 ABCC7 F508 Mutation Misfolding, ERAD 36-39,130 G85E Mutation Impaired protein maturation 130-132 G91R Mutation Impaired protein maturation 130-132 N1303K Mutation Impaired protein maturation 130-132 ABCC8 WT Wild type Ubiquitin-proteasome degradation 133 A116P Mutation Ubiquitin-proteasome degradation 133 V187D Mutation Ubiquitin-proteasome degradation 133 F1388 Mutation Impaired protein trafficking 134 L1544P Mutation Impaired protein trafficking 135,136 ABCC11a G180R SNP Ubiquitin-proteasome degradation 50 27 Mutation Ubiquitin-proteasome degradation 50 ABCG2a V12M SNP Altered protein localization 96 Q141K SNP Ubiquitin-proteasome degradation 102 F208S SNP Ubiquitin-proteasome degradation 78,99 S441N SNP Ubiquitin-proteasome degradation 78,99 Mutations of ABCA1, ABCA3, ABCA4, ABCB4, ABCB11, ABCC2, ABCC7 (CFTR), and ABCC8 are associated with Tangier disease, fatal surfactant deficiency, Stargardt disease, progressive familial intrahepatic cholestasis type 3 (PFIC-3), progressive familial intrahepatic cholestasis type 2 (PFIC-2), Dubin-Johnson syndrome, cystic fibrosis, and familial hyperinsulinism, respectively. Login to comment

[hide] An intronic ABCA3 mutation that is responsible for... Pediatr Res. 2012 Jun;71(6):633-7. doi: 10.1038/pr.2012.21. Epub 2012 Feb 15. Agrawal A, Hamvas A, Cole FS, Wambach JA, Wegner D, Coghill C, Harrison K, Nogee LM
An intronic ABCA3 mutation that is responsible for respiratory disease.
Pediatr Res. 2012 Jun;71(6):633-7. doi: 10.1038/pr.2012.21. Epub 2012 Feb 15., [PMID:22337229]

Abstract [show]
INTRODUCTION: Member A3 of the ATP-binding cassette family of transporters (ABCA3) is essential for surfactant metabolism. Nonsense, missense, frameshift, and splice-site mutations in the ABCA3 gene (ABCA3) have been reported as causes of neonatal respiratory failure (NRF) and interstitial lung disease. We tested the hypothesis that mutations in noncoding regions of ABCA3 may cause lung disease. METHODS: ABCA3-specific cDNA was generated and sequenced from frozen lung tissue from a child with fatal lung disease with only one identified ABCA3 mutation. ABCA3 was sequenced from genomic DNA prepared from blood samples obtained from the proband, parents, and other children with NRF. RESULTS: ABCA3 cDNA from the proband contained sequences derived from intron 25 that would be predicted to alter the structure and function of the ABCA3 protein. Genomic DNA sequencing revealed a heterozygous C>T transition in intron 25 trans to the known mutation, creating a new donor splice site. Seven additional infants with an ABCA3-deficient phenotype and inconclusive genetic findings had this same variant, which was not found in 2,132 control chromosomes. DISCUSSION: These findings support that this variant is a disease-causing mutation that may account for additional cases of ABCA3 deficiency with negative genetic studies.

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84 Mutation associated with disease in other patients, lung histopathology Alive with ILD I Caucasian Newborn, RDS p.R43H IVS25-98T Mutation associated with disease in other patients, lung histopathology Alive with ILD J African American ILD p.R280C ? Login to comment

[hide] Some ABCA3 mutations elevate ER stress and initiat... Respir Res. 2011 Jan 7;12:4. Weichert N, Kaltenborn E, Hector A, Woischnik M, Schams A, Holzinger A, Kern S, Griese M
Some ABCA3 mutations elevate ER stress and initiate apoptosis of lung epithelial cells.
Respir Res. 2011 Jan 7;12:4., [PMID:21214890]

Abstract [show]
BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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4 Methods: 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. Login to comment
8 Results: 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. Login to comment
35 Fibrosis is one of the hallmarks documented in ABCA3-associated ILD [12,16,17] and knowing that ABCA3 mutations can cause ER retention of the mutated transporter [6,20], we investigated the influence of three ABCA3 mutations, R43L, R280C and L101P, found in children with surfactant deficiency and chronic ILD [10,14,19], on ER stress and apoptosis induction in lung epithelial A549 cells. Login to comment
39 Three hABCA3 point mutations R43L, R280C and L101P were introduced in the WT ABCA3 in both vector types by PCR-based site-directed mutagenesis (QuickChange Site-Directed Mutagenesis, Stratagene, La Jolla, CA). Login to comment
40 Mutagenesis primers were as follows: R43L-For 5`-CAT CTG GCT CCTCTT GAA GAT TC-3`, R43L-Rev 5`-GAA TCT TCA AGAGGA GCC AGA TG-3`, L101P-For 5`-CAG TGC GCA GGG CAC CTG TGA TCA AC-3`, L101P-Rev 5`- GTT GAT CAC AGG TGC CCT GCG CAC TG-3`, R280C-For 5`-CAT TGC CTG TGC TGT CGT G-3`, R280C-Rev 5`-CAC GAC AGC ACAGGC AAT G-3`. Login to comment
82 Results General characterization of R43L, R280C and L101P ABCA3 mutations A) Localization and trafficking Three clinically relevant ABCA3 mutations identified in patients with neonatal surfactant deficiency (R43L and L101P) and chronic ILD (R280C) were chosen for the study. Login to comment
83 While cell biology of R43L and R280C mutations has not been studied yet, L101P mutation was previously described as a trafficking/folding defect resulting in the ER accumulation of L101P protein [6,20] and was deliberately chosen for this study as a cause for the ABCA3 ER retention. Login to comment
84 Initially we investigated intracellular localization of the WT and R43L, R280C and L101P transporters. Login to comment
91 R280C protein colocalized frequently with LAMP3, however the colocalization was not absolute, showing often cytoplasmic distribution that overlapped with the fluorescence of calnexin (Figure 1A, B). Login to comment
94 Dual localization of R280C protein might be a sign of hindrance in the processing and folding of this mutant which slows down but does not abolish its progress through the ER, Golgi and toward LAMP3+ vesicles. Login to comment
95 B) Processing and maturation In immunoblots with anti-GFP antibody on cell lysates from transfected A549 cells expressing YFP labeled WT, R43L and R280C proteins, two protein bands of 180 kDa (150 kDa ABCA3 plus 30 kDa YFP) and 220 kDa (190 kDa ABCA3 plus 30 kDa YFP) were detected (Figure 2A). Login to comment
99 Processing of oligosaccharides and protein progress down the ER-Golgi maturation pathway Figure 1 Intracellular localization of the WT and mutant R43L, R280C and L101P ABCA3 proteins. Login to comment
101 YFP fluorescence of ABCA3-YFP fusions (green) was used to detect ABCA3 WT and R43L, R280C and L101P proteins. Login to comment
103 WT and R43L localized in LAMP3+ vesicles, R280C partially in LAMP3+ vesicles and partially in the ER and L101P completely in the ER. Login to comment
104 (C) Partial ER localization of HA-tagged R280C in A549 cells transfected with pUB6/HA-R280C plasmid confirms the partial R280C ER retention as independent on the type of the plasmid or protein tag. Login to comment
107 Both sugar types were present in WT, R43L and R280C proteins, as visible by the resistance of a portion of the 220 kDa band to the EndoH treatment. Login to comment
109 This confirms the localization studies showing retention of the L101P mutant in the ER and ability of WT, R43L and R280C to progress further from the ER to the Golgi. Login to comment
111 However, R43L and R280C mutation are mostly (R280C) or completely (R43L) correctly localized and potentially functional (Figure 1A, B). Login to comment
113 Liposomes containing NBD-labeled major surfactant phospholipid phosphatidyl-choline (C12-NBD-PC) and NBD-labeled minor surfactant phospholipid phosphatidylethanol-amine (C12-NBD-PE) were incubated with A549 cells expressing WT, R43L, R280C and L101P HA-tagged proteins. Login to comment
116 Interestingly, uptake of fluorescent liposomes into A549 cells was prominent in all cells, including those expressing L101P mutants (Figure 3) and therefore Figure 2 Processing of the WT and mutant R43L, R280C and L101P ABCA3. Login to comment
117 (A) Immunodetection with anti-GFP antibody showed two ABCA3 protein bands (180 kDa and 220 kDa) in whole cell lysates of A549 cells expressing WT and R43L and R280C mutations, and only one protein band in the cells expressing L101P mutation. Login to comment
118 (B) Deglycosylation assay with PNGaseF and EndoH on the membrane fractions from A549 cells transfected with pEYFP-N1/ ABCA3 plasmids and subsequent ABCA3-YFP immunodetection with anti-GFP antibody showed presence of high-mannose and complex oligosaccharides in WT, R43L and R280C proteins, as well as only high-mannose and no complex oligosaccharides in the L101P mutant resulting from the L101P ER retention. Login to comment
119 Figure 3 Function of the R43L and R280C transporters. Login to comment
122 HA-tag was used to detect ABCA3 WT and R43L, R280C and L101P by immunofluorescence (red). Login to comment
123 Both C12-NBD-PC and C12-NBD-PE fluorescence (green) frequently colocalized with the ring-like ABCA3 WT signal as well as within the ABCA3-WT vesicles and almost never with the R43L and R280C vesicles. Login to comment
127 WT ABCA3 (green) induced biogenesis of LAMP3+ vesicles (red) increasing their number and size in A549 cells, while R43L, R280C and L101P proteins showed no such effect (the same was observed in A549 pEYFP-N1/ABCA3 transfected cells - not shown). Login to comment
133 Similar colocalization of NBD fluorescence with ABCA3-HA vesicles was extremely rarely observed in cells expressing R43L and R280C mutations (Figure 3A, B). Login to comment
134 This probably indicates the ability of WT-ABCA3-HA vesicles to take up and accumulate both fluorescent lipids, while R280C-ABCA3-HA and R43L-ABCA3-HA vesicles did not show such ability. Login to comment
137 Expression of R43L, R280C and L101P mutations had a negative effect on vesicle formation and induced a lower number of smaller compact LAMP3+ vesicles, with the most drastic effect in L101P mutant (Figure 3D). Login to comment
139 Decreased uptake of NBD fluorescence in lamellar bodies and impact on lamellar body biogenesis together suggest functional impairment of the R43L and R280C proteins. Login to comment
140 L101P and R280C mutation upregulate ER stress marker BiP BiP/Grp78 is an essential ER chaperone of the Hsp70 family, which assists the translocation of a nascent protein chain into the ER and its subsequent folding. Login to comment
142 Immunoblotting of whole cell lysates from A549 cells expressing ABCA3-WT and three mutants revealed significant upregulation of BiP chaperone in the case of L101P mutation and R280C mutation in comparison to WT, caused by complete (L101P) or partial ER retention (R280C) of these two mutated ABCA3 transporters (Figure 4A, B). Login to comment
145 L101P and R280C mutations increase susceptibility of A549 cells to ER stress Upon ER accumulation of misfolded proteins BiP dissociates from the luminal domain of IRE1, allows IRE1 dimerization and synthesis of active XBP1 protein, a UPR transcription factor which regulates expression of ER stress proteins including BiP. Login to comment
147 To confirm previous observation on Figure 4 Increase in the ER stress chaperone BiP in A549 cells expressing R280C and L101P mutations. Login to comment
148 (A) A549 cells with ER retained L101P mutant or partially ER retained R280C protein showed upregulation of the immunodetected ER chaperone BiP in comparison to WT and A549 cells. Login to comment
156 Probably because of the robustness of the method, finer differences between WT and R43L and R280C were not observable, and the effect was measurable only in the case of the L101P mutant with the strongest protein defect (Figure 5A, D). Login to comment
161 (A) XBP1 splicing in untransfected A549 cells with and without tunicamycin (TM) treatment (10 μg/ml, 14 h) and in A549 cells with R43L, R280C and L101P mutations. Login to comment
168 Lower effect of L101P mutation on XBP1 splicing in A549 cells and no effect in A549 with WT and R43L and R280C mutations were observed. Login to comment
169 (B, E) TM treatment (10 μg/ml, 14 h) strongly induced XBP1 splicing (disappearance of unspliced bands u1 and u2) in all A549 cells expressing ABCA3 mutations, with the most significant increase in A549 expressing R280C and L101P mutations (increase in spliced band s). Login to comment
172 However, after exposure to tunicamycin XBP1 splicing was considerably more pronounced in R280C and L101P mutations if compared to A549 cells with WT and R43L mutations (Figure 5B, E). Login to comment
173 Obviously, although XBP1 splicing was measurable only for the strongest L101P defect under non-stimulated condition, cells with L101P and R280C mutations were significantly more prone to further elevation of ER stress upon exposure to an external stressor. Login to comment
174 L101P and to a lesser extent R280C mutation induce apoptosis of A549 cells Since prolonged ER stress can activate apoptosis, we analyzed if ABCA3 mutations can induce early and late apoptotic markers in A549 cells. Login to comment
178 Flow cytometry assay of Cy5-coupled Annexin V surface binding showed an increase in the number of annexin V+ /PI- cells in transfected YFP+ cells in the case of R280C and L101P mutations when compared to WT and R43L indicating an early apoptotic state of those cells (Figure 6A). Login to comment
181 Intracellular GSH level, measured by flow cytometry of monochlorobimane binding to GSH and generation of a fluorescent adduct, was decreased in the YFP+ cells with L101P protein compared to YFP+ WT, R43L and also compared to R280C (Figure 6B). Login to comment
188 Elevated early and late apoptotic markers were detectable in cells expressing L101P mutation, and one early marker (Annexin V) in cells expressing R280C mutation. Login to comment
190 In summary, while R43L mutation did not raise apoptotic signaling above the A549 or WT level, R280C mutation increased one early apoptotic marker and ER-localized L101P mutations significantly elevated early and late apoptotic markers, indicating injury of the cells with L101P protein. Login to comment
191 Prolonged ER stress leads to apoptosis through caspase 4 activation in cells expressing R280C and L101P mutations To examine if initiation of apoptosis in cells with ABCA3 mutations is indeed a consequence of the ER stress signaling, we assessed activation of caspase 4, which is activated by apoptotic stimuli that cause ER stress, but not other apoptotic stimuli [28,37]. Login to comment
195 Immunoblotting of whole cell lysates from the cells expressing WT or R43L, R280C or L101P mutations showed insignificant changes in pro-caspase 4 level between WT and mutations, but the level of pro-caspase 4 was somewhat higher in transfected cells then in A549 (Figure 7B). Login to comment
196 In contrast, cleaved caspase 4 in R280C and L101P mutants increased significantly in comparison to WT. Login to comment
198 This shows that caspase 4 is involved in apoptotic signaling in cells with L101P and R280C mutations and that activation of the apoptotic pathway can be a consequence of the ER stress caused by complete or partial ER retention of the ABCA3 protein. Login to comment
201 In this study we investigated the influence of three ABCA3 mutations, R43L, R280C and L101P, on intracellular stress and induction of apoptosis in cultured lung epithelial A549 cells. Login to comment
202 All three mutations were found in children with ABCA3-associated lung disease being either fatal neonatal respiratory distress syndrome (L101P and R43L [10,14]) or chronic ILD (R280C; own unpublished data, [19]). Login to comment
203 While cell biology of R43L and R280C mutations was studied here for the first time, L101P mutation was used as a known example of the trafficking/folding defect leading to the ER retention of ABCA3 with no information on ER stress [6,20]. Login to comment
205 We showed correct localization of WT and R43L proteins in LAMP3+ vesicles and dual localization of R280C protein in LAMP3+ vesicles Figure 7 Apoptotic signaling in cells with L101P and R280C mutations is activated by ER stress. Login to comment
206 (A) Immunoblotting on whole cell lysates from A549 cells transfected with pEYFP-N1/ABCA3 and densitometric analyses of (B) pro-caspase 4 and (C) cleaved caspase 4 demonstrated increased caspase 4 cleavage in cells expressing L101P and R280C mutations, as well as after TNFa treatment of A549 (25 ng/ml, 16 h) in comparison to WT and untreated A549. Login to comment
207 No significant changes in the pro-caspase 4 level in transfected cells with WT, R43L, R280C and L101P mutations were detected but pro-caspase 4 was slightly increased in transfected cells compared to A549 (B). Login to comment
210 and calnexin+ ER compartment (Figure 1A, B and 1C), indicating less efficient but not abolished R280C trafficking. Login to comment
212 R43L and R280C proteins showed WT-processing with two protein bands (Figure 2A) and presence of complex oligosaccharides (Figure 2B) confirming their ability to proceed from the ER to the Golgi. Login to comment
214 While ER retention of L101P excludes ABCA3 function, the function of R43L and R280C transporters was studied additionally. Login to comment
220 In the case of R43L and R280C mutations such colocalization was rarely observed suggesting functional impairment of R43L and R280C proteins. Login to comment
231 The ER stress caused by R280C mutation was slightly lower and surface staining with annexin V, as an early apoptosis sign, was the only apoptotic marker detected in R280C cells. Login to comment
233 The connection between ER stress and apoptosis induction was established through the upregulation of caspase 4 in the case of both L101P and R280C mutations (Figure 7). Login to comment
237 The cells with mutations R280C and L101P, which impair ABCA3 trafficking, were more prone to further XBP1 splicing than the WT or A549. Login to comment

[hide] Unexplained neonatal respiratory distress due to c... J Pediatr. 2007 Jun;150(6):649-53, 653.e1. Somaschini M, Nogee LM, Sassi I, Danhaive O, Presi S, Boldrini R, Montrasio C, Ferrari M, Wert SE, Carrera P
Unexplained neonatal respiratory distress due to congenital surfactant deficiency.
J Pediatr. 2007 Jun;150(6):649-53, 653.e1., [PMID:17517255]

Abstract [show]
Genetic abnormalities of pulmonary surfactant were identified by DNA sequence analysis in 14 (12 full-term, 2 preterm) of 17 newborn infants with fatal respiratory distress of unknown etiology. Deficiency of adenosine triphosphate-binding cassette protein, member A3 (n = 12) was a more frequent cause of this phenotype than deficiency of surfactant protein B (n = 2).

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51 Characteristics of patients n GA (W) BW (G) Sex Familial Therapies Age at death Gene/mutation Histology Immunostaining Electron microscopy 1 40 3400 M No MV, surfactant, HFOV 4 hours No mutations NA NA NA 2 40 3700 F No MV 2 hours No mutations NA NA NA 3 37 3110 M No Corticosteroids, MV, surfactant, prostacyclin, HFOV 3 days No mutations HMD ϩ SP-B - proSP-C, alveolar epithelium NA 4 40 3050 F Yes Corticosteroids, MV, surfactant, prostacyclin, iNO, HFOV 28 days SFTPB mutations 121ins2/ 122delC PAP Absent SP-B and proSP-B PAP material pro-SP-C ϩ NA 5 39 3200 F Yes MV, surfactant 38 days SFTPB mutations 121ins2/ 122delC PAP Absent SP-B and proSP-B PAP material pro-SP-C ϩ NA 6 38 3650 F Yes MV, surfactant 27 days ABCA3 mutations 4240delC/ W165X DIP ϩ SP-B ϩ proSP-C, alveolar epithelium NA 7 39 2850 M No MV 2 days ABCA3 mutation R280C/wt NA NA NA 8 35 3000 M No MV, surfactant 2 days ABCA3 mutation E292V/wt NA NA NA 9 40 3700 F No MV, surfactant 37 days ABCA3 mutations R208W/ T1423I DIP ϩ SP-B ϩ proSP-C, alveolar epithelium Numerous small LBs with dense cores 10 40 3220 M Yes MV, surfactant 30 days ABCA3 mutations 3997delAG/3997delAG DIP ϩ SP-B ϩ proSP-C, alveolar epithelium Few small LBs with dense cores 11 38 2700 F Yes MV, surfactant, corticosteroids 13 days ABCA3 mutations R155Q/ R155Q DIP ϩ SP-B ϩ proSP-C, alveolar epithelium 12 40 3050 M No MV, surfactant, iNO, prostacyclin 30 days ABCA3 mutations R43L/ R1482W DIP ϩ SP-B ϩ proSP-C, alveolar epithelium Numerous small LBs with dense cores 13 41 3420 F No MV, surfactant 180 days ABCA3 mutation S341N/wt NA NA NA 14 39 3150 M Yes MV, surfactant 64 days ABCA3 mutations P248L/ P248L DIP ϩ SP-B ϩ proSP-C, alveolar epithelium NA 15 38 3280 M Yes MV, surfactant, HFOV, corticosteroids 66 days ABCA3 mutations 4240delC/ W165X NA NA NA 16 41 3000 F No MV, surfactant, HFOV 50 days ABCA3 mutations R208W/ 4296_4301delATCACG NA NA NA 17 33 1750 M No MV, surfactant, HFOV 206 days ABCA3 mutations P147L/ R155Q DIP ϩ SP-B ϩ proSP-C, alveolar epithelium Numerous small LBs with dense cores GA, gestational age; BW, birth weight; MV, mechanical ventilation; HFOV, high-frequency oscillatory ventilation; iNO, inhaled nitric oxide; wt, wild type; LB, lamellar body; HMD, hyaline membrane disease; PAP, pulmonary alveolar proteinosis; DIP, desquamative intersititial pneumonia; HMD, hyaline membrane disease; NA, not available. Login to comment
48 Characteristics of patients n GA (W) BW (G) Sex Familial Therapies Age at death Gene/mutation Histology Immunostaining Electron microscopy 40 3400 M No MV, surfactant, HFOV 4 hours No mutations NA NA NA 2 40 3700 F No MV 2 hours No mutations NA NA NA 3 37 3110 M No Corticosteroids, MV, surfactant, prostacyclin, HFOV 3 days No mutations HMD af9; SP-B afa; proSP-C, alveolar epithelium NA 4 40 3050 F Yes Corticosteroids, MV, surfactant, prostacyclin, iNO, HFOV 28 days SFTPB mutations 121ins2/ 122delC PAP Absent SP-B and proSP-B PAP material pro-SP-C af9; NA 5 39 3200 F Yes MV, surfactant 38 days SFTPB mutations 121ins2/ 122delC PAP Absent SP-B and proSP-B PAP material pro-SP-C af9; NA 6 38 3650 F Yes MV, surfactant 27 days ABCA3 mutations 4240delC/ W165X DIP af9; SP-B af9; proSP-C, alveolar epithelium NA 7 39 2850 M No MV 2 days ABCA3 mutation R280C/wt NA NA NA 8 35 3000 M No MV, surfactant 2 days ABCA3 mutation E292V/wt NA NA NA 9 40 3700 F No MV, surfactant 37 days ABCA3 mutations R208W/ T1423I DIP af9; SP-B af9; proSP-C, alveolar epithelium Numerous small LBs with dense cores 10 40 3220 M Yes MV, surfactant 30 days ABCA3 mutations 3997delAG/3997delAG DIP af9; SP-B af9; proSP-C, alveolar epithelium Few small LBs with dense cores 11 38 2700 F Yes MV, surfactant, corticosteroids 13 days ABCA3 mutations R155Q/ R155Q DIP af9; SP-B af9; proSP-C, alveolar epithelium 12 40 3050 M No MV, surfactant, iNO, prostacyclin 30 days ABCA3 mutations R43L/ R1482W DIP af9; SP-B af9; proSP-C, alveolar epithelium Numerous small LBs with dense cores 13 41 3420 F No MV, surfactant 180 days ABCA3 mutation S341N/wt NA NA NA 14 39 3150 M Yes MV, surfactant 64 days ABCA3 mutations P248L/ P248L DIP af9; SP-B af9; proSP-C, alveolar epithelium NA 15 38 3280 M Yes MV, surfactant, HFOV, corticosteroids 66 days ABCA3 mutations 4240delC/ W165X NA NA NA 16 41 3000 F No MV, surfactant, HFOV 50 days ABCA3 mutations R208W/ 4296_4301delATCACG NA NA NA 17 33 1750 M No MV, surfactant, HFOV 206 days ABCA3 mutations P147L/ R155Q DIP af9; SP-B af9; proSP-C, alveolar epithelium Numerous small LBs with dense cores GA, gestational age; BW, birth weight; MV, mechanical ventilation; HFOV, high-frequency oscillatory ventilation; iNO, inhaled nitric oxide; wt, wild type; LB, lamellar body; HMD, hyaline membrane disease; PAP, pulmonary alveolar proteinosis; DIP, desquamative intersititial pneumonia; HMD, hyaline membrane disease; NA, not available. Login to comment

[hide] Single ABCA3 mutations increase risk for neonatal ... Pediatrics. 2012 Dec;130(6):e1575-82. doi: 10.1542/peds.2012-0918. Epub 2012 Nov 19. Wambach JA, Wegner DJ, Depass K, Heins H, Druley TE, Mitra RD, An P, Zhang Q, Nogee LM, Cole FS, Hamvas A
Single ABCA3 mutations increase risk for neonatal respiratory distress syndrome.
Pediatrics. 2012 Dec;130(6):e1575-82. doi: 10.1542/peds.2012-0918. Epub 2012 Nov 19., [PMID:23166334]

Abstract [show]
BACKGROUND AND OBJECTIVE: Neonatal respiratory distress syndrome (RDS) due to pulmonary surfactant deficiency is heritable, but common variants do not fully explain disease heritability. METHODS: Using next-generation, pooled sequencing of race-stratified DNA samples from infants >/=34 weeks' gestation with and without RDS (n = 513) and from a Missouri population-based cohort (n = 1066), we scanned all exons of 5 surfactant-associated genes and used in silico algorithms to identify functional mutations. We validated each mutation with an independent genotyping platform and compared race-stratified, collapsed frequencies of rare mutations by gene to investigate disease associations and estimate attributable risk. RESULTS: Single ABCA3 mutations were overrepresented among European-descent RDS infants (14.3% of RDS vs 3.7% of non-RDS; P = .002) but were not statistically overrepresented among African-descent RDS infants (4.5% of RDS vs 1.5% of non-RDS; P = .23). In the Missouri population-based cohort, 3.6% of European-descent and 1.5% of African-descent infants carried a single ABCA3 mutation. We found no mutations among the RDS infants and no evidence of contribution to population-based disease burden for SFTPC, CHPT1, LPCAT1, or PCYT1B. CONCLUSIONS: In contrast to lethal neonatal RDS resulting from homozygous or compound heterozygous ABCA3 mutations, single ABCA3 mutations are overrepresented among European-descent infants >/=34 weeks' gestation with RDS and account for ~10.9% of the attributable risk among term and late preterm infants. Although ABCA3 mutations are individually rare, they are collectively common among European- and African-descent individuals in the general population.

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57 Although the European-descent RDS infants had a lower mean gestational age than non-RDS infants (Table 1), there was no statistical difference in mean gestational age or birth weight for European-descent infants with or without ABCA3 mutations, thereby suggesting that ABCA3 mutations are associated with RDS rather than TABLE 3 Rare Mutations Identified Among Infants of European Descent Gene Mutation RDS (n = 112) Non-RDS (n = 161) Missouri Population (n = 871) ESP (n = 3510) ABCA3 R20W 2 R43C 1 V129M 1 A132T 1 V133M 1 R208W 1 L212M 3 14 P246L 1 R280C 1 R280H 12 R288K 6 (5.3%)a 2 (1.2%)a 14 (1.6%)a 54 (1.5%)a E292V 7 (6.2%)a 1 (0.6%)a 1 (0.1%)a 32 (0.9%)a V480M 1 E522K 1 I561F 1 G594R 1 L654V 2 G668D 1 R671C 1 S693L 1 7 E725K 1 T761K 1 R1081W 1 I1117M 1 A1119E 1 A1297T 1 I1382M 1 T1424M 1 M1428L 2 R1457Q 1 A1466T 1 R1474W 1 3 8 29 V1495M 1 S1516N 1 R1561Q 1 V1588M 1 c.3863-98 C.T 1 ABCA3 allele (carrier) frequency 16 (14.3%)a 6 (3.7%)a 31 (3.6%)a 176 (5.0%)a SFTPC D15N 1 I26V 1 A53T 1 1 L110R 1 SFTPC allele (carrier) frequency 1 (0.1%)a 4 (0.1%)a CHPT1 S40W 4 W60C 1 D132E 2 CHPT1 allele (carrier) frequency 7 (0.2%)a LPCAT1 G110S 1 P230S 1 R237Q 1 M298V 1 E312K 1 F460V 1 R526W 1 LPCAT1 allele (carrier) frequency 1 (0.1%)a 6 (0.2%)a PCYT1B V192F 1(0.03%)a Identified mutations are predicted to be damaging according to both SIFT and PolyPhen (accessed March 2012) or previous association with pediatric respiratory disease. Blank boxes indicate the mutations were not observed in that specific cohort. Login to comment
74 TABLE 4 Rare Mutations Identified Among Infants of African Descent Gene Mutations RDS (n = 44) Non-RDS (n = 196) Missouri Population (n = 195) ESP (n = 1869) ABCA3 R20W 2 V129M 12 F245L 1 R280C 1 R280H 2 R288K 7 (0.4%)a E292V 4 (0.2%)a F353L 3 N555S 5 G571R 1 T574I 1 2 P585S 1 L707F 14 G739A 2 15 V968M 1 1 F1164V 1 N1418S 1 R1474W 1 1 A1660V 1 Infants with variant 2 (4.5%)a 3 (1.5%)a 3 (1.5%)a 72 (3.9%)a SFTPC R35C 1 V39M 1 G57S 1 R81C 1 SFTPC allele (carrier) frequency 4 (0.2%)a CHPT1 G70R 2 T87M 1 G115A 1 Y365H 3 CHPT1 allele (carrier) frequency 7 (0.4%)a LPCAT1 A194V 6 L255Q 2 D392H 1 R526W 1 LPCAT1 allele (carrier) frequency 10 (0.5%)a PCYT1B G199D 1 (0.05%)a Identified mutations are predicted to be damaging according to both SIFT and PolyPhen (accessed March 2012) or previous association with pediatric respiratory disease. Blank boxes indicate the mutations were not observed in that specific cohort. Login to comment
94 Only 2 of these mutations were found in our study: p.R280C, which disrupts ABCA3 folding and trafficking, and p.E292V, which disrupts ATP hydrolysis and decreases phospholipid transport across the lamellar body membrane.29,30 Our combined genomic, computational, and disease-based variant discovery strategy permits prioritization of mutations for further functionalinvestigation,whichiscritical for understanding disease pathogenesis. Login to comment

[hide] Genotype-phenotype correlations for infants and ch... Am J Respir Crit Care Med. 2014 Jun 15;189(12):1538-43. doi: 10.1164/rccm.201402-0342OC. Wambach JA, Casey AM, Fishman MP, Wegner DJ, Wert SE, Cole FS, Hamvas A, Nogee LM
Genotype-phenotype correlations for infants and children with ABCA3 deficiency.
Am J Respir Crit Care Med. 2014 Jun 15;189(12):1538-43. doi: 10.1164/rccm.201402-0342OC., [PMID:24871971]

Abstract [show]
RATIONALE: Recessive mutations in the ATP-binding cassette transporter A3 (ABCA3) cause lethal neonatal respiratory failure and childhood interstitial lung disease. Most ABCA3 mutations are private. OBJECTIVES: To determine genotype-phenotype correlations for recessive ABCA3 mutations. METHODS: We reviewed all published and unpublished ABCA3 sequence and phenotype data from our prospective genetic studies of symptomatic infants and children at Washington and Johns Hopkins Universities. Mutations were classified based on their predicted disruption of protein function: frameshift and nonsense mutations were classified as "null," whereas missense, predicted splice site mutations, and insertion/deletions were classified as "other." We compared age of presentation and outcomes for the three genotypes: null/null, null/other, and other/other. MEASUREMENTS AND MAIN RESULTS: We identified 185 infants and children with homozygous or compound heterozygous ABCA3 mutations and lung disease. All of the null/null infants presented with respiratory failure at birth compared with 75% of infants with null/other or other/other genotypes (P = 0.00011). By 1 year of age, all of the null/null infants had died or undergone lung transplantation compared with 62% of the null/other and other/other children (P < 0.0001). CONCLUSIONS: Genotype-phenotype correlations exist for homozygous or compound heterozygous mutations in ABCA3. Frameshift or nonsense ABCA3 mutations are predictive of neonatal presentation and poor outcome, whereas missense, splice site, and insertion/deletions are less reliably associated with age of presentation and prognosis. Counseling and clinical decision making should acknowledge these correlations.

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134 Alleles with ABCA3 Variants in Cis Allele Number of Subjects with Allele R43C-P1653L 1 D115E-D253H 1 (2 alleles, 1 subject homozygous) V129M-V1495M 1 W179C-P770L 3 (3 subjects heterozygous) E195K-R1271Q 1 R280C-Q1589X 2 (3 alleles, 1 subject homozygous, 1 subject heterozygous) R288K-S693L 2 (2 subjects heterozygous) c.1474_1475insT-D953N 4 (3 siblings homozygous, 1 subject heterozygous) P766S-L960F 4 (4 subjects heterozygous) H778R-L1252P 1 A54T-R1482W-IVS25-98 C . Login to comment

[hide] Lost after translation: insights from pulmonary su... Am J Physiol Lung Cell Mol Physiol. 2015 Sep 15;309(6):L507-25. doi: 10.1152/ajplung.00139.2015. Epub 2015 Jul 17. Mulugeta S, Nureki S, Beers MF
Lost after translation: insights from pulmonary surfactant for understanding the role of alveolar epithelial dysfunction and cellular quality control in fibrotic lung disease.
Am J Physiol Lung Cell Mol Physiol. 2015 Sep 15;309(6):L507-25. doi: 10.1152/ajplung.00139.2015. Epub 2015 Jul 17., [PMID:26186947]

Abstract [show]
Dating back nearly 35 years ago to the Witschi hypothesis, epithelial cell dysfunction and abnormal wound healing have reemerged as central concepts in the pathophysiology of idiopathic pulmonary fibrosis (IPF) in adults and in interstitial lung disease in children. Alveolar type 2 (AT2) cells represent a metabolically active compartment in the distal air spaces responsible for pulmonary surfactant biosynthesis and function as a progenitor population required for maintenance of alveolar integrity. Rare mutations in surfactant system components have provided new clues to understanding broader questions regarding the role of AT2 cell dysfunction in the pathophysiology of fibrotic lung diseases. Drawing on data generated from a variety of model systems expressing disease-related surfactant component mutations [surfactant proteins A and C (SP-A and SP-C); the lipid transporter ABCA3], this review will examine the concept of epithelial dysfunction in fibrotic lung disease, provide an update on AT2 cell and surfactant biology, summarize cellular responses to mutant surfactant components [including endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and intrinsic apoptosis], and examine quality control pathways (unfolded protein response, the ubiquitin-proteasome system, macroautophagy) that can be utilized to restore AT2 homeostasis. This integrated response and its derangement will be placed in the context of cell stress and quality control signatures found in patients with familial or sporadic IPF as well as non-surfactant-related AT2 cell dysfunction syndromes associated with a fibrotic lung phenotype. Finally, the need for targeted therapeutic strategies for pulmonary fibrosis that address epithelial ER stress, its downstream signaling, and cell quality control are discussed.

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267 Summary of reported phenotypic features for surfactant component mutations Mutation (Domain) Clinical Diagnosis Lung Phenotype (in vivo) Subcellular Localization Trafficking Cellular Responses (in vitro) References SFTPA2 F198S (CRD) G231V (CRD) Familial pulmonary fibrosis Total BAL [SP-A] Normal ER retention Intracellular aggregation Not secreted (af9;) ER stress, cleared by ERAD (af9;) TGFbeta1 elaboration 99, 100, 175 SFTPC Group A1 èc;Exon4 (BRICHOS) L188Q (BRICHOS) G100S (BRICHOS) NSIP (Children) IPF/UIP (Adult) Absence of mature SP-C (humans) Arrested lung development (mice) ER stress (humans; mice) 1Sensitivity to bleomycin (mice) Epithelial cytotoxicity ER retention&#a1; aggresomes Intracellular aggregates ERAD requires Erdj 4/5 MG132 blocks degradation 4-PBA improves aggregates (af9;) ER stress (af9;) Apoptosis (af9;) Incomplete or absent proSP-C processing (af9;) IL-8/TGFbeta1 expression (af9;) Polyubiquitinated isoforms 21, 39, 97, 98, 100, 111, 112, 116, 117, 120, 153, 159, 160, 173, 193 Group A2 L110R (BRICHOS) P115L (BRICHOS) A116D (BRICHOS) Unspecified ILD Unspecified ILD Unspecified chILD Phenotype not reported EEA-1 (af9;); Syntaxin2 (afa;) Intracellular aggregation 2 PC secretion (af9;) Aberrant processing, 2 cell viability 1 HSP response (af9;) Congo red aggregates 160, 193 Group B1 E66K (Linker) I73T (Linker) NSIP/PAP (Child) IPF/UIP (Adult) 1 Phospholipid; 1SP-A, PAS positive staining Biopsy: PM and EE localization Misprocessed SP-C (BAL) Misprocessed SP-B (BAL) Plasma membrane&#a1;EE&#a1;LE/MVB (af9;) Aberrantly processed protein (af9;) Late autophagy block 2 Mitophagy 1 Mysfunctional mitochondria 1, 19, 24, 26, 49, 116, 118, 128, 152 Group B2 èc;91-93 (Non-BRICHOS) NSIP/PAP 2 BAL SP-B 1 BAL SP-A 2 Surfactant surface tension (af9;) Intracellular aggregates (af9;) Congo red staining Plasma membraneߥ EEA1 (af9;) compartmentsߥ Not reported 55, 181 Group C P30L (NH2-terminal) Unspecified ILD Phenotype not reported (af9;) ER retention 1 Bip expression (af9;) Polyubiquitinated isoforms 13, 116, 160 ABCA3 Group I (Trafficking Defective) L101P (1st luminal loop) R280C (1st cytosolic loop) L982P (3rd luminal loop) G1221S (11th TM domain) L1553P (COOH-terminal) Q1591P (COOH-terminal) Surfactant deficiency* RDS* chILDߤ Phenotype not reported Phenotype not reported Phenotype not reported (af9;) ER retention Non-LRO cytosolic vesicles (af9;) ER stress 30, 31, 103, 147, 172, 177 Group II (Functionally Defective) R43L (1st luminal loop) D253H (1st luminal loop) E292V (1st cytosolic loop) N568D (ABC1) E690K (ABC1) T1114M (8thTM domain) T1173R (1st luminal loop) L1580P (COOH-terminal) Surfactant deficiency* RDS* chILD (CPI)ߤ Reduced SP-B and SP-C (afa;) ER retention Lysosomes or LROs (normal) Impaired lipid transport Impaired ATP hydrolysis Impaired ATP binding Abnormal LBs 1 IL8 secretion 20, 25, 103, 104, 147, 148, 177 *Seen with homozygous or compound heterozygous ABCA3 expression; ߤfound with heterozugous ABCA3 expression. Login to comment