Stromal Microenvironment Shapes the Intratumoral Architecture of Pancreatic Cancer.

Single-cell technologies have described heterogeneity across tissues, but the spatial distribution and forces that drive single-cell phenotypes have not been well defined. Combining single-cell RNA and protein analytics in studying the role of stromal cancer-associated fibroblasts (CAFs) in modulating heterogeneity in pancreatic cancer (pancreatic ductal adenocarcinoma [PDAC]) model systems, we have identified significant single-cell population shifts toward invasive epithelial-to-mesenchymal transition (EMT) and proliferative (PRO) phenotypes linked with mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling. Using high-content digital imaging of RNA in situ hybridization in 195 PDAC tumors, we quantified these EMT and PRO subpopulations in 319,626 individual cancer cells that can be classified within the context of distinct tumor gland "units." Tumor gland typing provided an additional layer of intratumoral heterogeneity that was associated with differences in stromal abundance and clinical outcomes. This demonstrates the impact of the stroma in shaping tumor architecture by altering inherent patterns of tumor glands in human PDAC.

NR4A1 regulates expression of immediate early genes, suppressing replication stress in cancer.

Deregulation of oncogenic signals in cancer triggers replication stress. Immediate early genes (IEGs) are rapidly and transiently expressed following stressful signals, contributing to an integrated response. Here, we find that the orphan nuclear receptor NR4A1 localizes across the gene body and 3' UTR of IEGs, where it inhibits transcriptional elongation by RNA Pol II, generating R-loops and accessible chromatin domains. Acute replication stress causes immediate dissociation of NR4A1 and a burst of transcriptionally poised IEG expression. Ectopic expression of NR4A1 enhances tumorigenesis by breast cancer cells, while its deletion leads to massive chromosomal instability and proliferative failure, driven by deregulated expression of its IEG target, FOS. Approximately half of breast and other primary cancers exhibit accessible chromatin domains at IEG gene bodies, consistent with this stress-regulatory pathway. Cancers that have retained this mechanism in adapting to oncogenic replication stress may be dependent on NR4A1 for their proliferation.

An interactive resource to identify cancer genetic and lineage dependencies targeted by small molecules.

The high rate of clinical response to protein-kinase-targeting drugs matched to cancer patients with specific genomic alterations has prompted efforts to use cancer cell line (CCL) profiling to identify additional biomarkers of small-molecule sensitivities. We have quantitatively measured the sensitivity of 242 genomically characterized CCLs to an Informer Set of 354 small molecules that target many nodes in cell circuitry, uncovering protein dependencies that: (1) associate with specific cancer-genomic alterations and (2) can be targeted by small molecules. We have created the Cancer Therapeutics Response Portal (http://www.broadinstitute.org/ctrp) to enable users to correlate genetic features to sensitivity in individual lineages and control for confounding factors of CCL profiling. We report a candidate dependency, associating activating mutations in the oncogene ß-catenin with sensitivity to the Bcl-2 family antagonist, navitoclax. The resource can be used to develop novel therapeutic hypotheses and to accelerate discovery of drugs matched to patients by their cancer genotype and lineage.

4-Octyl Itaconate Alleviates Airway Eosinophilic Inflammation by Suppressing Chemokines and Eosinophil Development.

4-Octyl itaconate (4-OI) is a derivative of the Krebs cycle-derived metabolite itaconate and displays an array of antimicrobial and anti-inflammatory properties through modifying cysteine residues within protein targets. We have found that 4-OI significantly reduces the production of eosinophil-targeted chemokines in a variety of cell types, including M1 and M2 macrophages, Th2 cells, and A549 respiratory epithelial cells. Notably, the suppression of these chemokines in M1 macrophages was found to be NRF2-dependent. In addition, 4-OI can interfere with IL-5 signaling and directly affect eosinophil differentiation. In a model of eosinophilic airway inflammation in BALB/c mice, 4-OI alleviated airway resistance and reduced eosinophil recruitment to the lungs. Our findings suggest that itaconate derivatives could be promising therapeutic agents for the treatment of eosinophilic asthma.

Structural Basis of Transcription Inhibition by Fidaxomicin (Lipiarmycin A3).

Fidaxomicin is an antibacterial drug in clinical use for treatment of Clostridium difficile diarrhea. The active ingredient of fidaxomicin, lipiarmycin A3 (Lpm), functions by inhibiting bacterial RNA polymerase (RNAP). Here we report a cryo-EM structure of Mycobacterium tuberculosis RNAP holoenzyme in complex with Lpm at 3.5-Å resolution. The structure shows that Lpm binds at the base of the RNAP "clamp." The structure exhibits an open conformation of the RNAP clamp, suggesting that Lpm traps an open-clamp state. Single-molecule fluorescence resonance energy transfer experiments confirm that Lpm traps an open-clamp state and define effects of Lpm on clamp dynamics. We suggest that Lpm inhibits transcription by trapping an open-clamp state, preventing simultaneous interaction with promoter -10 and -35 elements. The results account for the absence of cross-resistance between Lpm and other RNAP inhibitors, account for structure-activity relationships of Lpm derivatives, and enable structure-based design of improved Lpm derivatives.

VISTA is an acidic pH-selective ligand for PSGL-1.

Co-inhibitory immune receptors can contribute to T cell dysfunction in patients with cancer1,2. Blocking antibodies against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death 1 (PD-1) partially reverse this effect and are becoming standard of care in an increasing number of malignancies3. However, many of the other axes by which tumours become inhospitable to T cells are not fully understood. Here we report that V-domain immunoglobulin suppressor of T cell activation (VISTA) engages and suppresses T cells selectively at acidic pH such as that found in tumour microenvironments. Multiple histidine residues along the rim of the VISTA extracellular domain mediate binding to the adhesion and co-inhibitory receptor P-selectin glycoprotein ligand-1 (PSGL-1). Antibodies engineered to selectively bind and block this interaction in acidic environments were sufficient to reverse VISTA-mediated immune suppression in vivo. These findings identify a mechanism by which VISTA may engender resistance to anti-tumour immune responses, as well as an unexpectedly determinative role for pH in immune co-receptor engagement.

Landscape fire smoke airway exposure impairs respiratory and cardiac function and worsens experimental asthma.

BACKGROUND: Millions of people are exposed to landscape fire smoke (LFS) globally, and inhalation of LFS particulate matter (PM) is associated with poor respiratory and cardiovascular outcomes. However, how LFS affects respiratory and cardiovascular function is less well understood. OBJECTIVE: We aimed to characterize the pathophysiologic effects of representative LFS airway exposure on respiratory and cardiac function and on asthma outcomes. METHODS: LFS was generated using a customized combustion chamber. In 8-week-old female BALB/c mice, low (25 µg/m3, 24-hour equivalent) or moderate (100 µg/m3, 24-hour equivalent) concentrations of LFS PM (10 µm and below [PM10]) were administered daily for 3 (short-term) and 14 (long-term) days in the presence and absence of experimental asthma. Lung inflammation, gene expression, structural changes, and lung function were assessed. In 8-week-old male C57BL/6 mice, low concentrations of LFS PM10 were administered for 3 days. Cardiac function and gene expression were assessed. RESULTS: Short- and long-term LFS PM10 airway exposure increased airway hyperresponsiveness and induced steroid insensitivity in experimental asthma, independent of significant changes in airway inflammation. Long-term LFS PM10 airway exposure also decreased gas diffusion. Short-term LFS PM10 airway exposure decreased cardiac function and expression of gene changes relating to oxidative stress and cardiovascular pathologies. CONCLUSIONS: We characterized significant detrimental effects of physiologically relevant concentrations and durations of LFS PM10 airway exposure on lung and heart function. Our study provides a platform for assessment of mechanisms that underpin LFS PM10 airway exposure on respiratory and cardiovascular disease outcomes.

Smoking and tetramer tryptase accelerate intervertebral disc degeneration by inducing METTL14-mediated DIXDC1 m6 modification.

Although cigarette smoking (CS) and low back pain (LBP) are common worldwide, their correlations and the mechanisms of action remain unclear. We have shown that excessive activation of mast cells (MCs) and their proteases play key roles in CS-associated diseases, like asthma, chronic obstructive pulmonary disease (COPD), blood coagulation, and lung cancer. Previous studies have also shown that MCs and their proteases induce degenerative musculoskeletal disease. By using a custom-designed smoke-exposure mouse system, we demonstrated that CS results in intervertebral disc (IVD) degeneration and release of MC-restricted tetramer tryptases (TTs) in the IVDs. TTs were found to regulate the expression of methyltransferase 14 (METTL14) at the epigenetic level by inducing N6-methyladenosine (m6A) deposition in the 3' untranslated region (UTR) of the transcript that encodes dishevelled-axin (DIX) domain-containing 1 (DIXDC1). That reaction increases the mRNA stability and expression of Dixdc1. DIXDC1 functionally interacts with disrupted in schizophrenia 1 (DISC1) to accelerate the degeneration and senescence of nucleus pulposus (NP) cells by activating a canonical Wnt pathway. Our study demonstrates the association between CS, MC-derived TTs, and LBP. These findings raise the possibility that METTL14-medicated DIXDC1 m6A modification could serve as a potential therapeutic target to block the development of degeneration of the NP in LBP patients.

Human milk oligosaccharides promote intestinal epithelium regeneration independent of the microbiota during necrotizing enterocolitis.

PURPOSE: Necrotizing enterocolitis (NEC) is a severe intestinal disease primarily affecting premature infants, marked by impaired epithelial regeneration. Breastfed infants are less susceptible to NEC than formula-fed ones, and human milk oligosaccharides (HMO) found in breast milk have prebiotic properties that can protect against NEC. However, it is unclear how HMOs influence intestinal epithelium regeneration in relation to the gut microbiota. METHODS: Broad-spectrum antibiotics were administered to pregnant dams to reduce the microbiota in offspring. NEC was induced through administration of hyperosmolar formula, lipopolysaccharide, and hypoxia from postnatal days (p) 5-9. Intestinal epithelial organoids were derived from p9 mice. HMOs were isolated from human donor breast milk and then solubilized in the formula for each feed or culture media for organoids. RESULTS: HMOs did not alter the microbiota profile in the presence of a normal or reduced microbiota. In the reduced microbiota, HMO treatment decreased NEC intestinal injury, and increased proliferation and stem cell activity. Additionally, in the complete absence of the microbiota, HMOs stimulated intestinal organoid growth. CONCLUSION: This study demonstrates that HMOs promoted intestinal epithelial regeneration independent of the gut microbiota. These findings provide further insight into the various benefits HMOs may have in the protection against NEC.

Accelerating σ-Bond Metathesis at Sn(II) Centers.

Molecular main-group hydride catalysts are attractive as cheap and Earth-abundant alternatives to transition-metal analogues. In the case of the latter, specific steric and electronic tuning of the metal center through ligand choice has enabled the iterative and rational development of superior catalysts. Analogously, a deeper understanding of electronic structure-activity relationships for molecular main-group hydrides should facilitate the development of superior main-group hydride catalysts. Herein, we report a modular Sn-Ni bimetallic system in which we systematically vary the ancillary ligand on Ni, which, in turn, tunes the Sn center. This tuning is probed using Sn L1 XAS as a measure of electron density at the Sn center. We demonstrate that increased electron density at Sn centers accelerates the rate of σ-bond metathesis, and we employ this understanding to develop a highly active Sn-based catalyst for the hydroboration of CO2 using pinacolborane. Additionally, we demonstrate that engineering London dispersion interactions within the secondary coordination sphere of Sn allows for further rate acceleration. These results show that the electronics of main-group catalysts can be controlled without the competing effects of geometry perturbations and that this manifests in substantial reactivity differences.

Reversible CO2 Capture and On-Demand Release by an Acidity-Matched Organic Photoswitch.

Separation of carbon dioxide (CO2) from point sources or directly from the atmosphere can contribute crucially to climate change mitigation plans in the coming decades. A fundamental practical limitation for the current strategies is the considerable energy cost required to regenerate the sorbent and release the captured CO2 for storage or utilization. A directly photochemically driven system that demonstrates efficient passive capture and on-demand CO2 release triggered by sunlight as the sole external stimulus would provide an attractive alternative. However, little is known about the thermodynamic requirements for such a process or mechanisms for modulating the stability of CO2-derived dissolved species by using photoinduced metastable states. Here, we show that an organic photoswitchable molecule of precisely tuned effective acidity can repeatedly capture and release a near-stoichiometric quantity of CO2 according to dark-light cycles. The CO2-derived species rests as a solvent-separated ion pair, and key aspects of its excited-state dynamics that regulate the photorelease efficiency are characterized by transient absorption spectroscopy. The thermodynamic and kinetic concepts established herein will serve as guiding principles for the development of viable solar-powered negative emission technologies.

RIPK1 kinase-dependent inflammation and cell death contribute to the pathogenesis of COPD.

BACKGROUND: Receptor-interacting protein kinase 1 (RIPK1) is a key mediator of regulated cell death (including apoptosis and necroptosis) and inflammation, both drivers of COPD pathogenesis. We aimed to define the contribution of RIPK1 kinase-dependent cell death and inflammation in the pathogenesis of COPD. METHODS: We assessed RIPK1 expression in single-cell RNA sequencing (RNA-seq) data from human and mouse lungs, and validated RIPK1 levels in lung tissue of COPD patients via immunohistochemistry. Next, we assessed the consequences of genetic and pharmacological inhibition of RIPK1 kinase activity in experimental COPD, using Ripk1 S25D/S25D kinase-deficient mice and the RIPK1 kinase inhibitor GSK'547. RESULTS: RIPK1 expression increased in alveolar type 1 (AT1), AT2, ciliated and neuroendocrine cells in human COPD. RIPK1 protein levels were significantly increased in airway epithelium of COPD patients compared with never-smokers and smokers without airflow limitation. In mice, exposure to cigarette smoke (CS) increased Ripk1 expression similarly in AT2 cells, and further in alveolar macrophages and T-cells. Genetic and/or pharmacological inhibition of RIPK1 kinase activity significantly attenuated airway inflammation upon acute and subacute CS exposure, as well as airway remodelling, emphysema, and apoptotic and necroptotic cell death upon chronic CS exposure. Similarly, pharmacological RIPK1 kinase inhibition significantly attenuated elastase-induced emphysema and lung function decline. Finally, RNA-seq on lung tissue of CS-exposed mice revealed downregulation of cell death and inflammatory pathways upon pharmacological RIPK1 kinase inhibition. CONCLUSIONS: RIPK1 kinase inhibition is protective in experimental models of COPD and may represent a novel promising therapeutic approach.

Airway and parenchyma transcriptomics in a house dust mite model of experimental asthma.

Lung transcriptomics studies in asthma have provided valuable information in the whole lung context, however, deciphering the individual contributions of the airway and parenchyma in disease pathogenesis may expedite the development of novel targeted treatment strategies. In this study, we performed transcriptomics on the airway and parenchyma using a house dust mite (HDM)-induced model of experimental asthma that replicates key features of the human disease. HDM exposure increased the expression of 3,255 genes, of which 212 were uniquely increased in the airways, 856 uniquely increased in the parenchyma, and 2187 commonly increased in both compartments. Further interrogation of these genes using a combination of network and transcription factor enrichment analyses identified several transcription factors that regulate airway and/or parenchymal gene expression, including transcription factor EC (TFEC), transcription factor PU.1 (SPI1), H2.0-like homeobox (HLX), metal response element binding transcription factor-1 (MTF1) and E74-like factor 4 (ets domain transcription factor, ELF4) involved in controlling innate immune responses. We next assessed the effects of inhibiting lung SPI1 responses using commercially available DB1976 and DB2313 on key disease outcomes. We found that both compounds had no protective effects on airway inflammation, however DB2313 (8 mg/kg) decreased mucus secreting cell number, and both DB2313 (1 mg/kg) and DB1976 (2.5 mg/kg and 1 mg/kg) reduced small airway collagen deposition. Significantly, both compounds decreased airway hyperresponsiveness. This study demonstrates that SPI1 is important in HDM-induced experimental asthma and that its pharmacological inhibition reduces HDM-induced airway collagen deposition and hyperresponsiveness.

Characterization and inhibition of inflammasome responses in severe and non-severe asthma.

BACKGROUND: Increased airway NLRP3 inflammasome-mediated IL-1ß responses may underpin severe neutrophilic asthma. However, whether increased inflammasome activation is unique to severe asthma, is a common feature of immune cells in all inflammatory types of severe asthma, and whether inflammasome activation can be therapeutically targeted in patients, remains unknown. OBJECTIVE: To investigate the activation and inhibition of inflammasome-mediated IL-1ß responses in immune cells from patients with asthma. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from patients with non-severe (n = 59) and severe (n = 36 stable, n = 17 exacerbating) asthma and healthy subjects (n = 39). PBMCs were stimulated with nigericin or lipopolysaccharide (LPS) alone, or in combination (LPS + nigericin), with or without the NLRP3 inhibitor MCC950, and the effects on IL-1ß release were assessed. RESULTS: PBMCs from patients with non-severe or severe asthma produced more IL-1ß in response to nigericin than those from healthy subjects. PBMCs from patients with severe asthma released more IL-1ß in response to LPS + nigericin than those from non-severe asthma. Inflammasome-induced IL-1ß release from PBMCs from patients with severe asthma was not increased during exacerbation compared to when stable. Inflammasome-induced IL-1ß release was not different between male and female, or obese and non-obese patients and correlated with eosinophil and neutrophil numbers in the airways. MCC950 effectively suppressed LPS-, nigericin-, and LPS + nigericin-induced IL-1ß release from PBMCs from all groups. CONCLUSION: An increased ability for inflammasome priming and/or activation is a common feature of systemic immune cells in both severe and non-severe asthma, highlighting inflammasome inhibition as a universal therapy for different subtypes of disease.

Trends in Management of Index Adhesive Small Bowel Obstruction in Children.

INTRODUCTION: To examine practice patterns and surgical outcomes of nonoperative versus operative management (OPM) of children presenting with an index adhesive small bowel obstruction (ASBO). METHODS: A California statewide health discharge database was used to identify children (<18 y old) with an index ASBO from 2007 to 2020. The primary study outcome was evaluating initial management patterns (nonoperative versus OPM and early [≤3 d] versus late surgery [>3 d]) of ASBO. Secondary outcomes were hospital characteristics, patient demographics, and postoperative complications. RESULTS: Of the 2297 patients identified, 1948 (85%) underwent OPM for ASBO during the index admission. Of these, 14.7% underwent early surgery within 3 d. Teaching hospitals had higher operative intervention than nonteaching centers (87.1% versus 83.7%, P = 0.034). OPM was the highest in 0-5-year-olds compared to other ages (89% versus 82%, P < 0.001). In comparison to early surgery, late surgery was associated with longer length of stay (early 7[interquartile range 5-10], late 9[interquartile range 6-17], P < 0.001), increased infectious complications (16.4% versus 9.8%, P = 0.004), and greater use of total parenteral nutrition (28.0% versus 14.3%, P = 0.001); there was no difference in bowel resection (21% versus 18%, P = 0.102) or mortality (P = 0.423). CONCLUSIONS: Our pediatric study demonstrated a high rate of OPM for index ASBO, especially in newborns and toddlers. Although operative intervention, especially late surgery, was associated with increased length of stay, increased infectious complications, and increased total parenteral nutrition use, the rates of bowel resection and mortality did not differ by management strategy. These trends need to be further evaluated to optimize outcomes.

Improved outcome in penile cancer with radiologically enhanced stratification protocol for lymph node staging procedures: a study in 316 inguinal basins with a mean follow-up of 5 years.

BACKGROUND: Lymph node metastasis is the main determinant of survival in penile cancer patients. Conventionally clinical palpability is used to stratify patients to Inguinal Lymph node dissection (ILND) if clinically node positive (cN +) or Dynamic sentinel node biopsy (DSNB) if clinically node negative (cN0). Studies suggest a false negative rate (FNR) of around 10% (5-13%) for DSNB. To our knowledge there are no studies reporting harder end point of survival and outcomes of all clinically node positive (cN +) patients. We present our outcome data of all patients with penile cancer including false negative rates and survival in both DSNB and ILND groups. METHODS: One hundred fifty-eight consecutive patients (316 inguinal basins), who had lymph node surgery for penile cancer in a tertiary referral centre from Jan 2008 to 2018, were included in the study. All patients underwent ultrasound (US) ± fine needle aspiration cytology (FNAC) and then MRI/ CT, if needed, to stage their disease. We used combined clinical and radiological criteria (node size, architecture loss, irregular margins) to stratify patients to DSNB vs ILND as opposed to clinical palpability alone. RESULTS: 11.2% i.e., 27/241 inguinal basins had lymph node positive disease by DSNB. 54.9% i.e., 39/71 inguinal basins (IBs) had lymph node-positive disease by ILND. 4 inguinal basins with no tracer uptake in sentinel node scans are being monitored at patient's request and have not had any recurrences to date. With a mean follow-up of 65 months (range 24-150), the false-negative rate (FNR) for DSNB is 0%. Judicious uses of cross-sectional imaging necessitated ILND in 2 inguinal basins with non-palpable nodes and negative US with false positive rate of 6.3% (2/32) for ILND. The same cohort of DSNB patients might have had 11.1% (3/27) FNR if only palpability criteria was used. 43 (28%) patients who did require cross sectional imaging as per our criteria had a low node positive rate of 4.7% (p = 0.03). Mean cancer specific survival of all node-positive patients was 105 months. CONCLUSION: The performance of DSNB improved with enhanced radiological stratification of patients to either DSNB or ILND. We for the first time report the comprehensive outcome of all lymph node staging procedures in penile cancer.

Mechanistic insights into hormesis induced by erythromycin in the marine alga Thalassiosira weissflogii.

Erythromycin (ERY) is a typical macrolide antibiotic with large production and extensive use on a global scale. Detection of ERY in both freshwaters and coaster seawaters, as well as relatively high ecotoxicity of ERY have been documented. Notably, hormesis has been reported on several freshwater algae under ERY stress, where growth was promoted at relatively lower exposures but inhibited at higher treatment levels. On the contrary, there is limited information of ERY toxicity in marine algae, hampering the risk assessment on ERY in the coaster waters. The presence of hormesis may challenge the current concept of dose-response adopted in chemical risk assessment. Whether and how exposure to ERY can induce dose-dependent toxicity in marine algae remain virtually unknown, especially at environmentally relevant concentrations. The present study used a model marine diatom Thalassiosira weissflogii (T. weissflogii) to reveal its toxicological responses to ERY at different biological levels and decipher the underlying mechanisms. Assessment of multiple apical endpoints shows an evident growth promotion following ERY exposure at an environmentally relevant concentration (1 µg/L), associated with increased contents reactive oxygen species (ROS) and chlorophyll-a (Chl-a), activated signaling pathways related to ribosome biosynthesis and translation, and production of total soluble protein. By contrast, growth inhibition in the 750 and 2500 µg/L treatments was attributed to reduced viability, increased ROS formation, reduced content of total soluble protein, inhibited photosynthesis, and perturbed signaling pathways involved in xenobiotic metabolism, ribosome, metabolism of amino acid, and nitrogen metabolism. Measurements of multiple apical endpoints coupled with de novo transcriptomics analysis applied in the present study, a systems biology approach, can generate detailed mechanistic information of chemical toxicity including dose-response and species sensitivity difference used in environmental risk assessment.

Airway and parenchymal transcriptomics in a novel model of asthma and COPD overlap.

BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) are common chronic respiratory diseases, and some patients have overlapping disease features, termed asthma-COPD overlap (ACO). Patients characterized with ACO have increased disease severity; however, the mechanisms driving this have not been widely studied. OBJECTIVES: This study sought to characterize the phenotypic and transcriptomic features of experimental ACO in mice induced by chronic house dust mite antigen and cigarette smoke exposure. METHODS: Female BALB/c mice were chronically exposed to house dust mite antigen for 11 weeks to induce experimental asthma, cigarette smoke for 8 weeks to induce experimental COPD, or both concurrently to induce experimental ACO. Lung inflammation, structural changes, and lung function were assessed. RNA-sequencing was performed on separated airway and parenchyma lung tissues to assess transcriptional changes. Validation of a novel upstream driver SPI1 in experimental ACO was assessed using the pharmacological SPI1 inhibitor, DB2313. RESULTS: Experimental ACO recapitulated features of both asthma and COPD, with mixed pulmonary eosinophilic/neutrophilic inflammation, small airway collagen deposition, and increased airway hyperresponsiveness. Transcriptomic analysis identified common and distinct dysregulated gene clusters in airway and parenchyma samples in experimental asthma, COPD, and ACO. Upstream driver analysis revealed increased expression of the transcription factor Spi1. Pharmacological inhibition of SPI1 using DB2313, reduced airway remodeling and airway hyperresponsiveness in experimental ACO. CONCLUSIONS: A new experimental model of ACO featuring chronic dual exposures to house dust mite and cigarette smoke mimics key disease features observed in patients with ACO and revealed novel disease mechanisms, including upregulation of SPI1, that are amenable to therapy.

Relationship between type 2 cytokine and inflammasome responses in obesity-associated asthma.

BACKGROUND: Obesity is a risk factor for asthma, and obese asthmatic individuals are more likely to have severe, steroid-insensitive disease. How obesity affects the pathogenesis and severity of asthma is poorly understood. Roles for increased inflammasome-mediated neutrophilic responses, type 2 immunity, and eosinophilic inflammation have been described. OBJECTIVE: We investigated how obesity affects the pathogenesis and severity of asthma and identified effective therapies for obesity-associated disease. METHODS: We assessed associations between body mass index and inflammasome responses with type 2 (T2) immune responses in the sputum of 25 subjects with asthma. Functional roles for NLR family, pyrin domain-containing (NLRP) 3 inflammasome and T2 cytokine responses in driving key features of disease were examined in experimental high-fat diet-induced obesity and asthma. RESULTS: Body mass index and inflammasome responses positively correlated with increased IL-5 and IL-13 expression as well as C-C chemokine receptor type 3 expression in the sputum of subjects with asthma. High-fat diet-induced obesity resulted in steroid-insensitive airway hyperresponsiveness in both the presence and absence of experimental asthma. High-fat diet-induced obesity was also associated with increased NLRP3 inflammasome responses and eosinophilic inflammation in airway tissue, but not lumen, in experimental asthma. Inhibition of NLRP3 inflammasome responses reduced steroid-insensitive airway hyperresponsiveness but had no effect on IL-5 or IL-13 responses in experimental asthma. Depletion of IL-5 and IL-13 reduced obesity-induced NLRP3 inflammasome responses and steroid-insensitive airway hyperresponsiveness in experimental asthma. CONCLUSION: We found a relationship between T2 cytokine and NLRP3 inflammasome responses in obesity-associated asthma, highlighting the potential utility of T2 cytokine-targeted biologics and inflammasome inhibitors.

Temporal and Spatial Patterns of Inflammation and Tissue Injury in Patients with Postoperative Respiratory Failure after Lung Resection Surgery: A Nested Case-Control Study.

Thoracic surgeries involving resection of lung tissue pose a risk of severe postoperative pulmonary complications, including acute respiratory distress syndrome (ARDS) and respiratory failure. Lung resections require one-lung ventilation (OLV) and, thus, are at higher risk of ventilator-induced lung injury (VILI) attributable to barotrauma and volutrauma in the one ventilated lung, as well as hypoxemia and reperfusion injury on the operated lung. Further, we also aimed to assess the differences in localized and systemic markers of tissue injury/inflammation in those who developed respiratory failure after lung surgery versus matched controls who did not develop respiratory failure. We aimed to assess the different inflammatory/injury marker patterns induced in the operated and ventilated lung and how this compared to the systemic circulating inflammatory/injury marker pattern. A case-control study nested within a prospective cohort study was performed. Patients with postoperative respiratory failure after lung surgery (n = 5) were matched with control patients (n = 6) who did not develop postoperative respiratory failure. Biospecimens (arterial plasma, bronchoalveolar lavage separately from ventilated and operated lungs) were obtained from patients undergoing lung surgery at two timepoints: (1) just prior to initiation of OLV and (2) after lung resection was completed and OLV stopped. Multiplex electrochemiluminescent immunoassays were performed for these biospecimen. We quantified 50 protein biomarkers of inflammation and tissue injury and identified significant differences between those who did and did not develop postoperative respiratory failure. The three biospecimen types also display unique biomarker patterns.