Carmona, Eva M

Pneumocystis jirovecii is a fungal pathogen that can cause life-threatening infections in individuals who are immunocompromised. Acquired via inhalation, upon entering the respiratory tract, the fungi first encounter innate immune cells such as alveolar macrophages (AMs). Relatively little is known about the AM cellular responses to the organism, and particularly transcription factor (TF) profiles leading to early host responses during infection. Utilizing the Mouse Transcription Factors RT2 Profiler™ PCR Array, we report an initial TF survey of these macrophage and Pneumocystis interactions. Expression levels of a panel of mouse TFs were compared between unstimulated and Pneumocystis murina-stimulated AMs. Interestingly, a number of TFs previously implicated in pathogen–host cell interactions were highly up- or downregulated, including hif1a and Pparg. qPCR experiments were further conducted to verify the results of these surveyed transcripts. Furthermore, with immunoblotting, we show that HIF-1A and PPAR-γ are indeed significantly upregulated and downregulated, respectively. Lastly, and importantly, we report that in the mouse model of Pneumocystis pneumonia (PCP), which mimics human Pneumocystis jirovecii pneumonia (PJP), qPCR analysis of Pneumocystis murina lungs also mimic the initial TF profile analysis, suggesting an importance for these TFs in immunocompromised hosts with Pneumocystis pneumonia. These data demonstrate the use of TF profiling in host AMs and Pneumocystis organism interactions that may lead to a better understanding of the specific inflammatory responses of the host to Pneumocystis pneumonia and may inform novel strategies for potential therapeutics.

Abstract B-cell activation is increasingly linked to numerous fibrotic lung diseases, and it is well known that aggregates of lymphocytes form in the lung of many of these patients. Activation of B-cells by pattern recognition receptors (PRRs) drives the release of inflammatory cytokines, chemokines, and metalloproteases important in the pathophysiology of pulmonary fibrosis. However, the specific mechanisms of B-cell activation in patients with idiopathic pulmonary fibrosis (IPF) are poorly understood. Herein, we have demonstrated that B-cell activation by microbial antigens contributes to the inflammatory and profibrotic milieu seen in patients with IPF. B-cell stimulation by CpG and β-glucan via PRRs resulted in activation of mTOR-dependent and independent pathways. Moreover, we showed that the B-cell–secreted inflammatory milieu is specific to the inducing antigen and causes differential fibroblast migration and activation. B-cell responses to infectious agents and subsequent B-cell–mediated fibroblast activation are modifiable by antifibrotics, but each seems to exert a specific and different effect. These results suggest that, upon PRR activation by microbial antigens, B-cells can contribute to the inflammatory and fibrotic changes seen in patients with IPF, and antifibrotics are able to at least partially reverse these responses.

Abstract The American Thoracic Society Core Curriculum updates clinicians annually in adult and pediatric pulmonary disease, medical critical care, and sleep medicine in a 3- to 4-year recurring cycle of topics. The topics of the 2020 Pulmonary Core Curriculum include pulmonary vascular disease (submassive pulmonary embolism, chronic thromboembolic pulmonary hypertension, and pulmonary hypertension) and pulmonary infections (community-acquired pneumonia, pulmonary nontuberculous mycobacteria, opportunistic infections in immunocompromised hosts, and coronavirus disease [COVID-19]).

ObjectivesThe aim of this study was to assess bleomycin‐induced pulmonary fibrosis on ex vivo mouse lungs using ultrasound image grading and texture analysis.MethodsExcised mouse lungs were divided into 3 groups: control, mild fibrosis, and severe fibrosis based on the monitored indicators of health. B‐mode ultrasound images were obtained via scanning the mouse lungs ex vivo. The surface smoothness, echo density, and angle of lesions or the lung margin were graded, and the imaging contrast, correlation, homogeneity, and entropy were assessed via texture analysis.ResultsThe grades of surface smoothness, echo density, and angle were statistically higher for the severe fibrosis group compared with those of the control and mild fibrosis groups (P < .05). In addition, statistically significant differences in the contrast, correlation, and homogeneity between mild and severe fibrosis groups were observed (P < .05).ConclusionsThe results obtained in this study suggest that ultrasound image grading and texture analysis are valuable and meaningful methods for assessing pulmonary fibrosis in a bleomycin mouse model.

Pneumocystis jirovecii , the opportunistic fungus that causes Pneumocystis pneumonia (PCP) in humans, is a significant contributor to morbidity and mortality in immunocompromised patients. Given the profound deleterious inflammatory effects of the major β-glucan cell wall carbohydrate constituents of Pneumocystis through Dectin-1 engagement and downstream caspase recruitment domain-containing protein 9 (CARD9) immune activation, we sought to determine whether the pharmacodynamic activity of the known CARD9 inhibitor BRD5529 might have a therapeutic effect on macrophage innate immune signaling and subsequent downstream anti-inflammatory activity.

AbstractBackgroundPneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans.MethodsMajor surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan.ResultsThe silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response.ConclusionsTaken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.

Abstract Background: Sarcoidosis is a systemic granulomatous disease that may affect the myocardium. This study evaluated the diagnostic and prognostic value of 2-dimensional speckle tracking echocardiography in cardiac sarcoidosis (CS). Methods: Eighty-three patients with extracardiac, biopsy-proven sarcoidosis and definite/probable diagnosis of cardiac involvement diagnosed from January 2005 through December 2016 were included. Strain parameters in early stages of CS, in a subgroup of 23 CS patients with left ventricular ejection fraction (LVEF) within normal limits (LVEF>52% for men: >54% for women, mean value: 57.3%±3.8%) and no wall motion abnormalities was compared with 97 controls (1:4) without cardiac disease. LV and right ventricular (RV) global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain and strain rate (SR) analyses were performed with TomTec software and correlated with cardiac outcomes (including heart failure and arrhythmias). This study was approved by the Mayo Clinic Institutional Review Board, and all patients gave informed written consent to participate. Results: Mean age of CS patients was 53.6±10.8 years, and 34.9% were women. Mean LVEF was 43.2%±12.4%; LV GLS, -12.4%±3.7%; LV GCS, -17.1%±6.5%; LV GRS, 29.3%±12.8%; and RV wall GLS, 14.6%±6.3%. In the 23 patients with early stage CS with normal LVEF and RV systolic function, strain parameters were significantly reduced when compared with controls (respectively: LV GLS, -15.9%±2.5% vs -18.2%±2.7% [ P =.001]; RV GLS, -16.9%±4.5% vs -24.1%±4.0% [ P <.001]). A LV GLS value of -16.3% provided 82.2% sensitivity and 81.2% specificity for the diagnosis of CS (AUC 0.91), while a RV value of -19.9% provided 88.1% sensitivity and 86.7% specificity (AUC 0.93). Hospital admission and heart failure significantly correlated to impaired LV GLS (> -14%). Conclusion: Reduced strain values in the LV GLS and RV GLS can be used in the diagnostic algorithm in patients with suspicion of cardiac sarcoidosis. These values also correlate with adverse cardiovascular events.