mTOR signaling regulates aberrant epithelial cell proliferative and migratory behaviors characteristic of airway mucous metaplasia in asthma

In asthma, the airway epithelium is hyperplastic, hypertrophied, and lined with numerous large MUC5AC-containing goblet cells (GC). Furthermore, the normal epithelial architecture is disorganized with numerous, what we here describe as, ectopic goblet cells (eGC) deep within the thickened epithelial layer disconnected from the lumenal surface. mTOR is a highly conserved pathway that regulates cell size and proliferation. We hypothesized that the balance between mTOR and autophagy signaling regulates key features of the asthma epithelial layer. Airway histological sections from subjects with asthma had increased frequency of eGC and increased levels of mTOR phosphorylation target-Ribosomal S6. Using human airway epithelial cells (hAECs) with IL-13 stimulation and timed withdrawal to stimulate resolution, we found that multiple key downstream phosphorylation targets downstream from the mTOR complex were increased during early IL-13-mediated mucous metaplasia, and then significantly declined during resolution. The IL-13-mediated changes in mTOR signaling were paralleled by morphologic changes with airway epithelial hypertrophy, hyperplasia, and frequency of eGC. We then examined the relationship between mTOR and autophagy using mice deficient in autophagy protein Atg16L1. Despite having increased cytoplasmic mucins, mouse AECs from Atg16L1 deficient mice had no significant difference in mTOR downstream signaling. mTOR inhibition with rapamycin led to a loss of IL-13-mediated epithelial hypertrophy, hyperplasia, ectopic GC distribution, and reduction in cytoplasmic MUC5AC levels. mTOR inhibition was also associated with a reduction in aberrant IL-13-mediated hAEC proliferation and migration. Our findings demonstrate that mTOR signaling is associated with mucous metaplasia and is crucial to the disorganized airway epithelial structure and function characteristic of muco-obstructive airway diseases such as asthma.

Graphical Abstract Key Concepts

The airway epithelium in asthma is disorganized and characterized by cellular proliferation, aberrant migration, and goblet cell mucous metaplasia.mTOR signaling is a dynamic process during IL-13-mediated mucous metaplasia, increasing with IL-13 stimulation and declining during resolution.mTOR signaling is strongly increased in the asthmatic airway epithelium.mTOR signaling is associated with the development of key features of the metaplastic airway epithelium including cell proliferation and ectopic distribution of goblet cells and aberrant cellular migration.Inhibition of mTOR leads to decreased epithelial hypertrophy, reduced ectopic goblet cells, and cellular migration.

Restless legs syndrome is prevalent in adults with cystic fibrosis and impacts sleep quality

BACKGROUND

Restless legs syndrome (RLS) is a sensorimotor disorder that is prevalent in chronic inflammatory conditions. RLS prevalence, risk factors, and impact on sleep in CF have not been extensively characterized to date.

METHODS

An initial cohort was examined, including 75 persons with CF (PwCF) and 75 control subjects, to look at the prevalence and severity of RLS. A second validation cohort of 191 PwCF was then enrolled from two CF centers to examine risk factors for RLS. A diagnosis of RLS was made according to the International RLS Study Group (IRLSSG) criteria. Sleep quality was identified using the Pittsburgh sleep quality index (PSQI). Epworth sleepiness scale (ESS) was used to measure daytime sleepiness. We then analyzed laboratory and clinical risk factors and sleep symptoms for potential risk factors for RLS.

RESULTS

In the initial cohort, 36 % of PwCF had RLS, and 9 % of these had significant RLS. In contrast, only 15 % of controls had RLS, and none had significant RLS. In the second larger validation cohort with 191 subjects, a comparable prevalence of RLS was identified. Higher hemoglobin A1c, use of SSRI/SNRI medications, worse PSQI and ESS sleep quality scores, lower lung function, and higher antibiotic usage were significantly associated with a diagnosis of RLS. By multivariate multinominal logistic regression analysis, higher HbA1c and worse PSQI global sleep quality scores were independent predictors of significant RLS.

CONCLUSIONS

RLS is highly prevalent in CF. Higher HbA1c and poor sleep quality, signified by higher PSQI, were each independent predictors of RLS.

Researching COVID to Enhance Recovery (RECOVER) adult study protocol: Rationale, objectives, and design

IMPORTANCE

SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis.

METHODS

RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged ≥18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms.

DISCUSSION

RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options.

REGISTRATION

NCT05172024.

Neutralization of IL-33 modifies the type 2 and type 3 inflammatory signature of viral induced asthma exacerbation

Background

Respiratory viral infections are one of the leading causes of need for emergency care and hospitalizations in asthmatic individuals, and airway-secreted cytokines are released within hours of viral infection to initiate these exacerbations. IL-33, specifically, contributes to these allergic exacerbations by amplifying type 2 inflammation. We hypothesized that blocking IL-33 in RSV-induced exacerbation would significantly reduce allergic inflammation.

Methods

Sensitized BALB/c mice were challenged with aerosolized ovalbumin (OVA) to establish allergic inflammation, followed by RSV-A2 infection to yield four treatment groups: saline only (Saline), RSV-infected alone (RSV), OVA alone (OVA), and OVA-treated with RSV infection (OVA-RSV). Lung outcomes included lung mRNA and protein markers of allergic inflammation, histology for mucus cell metaplasia and lung immune cell influx by cytospin and flow cytometry.

Results

While thymic stromal lymphopoietin (TSLP) and IL-33 were detected 6 h after RSV infection in the OVA-RSV mice, IL-23 protein was uniquely upregulated in RSV-infected mice alone. OVA-RSV animals varied from RSV- or OVA-treated mice as they had increased lung eosinophils, neutrophils, group 2 innate lymphoid cells (ILC2) and group 3 innate lymphoid cells (ILC3) detectable as early as 6 h after RSV infection. Neutralized IL-33 significantly reduced ILC2 and eosinophils, and the prototypical allergic proteins, IL-5, IL-13, CCL17 and CCL22 in OVA-RSV mice. Numbers of neutrophils and ILC3 were also reduced with anti-IL-33 treatment in both RSV and OVA-RSV treated animals as well.

Conclusions

Taken together, our findings indicate a broad reduction in allergic-proinflammatory events mediated by IL-33 neutralization in RSV-induced asthma exacerbation.

Autophagy of mucin granules contributes to resolution of airway mucous metaplasia

Exacerbations of muco-obstructive airway diseases such as COPD and asthma are associated with epithelial changes termed mucous metaplasia (MM). Many molecular pathways triggering MM have been identified; however, the factors that regulate resolution are less well understood. We hypothesized that the autophagy pathway is required for resolution of MM by eliminating excess non-secreted intracellular mucin granules. We found increased intracellular levels of mucins Muc5ac and Muc5b in mice deficient in autophagy regulatory protein, Atg16L1, and that this difference was not due to defects in the known baseline or stimulated mucin secretion pathways. Instead, we found that, in mucous secretory cells, Lc3/Lamp1 vesicles colocalized with mucin granules particularly adjacent to the nucleus, suggesting that some granules were being eliminated in the autophagy pathway rather than secreted. Using a mouse model of MM resolution, we found increased lysosomal proteolytic activity that peaked in the days after mucin production began to decline. In purified lysosomal fractions, Atg16L1-deficient mice had reduced proteolytic degradation of Lc3 and Sqstm1 and persistent accumulation of mucin granules associated with impaired resolution of mucous metaplasia. In normal and COPD derived human airway epithelial cells (AECs), activation of autophagy by mTOR inhibition led to a reduction of intracellular mucin granules in AECs. Our findings indicate that during peak and resolution phases of MM, autophagy activity rather than secretion is required for elimination of some remaining mucin granules. Manipulation of autophagy activation offers a therapeutic target to speed resolution of MM in airway disease exacerbations.

Procalcitonin predicts the severity of cystic fibrosis pulmonary exacerbations and readmissions in adult patients: a prospective cohort study

Patients with cystic fibrosis (CF) experience multiple pulmonary exacerbations throughout their lifetime, resulting in repeated antibiotic exposure and hospital admissions. Reliable diagnostic markers to guide antibiotic treatment in patients with CF, however, are lacking. Given that the CF airway is characterized by persistent and frequent bacterial infection, our goal was to determine if procalcitonin (PCT) could be used as a severity and prognostic marker of CF exacerbation. We enrolled 40 participants at the time of diagnosis of CF pulmonary exacerbation. Inclusion criteria: age ≥19 years with exacerbation requiring antibiotics as determined by the treating physician. Exclusion criteria: antibiotics initiated more than 48 hours prior to enrollment, and pregnancy. Blood samples were collected on enrollment day and after 7-10 days of treatment. Of the 40 patients enrolled, 23 (57.5%) had detectable levels of PCT (≥0.05 ng/mL). PCT levels were significantly associated with pulmonary exacerbation scores (p=0.01) and per cent decrease in forced expiratory volume in 1 second (FEV₁) (p=0.01) compared with the best in the last 12 months. Those who had worsening PCT during treatment had less improvement in FEV₁ (p=0.001) and were more likely to be readmitted to the hospital sooner (p<0.0001). Likewise, those who had a detectable PCT at the time of admission were more likely to be readmitted sooner (p=0.03). PCT elevation during antibiotic treatment is associated with less improvement in FEV₁ and earlier readmission. A detectable PCT level occurs only in more severe CF exacerbations. Multicenter trials are needed to confirm whether PCT may play a role in the clinical care of patients with CF.

MyD88 regulates a prolonged adaptation response to environmental dust exposure-induced lung disease

BACKGROUND

Environmental organic dust exposures enriched in Toll-like receptor (TLR) agonists can reduce allergic asthma development but are associated with occupational asthma and chronic bronchitis. The TLR adaptor protein myeloid differentiation factor88 (MyD88) is fundamental in regulating acute inflammatory responses to organic dust extract (ODE), yet its role in repetitive exposures is unknown and could inform future strategies.

METHODS

Wild-type (WT) and MyD88 knockout (KO) mice were exposed intranasally to ODE or saline daily for 3 weeks (repetitive exposure). Repetitively exposed animals were also subsequently rested with no treatments for 4 weeks followed by single rechallenge with saline/ODE.

RESULTS

Repetitive ODE exposure induced neutrophil influx and release of pro-inflammatory cytokines and chemokines were profoundly reduced in MyD88 KO mice. In comparison, ODE-induced cellular aggregates, B cells, mast cell infiltrates and serum IgE levels remained elevated in KO mice and mucous cell metaplasia was increased. Expression of ODE-induced tight junction protein(s) was also MyD88-dependent. Following recovery and then rechallenge with ODE, inflammatory mediators, but not neutrophil influx, was reduced in WT mice pretreated with ODE coincident with increased expression of IL-33 and IL-10, suggesting an adaptation response. Repetitively exposed MyD88 KO mice lacked inflammatory responsiveness upon ODE rechallenge.

CONCLUSIONS

MyD88 is essential in mediating the classic airway inflammatory response to repetitive ODE, but targeting MyD88 does not reduce mucous cell metaplasia, lymphocyte influx, or IgE responsiveness. TLR-enriched dust exposures induce a prolonged adaptation response that is largely MyD88-independent. These findings demonstrate the complex role of MyD88-dependent signaling during acute vs. chronic organic dust exposures.

Ovalbumin-sensitized mice have altered airway inflammation to agriculture organic dust

Agriculture exposures are associated with reducing the risk of allergy and asthma in early life; yet, repeated exposures later in life are associated with chronic bronchitis and obstructive pulmonary diseases. The objective of this study was to investigate the airway inflammatory response to organic dust extract (ODE) in mice with established ovalbumin (OVA)-induced experimental asthma. C57BL/6 mice were either OVA sensitized/aerosol-exposed or saline (Sal) sensitized/aerosol-challenged. Both groups were then subsequently challenged once with intranasal saline or swine confinement ODE to obtain 4 treatment groups of Sal-Sal, Sal-ODE, OVA-Sal, and OVA-ODE. Airway hyper-responsiveness (AHR) to methacholine, bronchiolar lavage fluid, lung tissues, and serum were collected. Intranasal inhalation of ODE in OVA-treated (asthmatic) mice (OVA-ODE) increased AHR and total cellular influx marked by elevated neutrophil and eosinophil counts. Flow cytometry analysis further demonstrated that populations of CD11chi dendritic cells (DC), CD3+ T cells, CD19+ B cells, and NKp46+ group 3 innate lymphoid cells (ILC3) were increased in lavage fluid of OVA-ODE mice as compared to ODE or OVA alone. Alveolar macrophages, DC, and T cells were significantly increased with co-exposure to OVA-ODE as compared to OVA alone. Lung ILC2 and ILC3 were only increased in OVA-Sal mice. Cytokine/chemokine levels varied with exposure to OVA-ODE reflecting an additive mixture of the pro- and allergic-inflammatory profiles. Collectively, ODE increased airway inflammatory cells and chemotactic mediator release in allergic (OVA) sensitized mice to suggest that persons with allergy/asthma be identified and warned prior to the occupational exposure of potentially worsening airway disease.

MyD88 controls airway epithelial Muc5ac expression during TLR activation conditions from agricultural organic dust exposure

Inflammation from airborne microbes can overwhelm compensatory mucociliary clearance mechanisms, leading to mucous cell metaplasia. Toll-like receptor (TLR) activation via myeloid differentiation factor 88 (MyD88) signaling is central to pathogen responses. We have previously shown that agricultural organic dust extract (ODE), with abundant microbial component diversity, activates TLR-induced airway inflammation. With the use of an established model, C57BL/6J wild-type (WT) and global MyD88 knockout (KO) mice were treated with intranasal inhalation of ODE or saline, daily for 1 wk. ODE primarily increased mucin (Muc)5ac levels relative to Muc5b. Compared with ODE-challenged WT mice, ODE-challenged, MyD88-deficient mice demonstrated significantly increased Muc5ac immunostaining, protein levels by immunoblot, and expression by quantitative PCR. The enhanced Muc5ac levels in MyD88-deficient mice were not explained by differences in the differentiation program of airway secretory cells in naïve mice. Increased Muc5ac levels in MyD88-deficient mice were also not explained by augmented inflammation, IL-17A, or neutrophil elastase levels. Furthermore, the enhanced airway mucins in the MyD88-deficient mice were not due to defective secretion, as the mucin secretory capacity of MyD88-KO mice remained intact. Finally, ODE-induced Muc5ac levels were enhanced in MyD88-deficient airway epithelial cells in vitro. In conclusion, MyD88 deficiency enhances airway mucous cell metaplasia under environments with high TLR activation.

Autophagy regulates DUOX1 localization and superoxide production in airway epithelial cells during chronic IL-13 stimulation

The airway epithelium is a broad interface with the environment, mandating well-orchestrated responses to properly modulate inflammation. Classically, autophagy is a homeostatic pathway triggered in response to external cellular stresses, and is elevated in chronic airway diseases. Recent findings highlight the additional role of autophagy in vesicle trafficking and protein secretion, implicating autophagy pathways in complex cellular responses in disease. Th2 cytokines, IL-13 and IL-4, are increased in asthma and other airway diseases contributing to chronic inflammation. Previously, we observed that IL-13 increases reactive oxygen species (ROS) in airway epithelial cells in an autophagy-dependent fashion. Here, we tested our hypothesis that autophagy is required for IL-13-mediated superoxide production via the NADPH oxidase DUOX1. Using a mouse model of Th2-mediated inflammation induced by OVA-allergen, we observed elevated lung amounts of IL-13 and IL-4 accompanied by increased autophagosome levels, determined by LC3BII protein levels and immunostaining. ROS levels were elevated and DUOX1 expression was increased 70-fold in OVA-challenged lungs. To address the role of autophagy and ROS in the airway epithelium, we treated primary human tracheobronchial epithelial cells with IL-13 or IL-4. Prolonged, 7-day treatment increased autophagosome formation and degradation, while brief activation had no effect. Under parallel culture conditions, IL-13 and IL-4 increased intracellular superoxide levels as determined by electron paramagnetic resonance (EPR) spectroscopy. Prolonged IL-13 activation increased DUOX1, localized at the apical membrane. Silencing DUOX1 by siRNA attenuated IL-13-mediated increases in superoxide, but did not reduce autophagy activities. Notably, depletion of autophagy regulatory protein ATG5 significantly reduced superoxide without diminishing total DUOX1 levels. Depletion of ATG5, however, diminished DUOX1 localization at the apical membrane. The findings suggest non-canonical autophagy activity regulates DUOX1-dependent localization required for intracellular superoxide production during Th2 inflammation. Thus, in chronic Th2 inflammatory airway disease, autophagy proteins may be responsible for persistent intracellular superoxide production.

The role of type 2 innate lymphoid cells in RSV-induced asthma exacerbation

Respiratory viral infections cause devastating airway inflammation and remodeling in asthmatic children and adults. Type 2 innate lymphoid cells (ILC2) have been characterized individually in both asthma and viral infections. We hypothesize that ILC2 are activated by IL-33 in our model, and thereby enhance the asthmatic phenotype in the lung. Asthma induction was performed in eight week old, female BALB/c mice using ovalbumin (OVA) sensitization and airway challenge. After the last airway challenge, mice were infected with RSV (3,250 TCID50 U/mouse). Lungs were collected for ILC2 sorting, immune cell quantitation, and analysis of IL-4, IL-13, IL-33 and IL-25 on days 1–4 of infection. A subset of lungs were collected and fixed for histological analysis. Results show that mucus production (PAS+ cells) and lymphocytic recruitment were enhanced with RSV infection and asthma. The expression of MUC5AC, CLCA3, IL-25 and IL-33 mRNA levels were increased at least two-fold in the lungs of OVA+RSV mice compared to RSV-infected alone. We detected comparable numbers of ILC2 in BAL fluid from both OVA+ and OVA+RSV mice, yet an evaluation of total lung lymphocytes yielded more ILC2 in the OVA+RSV mice as compared to OVA alone. ILC2 from OVA+RSV mice were sorted and treated with IL-33 for 24 hours. These cells produced greater IL-4 mRNA than cells isolated from OVA only mice. Our results describe a potential role for ILC2 in the exacerbation of asthma with RSV infection. Future studies are planned to determine the exact contribution of ILC2 to type 2 immunity and pulmonary function in our asthma-viral infection model.

IL13 activates autophagy to regulate secretion in airway epithelial cells

Cytokine modulation of autophagy is increasingly recognized in disease pathogenesis, and current concepts suggest that type 1 cytokines activate autophagy, whereas type 2 cytokines are inhibitory. However, this paradigm derives primarily from studies of immune cells and is poorly characterized in tissue cells, including sentinel epithelial cells that regulate the immune response. In particular, the type 2 cytokine IL13 (interleukin 13) drives the formation of airway goblet cells that secrete excess mucus as a characteristic feature of airway disease, but whether this process is influenced by autophagy was undefined. Here we use a mouse model of airway disease in which IL33 (interleukin 33) stimulation leads to IL13-dependent formation of airway goblet cells as tracked by levels of mucin MUC5AC (mucin 5AC, oligomeric mucus/gel forming), and we show that these cells manifest a block in mucus secretion in autophagy gene Atg16l1-deficient mice compared to wild-type control mice. Similarly, primary-culture human tracheal epithelial cells treated with IL13 to stimulate mucus formation also exhibit a block in MUC5AC secretion in cells depleted of autophagy gene ATG5 (autophagy-related 5) or ATG14 (autophagy-related 14) compared to nondepleted control cells. Our findings indicate that autophagy is essential for airway mucus secretion in a type 2, IL13-dependent immune disease process and thereby provide a novel therapeutic strategy for attenuating airway obstruction in hypersecretory inflammatory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis lung disease. Taken together, these observations suggest that the regulation of autophagy by Th2 cytokines is cell-context dependent.

11q22.3 deletion in B-chronic lymphocytic leukemia is specifically associated with bulky lymphadenopathy and ZAP-70 expression but not reduced expression of adhesion/cell surface receptor molecules

The presence of chromosome abnormalities promotes tumor progression in B-chronic lymphocytic leukemia (CLL). However, the molecular pathways that are relevant to tumor progression remain unclear. In this study, we screened for common chromosome abnormalities [13q14 del, 11q22.3 (ATM) del, 17p13 (p53) del and trisomy 12] by fluorescent in situ hybridization in 40 B-CLL patients. Each of the four chromosome abnormality groups was compared to several clinical factors related to lymphocyte behaviour in CLL. The 11q22.3 (ATM) deletion group was significantly associated with the presence of bulky abdominal/mediastinal lymphadenopathy (P = 0.014). We hypothesized that this phenotype would be associated with an altered transcription pattern of genes. Class comparison analysis by significance analysis of microarrays on a subset of CLL samples (n = 14) indicated that a number of cell surface receptor and adhesion related genes were under-expressed in the 11q22.3 deletion group (CD44, CD11a, PTPRC, CD79a, chemokine ligand 17 and chemokine receptor type 6). The presence of additional prognostic factors, such as CD38 and immunoglobulin heavy chain variable region mutational status, may also influence the transcriptional pathways between the two groups. Therefore, we employed a novel analysis technique for the correlation of log(2) gene expression ratios with the percentage of each tumor that carried the 11q22.3 deletion. Using Spearman's correlation, ZAP-70, chemokine ligand 17, BSAP (PAX5), CD7, LAG3 and PTPR6 were significantly correlated with the percentage of cells with the 11q22.3 deletion. However, the down-regulation of cell surface receptors and adhesion molecules observed by class comparison could not be confirmed to be specific for the 11q22.3 deletion by this method.

Hedgehog-induced survival of B-cell chronic lymphocytic leukemia cells in a stromal cell microenvironment: a potential new therapeutic target

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by an accumulation of neoplastic B cells due to their resistance to apoptosis and increased survival. Among various factors, the tumor microenvironment is known to play a role in the regulation of cell proliferation and survival of many cancers. However, it remains unclear how the tumor microenvironment contributes to the increased survival of B-CLL cells. Therefore, we studied the influence of bone marrow stromal cell-induced hedgehog (Hh) signaling on the survival of B-CLL cells. Our results show that a Hh signaling inhibitor, cyclopamine, inhibits bone marrow stromal cell-induced survival of B-CLL cells, suggesting a role for Hh signaling in the survival of B-CLL cells. Furthermore, gene expression profiling of primary B-CLL cells (n = 48) indicates that the expression of Hh signaling molecules, such as GLI1, GLI2, SUFU, and BCL2, is significantly increased and correlates with disease progression of B-CLL patients with clinical outcome. In addition, SUFU and GLI1 transcripts, as determined by real-time PCR, are significantly overexpressed and correlate with adverse indicators of clinical outcome in B-CLL patients, such as cytogenetics or CD38 expression. Furthermore, selective down-regulation of GLI1 by antisense oligodeoxynucleotides (GLI1-ASO) results in decreased BCL2 expression and cell survival, suggesting that GLI1 may regulate BCL2 and, thereby, modulate cell survival in B-CLL. In addition, there was significantly increased apoptosis of B-CLL cells when cultured in the presence of GLI1-ASO and fludarabine. Together, these results reveal that Hh signaling is important in the pathogenesis of B-CLL and, hence, may be a potential therapeutic target.

ATM, CTLA4, MNDA, and HEM1 in High versus Low CD38–Expressing B-Cell Chronic Lymphocytic Leukemia

PURPOSE

In B-cell chronic lymphocytic leukemia (CLL), high CD38 expression has been associated with unfavorable clinical course, advanced disease, resistance to therapy, shorter time to first treatment, and shorter survival. However, the genes associated with CLL patient subgroups with high and low CD38 expression and their potential role in disease progression is not known.

EXPERIMENTAL DESIGN

To identify the genes associated with the clinical disparity in CLL patients with high versus low CD38 expression, transcriptional profiles were obtained from CLL cells from 39 different patients using oligonucleotide microarray. Gene expression was also compared between CLL cells and B cells from healthy individuals.

RESULTS

Gene expression analysis identified 76 differentially expressed genes in CD38 high versus low groups. Out of these genes, HEM1, CTLA4, and MNDA were selected for further studies and their differential expression was confirmed by real-time PCR. HEM1 overexpression was associated with poor outcome, whereas the overexpression of CTLA4 and MNDA was associated with good outcome. Down-regulation of HEM1 expression in patient CLL cells resulted in a significant increase in their susceptibility to fludarabine-mediated killing. In addition, when gene expression patterns in CD38 high and low CLL cells were compared with normal B-cell profiles, ATM expression was found to be significantly lower in CD38 high compared with CD38 low CLL as confirmed by real-time reverse transcription-PCR.

CONCLUSIONS

These results identify the possible genes that may be involved in cell proliferation and survival and, thus, determining the clinical behavior of CLL patients expressing high or low CD38.

Bulky lymphadenopathy with poor clinical outcome is associated with ATM downregulation in B-cell chronic lymphocytic leukemia patients irrespective of 11q23 deletion

B-cell chronic lymphocytic leukemia (B-CLL) is the most common B-cell leukemia among older populations in Western countries. The clinical course of B-CLL is heterogeneous: in some patients the disease course is indolent, in others it is aggressive. The B-CLL subgroups with chromosome 11q23 deletion have been associated with aggressive disease course involving ATM deletion, extensive bulky lymphadenopathy (BLA), and inferior clinical outcome. Using real-time reverse transcriptase-polymerase chain reaction, we found that ATM was consistently underexpressed in B-CLL patients with BLA, irrespective of 11q23 deletion status. In addition, B-CLL patients who presented with BLA had a significantly shorter time to treatment (2 months) than did patients without BLA (74 months). Moreover, gene expression analysis in B-CLL patients with and without BLA revealed differences in expression for genes involved in apoptosis, cell cycle, and cell adhesion. These results indicate an association between BLA and reduced expression of ATM, suggesting a role for ATM in disease progression in B-CLL.

Genomic abnormalities in chronic lymphocytic leukemia influence gene expression by a gene dosage effect

This work describes the identification and impact of somatic genomic abnormalities in human chronic lymphocytic leukemia (CLL). Using molecular cytogenetics (FISH) and G-banding cytogenetic analysis, chromosome abnormalities were detected in 37 of 46 (80.4%) CLL patients. 13q14 deletion was the most common finding followed by trisomy 12 and 11q22.3 deletion. 17p13 deletion was also detected as were several less frequent chromosome abnormalities. The presence of these abnormalities significantly influenced the period of treatment-free survival as well as other clinical characteristics. In particular, CLL samples with trisomy 12 and 11q22.3 deletion were associated with shorter treatment-free survival. In order to identify the under-lying molecular differences among CLL subgroups with different chromosome abnormalities, gene expression profiling was performed on a custom DNA microarray consisting of 10,000 human gene-specific oligonucleotides. A gene dosage effect was observed where the expression of genes at the genetic loci of the sites of the somatic genomic abnormality was altered in a fashion according to the type of genomic change. This phenomenon was particularly evident in CLL samples with trisomy 12 and 17p13 deletion. Thus, this study demonstrates that genomic abnormalities influence gene expression in CLL by a dosage effect.

Unique gene expression and clinical characteristics are associated with the 11q23 deletion in chronic lymphocytic leukaemia

Chromosome abnormalities influence prognosis and tumour progression in B-cell Chronic Lymphocytic Leukaemia (CLL). This study sought to determine whether these different disease subgroups were associated with unique gene expression patterns. Thirty-four cases of CLL were screened for the 11q23, 13q14, 17p13 deletions, and trisomy 12 by fluorescence in situ hybridization (FISH). Expression of 205 cell signalling and apoptosis genes were compared by cDNA array among cases with different chromosome abnormalities. A majority of the statistically differentially expressed genes were present in the 11q23 deletion group by hierarchical clustering. CDC2, a serine/threonine kinase, was overexpressed in the 11q23 deletion group (P = 0.0004) and confirmed by Taqman real-time polymerase chain reaction. Several other genes associated with cell signalling were overexpressed in the 11q23 deletion group. A strong overall correlation existed between the presence of different chromosome abnormalities and a number of prognostic factors including immunoglobulin heavy chain variable region mutation status (P = 0.011), time to treatment (P = 0.025) and lymphocyte doubling time (P = 0.034). This study confirmed the prognostic impact of chromosome abnormalities identified by FISH in CLL, particularly the 11q23 deletion and trisomy 12. In addition, the 11q23 deletion group was associated with a unique gene expression pattern involving cell signalling and apoptosis genes.

Surgical removal of subfoveal choroidal neovascularization in presumed ocular histoplasmosis: stability of early visual results

PURPOSE

The authors assess the stability of visual acuity outcomes after the surgical removal of subfoveal choroidal neovascularization in a large series of patients with presumed ocular histoplasmosis syndrome (POHS).

METHODS

A retrospective study of 117 consecutive patients undergoing vitrectomy between February 1990 and December 1994 was performed. All patients underwent the surgical removal of subfoveal choroidal neovascularization due to POHS and had at least 3 months of follow-up. Postoperative Snellen visual acuity was the primary study endpoint.

RESULTS

With a median follow-up of 13 months (range, 3-46 months), 35% of patients had postoperative visual acuity of 20/40 or better, and 40% had improvement of three or more Snellen lines after surgery. In a subset of 54 eyes followed for at least 1 year, 91% showed stable or improved vision between the 3- and 12-month time points, and 85% showed stable or improved vision between 3 months and final visit.

CONCLUSION

Follow-up of a large number of patients appears to confirm initially encouraging results and to suggest stability of beneficial effect after the surgical removal of subfoveal choroidal neovascularization in POHS.

Managing recurrent neovascularization after subfoveal surgery in presumed ocular histoplasmosis syndrome

PURPOSE

To report the authors' experience with recurrent neovascularization after subfoveal surgery in the presumed ocular histoplasmosis syndrome (POHS).

METHODS

One-hundred seventeen patients with POHS and subfoveal choroidal neovascularization were followed a median of 13 months after submacular surgery.

RESULTS

Recurrent neovascularization developed in 51 eyes (44%). The median time to recurrence was 3 months (range, 0.5-28 months). Recurrence location was extrafoveal in 16%, juxtafoveal in 18%, and subfoveal in 66%. Sixteen eyes were treated with laser photocoagulation, 17 eyes underwent repeat submacular surgery, and 18 eyes were observed. The visual outcome for patients with recurrences amenable to laser was better than that for patients who were observed or who underwent surgery.

CONCLUSION

Recurrent neovascularization after surgery is common; prompt recognition may allow laser photocoagulation.

Visual results after surgical removal of subfoveal choroidal neovascular membranes

PURPOSE

The authors report their experience with the surgical removal of subfoveal choroidal neovascularization. Correlations between preoperative characteristics and final postoperative visual acuity are explored.

METHODS

A retrospective study of 159 consecutive patients was performed between February 1990 and August 1993. Follow-up of 2 or more months was available for 147 eyes: presumed ocular histoplasmosis syndrome, 67 eyes; age-related macular degeneration, 41 eyes; myopia, 10 eyes; multifocal choroiditis, 9 eyes; idiopathic, 8 eyes; angioid streaks, 4 eyes; and miscellaneous, 8 eyes.

RESULTS

Sixty-seven eyes had presumed ocular histoplasmosis syndrome: mean follow-up was 10.5 months. Visual acuity was stable or improved in 56 (83%) eyes and 20/40 or greater in 21 (31%) eyes. Mean interval to best visual acuity was 3 months. A recurrence rate of 37% had no significant effect on final visual outcome (P = 0.952). Forty-one eyes had age-related macular degeneration: mean follow-up was 15 months. Visual acuity was improved in only five (12%) eyes and was 20/40 or greater in only two (5%) eyes. The interval to best visual acuity was 5 months. A recurrence rate of 27% had not significant effect on final visual outcome (P = 0.31). The visual results and recurrence rates for eyes with less common disorders are presented.

CONCLUSION

The surgical excision of subfoveal choroidal neovascularization may stabilize or improve visual acuity in selected cases. Patients with focal disorders of the retinal pigment epithelium-Bruch's membrane complex appear to have a better surgical outcome than those with diffuse disease.