Limper, Andrew H.

Respiratory viral infections, like IAV and respiratory syncytial virus (RSV) infections, impose great challenges to public health. Alveolar macrophages (AM) are lung-resident immune cells that play important roles in protecting the host against IAV and RSV infections. However, the underlying molecular mechanisms by which AM modulate host inflammation, disease development, and tissue recovery are not very well understood. Here we identify that PPAR-γ expression in AM is crucial to suppress pulmonary inflammation and diseases and to promote fast host recovery from IAV and RSV infections. Our data suggest that targeting macrophage PPAR-γ may be a promising therapeutic option in the future to suppress acute inflammation and simultaneously promote recovery from severe diseases associated with respiratory viral infections.

Quantitative activity through the TCR-proximal protein network specifies thymic positive versus negative selection.

Abstract Rationale Chronic obstructive pulmonary disease is an independent risk factor for lung cancer, but the underlying molecular mechanisms are unknown. We hypothesized that lung stromal cells activate pathological gene expression programs that support oncogenesis. Objectives To identify molecular mechanisms operating in the lung stroma that support the development of lung cancer. Methods The study included subjects with and without lung cancer across a spectrum of lung-function values. We conducted a multiomics analysis of nonmalignant lung tissue to quantify the transcriptome, translatome, and proteome. Measurements and Main Results Cancer-associated gene expression changes predominantly manifested as alterations in the efficiency of mRNA translation modulating protein levels in the absence of corresponding changes in mRNA levels. The molecular mechanisms that drove these cancer-associated translation programs differed based on lung function. In subjects with normal to mildly impaired lung function, the mammalian target of rapamycin (mTOR) pathway served as an upstream driver, whereas in subjects with severe airflow obstruction, pathways downstream of pathological extracellular matrix emerged. Consistent with a role during cancer initiation, both the mTOR and extracellular matrix gene expression programs paralleled the activation of previously identified procancer secretomes. Furthermore, an in situ examination of lung tissue showed that stromal fibroblasts expressed cancer-associated proteins from two procancer secretomes: one that included IL-6 (in cases of mild or no airflow obstruction), and one that included BMP1 (in cases of severe airflow obstruction). Conclusions Two distinct stromal gene expression programs that promote cancer initiation are activated in patients with lung cancer depending on lung function. Our work has implications both for screening strategies and for personalized approaches to cancer treatment.

Abstract Rationale Chronic obstructive pulmonary disease (COPD) is an independent risk factor for lung cancer, but the underlying molecular mechanisms are unknown. We hypothesized that stromal cells comprising the COPD lung contain pathological gene expression programs supporting oncogenesis. Objectives To identify molecular mechanisms operating in the lung stroma that support the development of lung cancer. Methods Study subjects included patients with COPD with (n = 30) or without (n = 30) lung cancer across a spectrum of COPD severity. We conducted multi-omics analysis of nonmalignant lung tissue to quantify the transcriptome, translatome, and proteome. Results Cancer-associated gene expression changes predominantly manifested as alterations in the efficiency of mRNA translation impacting protein levels in the absence of corresponding changes in mRNA levels. The molecular mechanisms driving these procancer translation programs differed on the basis of COPD severity. In mild or no COPD, the mammalian target of rapamycin pathway served as an upstream driver; whereas in advanced COPD, pathways downstream of pathological extracellular matrix emerged. Both the mammalian target of rapamycin and extracellular matrix gene expression programs paralleled activation of previously identified secretomes that can be independently induced and promote cancer initiation in mouse models. These included the senescence secretome in mild to no COPD and the ETS2 (erythroblast transformation-specific 2) secretome in moderate to severe COPD. Furthermore, in situ examination of COPD lung tissue documented stromal fibroblasts expressing key cancer-associated proteins from procancer secretomes including IL-6 (senescence secretome) in mild COPD and bone morphogenetic protein-1 (ETS2 secretome) in advanced COPD. Conclusions Two distinct stromal gene expression programs promoting cancer initiation are activated in patients with lung cancer depending on the severity of COPD as measured by lung function. Our work has implications both for screening strategies and personalized approaches to prevent cancer in COPD.

AbstractThe 14th International Workshops on Opportunistic Protists (IWOP‐14) was held August 10–12, 2017 in Cincinnati, OH, USA. The IWOP meetings focus on opportunistic protists (OIs); for example, free‐living amoebae, Pneumocystis spp., Cryptosporidium spp., Toxoplasma, the Microsporidia, and kinetoplastid flagellates. The highlights of Pneumocystis spp. research included the reports of primary homothallism for mating; a potential requirement for sexual replication in its life cycle; a new antigen on the surface of small asci; roles for CLRs, Dectin‐1, and Mincle in host responses; and identification of MSG families and mechanisms used for surface variation. Studies of Cryptosporidia spp. included comparative genomics, a new cryopreservation method; the role of mucin in attachment and invasion, and epidemiological surveys illustrating species diversity in animals. One of the five identified proteins in the polar tube of Microsporidia, PTP4, was shown to play a role in host infection. Zebrafish were used as a low cost vertebrate animal model for an evaluation of potential anti‐toxoplasma drugs. Folk medicine compounds with anti‐toxoplasma activity were presented, and reports on the chronic toxoplasma infection provided evidence for increased tractability for the study of this difficult life cycle stage. Escape from the parasitophorus vacuole and cell cycle regulation were the topics of the study in the acute phase.

A key question asked when faced with an infection, an infestation, or environmental damage is whether it is a fungus. Identification of fungi as the cause of the problem can lead to remediation or treatment. Zygomycetes and ascomycetes account for the vast majority of fungal causes of human, animal, and plant disease, large-scale biodiversity loss, agricultural spoilage, and contamination of water-damaged buildings. These studies revealed the conservation of a common cell wall structural component of zygomycetes and ascomycetes to be a diagnostic target applicable to multiple pathogenic fungi and have leveraged that insight for practical use. Monoclonal antibodies reactive with this pan-fungal structure were produced and used to construct immunoassays (including ELISA and lateral flow assay) for detection of a broad range of pathogenic fungi.

Background. The FilmArray Respiratory Panel (FARP) (BioFire Diagnostics, Inc.) is a multiplex, polymerase chain reaction (PCR) technique that can detect 17 respiratory viruses and 3 bacterial targets in a single reaction. Immunocompromised hosts (ICH) with respiratory illnesses often undergo bronchoscopy with bronchoalveolar lavage (BAL). This prospective study aimed to evaluate the yield and concordance of NP and BAL FARP testing when performed on the same patient concurrently. Methods. From February to December 2016, 125 patients (100 ICH and 25 non-ICH) were enrolled. NP swabs and BAL samples were sent for FARP testing. Results. The yield of the BAL FARP among ICH and non-ICH was 24% (24/100) and 8% (2/25), respectively. The yield of positive NP swabs in ICH was 27% (27/100) versus 4% (1/25) in non-ICH. The majority of patients (89%; 111/125) had concordant results between NP and BAL specimens. Of the 24 ICH patients who had a positive BAL FARP, the majority (79%) had the same pathogen detected from the NP swab. Conclusion. The FARP may be useful in the ICH. Given the high concordance, in patients whom a pathogen is identified on the NP FARP, a FARP performed on BAL will likely yield the same result. However, if the NP FARP is negative, performing the test on a BAL sample may have an incremental yield.

Introduction. The diagnostic standard forPneumocystis jiroveciipneumonia (PCP) is direct microscopic identification; however, in recent years, polymerase chain reaction (PCR) from bronchoalveolar lavage (BAL) samples to detectPneumocystisnucleic acids has proven to be more sensitive and specific. Sputum samples have been presumed inferior to bronchoscopic samples secondary to variability and adequacy of sample collection. We observed several cases of positive sputum PCP-PCR results with negative PCP-PCR BAL results. The aim of the current study was to further characterize the clinical setting and outcomes in patients with positive sputum PCP-PCR samples and negative BAL PCP-PCR samples.Methods. We identified all patients who underwentP. jirovecii-PCR testing at Mayo Clinic between 2011 and 2016. Patients with a positive sputum and negative BAL sample collected within a 14-day time frame were identified and underwent further chart review for demographics, immunocompromised state, and clinical outcome.Results. From 2011 to 2016, 4431 respiratory samples from 3021 unique patients were tested for the presence ofP. jiroveciiby PCR. Fifty-five samples (1.2% of all samples collected) belonging to 24 unique patients (0.79% of patients tested) were identified as having a positive and negative sample collected within 14 days. Of these 24 patients, 10 (46%) patients had a positive sputum or tracheal secretion sample with negative BAL or bronchial washings. Out of these 10 patients, 8 were immunocompromised and 9 underwent treatment for PCP with 6 patients improving.Conclusion. Our results suggest that discordantP. jirovecii-PCR testing results from sputum and bronchoscopic specimens are an infrequent occurrence. Patients with positiveP. jirovecii-PCR sputum/tracheal secretion samples and negative bronchoscopic samples appear to be clinically infected and respond to PCP treatment. SputumP. jirovecii-PCR testing may be a viable alternative to invasive testing.