Prolidase deficiency diagnosed by whole exome sequencing in a child with pulmonary capillaritis

Diffuse alveolar haemorrhage (DAH) is rare in the paediatric population and the biological mechanisms remain poorly understood [1]. We retrospectively studied 12 children at our centre, identified from our pathology database, with idiopathic DAH between 2005–2017 who had undergone lung biopsy (SickKids ethics approval number: 1000029185). Two children in this cohort were offered clinical whole exome sequencing (WES) as an investigational diagnostic procedure based on a family history of lung disease. Both children who underwent WES, including the one presented here and one who we had previously reported [2], had single gene mutations that explained the pathogenesis of their pulmonary haemorrhage.

The case of a young boy with pulmonary haemorrhage who was ultimately diagnosed on whole exome sequencing with a rare condition called prolidase deficiency. This case demonstrates the utility of modern genomic testing in paediatric rare lung disease.http://ow.ly/rDGz30o8pcd

Alveolar capillary dysplasia with misalignment of the pulmonary veins: clinical, histological, and genetic aspects

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare and lethal disorder mainly involving the vascular development of the lungs. Since its first description, significant achievements in research have led to a better understanding of the underlying molecular mechanism of ACD/MPV and genetic studies have identified associations with genomic alterations in the locus of the transcription factor FOXF1. This in turn has increased the awareness among clinicians resulting in over 200 cases reported so far, including genotyping of patients in most recent reports. Collectively, this promoted a better stratification of the patient group, leading to new perspectives in research on the pathogenesis. Here, we provide an overview of the clinical aspects of ACD/MPV, including guidance for clinicians, and review the ongoing research into the complex molecular mechanism causing this severe lung disorder.

Disrupted apical exocytosis of cargo vesicles causes enteropathy in FHL5 patients with Munc18-2 mutations

Familial hemophagocytic lymphohistiocytosis 5 (FHL5) is an autosomal recessive disease caused by mutations in STXBP2, coding for Munc18-2, which is required for SNARE-mediated membrane fusion. FHL5 causes hematologic and gastrointestinal symptoms characterized by chronic enteropathy that is reminiscent of microvillus inclusion disease (MVID). However, the molecular pathophysiology of FHL5-associated diarrhea is poorly understood. Five FHL5 patients, including four previously unreported patients, were studied. Morphology of duodenal sections was analyzed by electron and fluorescence microscopy. Small intestinal enterocytes and organoid-derived monolayers displayed the subcellular characteristics of MVID. For the analyses of Munc18-2-dependent SNARE-protein interactions, a Munc18-2 CaCo2-KO model cell line was generated by applying CRISPR/Cas9 technology. Munc18-2 is required for Slp4a/Stx3 interaction in fusion of cargo vesicles with the apical plasma membrane. Cargo trafficking was investigated in patient biopsies, patient-derived organoids, and the genome-edited model cell line. Loss of Munc18-2 selectively disrupts trafficking of certain apical brush-border proteins (NHE3 and GLUT5), while transport of DPPIV remained unaffected. Here, we describe the molecular mechanism how the loss of function of Munc18-2 leads to cargo-selective mislocalization of brush-border components and a subapical accumulation of cargo vesicles, as it is known from the loss of polarity phenotype in MVID.

Abnormal Rab11-Rab8-vesicles cluster in enterocytes of patients with microvillus inclusion disease

Microvillus inclusion disease (MVID) is a congenital enteropathy characterized by accumulation of vesiculo-tubular endomembranes in the subapical cytoplasm of enterocytes, historically termed "secretory granules." However, neither their identity nor pathophysiological significance is well defined. Using immunoelectron microscopy and tomography, we studied biopsies from MVID patients (3× Myosin 5b mutations and 1× Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations. Duodenal biopsies from 2 patients with novel Myosin 5b mutations and typical clinical symptoms showed unusual ultrastructural phenotypes: aberrant subapical vesicles and tubules were prominent in the enterocytes, though other histological hallmarks of MVID were almost absent (ectopic intra-/intercellular microvilli, brush border atrophy). We identified these enigmatic vesiculo-tubular organelles as Rab11-Rab8-positive recycling compartments of altered size, shape and location harboring the apical SNARE Syntaxin3, apical transporters sodium-hydrogen exchanger 3 (NHE3) and cystic fibrosis transmembrane conductance regulator. Our data strongly indicate that in MVID disrupted trafficking between cargo vesicles and the apical plasma membrane is the primary cause of a defect of epithelial polarity and subsequent facultative loss of brush border integrity, leading to malabsorption. Furthermore, they support the notion that mislocalization of transporters, such as NHE3 substantially contributes to the reported sodium loss diarrhea.

Loss of the Arp2/3 complex component ARPC1B causes platelet abnormalities and predisposes to inflammatory disease

Human actin-related protein 2/3 complex (Arp2/3), required for actin filament branching, has two ARPC1 component isoforms, with ARPC1B prominently expressed in blood cells. Here we show in a child with microthrombocytopenia, eosinophilia and inflammatory disease, a homozygous frameshift mutation in ARPC1B (p.Val91Trpfs*30). Platelet lysates reveal no ARPC1B protein and greatly reduced Arp2/3 complex. Missense ARPC1B mutations are identified in an unrelated patient with similar symptoms and ARPC1B deficiency. ARPC1B-deficient platelets are microthrombocytes similar to those seen in Wiskott–Aldrich syndrome that show aberrant spreading consistent with loss of Arp2/3 function. Knockout of ARPC1B in megakaryocytic cells results in decreased proplatelet formation, and as observed in platelets from patients, increased ARPC1A expression. Thus loss of ARPC1B produces a unique set of platelet abnormalities, and is associated with haematopoietic/immune symptoms affecting cell lineages where this isoform predominates. In agreement with recent experimental studies, our findings suggest that ARPC1 isoforms are not functionally interchangeable.

ARPC1B is a component of the actin-related protein 2/3 complex (Arp2/3), which is required for actin filament branching. Kahr et al. show that ARPC1B deficiency in humans is associated with severe multisystem disease that includes platelet abnormalities, eosinophilia, eczema and other indicators of immune disease.

Liver transplantation for children with acute liver failure associated with secondary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening systemic disease, characterized by overwhelming stimulation of the immune system and categorized as primary or secondary types. Occasionally, acute liver failure (ALF) may dominate the clinical presentation. Given the systemic nature of HLH and risk of recurrence, HLH is considered by many a contraindication to liver transplantation (LT). The aim of this study is to review our single-center experience with LT in children with secondary HLH and ALF (HLH-ALF). This is a cross-sectional, retrospective study of children with secondary HLH-ALF that underwent LT in 2005-2014. Of 246 LTs, 9 patients (3 males; median age, 5 years; range, 0.7-15.4 years) underwent LT for secondary HLH-ALF. Disease progression was rapid with median 14 days (range, 6-27 days) between first symptoms and LT. Low fibrinogen/high triglycerides, elevated ferritin, hemophagocytosis on liver biopsy, and soluble interleukin 2 receptor levels were the most commonly fulfilled diagnostic criteria; HLH genetic studies were negative in all patients. Immunosuppressive therapy after LT included corticosteroids adjusted to HLH treatment protocol and tacrolimus. Thymoglobulin (n = 5), etoposide (n = 4), and alemtuzumab (n = 2) were used in cases of recurrence. Five (56%) patients experienced HLH recurrence, 1 requiring repeat LT, and 3 died. Overall graft and patient survival were 60% and 67%, respectively. Six patients are alive and well at a median of 24 months (range, 15-72 months) after transplantation. In conclusion, LT can be beneficial in selected patients with secondary HLH-ALF and can restore good health in an otherwise lethal condition. Liver Transplantation 22 1245-1253 2016 AASLD.

Innervation of Pulmonary Neuroendocrine Cells and Neuroepithelial Bodies in Developing Rabbit Lung

We investigated the development of innervation of the pulmonary neuroendocrine cell (PNEC) system composed of single cells and organoid cell clusters, neuroepithelial bodies (NEB) in rabbit fetal and neonatal lungs. To visualize the nerve fibers and their contacts with PNECs/NEBs, we used confocal microscopy and multilabel immunohistochemistry (IHC) with pan-neural marker, synaptic vesicle protein 2 (SV2), and serotonin (5-HT) as markers for PNECs/NEBs, and smooth muscle actin or cytokeratin to identify airway landmarks. The numbers and distribution of PNEC/NEB at different stages of lung development (E16, 18, 21, 26, and P2) and the density of innervation were quantified. First PNECs immunoreactive for 5-HT were identified in primitive airway epithelium at E18 as single cells or as small cell clusters with or without early nerve contacts. At E21 a significant increase in the number of PNECs with formation of early innervated NEB corpuscules was observed. The overall numbers of PNECs/NEBs and the density of mucosal, submucosal, and intercorpuscular innervation increased with progressing gestation and peaked postnataly (P2). At term, the majority of NEBs and single PNECs within airway mucosa possessed neural contacts. Such an extensive and complex innervation of the PNEC system indicates a multifunctional role in developing lung and during neonatal adaptation.

Multilabel immunofluorescence and antigen reprobing on formalin-fixed paraffin-embedded sections: novel applications for precision pathology diagnosis

We report new methods for multilabel immunofluorescence (MIF) and reprobing of antigen epitopes on the same formalin-fixed paraffin-embedded (FFPE) sections. The MIF method includes an antigen-retrieval step followed by multilabel immunostaining and examination by confocal microscopy. As examples, we illustrate epitopes localized to the apical and basolateral membranes, and the cytoplasm of enterocytes of normal small intestine and in cases of congenital enteropathies (microvillous inclusion disease and congenital tufting enteropathy). We also demonstrate localization of the bile salt excretion pump protein (BSEP) in bile canalicular membrane of normal hepatocytes and in cases of primary sclerosing cholangitis. To demonstrate colocalization of cytoplasmic and nuclear epitopes we analyzed normal control and hyperplastic pulmonary neuroendocrine cells (PNEC) and neuroepithelial bodies (NEBs), presumed airway sensors in the lungs of infants with bronchopulmonary dysplasia (BPD). As cytoplasmic markers we used anti-bombesin or anti-synaptic vesicle protein 2 (SV2) antibody, respectively, and for nuclear localization, antibodies against neurogenic genes mammalian achaete-scute homolog (Mash1) and prospero homeobox 1 (Prox1), essential for NEB cells differentiation and maturation, hypoxia-inducible factor 1α (HIF1α) a downstream modulator of hypoxia response and a proliferation marker Ki67. The reprobing method consisted of removal of the previously immunolabeled target and immunostaining with different antibodies, facilitating colocalization of enterocyte brush border epitopes as well as HIF1α, Mash1 and Prox1 in PNEC/NEB PNEC and NEBs. As these methods are suitable for routine FFPE pathology samples from various tissues, allowing visualization of multiple epitopes in the same cells/sections with superior contrast and resolution, they are suitable for a wide range of applications in diagnostic pathology and may be particularly well suited for precision medicine diagnostics.

Liver transplantation for children with acute liver failure associated with secondary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening systemic disease, characterized by overwhelming stimulation of the immune system and categorized as primary or secondary types. Occasionally, acute liver failure (ALF) may dominate the clinical presentation. Given the systemic nature of HLH and risk of recurrence, HLH is considered by many a contraindication to liver transplantation (LT). The aim of this study is to review our single-center experience with LT in children with secondary HLH and ALF (HLH-ALF). This is a cross-sectional, retrospective study of children with secondary HLH-ALF that underwent LT in 2005-2014. Of 246 LTs, 9 patients (3 males; median age, 5 years; range, 0.7-15.4 years) underwent LT for secondary HLH-ALF. Disease progression was rapid with median 14 days (range, 6-27 days) between first symptoms and LT. Low fibrinogen/high triglycerides, elevated ferritin, hemophagocytosis on liver biopsy, and soluble interleukin 2 receptor levels were the most commonly fulfilled diagnostic criteria; HLH genetic studies were negative in all patients. Immunosuppressive therapy after LT included corticosteroids adjusted to HLH treatment protocol and tacrolimus. Thymoglobulin (n = 5), etoposide (n = 4), and alemtuzumab (n = 2) were used in cases of recurrence. Five (56%) patients experienced HLH recurrence, 1 requiring repeat LT, and 3 died. Overall graft and patient survival were 60% and 67%, respectively. Six patients are alive and well at a median of 24 months (range, 15-72 months) after transplantation. In conclusion, LT can be beneficial in selected patients with secondary HLH-ALF and can restore good health in an otherwise lethal condition. Liver Transplantation 22 1245-1253 2016 AASLD.

Variants in TRIM22 That Affect NOD2 Signaling Are Associated With Very-Early-Onset Inflammatory Bowel Disease

BACKGROUND & AIMS

Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents.

METHODS

We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very-early-onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs noninflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture.

RESULTS

We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. TRIM22 is also associated with antiviral and mycobacterial effectors and markers of inflammation, such as fecal calprotectin, C-reactive protein, and Crohn's disease activity index scores.

CONCLUSIONS

In WES and targeted exome sequence analyses of an infant with severe IBD characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affects the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and antibacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD.

Hyperplasia and hypertrophy of pulmonary neuroepithelial bodies, presumed airway hypoxia sensors, in hypoxia-inducible factor prolyl hydroxylase-deficient mice

Pulmonary neuroepithelial bodies (NEBs), presumed polymodal airway sensors, consist of innervated clusters of amine (serotonin) and peptide-producing cells. While NEB responses to acute hypoxia are mediated by a membrane-bound O2 sensor complex, responses to sustained and/or chronic hypoxia involve a prolyl hydroxylase (PHD)-hypoxia-inducible factor-dependent mechanism. We have previously reported hyperplasia of NEBs in the lungs of Phd1-/- mice associated with enhanced serotonin secretion. Here we use a novel multilabel immunofluorescence method to assess NEB distribution, frequency, and size, together with the number and size of NEB cell nuclei, and to colocalize multiple cytoplasmic and nuclear epitopes in the lungs of Phd1-/-, Phd2+/-, and Phd3-/- mice and compare them with wild-type controls. To define the mechanisms of NEB cell hyperplasia, we used antibodies against Mash1 and Prox1 (neurogenic genes involved in NEB cell differentiation/maturation), hypoxia-inducible factor-1alpha, and the cell proliferation marker Ki67. Morphometric analysis of (% total lung area) immunostaining for synaptophysin (% synaptophysin), a cytoplasmic marker of NEB cells, was significantly increased in Phd1-/- and Phd3-/- mice compared to wild-type mice. In addition, NEB size and the number and size of NEB nuclei were also significantly increased, indicating that deficiency of Phds is associated with striking hyperplasia and hypertrophy of NEBs. In Phd2+/- mice, while mean % synaptophysin was comparable to wild-type controls, the NEB size was moderately increased, suggesting an effect even in heterozygotes. NEBs in all Phd-deficient mice showed increased expression of Mash1, Prox1, Ki67, and hypoxia-inducible factor-1alpha, in keeping with enhanced differentiation from precursor cells and a minor component of cell proliferation. Since the loss of PHD activity mimics chronic hypoxia, our data provide critical information on the potential role of PHDs in the pathobiology and mechanisms of NEB cell hyperplasia that is relevant to a number of pediatric lung disorders.

Hyperplasia of pulmonary neuroendocrine cells in infancy and childhood

Pulmonary neuroendocrine cells (PNEC) are widely distributed throughout the airway mucosa of mammalian lung as solitary cells and as distinctive innervated clusters, neuroepithelial bodies (NEB). These cells differentiate early during lung development and are more prominent in fetal/neonatal lungs compared to adults. PNEC/NEB cells produce biogenic amine (serotonin) and a variety of peptides (i.e., bombesin) involved in regulation of lung function. During the perinatal period, NEB are thought to function as airway O(2)/CO(2) sensors. Increased numbers of PNEC/NEBs have been observed in a variety of perinatal and postnatal lung disorders. Recent advances in cellular and molecular biology of these cells, as they relate to perinatal and postnatal lung disorders associated with PNEC/NEB cell hyperplasia are reviewed and their possible role in pulmonary pathobiology discussed (WC 125).

Mutations in Plasmalemma Vesicle Associated Protein Result in Sieving Protein-Losing Enteropathy Characterized by Hypoproteinemia, Hypoalbuminemia, and Hypertriglyceridemia

BACKGROUND & AIMS METHODS

Severe intestinal diseases observed in very young children are often the result of monogenic defects. We used whole exome sequencing (WES) to examine the genetic cause in a patient with a distinct severe form of protein losing enteropathy (PLE) characterized by hypoproteinemia, hypoalbuminemia, and hypertriglyceridemia.

METHODS

WES was performed at the Centre for Applied Genomics, Hospital for Sick Children, Toronto, Canada. Exome library preparation was performed using the Ion Torrent AmpliSeq RDY Exome Kit. Functional studies were carried out based on the identified mutation.

RESULTS

Using whole exome sequencing we identified a homozygous nonsense mutation (1072C>T; p.Arg358*) in the PLVAP (plasmalemma vesicle associated protein) gene in an infant from consanguineous parents who died at five months of age of severe protein losing enteropathy. Functional studies determined that the mutated PLVAP mRNA and protein were not expressed in the patient biopsy tissues, presumably secondary to nonsense-mediated mRNA decay. Pathological analysis showed that the loss of PLVAP resulted in disruption of endothelial fenestrated diaphragms.

CONCLUSIONS

PLVAP p.Arg358* mutation resulted in loss of PLVAP expression with subsequent deletion of the diaphragms of endothelial fenestrae leading to plasma protein extravasation, protein-losing enteropathy and ultimately death.

The Celiac Disease and Diabetes-Dietary Intervention and Evaluation Trial (CD-DIET) protocol: a randomised controlled study to evaluate treatment of asymptomatic coeliac disease in type 1 diabetes

INTRODUCTION

Coeliac disease (CD) is an autoimmune condition characterised by gluten-induced intestinal inflammation, and observed at a 5-10 fold greater prevalence in type 1 diabetes. While universal screening for CD in patients with diabetes is frequently advocated, objective data is limited as to benefits on diabetes control, bone health or quality of life related to the adoption of a gluten-free diet (GFD) in the large proportion of patients with diabetes with asymptomatic CD. The Celiac Disease and Diabetes-Dietary Intervention and Evaluation Trial (CD-DIET) study is a multicenter, randomised controlled trial to evaluate the efficacy and safety of a GFD in patients with type 1 diabetes with asymptomatic CD.

METHODS AND ANALYSIS

Children and adults (8-45 years) with type 1 diabetes will be screened for asymptomatic CD. Eligible patients with biopsy-proven CD will be randomly assigned in a 1:1 ratio to treatment with a GFD for 1 year, or continue with a gluten-containing diet. The primary outcome will evaluate the impact of the GFD on change in glycated haemoglobin. Secondary outcomes will evaluate changes in bone mineral density, blood glucose variability and health-related quality of life between GFD-treated and the regular diet group over a 1-year period. The study was initiated in 2012 and has subsequently expanded to multiple paediatric and adult centres in Ontario, Canada.

ETHICS AND DISSEMINATION

The findings from this study will provide high-quality evidence as to the impact of GFD treatment on glycaemic control and complications in asymptomatic children and adults with CD and type 1 diabetes.

TRIAL REGISTRATION NUMBER

NCT01566110.

Pulmonary neuroepithelial bodies are polymodal airway sensors: Evidence for CO2/H+ sensing

Pulmonary neuroepithelial bodies (NEB) in mammalian lungs are thought to function as airway O2 sensors that release serotonin (5-HT) in response to hypoxia. Direct evidence that NEB cells also respond to airway hypercapnia/acidosis (CO2/H+) is presently lacking. We tested the effects of CO2/H+ alone or in combination with hypoxia on 5-HT release from intact NEB cells in a neonatal hamster lung slice model. For the detection of 5-HT release we used carbon fiber amperometry. Fluorescence Ca2+ imaging method was used to assess CO2/H+-evoked changes in intracellular Ca2+. Exposure to 10 and 20% CO2 or pH 6.8–7.2 evoked significant release of 5-HT with a distinct rise in intracellular Ca2+ in hamster NEBs. This secretory response was dependent on the voltage-gated entry of extracellular Ca2+. Moreover, the combined effects of hypercapnia and hypoxia were additive. Critically, an inhibitor of carbonic anhydrase (CA), acetazolamide, suppressed CO2/H+-mediated 5-HT release. The expression of mRNAs for various CA isotypes, including CAII, was identified in NEB cells from human lung, and protein expression was confirmed by immunohistochemistry using a specific anti-CAII antibody on sections of human and hamster lung. Taken together our findings provide strong evidence for CO2/H+ sensing by NEB cells and support their role as polymodal airway sensors with as yet to be defined functions under normal and disease conditions.

Carbonic anhydrase II mediates malignant behavior of pulmonary neuroendocrine tumors

In normal lung, the predominant cytoplasmic carbonic anhydrase (CA) isozyme (CAII) is highly expressed in amine- and peptide-producing pulmonary neuroendocrine cells where its role involves CO2 sensing. Here, we report robust cytoplasmic expression of CAII by immunohistochemistry in the tumor cells of different native neuroendocrine tumor (NET) types, including typical and atypical carcinoids and small-cell lung carcinomas, and in NET and non-NET tumor cell lines. Because, in both pulmonary neuroendocrine cell and related NETs, the hypercapnia-induced secretion of bioactive serotonin (5-hydroxytryptamine) is mediated by CAII, we investigated the role of CAII in the biological behavior of carcinoid cell line H727 and the type II cell-derived A549 using both in vitro clonogenicity and in vivo xenograft model. We show that short hairpin RNA-mediated down-regulation of CAII resulted in significant reduction in clonogenicity of H727 and A549 cells in vitro, and marked suppression of tumor growth in vivo. CAII-short hairpin RNA cell-derived xenografts showed significantly reduced mitosis (phosphohistone H3 marker) and proliferation associated antigen Ki-67 (Ki67 marker), and significantly increased apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Using an apoptosis gene array, we found no association with caspases 3 and 8, but with a novel association of CAII-mediated apoptosis with specific mitochondrial apoptosis-associated proteins. Furthermore, these xenografts showed a significantly reduced vascularization (CD31 marker). Thus, CAII may play a critical role in NET lung tumor growth, angiogenesis, and survival, possibly via 5-hydroxytryptamine, known to drive autocrine tumor growth. As such, CAII is a potential therapeutic target for the difficult-to-treat lung NETs.

Loss of ADAM17 is associated with severe multiorgan dysfunction

ADAM metallopeptidase domain 17 (ADAM17) is responsible for processing large numbers of proteins. Recently, 1 family involving 2 patients with a homozygous mutation in ADAM17 were described, presenting with skin lesions and diarrhea. In this report, we describe a second family confirming the existence of this syndrome. The proband presented with severe diarrhea, skin rash, and recurrent sepsis, eventually leading to her death at the age of 10 months. We performed exome sequencing and detailed pathological and immunological investigations. We identified a novel homozygous frameshift mutation in ADAM17 (NM_003183.4:c.308dupA) leading to a premature stop codon. CD4(+) and CD8(+) T-cell stimulation assays showed severely diminished tumor necrosis factor-α and interleukin-2 production. Skin biopsies indicated a focal neutrophilic infiltrate and spongiotic dermatitis. Interestingly, the patient developed unexplained systolic hypertension and nonspecific hepatitis with apoptosis. This report provides evidence for an important role of ADAM17 in human immunological response and underscores its multiorgan involvement.

Aggregates of mutant CFTR fragments in airway epithelial cells of CF lungs: new pathologic observations

Cystic fibrosis (CF) is caused by a mutation in the CF transmembrane conductance regulator (CFTR) gene resulting in a loss of Cl(-) channel function, disrupting ion and fluid homeostasis, leading to severe lung disease with airway obstruction due to mucus plugging and inflammation. The most common CFTR mutation, F508del, occurs in 90% of patients causing the mutant CFTR protein to misfold and trigger an endoplasmic reticulum based recycling response. Despite extensive research into the pathobiology of CF lung disease, little attention has been paid to the cellular changes accounting for the pathogenesis of CF lung disease. Here we report a novel finding of intracellular retention and accumulation of a cleaved fragment of F508del CFTR in concert with autophagic like phagolysosomes in the airway epithelium of patients with F508del CFTR. Aggregates consisting of poly-ubiquitinylated fragments of only the N-terminal domain of F508del CFTR but not the full-length molecule accumulate to appreciable levels. Importantly, these undegraded intracytoplasmic aggregates representing the NT-NBD1 domain of F508del CFTR were found in ciliated, in basal, and in pulmonary neuroendocrine cells. Aggregates were found in both native lung tissues and ex-vivo primary cultures of bronchial epithelial cells from CF donors, but not in normal control lungs. Our findings present a new, heretofore, unrecognized innate CF gene related cell defect and a potential contributing factor to the pathogenesis of CF lung disease. Mutant CFTR intracytoplasmic aggregates could be analogous to the accumulation of misfolded proteins in other degenerative disorders and in pulmonary "conformational protein-associated" diseases. Consequently, potential alterations to the functional integrity of airway epithelium and regenerative capacity may represent a critical new element in the pathogenesis of CF lung disease.

Abstract 3133: The anti-tumor effects of acetazolamide and sulforaphane on bronchial carcinoids: Preclinical modeling and mechanism

Background: The prognosis of patients with metastatic bronchial carcinoid remains poor despite current conventional and targeted therapies. Here we evaluated the therapeutic potential of acetazolamide (AZ; a pan carbonic anhydrase inhibitor affecting pH regulation and homeostasis) and sulforaphane (SFN; a natural isothiocyanate compound targeting multiple pathways in cancer cells), for their anti-cancer properties. Methods: In vitro and in vivo studies were conducted on H-727 (typical carcinoid) and H-720 (atypical carcinoid) bronchial carcinoid cell lines. We developed a lung orthotopic bronchial carcinoid tumor xenograft model in NOD/SCID mice. Results: AZ and/or SFN significantly inhibited cell viability and clonogenic capacity in a dose-dependent manner (0-80 μM, 48 hours and 7 days). AZ and/or SFN downregulated phosphoH3, Ki67, EPCAM, CA9, Akt1 and upregulated p21 and Nrf2 proteins compared to controls as confirmed by Western blot. Upregulation of Nrf2 gene expression was confirmed by qPCR. AZ and/or SFN significantly reduced xenograft growth and serotonin content after two weeks treatment. In the lung orthotopic model, MR imaging at 3 Tesla precisely identified growth of H-727 injected cells in the ipsilateral side, and revealed liver metastasis as confirmed by histology. A tumor initiating cell (TIC) fraction isolated under stem cell culture conditions showing significantly enhanced tumorigenicity was also studied. Conclusions: AZ and/or SFN inhibited tumor survival, proliferation, invasiveness, serotonin secretion and tumorigenic potential of bronchial carcinoid cell lines. Since the combination of AZ+SFN was more effective than either single agent, we postulate that AZ potentiates the effects of SFN by inhibiting PI3K/AKT, which could enhance the inhibitory effect of SFN on P21, Ki67 and phosphoH3. Interestingly, Nrf2 upregulation by both AZ and by SFN suggested a potent antioxidant response. The lung orthotopic tumor model of bronchial carcinoids permits study of carcinoid metastatic progression. As the doses used in this study are clinically bioavailable we suggest that AZ and SFN may have promising potential for carcinoid therapy and resolution of the carcinoid syndrome.

Citation Format: Reza Bayat Mokhtari, Syed S. Islam, Narges Baluch, Karen Aitken, Sushil Kumar, Hai-Ling Margaret Cheng, Mehrdad Yazdanpanah, Khosrow Adeli, Yuanxiang Zhou, Ernest Cutz, Herman Yeger. The anti-tumor effects of acetazolamide and sulforaphane on bronchial carcinoids: Preclinical modeling and mechanism. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3133. doi:10.1158/1538-7445.AM2014-3133

Pulmonary venoocclusive disease in childhood

BACKGROUND

Pulmonary venoocclusive disease (PVOD) is a rare lung disease, diagnosed in 5% to 10% of patients with pulmonary hypertension (PH). The incidence, prevalence, and etiology of PVOD in children are not well defined. The mortality remains high, related, at least partly, to the limited treatment options.

METHODS

This retrospective analysis (1985-2011) summarizes symptoms, associated factors, treatment, and outcomes of nine pediatric patients (five girls, four boys) with histologic confirmation of PVOD.

RESULTS

PH was diagnosed at a mean age of 13.5 years (range, 8-16 years), followed by the definitive diagnosis of PVOD at a mean age of 14.3 years (range, 10-16 years). Symptoms such as decreased exercise tolerance (n = 6) and/or shortness of breath (n = 9) preceded the diagnosis by 21 months on average; the mean survival time after diagnosis was 14 months (range, 0-47 months). CT scans of the lungs showed typical radiologic features. Treatment included supplemental home oxygen (n = 5), diuretics (n = 9), warfarin (n = 4), and pulmonary vasodilators (n = 4). Four children were listed for lung transplantation, and three have undergone transplantation. Eight patients died, including two after lung transplantation. One patient with lung transplant survived with good quality of life.

CONCLUSIONS

PVOD is an important differential diagnosis for pediatric patients with PH. CT scanning is a valuable tool to image lung abnormalities; the definitive diagnosis can only be made by examination of lung biopsy specimens, which subjects the patient to additional risk. Early listing for lung transplantation is essential, as the mean survival time is only 14 months.

Tachypnea of infancy as the first sign of Sanfilippo syndrome

This report describes the first known case of Mucopolysaccharidosis type IIIA presenting with respiratory symptoms and characteristic lung pathology. This case highlights under-recognized areas of systemic involvement and earlier modes of presentation in lysosomal storage disorders as well as the importance of investigating infants who have persistent tachypnea.

Loss of syntaxin 3 causes variant microvillus inclusion disease

Microvillus inclusion disease (MVID) is a disorder of intestinal epithelial differentiation characterized by life-threatening intractable diarrhea. MVID can be diagnosed based on loss of microvilli, microvillus inclusions, and accumulation of subapical vesicles. Most patients with MVID have mutations in myosin Vb that cause defects in recycling of apical vesicles. Whole-exome sequencing of DNA from patients with variant MVID showed homozygous truncating mutations in syntaxin 3 (STX3). STX3 is an apical receptor involved in membrane fusion of apical vesicles in enterocytes. Patient-derived organoid cultures and overexpression of truncated STX3 in Caco-2 cells recapitulated most characteristics of variant MVID. We conclude that loss of STX3 function causes variant MVID.

The distribution and frequency of pulmonary neuroendocrine cells in Down syndrome fetal lungs

The pulmonary neuroendocrine cells (PNEC) are located in the epithelial lining of the airways and consist of solitary neuroendocrine cells (NEC) and NEC clusters, the neuroepithelial bodies (NEB). During fetal life, PNEC are the first to differentiate within the primitive airway epithelium, and bombesin expression favors branching of the respiratory tree. We investigated PNEC in Down syndrome (DS), where the lungs often show enlarged and reduced number of alveoli. Immunohistochemistry for bombesin and synaptophysin, PNEC markers, was evaluated in fetal lungs from 15 cases of DS and 11 age-matched controls from the 17th to 23rd week of gestation. Morphometric analysis assessed PNEC in the mucosal lining of each lung, expressed as number/mm. Nonparametric Mann-Whitney U test showed no statistical difference in frequency of PNEC in DS and controls. Our findings suggest that, at least in late second trimester, the distribution and frequency of PNEC in DS fetuses is not altered.

Mutations in tetratricopeptide repeat domain 7A result in a severe form of very early onset inflammatory bowel disease

BACKGROUND & AIMS

Very early onset inflammatory bowel diseases (VEOIBD), including infant disorders, are a diverse group of diseases found in children younger than 6 years of age. They have been associated with several gene variants. Our aim was to identify the genes that cause VEOIBD.

METHODS

We performed whole exome sequencing of DNA from 1 infant with severe enterocolitis and her parents. Candidate gene mutations were validated in 40 pediatric patients and functional studies were carried out using intestinal samples and human intestinal cell lines.

RESULTS

We identified compound heterozygote mutations in the Tetratricopeptide repeat domain 7 (TTC7A) gene in an infant from non-consanguineous parents with severe exfoliative apoptotic enterocolitis; we also detected TTC7A mutations in 2 unrelated families, each with 2 affected siblings. TTC7A interacts with EFR3 homolog B to regulate phosphatidylinositol 4-kinase at the plasma membrane. Functional studies demonstrated that TTC7A is expressed in human enterocytes. The mutations we identified in TTC7A result in either mislocalization or reduced expression of TTC7A. Phosphatidylinositol 4-kinase was found to co-immunoprecipitate with TTC7A; the identified TTC7A mutations reduced this binding. Knockdown of TTC7A in human intestinal-like cell lines reduced their adhesion, increased apoptosis, and decreased production of phosphatidylinositol 4-phosphate.

CONCLUSIONS

In a genetic analysis, we identified loss of function mutations in TTC7A in 5 infants with VEOIBD. Functional studies demonstrated that the mutations cause defects in enterocytes and T cells that lead to severe apoptotic enterocolitis. Defects in the phosphatidylinositol 4-kinase-TTC7A-EFR3 homolog B pathway are involved in the pathogenesis of VEOIBD.

Mutations in Alström protein impair terminal differentiation of cardiomyocytes

Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognise homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at two weeks postnatal compared to wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest.

Microvillus inclusion disease: loss of Myosin vb disrupts intracellular traffic and cell polarity

Microvillus inclusion disease (MVID) is a congenital enteropathy characterized by loss of apical microvilli and formation of cytoplasmic inclusions lined by microvilli in enterocytes. MVID is caused by mutations in the MYO5B gene, coding for the myosin Vb motor protein. Although myosin Vb is implicated in the organization of intracellular transport and cell surface polarity in epithelial cells, its precise role in the pathogenesis of MVID is unknown. We performed correlative immunohistochemistry analyses of sections from duodenal biopsies of a MVID patient, compound heterozygous for two novel MYO5B mutations, predicting loss of function of myosin Vb in duodenal enterocytes together with a stable MYO5B CaCo2 RNAi cell system. Our findings show that myosin Vb-deficient enterocytes display disruption of cell polarity as reflected by mislocalized apical and basolateral transporter proteins, altered distribution of certain endosomal/lysosomal constituents including Rab GTPases. Together, this severe disturbance of epithelial cell function could shed light on the pathology and symptoms of MVID.

Efficient gene delivery to pig airway epithelia and submucosal glands using helper-dependent adenoviral vectors

Airway gene delivery is a promising strategy to treat patients with life-threatening lung diseases such as cystic fibrosis (CF). However, this strategy has to be evaluated in large animal preclinical studies in order to translate it to human applications. Because of anatomic and physiological similarities between the human and pig lungs, we utilized pig as a large animal model to examine the safety and efficiency of airway gene delivery with helper-dependent adenoviral vectors. Helper-dependent vectors carrying human CFTR or reporter gene LacZ were aerosolized intratracheally into pigs under bronchoscopic guidance. We found that the LacZ reporter and hCFTR transgene products were efficiently expressed in lung airway epithelial cells. The transgene vectors with this delivery can also reach to submucosal glands. Moreover, the hCFTR transgene protein localized to the apical membrane of both ciliated and nonciliated epithelial cells, mirroring the location of wild-type CF transmembrane conductance regulator (CFTR). Aerosol delivery procedure was well tolerated by pigs without showing systemic toxicity based on the limited number of pigs tested. These results provide important insights into developing clinical strategies for human CF lung gene therapy.Molecular Therapy-Nucleic Acids (2013) 2, e127; doi:10.1038/mtna.2013.55; published online 8 October 2013.

Variable clinical outcome of ABCA3 deficiency in two siblings

This case report describes an unusual outcome of ABCA3 deficiency with resolution of symptoms, normalization of chest imaging and lung function in a 9-year-old child whose sibling died of the same disease in infancy.

Combination of carbonic anhydrase inhibitor, acetazolamide, and sulforaphane, reduces the viability and growth of bronchial carcinoid cell lines

Background

Bronchial carcinoids are pulmonary neuroendocrine cell-derived tumors comprising typical (TC) and atypical (AC) malignant phenotypes. The 5-year survival rate in metastatic carcinoid, despite multiple current therapies, is 14-25%. Hence, we are testing novel therapies that can affect the proliferation and survival of bronchial carcinoids.

Methods

In vitro studies were used for the dose–response (AlamarBlue) effects of acetazolamide (AZ) and sulforaphane (SFN) on clonogenicity, serotonin-induced growth effect and serotonin content (LC-MS) on H-727 (TC) and H-720 (AC) bronchial carcinoid cell lines and their derived NOD/SCID mice subcutaneous xenografts. Tumor ultra structure was studied by electron microscopy. Invasive fraction of the tumors was determined by matrigel invasion assay. Immunohistochemistry was conducted to study the effect of treatment(s) on proliferation (Ki67, phospho histone-H3) and neuroendocrine phenotype (chromogranin-A, tryptophan hydroxylase).

Results

Both compounds significantly reduced cell viability and colony formation in a dose-dependent manner (0–80 μM, 48 hours and 7 days) in H-727 and H-720 cell lines. Treatment of H-727 and H-720 subcutaneous xenografts in NOD/SCID mice with the combination of AZ + SFN for two weeks demonstrated highly significant growth inhibition and reduction of 5-HT content and reduced the invasive capacity of H-727 tumor cells. In terms of the tumor ultra structure, a marked reduction in secretory vesicles correlated with the decrease in 5-HT content.

Conclusions

The combination of AZ and SFN was more effective than either single agent. Since the effective doses are well within clinical range and bioavailability, our results suggest a potential new therapeutic strategy for the treatment of bronchial carcinoids.

Successful liver transplantation in an infant with stage 4S(M) neuroblastoma

We report a 2.5-month-old infant with bilateral adrenal neuroblastoma, stage 4S(M), with liver metastases and chemotherapy-induced veno-occlusive disease leading to cirrhosis requiring liver transplantation. Despite unknown tumour histology and MYCN-amplification status, we proceeded with liver transplant. This decision was based on clinical suspicion that our patient was MYCN-negative due to significant tumour regression, and was supported by evidence indicating that MYCN-amplification is rare in infants with favourable-stage neuroblastoma. This is the second case report of neuroblastoma requiring liver transplantation; however, in the previously reported case, the diagnosis of neuroblastoma was not established until after transplantation. We discuss this unique case to justify the potential use of life-saving liver transplants in infants with neuroblastoma.

IL-10R polymorphisms are associated with very-early-onset ulcerative colitis

BACKGROUND

Interleukin-10 (IL-10) signaling genes are attractive inflammatory bowel disease (IBD) candidate genes as IL-10 restricts intestinal inflammation, IL-10 polymorphisms have been associated with IBD in genome-wide association studies, and mutations in IL-10 and IL-10 receptor (IL-10R) genes have been reported in immunodeficient children with severe infantile-onset IBD. Our objective was to determine if IL-10R polymorphisms were associated with early-onset IBD (EO-IBD) and very-early-onset IBD (VEO-IBD).

METHODS

Candidate-gene analysis of IL10RA and IL10RB was performed after initial sequencing of an infantile onset-IBD patient identified a novel homozygous mutation. The discovery cohort included 188 EO-IBD subjects and 188 healthy subjects. Polymorphisms associated with IBD in the discovery cohort were genotyped in an independent validation cohort of 422 EO-IBD subjects and 480 healthy subjects.

RESULTS

We identified a homozygous, splice-site point mutation in IL10RA in an infantile-onset IBD patient causing a premature stop codon (P206X) and IL-10 insensitivity. IL10RA and IL10RB sequencing in the discovery cohort identified five IL10RA polymorphisms associated with ulcerative colitis (UC) and two IL10RB polymorphisms associated with Crohn's disease (CD). Of these polymorphisms, two IL10RA single nucleotide polymorphisms, rs2228054 and rs2228055, were associated with VEO-UC in the discovery cohort and replicated in an independent validation cohort (odds ratio [OR] 3.08, combined P = 2 x 10(-4); and OR 2.93, P = 6 x 10(-4), respectively).

CONCLUSIONS

We identified IL10RA polymorphisms that confer risk for developing VEO-UC. Additionally, we identified the first splice site mutation in IL10RA resulting in infantile-onset IBD. This study expands the phenotype of IL10RA polymorphisms to include both severe arthritis and VEO-UC.

Pulmonary hypertensive vasculopathy following tandem autologous transplantation in pediatric patients with central nervous system tumors

Tandem cycles of high-dose chemotherapy are an increasingly being used as alternative to radiation treatment in the management of infants and young children with central nervous system (CNS) tumors. Most of these protocols have a carboplatinum and thiotepa backbone. The toxicities of these regimens have been reported extensively; however, pulmonary arterial vasculopathy (PAV) with pulmonary arterial hypertension (PAH) has not been previously documented in patients treated with this approach. PAH is a disorder of the pulmonary vasculature characterized by a progressive increase in pulmonary vascular resistance, leading to right heart failure and potentially death. We evaluated PAH as a complication after high-dose chemotherapy and autologous stem cell transplantation (SCT). We performed a retrospective evaluation of all pediatric patients diagnosed with a CNS tumor between 2001 and 2010 scheduled to receive 3 cycles of high-dose chemotherapy with carboplatinum (17 mg/kd/day for 2 days) and thiotepa (10 mg/kg/day for 2 days), followed by autologous SCT. Our primary objective was to evaluate the incidence of PAV and PAH in this population, as well as patient outcomes after the development of PAH. Our cohort comprised 20 patients with a median age at diagnosis of 28 months (range, 3-131 months). Three patients developed biopsy-confirmed PAV with PAH, the 2 patients who developed PAV with PAH at the end of the third cycle succumbed to PAH. Death due to PAV and PAH was the sole toxic mortality observed during the study period. PAV with PAH is a major and possibly fatal complication after high-dose chemotherapy and sequential autologous SCT using carboplatinum and thiotepa in a tandem fashion. There is an urgent need to evaluate PAH as a potential complication after each cycle of high-dose chemotherapy when using such regimens in pediatric patients with CNS tumors.

Recent advances and contraversies on the role of pulmonary neuroepithelial bodies as airway sensors

Pulmonary neuroepithelial bodies are polymodal sensors widely distributed within the airway mucosa of mammals and other species. Neuroepithelial body cells store and most likely release serotonin and peptides as transmitters. Neuroepithelial bodies have a complex innervation that includes vagal sensory afferent fibers and dorsal root ganglion fibers. Neuroepithelial body cells respond to a number of intraluminal airway stimuli, including hypoxia, hypercarbia, and mechanical stretch. This article reviews recent findings in the cellular and molecular biology of neuroepithelial body cells and their potential role as airway sensors involved in the control of respiration, particularly during the perinatal period. Alternate hypotheses and areas of controversy regarding potential function as mechanosensory receptors involved in pulmonary reflexes are discussed.

NOX2 (gp91phox) is a predominant O2 sensor in a human airway chemoreceptor cell line: biochemical, molecular, and electrophysiological evidence

Pulmonary neuroepithelial bodies (NEBs), composed of clusters of amine [serotonin (5-HT)] and peptide-producing cells, are widely distributed within the airway mucosa of human and animal lungs. NEBs are thought to function as airway O(2)-sensors, since they are extensively innervated and release 5-HT upon hypoxia exposure. The small cell lung carcinoma cell line (H146) provides a useful model for native NEBs, since they contain (and secrete) 5-HT and share the expression of a membrane-delimited O(2) sensor [classical NADPH oxidase (NOX2) coupled to an O(2)-sensitive K(+) channel]. In addition, both native NEBs and H146 cells express different NADPH oxidase homologs (NOX1, NOX4) and its subunits together with a variety of O(2)-sensitive voltage-dependent K(+) channel proteins (K(v)) and tandem pore acid-sensing K(+) channels (TASK). Here we used H146 cells to investigate the role and interactions of various NADPH oxidase components in O(2)-sensing using a combination of coimmunoprecipitation, Western blot analysis (quantum dot labeling), and electrophysiology (patchclamp, amperometry) methods. Coimmunoprecipitation studies demonstrated formation of molecular complexes between NOX2 and K(v)3.3 and K(v)4.3 ion channels but not with TASK1 ion channels, while NOX4 associated with TASK1 but not with K(v) channel proteins. Downregulation of mRNA for NOX2, but not for NOX4, suppressed hypoxia-sensitive outward current and significantly reduced hypoxia -induced 5-HT release. Collectively, our studies suggest that NOX2/K(v) complexes are the predominant O(2) sensor in H146 cells and, by inference, in native NEBs. Present findings favor a NEB cell-specific plasma membrane model of O(2)-sensing and suggest that unique NOX/K(+) channel combinations may serve diverse physiological functions.

Abstract 4400: Novel combination of carbonic anhydrase inhibitor with a phytochemical for treatment of human bronchial carcinoids

Bronchial carcinoids are pulmonary neuroendocrine cell derived tumors comprising typical (TC) and atypical (AT) malignant phenotypes. The 5-year survival rate in metastatic disease, despite multiple current therapies, is 14-25%. Carcinoids are found in the gastrointestinal tract are more frequent (61%) and also more aggressive; however, 31% of carcinoids are located in bronchopumonary system, which can metastize beyond the longs. Therefore, new strategies are needed for effective treatment of carcinoid malignant progression and metastatic disease. The progenitor neuroendocrine cells are O2/CO2 chemosensory. Hypoxia and hypercapnia stimulate secretion of the neuroendocrine associated bioactive amine, serotonin, which can also serve as an autocrine growth factor. CO2 sensing and metabolism is associated with physiological activities of different carbonic anhydrases (CAs) which function in tumor cell pH homeostasis and therein regulation of growth, survival, and metastasis. CAs are abundantly expressed in lung carcinoids. We postulated that acetazolamide (AZ), a pan CA inhibitor, and the anti-tumor phytochemical sulforaphane (SFN), which can inhibit expression of serotonin receptors could function cooperatively and synergistically to inhibit growth of pulmonary carcinoids. A dose dependent effect of AZ (0-80 µM, 48h) and SFN (0-80µM, 48h) on carcinoid cell lines H727 (TC), H835 (intermediate phenotype) and H720 (AT) was assessed in vitro. Both compounds reduced cell viability (via Alamar Blue) and mitochondrial integrity (via JC-1 mitochondrial staining) dose-dependently in all cell lines. IC50 values for cell viability were 9.29 µM (H727), 16.67 µM (H835) and 30.85 µM (H720) for AZ and 51.93 µM (H727), 5.31 µM (H835) and 10.82 µM (H720) for SFN. The mitochondrial integrity JC1 IC50 values were 50.16 µM (H727), 15.52 µM (H835), 11.93 µM (H720) for AZ and 9.29 µM (H727), 16.67 µM (H835) and 30.85 µM (H720) for SFN treatment. Treatment of H727 subcutaneous xenografts in NOD/SCID mice for 2 weeks demonstrated modest growth inhibition with AZ (7%, 20mg/kg) and SFN (23%, 40mg/kg) alone. However, a highly significant reduction (57%; p=0.02) was shown with the combination treatment. Furthermore, the combination did not show any signs of morbidity in treated mice. Since these doses are at the low end and well within clinical range and bioavailability, our results suggest a potential new therapeutic strategy for the treatment of pulmonary carcinoids. The molecular mechanism underlying this synergistic anti-tumor effect, currently under investigation, suggests a novel targeting of tumor cell homeostasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4400. doi:1538-7445.AM2012-4400

Pulmonary alveolar proteinosis in patients with adenosine deaminase deficiency

BACKGROUND

Inherited defects in the function of adenosine deaminase (ADA) cause severe combined immunodeficiency (SCID) and affect many other cells and tissues.

OBJECTIVES

We sought to characterize the frequency and features of pulmonary alveolar proteinosis (PAP) in patients with ADA deficiency.

METHODS

Clinical and laboratory features of all patients with SCID caused by ADA deficiency in a single center were analyzed. Bronchoalveolar lavage (BAL) fluid and lung biopsy specimens were stained with hematoxylin and eosin and periodic acid-Schiff, visualized by means of electron microscopy, and studied for associated infections. As a control group, BAL fluid and biopsy specimens from 22 patients with SCID caused by other genetic abnormalities were similarly assessed.

RESULTS

Among 16 consecutive patients with ADA deficiency, 7 had BAL fluid containing periodic acid-Schiff-positive surfactant-like material with macrophages engulfing degenerating lamellar bodies and/or lung biopsy specimens with alveolar spaces filled with homogeneous granular eosinophilic material and large macrophages. The lung pathology was typical of PAP. Identification of various pathogens coincided with PAP in 3 of these patients. We have diagnosed PAP among patients with ADA deficiency more commonly in the last 10 years than previously (P= .05), likely reflecting increased awareness of this condition. There were no significant differences in the clinical or immunologic characteristics between patients with ADA deficiency with or without PAP. Similar findings of PAP were not found among patients with SCID caused by other genetic abnormalities (P= .001). ADA coupled to polyethylene glycol or allogeneic hematopoietic stem cell transplantation rapidly corrected this pulmonary complication. PAP seems to have contributed to the death of only 1 patient with ADA deficiency.

CONCLUSIONS

ADA deficiency predisposes to the development of PAP, which could be reversed after enzyme replacement or transplantation.

Hyperplasia of pulmonary neuroepithelial bodies (NEB) in lungs of prolyl hydroxylase -1(PHD-1) deficient mice

Pulmonary NEB, widely distributed within the airway mucosa of mammalian lungs, are presumed hypoxia sensitive airway O(2) sensors responding to changes in airway gas concentration. NEB cell hyperplasia has been reported after exposure to chronic hypoxia and in a variety of paediatric and adult lung disorders. Prolyl hydroxylases (PHD 1-3) regulate the stability of hypoxia-inducible factors (HIF's) in an O(2)-dependent manner and function as intrinsic oxygen sensors. To determine a possible role of PHD-1in NEB cells we have quantitated NEB's in lungs of neonatal (P2) and adult (2 months) PHD-1-deficient mice and compared them to wild type (WT) control mice. Lung tissues fixed in formalin and embedded in paraffin were processed for immunoperoxidase method and frozen sections for multilabel immunoflourescence using antibodies for NEB markers synaptophysin, synaptic vesicle protein 2 and the peptide CGRP. The frequency and size of NEB in lungs of PHD-1 deficient neonatal mice (P2) and at 2 months was increased significantly compared to WT controls (p < 0.01). The present data suggests an important role for PHD enzymes in NEB cell biology deserving further studies. Since the PHD-1 deficient mouse appears to be the first animal model showing NEB cell hyperplasia it may be useful for studies of NEB physiology and pathobiology.

Severe ulcerative colitis after rituximab therapy

B-cell-depletion therapy with rituximab is efficacious against steroid-dependent nephrotic syndrome (NS) in children and adults. Safety data are limited. Results of small studies have suggested that rituximab is usually well tolerated but that adverse events (such as severe mucocutaneous reactions, fatal infusion reactions, progressive multifocal leukoencephalopathy, and bowel perforation) can occur. We report here the first case (to our knowledge) of a pediatric patient with refractory minimal-change NS who developed severe immune-mediated ulcerative gastrointestinal disease 42 days after rituximab therapy. The disease was characterized by deep ulcers throughout the intestines and predominantly affected the colon. The child presented with severe abdominal pain, bloody diarrhea, weight loss, and fever. Her inflammatory markers were significantly elevated. Extensive evaluation revealed no evidence of infections and no characteristics of defined inflammatory bowel disease or Behçet disease. Colonoscopy revealed severe intestinal inflammation with deep ulcers. Histology of the colonic biopsy specimens revealed extensive infiltrates predominantly composed of CD8(+) T lymphocytes and evidence of high forkhead box P3 (FOXP3) expression. During this significant gastrointestinal disease, the NS remained quiescent. Corticosteroid therapy successfully controlled the severe immune-mediated intestinal inflammation after rituximab therapy. NS relapsed subsequently when CD19(+) and CD20(+) B-cell populations recovered.