Project description:Survivors of COVID-19 can experience long-term lung complications (pulmonary sequelae), but the underlying mechanisms remain unclear. While most patients with major COVID-19 lung injury eventually recover essentially completely, some experience significant residual damage. To investigate the underlying differences, we analyzed, using bronchoalveolar lavage fluid (BALF), the alveolar immune cell compartments of a group of patients with post-COVID-19 interstitial lung disease (ILD) six months after acute COVID-19. Patients were categorized into two groups, based on High-Resolution Computed Tomography (HRCT) evaluation a year later: those with persistent HRCT abnormalities compatible with fibrosis (persistent post-COVID-19 ILD, n=6) and those with resolved lung lesions (resolved post-COVID-19 ILD, n=13). Additionally, 6 patients with pre-existing ILD were included in the study, after recovery from COVID-19. Bulk RNA transcriptomics analyses of BALF cells revealed pathways of neutrophil and monocyte chemotaxis to be enriched in patients with persistent HRCT abnormalities, consistent with increased monocyte-like cell recruitment in the lungs. Furthermore, increased gene expression of markers of pro-fibrotic macrophages/monocytes, such as SPP1 and pro-inflammatory cytokines, such as Il-1b, was also observed. Conversely, patients with resolved post-COVID-19 ILD displayed BALF cell gene expression signatures indicative of T-cell activation. Additionally, BALF gene expression patterns associated with pro-fibrotic macrophage activation, neutrophil chemotaxis and downregulation of T-cell activation were also observed in patients with pre-existing fibrotic ILD following COVID-19. These findings suggest that immune response imbalance leading to prolonged activation of innate immunity and subdued adaptive immune responses may be associated with persistent post-COVID-19 ILD.
Project description:To clarify the profile of in BALF exosome collected from mice infected with influenza virus, we infected 100000 pfu of A/Puerto Rico/8/1934 (PR8) strain. BALF was collected at 24, 48, and 72 hour post infection (hpi). For comparison of the profile of the miRNA in BALF exosome induced by innate immune response, we also intranasally inoculated mice with 50 μg of poly(I:C) and collected BALF at 72 hour post inoculation. We found that some miRNAs were common to both influenza virus infectiona and poly(I:C) inoculation, suggesting that exosomal miRNAs in BALF may function in the innate immune response to virus infection.
Project description:Actinobacillus pleuropneumoniae is the etiologic agent of contagious pleuropneumonia, an economically important disease of commercially reared swine throughout the world. To cause this disease, A. pleuropneumoniae must rapidly overcome porcine pulmonary innate immune defenses. Since bronchoalveolar fluid (BALF) contains many of the innate immune components found in the lung, we examined the gene expression of a virulent serovar 1 strain of A. pleuropneumoniae after exposure to concentrated BALF. This experiment was also carried out with a malT mutant of the same strain.