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Rationale: Epidemiologic studies have demonstrated that exposure to molds and other fungi can play a role in a variety of allergic and pulmonary diseases in susceptible individuals. Species-specific mold antigen extracts are used in the clinical evaluation of suspected mold-related conditions; however, alignment between these extracts and the species of molds identified in the indoor environment of water-damaged homes has not been rigorously evaluated. Objectives: To identify the predominant genera and species of mold in the air of homes with water damage, mold growth, and/or occupants with respiratory complaints (complaint homes), and to assess their alignment with the mold antigen extracts used in clinical practice. Methods: The genera and species of molds identified in culture-type outdoor and indoor air samples collected from complaint homes throughout the United States and Canada from 2002 to 2017 were examined. Mold antigen extracts available and utilized for skin and serum testing in clinical practice were assessed, and alignment between these data were evaluated. Results: Culture data from 24,455 indoor air samples from 7,547 complaint homes and 29,493 outdoor samples were evaluated. Mean exposure values (colony-forming units [cfu]/m 3 ) were calculated for each genus and species and indoor versus outdoor values were compared. Penicillium was the predominant genus identified in water-damaged homes, with a mean exposure (233.3 cfu/m 3 ) 2.9 times higher than that of the Aspergillus genus (81.4 cfu/m 3 ). Five Penicillium ( P. aurantiogriseum , P. brevicompactum , P. citrinum , P. crustosum , and P. variabile ) and three Aspergillus ( A. versicolor , A. sydowii , and A. niger ) species were identified as the predominant indoor water-damage-related fungi. However, none of these Penicillium species and only one of the Aspergillus species is currently available as an antigen extract for use in skin testing or serum testing panels. Conclusions: Significant misalignment exists between the currently available mold antigen extracts and the predominant species of molds found in water-damaged homes. Improving alignment has the potential to enhance diagnosis of mold-related diseases, including allergic asthma and hypersensitivity pneumonitis and to improve patient outcomes via interventions, including antigen avoidance through building remediation and occupant relocation, consistent with the findings of a recent American Thoracic Society Workshop Report.

With highly active anti-retroviral therapy (HAART), higher incidence of airway abnormalities is common in the HIV population consistent with the concept of accelerated lung "aging". Our previous findings demonstrated that HIV induces human airway basal cells (BC) into destructive and inflammatory phenotypes. Since BC function as stem/progenitor cells of the small airway epithelium (SAE), responsible for self-renewal and differentiation of SAE, we hypothesized that BC from people living with HIV (PLWH) may have altered differentiation capacity that contribute to premature aging. The data demonstrates that BC from PLWH have impaired capacity to differentiate in vitro and senescent phenotypes including shortened telomeres, increased expression of β-galactosidase and cell cycle inhibitors, and mitochondrial dysfunction. In vitro studies demonstrated that BC senescence is partly due to adverse effects of HAART on BC. These findings provide an explanation for higher incidence of airway dysfunction and accelerated lung aging observed in PLWH., (© 2022. The Author(s).)

The club cell, a small airway epithelial (SAE) cell, plays a central role in human lung host defense. We hypothesized that subpopulations of club cells with distinct functions may exist. The SAE of healthy nonsmokers and healthy cigarette smokers were evaluated by single-cell RNA sequencing, and unsupervised clustering revealed subpopulations of SCGCB1A1 + KRT5 lo MUC5AC - club cells. Club cell heterogeneity was supported by evaluations of SAE tissue sections, brushed SAE cells, and in vitro air-liquid interface cultures. Three subpopulations included: (1) progenitor; (2) proliferating; and (3) effector club cells. The progenitor club cell population expressed high levels of mitochondrial, ribosomal proteins, and KRT5 relative to other club cell populations and included a differentiation branch point leading to mucous cell production. The small proliferating population expressed high levels of cyclins and proliferation markers. The effector club cell cluster expressed genes related to host defense, xenobiotic metabolism, and barrier functions associated with club cell function. Comparison of smokers vs. nonsmokers demonstrated that smoking limited the extent of differentiation of all three subclusters and altered SAM pointed domain-containing Ets transcription factor (SPDEF)-regulated transcription in the effector cell population leading to a change in the location of the branch point for mucous cell production, a potential explanation for the concomitant reduction in effector club cells and increase in mucous cells in smokers. These observations provide insights into both the makeup of human SAE club cell subpopulations and the smoking-induced changes in club cell biology., (© 2021. The Author(s).)

Background: The first step in SARS-CoV-2 infection is binding of the virus to angiotensin converting enzyme 2 (ACE2) on the airway epithelium. Asthma affects over 300 million people world-wide, many of whom may encounter SARS-CoV-2. Epidemiologic data suggests that asthmatics who get infected may be at increased risk of more severe disease. Our objective was to assess whether maintenance inhaled corticosteroids (ICS), a major treatment for asthma, is associated with airway ACE2 expression in asthmatics., Methods: Large airway epithelium (LAE) of asthmatics treated with maintenance ICS (ICS + ), asthmatics not treated with ICS (ICS - ), and healthy controls (controls) was analyzed for expression of ACE2 and other coronavirus infection-related genes using microarrays., Results: As a group, there was no difference in LAE ACE2 expression in all asthmatics vs controls. In contrast, subgroup analysis demonstrated that LAE ACE2 expression was higher in asthmatics ICS + compared to ICS‾ and ACE2 expression was higher in male ICS + compared to female ICS + and ICS‾ of either sex. ACE2 expression did not correlate with serum IgE, absolute eosinophil level, or change in FEV1 in response to bronchodilators in either ICS - or ICS + ., Conclusion: Airway ACE2 expression is increased in asthmatics on long-term treatment with ICS, an observation that should be taken into consideration when assessing the use of inhaled corticosteroids during the pandemic.

Despite the introduction of anti-retroviral therapy, chronic HIV infection is associated with an increased incidence of other comorbidities such as COPD. Based on the knowledge that binding of HIV to human airway basal stem/progenitor cells (BC) induces a destructive phenotype by increased MMP-9 expression through MAPK signaling pathways, we hypothesized that HIV induces the BC to express inflammatory mediators that contribute to the pathogenesis of emphysema. Our data demonstrate that airway BC isolated from HAART-treated HIV + nonsmokers spontaneously release inflammatory mediators IL-8, IL-1β, ICAM-1 and GM-CSF. Similarly, exposure of normal BC to HIV in vitro up-regulates expression of the same inflammatory mediators. These HIV-BC derived mediators induce migration of alveolar macrophages (AM) and neutrophils and stimulate AM proliferation. This HIV-induced inflammatory phenotype likely contributes to lung inflammation in HIV + individuals and provides explanation for the increased incidence of COPD in HIV + individuals.

COPD, chronic bronchitis (CB) and active smoking have all been associated with goblet cell hyperplasia (GCH) in small studies. Active smoking is strongly associated with CB, but there is a disconnect between CB clinical symptoms and pathology. Chronic cough and sputum production poorly correlate with the presence of GCH or COPD. We hypothesized that the primary determinant of GCH in ever smokers with or without airflow obstruction is active smoking. Goblet Cell Density (GCD) was measured in 71 current or former smokers [32 subjects without COPD and 39 COPD subjects]. Endobronchial mucosal biopsies were stained with Periodic Acid Schiff-Alcian Blue, and GCD was measured as number of goblet cells/mm basement membrane. GCD was divided into tertiles based on log 10 transformed values. Log 10 GCD was greater in current smokers compared to former smokers. Those with classically defined CB or SGRQ defined CB had a greater log 10 GCD compared to those without CB. Current smoking was independently associated with tertile 3 (high log 10 GCD) whereas CB was not in multivariable regression when adjusting for lung function and demographics. These results suggest that GCH is induced by active smoke exposure and does not necessarily correlate with the clinical symptoms of CB.

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic fibrotic lung disease with an irreversible decline of lung function. "Bronchiolization", characterized by ectopic appearance of airway epithelial cells in the alveolar regions, is one of the characteristic features in the IPF lung. Based on the knowledge that club cells are the major epithelial secretory cells in human small airways, and their major secretory product uteroglobin (SCGB1A1) is significantly increased in both serum and epithelial lining fluid of IPF lung, we hypothesize that human airway club cells contribute to the pathogenesis of IPF. By assessing the transcriptomes of the single cells from human lung of control donors and IPF patients, we identified two SCGB1A1+ club cell subpopulations, highly expressing MUC5B, a significant genetic risk factor strongly associated with IPF, and SCGB3A2, a marker heterogeneously expressed in the club cells, respectively. Interestingly, the cellular proportion of SCGB1A1+MUC5B+ club cells was significantly increased in IPF patients, and this club cell subpopulation highly expressed genes related to mucous production and immune cell chemotaxis. In contrast, though the cellular proportion did not change, the molecular phenotype of the SCGB1A1+SCGB3A2high club cell subpopulation was significantly altered in IPF lung, with increased expression of mucins, cytokine and extracellular matrix genes. The single cell transcriptomic analysis reveals the cellular and molecular heterogeneity of club cells, and provide novel insights into the biological functions of club cells in the pathogenesis of IPF., Competing Interests: K. Quast, S. Visvanathan, JS Fine, MJ Thomas are employees of Boehringer Ingelheim Pharmaceuticals; all other authors declare no conflict of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: The human small airway epithelium (SAE) plays a central role in the early events in the pathogenesis of most inherited and acquired lung disorders. Little is known about the molecular phenotypes of the specific cell populations comprising the SAE in humans, and the contribution of SAE specific cell populations to the risk for lung diseases., Methods: Drop-seq single-cell RNA-sequencing was used to characterize the transcriptome of single cells from human SAE of nonsmokers and smokers by bronchoscopic brushing., Results: Eleven distinct cell populations were identified, including major and rare epithelial cells, and immune/inflammatory cells. There was cell type-specific expression of genes relevant to the risk of the inherited pulmonary disorders, genes associated with risk of chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis and (non-mutated) driver genes for lung cancers. Cigarette smoking significantly altered the cell type-specific transcriptomes and disease risk-related genes., Conclusions: This data provides new insights into the possible contribution of specific lung cells to the pathogenesis of lung disorders.

Rationale: Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease (COVID-19), a predominantly respiratory illness. The first step in SARS-CoV-2 infection is binding of the virus to ACE2 (angiotensin-converting enzyme 2) on the airway epithelium. Objectives: The objective was to gain insight into the expression of ACE2 in the human airway epithelium. Methods: Airway epithelia sampled by fiberoptic bronchoscopy of trachea, large airway epithelia (LAE), and small airway epithelia (SAE) of nonsmokers and smokers were analyzed for expression of ACE2 and other coronavirus infection-related genes using microarray, RNA sequencing, and 10x single-cell transcriptome analysis, with associated examination of ACE2 -related microRNA. Measurements and Main Results: 1 ) ACE2 is expressed similarly in the trachea and LAE, with lower expression in the SAE; 2 ) in the SAE, ACE2 is expressed in basal, intermediate, club, mucus, and ciliated cells; 3 ) ACE2 is upregulated in the SAE by smoking, significantly in men; 4 ) levels of miR-1246 expression could play a role in ACE2 upregulation in the SAE of smokers; and 5 ) ACE2 is expressed in airway epithelium differentiated in vitro on air-liquid interface cultures from primary airway basal stem/progenitor cells; this can be replicated using LAE and SAE immortalized basal cell lines derived from healthy nonsmokers. Conclusions: ACE2 , the gene encoding the receptor for SARS-CoV-2, is expressed in the human airway epithelium, with variations in expression relevant to the biology of initial steps in SARS-CoV-2 infection.

Purpose: Diaphragmatic paralysis (DP) is an important cause of dyspnea with many underlying etiologies; however, frequently no cause is identified despite extensive investigation. We hypothesized that cervical spondylosis (CS), as manifest by cervical neuroforaminal stenosis on magnetic resonance imaging (MRI), is an underrecognized cause of unilateral DP., Methods: A retrospective study was performed assessing cervical spine imaging utilization in the investigation of unilateral DP, and the contribution of CS to its pathogenesis. To assess the relationship between CS and DP, comparison was made between severity of ipsilateral and contralateral foraminal stenosis on cervical spine MRI in individuals with idiopathic DP, and to controls with DP of known etiology., Results: Record searches identified 334 individuals with DP who were classified as idiopathic (n = 101) or DP of known etiology (n = 233). Of those with idiopathic DP, only 37% had undergone cervical spine imaging. Cervical spine MRIs, available for 32 individuals from the total cohort identified (n = 15 idiopathic DP, n = 17 DP of known etiology), were reviewed and severity of CS graded (0-2). In idiopathic DP, CS was significantly more severe (grade 2 stenosis) on the side of DP at C3-C4 (73% affected vs 13% unaffected side; p = 0.031) and C4-C5 (60% affected vs 20% unaffected side; p = 0.0039), while no difference was observed in DP of known etiology. Overall severity of CS across all cervical spine levels was significantly worse in idiopathic DP versus those with DP of known etiology., Conclusions: In unilateral idiopathic DP, severity of CS is associated with DP laterality and is an underrecognized cause of diaphragmatic dysfunction. We propose that evaluation of 'idiopathic' DP should routinely include cervical spine imaging, preferably by MRI.

Background: KRAS is a GTPase that activates pathways involved in cell growth, differentiation and survival. In normal cells, KRAS-activity is tightly controlled, but with specific mutations, the KRAS protein is persistently activated, giving cells a growth advantage resulting in cancer. While a great deal of attention has been focused on the role of mutated KRAS as a common driver mutation for lung adenocarcinoma, little is known about the role of KRAS in regulating normal human airway differentiation., Methods: To assess the role of KRAS signaling in regulating differentiation of the human airway epithelium, primary human airway basal stem/progenitor cells (BC) from nonsmokers were cultured on air-liquid interface (ALI) cultures to mimic the airway epithelium in vitro. Modulation of KRAS signaling was achieved using siRNA-mediated knockdown of KRAS or lentivirus-mediated over-expression of wild-type KRAS or the constitutively active G12 V mutant. The impact on differentiation was quantified using TaqMan quantitative PCR, immunofluorescent and immunohistochemical staining analysis for cell type specific markers. Finally, the impact of cigarette smoke exposure on KRAS and RAS protein family activity in the airway epithelium was assessed in vitro and in vivo., Results: siRNA-mediated knockdown of KRAS decreased differentiation of BC into secretory and ciliated cells with a corresponding shift toward squamous cell differentiation. Conversely, activation of KRAS signaling via lentivirus mediated over-expression of the constitutively active G12 V KRAS mutant had the opposite effect, resulting in increased secretory and ciliated cell differentiation and decreased squamous cell differentiation. Exposure of BC to cigarette smoke extract increased KRAS and RAS protein family activation in vitro. Consistent with these observations, airway epithelium brushed from healthy smokers had elevated RAS activation compared to nonsmokers., Conclusions: Together, these data suggest that KRAS-dependent signaling plays an important role in regulating the balance of secretory, ciliated and squamous cell differentiation of the human airway epithelium and that cigarette smoking-induced airway epithelial remodeling is mediated in part by abnormal activation of KRAS-dependent signaling mechanisms.

Airway remodelling in chronic obstructive pulmonary disease (COPD) originates, in part, from smoking-induced changes in airway basal stem/progenitor cells (BCs). Based on the knowledge that bone morphogenetic protein 4 (BMP4) influences epithelial progenitor function in the developing and adult mouse lung, we hypothesised that BMP4 signalling may regulate the biology of adult human airway BCs relevant to COPD.BMP4 signalling components in human airway epithelium were analysed at the mRNA and protein levels, and the differentiation of BCs was assessed using the BC expansion and air-liquid interface models in the absence/presence of BMP4, BMP receptor inhibitor and/or small interfering RNAs against BMP receptors and downstream signalling.The data demonstrate that in cigarette smokers, BMP4 is upregulated in ciliated and intermediate undifferentiated cells, and expression of the BMP4 receptor BMPR1A is enriched in BCs. BMP4 induced BCs to acquire a smoking-related abnormal phenotype in vitro mediated by BMPR1A/Smad signalling, characterised by decreased capacity to differentiate into normal mucociliary epithelium, while generating squamous metaplasia.Exaggerated BMP4 signalling promotes cigarette smoking-relevant airway epithelial remodelling by inducing abnormal phenotypes in human airway BCs. Targeting of BMP4 signalling in airway BCs may represent a novel target to prevent/treat COPD-associated airway disease., Competing Interests: Conflict of interest: W-L. Zuo has nothing to disclose. Conflict of interest: J. Yang has nothing to disclose. Conflict of interest: Y. Strulovici-Barel has nothing to disclose. Conflict of interest: J. Salit has nothing to disclose. Conflict of interest: M. Rostami has nothing to disclose. Conflict of interest: J.G. Mezey has nothing to disclose. Conflict of interest: S.L. O'Beirne has nothing to disclose. Conflict of interest: R.J. Kaner has nothing to disclose. Conflict of interest: R.G. Crystal has nothing to disclose., (Copyright ©ERS 2019.)

Rationale: There is an unmet need to investigate the lower airways in chronic obstructive pulmonary disease (COPD) to define pathogenesis and to identify potential markers to accelerate therapeutic development. Although bronchoscopy is well established to sample airways in various conditions, a comprehensive COPD research protocol has yet to be published., Objectives: To evaluate the safety and tolerability of a comprehensive research bronchoscopy procedure suitable for multicenter trials and to identify factors associated with adverse events., Methods: We report the detailed methodology used to conduct the bronchoscopy used in SPIROMICS (the Subpopulations and Intermediate Outcome Measures in COPD Study). The protocol entailed collection of tongue scrapings and oral rinses as well as bronchoscopy with airway inspection, bronchoalveolar lavage (BAL), protected brushings, and endobronchial biopsies. Visual airway characteristics were graded on a scale of 0 (normal appearance) to 3 (severe abnormality) in four domains: erythema, edema, secretions, and friability. Adverse events were defined as events requiring intervention. Logistic regression modeling assessed associations between adverse event occurrence and key variables., Results: We enrolled 215 participants. They were 61 ± 9 years old, 71% were white, 53% were male, and post-bronchodilator forced expiratory volume in 1 second was 89 ± 19% predicted. Self-reported asthma was present in 22% of bronchoscopy participants. Oral samples were obtained in greater than or equal to 99% of participants. Airway characteristics were recorded in 99% and were most often characterized as free of edema (61.9%). Less than 50% reported secretions, friability, or erythema. BAL yielded 111 ± 57 ml (50%) of the 223 ± 65 ml of infusate, brushes were completed in 98%, and endobronchial biopsies were performed in 82% of procedures. Adverse events requiring intervention occurred in 14 (6.7%) of 208 bronchoscopies. In logistic regression models, female sex (risk ratio [RR], 1.10; 95% confidence interval [CI], 1.02-1.19), self-reported asthma (RR, 1.17; 95% CI, 1.02-1.34), bronchodilator reversibility (RR, 1.17; 95% CI, 1.04-1.32), COPD (RR, 1.10; 95% CI, 1.02-1.20), forced expiratory volume in 1 second (RR, 0.97; 95% CI, 0.95-0.99), and secretions (RR, 1.85; 1.08-3.16) or friability (RR, 1.64; 95% CI, 1.04-2.57) observed during bronchoscopy were associated with adverse events., Conclusions: A research bronchoscopy procedure that includes oral sampling, BAL, endobronchial biopsy, and brushing can be safely performed. Airway characteristics during bronchoscopy, demographics, asthma or COPD, and lung function may convey increased risk for procedure-related events necessitating intervention.

Rationale: Little is known about human club cells, dome-shaped cells with dense cytoplasmic granules and microvilli that represent the major secretory cells of the human small airways (at least sixth-generation bronchi)., Objectives: To define the ontogeny and biology of the human small airway epithelium club cell., Methods: The small airway epithelium was sampled from the normal human lung by bronchoscopy and brushing. Single-cell transcriptome analysis and air-liquid interface culture were used to assess club cell ontogeny and biology., Measurements and Main Results: We identified the club cell population by unbiased clustering using single-cell transcriptome sequencing. Principal component gradient analysis uncovered an ontologic link between KRT5 (keratin 5) + basal cells and SCGB1A1 (secretoglobin family 1A member 1) + club cells, a hypothesis verified by demonstrating in vitro that a pure population of human KRT5 + SCGB1A1 - small airway epithelial basal cells differentiate into SCGB1A1 + KRT5 - club cells on air-liquid interface culture. Using SCGB1A1 as the marker of club cells, the single-cell analysis identified novel roles for these cells in host defense, xenobiotic metabolism, antiprotease, physical barrier function, monogenic lung disorders, and receptors for human viruses., Conclusions: These observations provide novel insights into the molecular phenotype and biologic functions of the human club cell population and identify basal cells as the human progenitor cells for club cells.

Rationale: Epidemiologic studies have demonstrated that exposure to particulate matter ambient pollution has adverse effects on lung health, exacerbated by cigarette smoking. Particulate matter less than or equal to 2.5 μm in aerodynamic diameter (PM 2.5 ) is among the most harmful urban pollutants and is closely linked to respiratory disease., Objectives: Based on the knowledge that the small airway epithelium (SAE) plays a central role in the pathogenesis of smoking-related lung disease, we hypothesized that elevated PM 2.5 levels are associated with dysregulation of SAE gene expression, which may contribute to the development of respiratory disease., Methods: From 2009 to 2012, healthy nonsmoker (n = 29) and smoker (n = 129) residents of New York City underwent bronchoscopy with SAE brushing (2.6 ± 1.3 samples/subject; total of 405 samples). SAE gene expression was assessed by Affymetrix HG-U133 Plus 2.0 microarray. New York City PM 2.5 levels (Environmental Protection Agency data) were averaged for the 30 days before bronchoscopy. A linear mixed model was used to assess PM 2.5 -related gene dysregulation accounting for multiple clinical and methodologic variables., Measurements and Main Results: Thirty-day mean PM 2.5 levels varied from 6.2 to 18 μg/m 3 . In nonsmokers, there was no dysregulation of SAE gene expression associated with ambient PM 2.5 levels. In marked contrast, n = 219 genes were significantly dysregulated in association with PM 2.5 levels in the SAE of smokers. Many of these genes relate to cell growth and transcription regulation. Interestingly, 11% of genes were mitochondria associated., Conclusions: PM 2.5 exposure contributes to significant dysregulation of the SAE transcriptome of smokers, linking pollution and airway epithelial biology in the risk of development of respiratory disease in susceptible individuals.

Background: Type 2 diabetes (T2D) susceptibility is influenced by genetic and lifestyle factors. To date, the majority of genetic studies of T2D have been in populations of European and Asian descent. The focus of this study is on genetic variations underlying T2D in Qataris, a population with one of the highest incidences of T2D worldwide., Results: Illumina HiSeq exome sequencing was performed on 864 Qatari subjects (574 T2D cases, 290 controls). Sequence kernel association test (SKAT) gene-based analysis identified an association for low frequency potentially deleterious variants in 6 genes. However, these findings were not replicated by SKAT analysis in an independent cohort of 12,699 exomes, primarly due to the absence of low frequency potentially deleterious variants in 5 of the 6 genes. Interestingly one of the genes identified, catenin beta 1 (CTNNB1, β-catenin), is the key effector of the Wnt pathway and interacts with the nuclear receptor transcription factor 7-like 2 (TCF7L2), variants which are the most strongly associated with risk of developing T2D worldwide. Single variant analysis did not identify any associated variants, suggesting the SKAT association signal was not driven by individual variants. None of the 6 associated genes were among 634 previously described T2D genes., Conclusions: The observation that genes not previously linked to T2D in prior studies of European and Asian populations are associated with T2D in Qatar provides new insights into the complexity of T2D pathogenesis and emphasizes the importance of understudied populations when assessing genetic variation in the pathogenesis of common disorders., Competing Interests: The authors have declared that no competing interests exist.

Background: Though the skin is affected in sarcoidosis in about one-third of cases, granulomatous tattoo reactions are an unusual manifestation of the disease. It is important phenomenon to recognize, as it frequently leads to the diagnosis of systemic sarcoidosis., Case Presentation: A 35-year-old Caucasian female with multiple tattoos presented with a 5-week history of tenderness of the black dye in a tattoo depicting a dragon. She also described a 15-month history of fatigue, polyarthralgia, and mild dyspnea. Skin biopsy demonstrated multiple dermal non-caseating granulomata with associated tattoo ink. Further investigation revealed the presence of systemic sarcoidosis. Her symptoms and skin changes improved with conservative management., Conclusion: Sarcoidal tattoo reactions in those without systemic sarcoidosis are a rare occurrence, and their presence should prompt a search for systemic involvement. The accurate identification of skin involvement in sarcoidosis is important, as it tends to occur early in the course of disease, and the skin is a readily accessible site for biopsy, allowing for prompt diagnosis.

Background: The prevalence of type 2 diabetes (T2D) is increasing in the Middle East. However, the genetic risk factors for T2D in the Middle Eastern populations are not known, as the majority of studies of genetic risk for T2D are in Europeans and Asians., Methods: All subjects were ≥3 generation Qataris. Cases with T2D (n = 1,124) and controls (n = 590) were randomly recruited and assigned to the 3 known Qatari genetic subpopulations [Bedouin (Q1), Persian/South Asian (Q2) and African (Q3)]. Subjects underwent genotyping for 37 single nucleotide polymorphisms (SNPs) in 29 genes known to be associated with T2D in Europeans and/or Asian populations, and an additional 27 tag SNPs related to these susceptibility loci. Pre-study power analysis suggested that with the known incidence of T2D in adult Qataris (22%), the study population size would be sufficient to detect significant differences if the SNPs were risk factors among Qataris, assuming that the odds ratio (OR) for T2D SNPs in Qatari's is greater than or equal to the SNP with highest known OR in other populations., Results: Haplotype analysis demonstrated that Qatari haplotypes in the region of known T2D risk alleles in Q1 and Q2 genetic subpopulations were similar to European haplotypes. After Benjamini-Hochberg adjustment for multiple testing, only two SNPs (rs7903146 and rs4506565), both associated with transcription factor 7-like 2 (TCF7L2), achieved statistical significance in the whole study population. When T2D subjects and control subjects were assigned to the known 3 Qatari subpopulations, and analyzed individually and with the Q1 and Q2 genetic subpopulations combined, one of these SNPs (rs4506565) was also significant in the admixed group. No other SNPs associated with T2D in all Qataris or individual genetic subpopulations., Conclusions: With the caveats of the power analysis, the European/Asian T2D SNPs do not contribute significantly to the high prevalence of T2D in the Qatari population, suggesting that the genetic risks for T2D are likely different in Qataris compared to Europeans and Asians.

An 82-year-old Japanese nonsmoking man presented with persistent dry cough and small left apical pneumothorax. High resolution CT scan of the chest demonstrated bilateral upper lobe pleuroparenchymal thickening and architectural distortion. Serial imaging revealed mild progression and development of small bilateral pneumothoraces, and pneumomediastinum. A surgical lung biopsy was required to confirm the diagnosis., (Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Epithelial to mesenchymal cell transition (EMT), whereby fully differentiated epithelial cells transition to a mesenchymal phenotype, has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). CXCR3 and its ligands are recognized to play a protective role in pulmonary fibrosis. In this study, we investigated the presence and extent of EMT and CXCR3 expression in human IPF surgical lung biopsies and assessed whether CXCR3 and its ligand CXCL9 modulate EMT in alveolar epithelial cells. Coexpression of the epithelial marker thyroid transcription factor-1 and the mesenchymal marker α-smooth muscle actin and CXCR3 expression was examined by immunohistochemical staining of IPF surgical lung biopsies. Epithelial and mesenchymal marker expression was examined by quantitative real-time PCR, Western blotting, and immunofluorescence in human alveolar epithelial (A549) cells treated with TGF-β1 and CXCL9, with Smad2, Smad3, and Smad7 expression and cellular localization examined by Western blotting. We found that significantly more cells were undergoing EMT in fibrotic versus normal areas of lung in IPF surgical lung biopsy samples. CXCR3 was expressed by type II pneumocytes and fibroblasts in fibrotic areas in close proximity to cells undergoing EMT. In vitro, CXCL9 abrogated TGF-β1-induced EMT. A decrease in TGF-β1-induced phosphorylation of Smad2 and Smad3 occurred with CXCL9 treatment. This was associated with increased shuttling of Smad7 from the nucleus to the cytoplasm where it inhibits Smad phosphorylation. This suggests a role for EMT in the pathogenesis of IPF and provides a novel mechanism for the inhibitory effects of CXCL9 on TGF-β1-induced EMT., (Copyright © 2015 by The American Association of Immunologists, Inc.)

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by fibrosis and abnormal vascularity. IL-13, a profibrotic cytokine that plays a role in IPF, functions through the Jak/STAT pathway after binding to the IL-13 receptor α1 (IL-13Rα1)/IL-4Rα complex. IL-13 also binds to IL-13Rα2, which has been thought to function as a nonsignaling decoy receptor, although possible signaling roles of this receptor have been proposed. CXCR3 and its IFN-inducible ligands-CXCL9, CXCL10, and CXCL11-have been implicated in vascular remodeling and fibroblast motility during the development of IPF. In this study, CXCR3 expression was demonstrated in cultured pulmonary fibroblasts from wild-type BALB/c mice and was found to be necessary for the IL-13-mediated gene and protein up-regulation of IL-13Rα2. In fibroblasts from CXCR3-deficient mice, STAT6 activation was prolonged. This study is the first to demonstrate the expression of CXCR3 in fibroblasts and its association with the expression of IL-13Rα2. Taken together, the results from this study point strongly to a requirement for CXCR3 for IL-13-mediated IL-13Rα2 gene expression. Understanding the function of CXCR3 in IL-13-mediated lung injury may lead to novel approaches to combat the development of pulmonary fibrosis, whether by limiting the effects of IL-13 or by manipulation of angiostatic pathways. The elucidation of the complex relationship between these antifibrotic receptors and manipulation of the CXCR3-mediated regulation of IL-13Rα2 may represent a novel therapeutic modality in cases of acute lung injury or chronic inflammation that may progress to fibrosis.

Background: Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of macro- and micro-blood vessels. In this study our primary objective is to explore the role of SLMAP gene polymorphisms in the susceptibility of type 2 diabetes (T2DM) with or without diabetic retinopathy (DR) in the Qatari population., Methods: A total of 342 Qatari subjects (non-diabetic controls and T2DM patients with or without DR) were genotyped for SLMAP gene polymorphisms (rs17058639 C > T; rs1043045 C > T and rs1057719 A > G) using Taqman SNP genotyping assay., Results: SLMAP rs17058639 C > T polymorphism was associated with the presence of DR among Qataris with T2DM. One-way ANOVA and multiple logistic regression analysis showed SLMAP SNP rs17058639 C > T as an independent risk factor for DR development. SLMAP rs17058639 C > T polymorphism also had a predictive role for the severity of DR. Haplotype Crs17058639Trs1043045Ars1057719 was associated with the increased risk for DR among Qataris with T2DM., Conclusions: The data suggests the potential role of SLMAP SNPs as a risk factor for the susceptibility of DR among T2DM patients in the Qatari population.