Project description:Bacille Calmette Guerin (BCG) is the only licensed vaccine against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB) disease. However, BCG has limited efficacy, necessitating the development of better vaccines. Non-tuberculous mycobacteria (NTM), a distinct lineage from Mtb, are opportunistic pathogens present in the environment. TB endemic countries experience higher exposure to NTM, but previous studies have not elucidated the relationship between NTM exposure and BCG efficacy. Therefore, we developed a mouse model (BCG+NTM) that mimics human BCG vaccination at an early stage and continuous NTM exposure via the oral route, including during TB infection. Our results show that BCG+NTM mice had improved protection against pulmonary TB correlating with increased pulmonary influx of B-cells, higher titers of anti-Mtb IgA and IgG antibodies in serum and airways, compared to mice vaccinated with BCG alone. Notably, the lungs of BCG+NTM mice developed B-cell aggregates expressing markers of germinal center formation as determined by spatial transcriptomics. We conclude a direct correlation between NTM exposure and protection from TB, with B-cells playing a crucial role.
Project description:The immunologic features of nontuberculous mycobacterial pulmonary disease (NTM-PD) are largely unclear. This study investigated the immunologic features of NTM-PD using digital spatial profiling techniques. Lung tissues obtained from six patients with NTM-PD between January 1, 2006, and December 31, 2020, at Seoul National University Hospital were subjected to RNA sequencing. Cores from the peribronchial and fibrotic stromal areas were stained with CD3, CD68, and DNASyto13, and gene expression at the whole-transcriptome level was quantified using PCR amplification and Illumina sequencing. Lung tissues from four patients with bronchiectasis collected during the same period were used as controls. The RNA sequencing results were validated using immunohistochemistry (IHC) in another cohort (30 patients with NTM-PD and 15 patients with bronchiectasis). NTM-PD exhibited distinct gene expression patterns in T cells and macrophages. Gene set enrichment analysis revealed that pathways related to antigen presentation and processing were upregulated in NTM-PD, particularly in macrophages. Macrophages were more prevalent and the expression of genes associated with the M1 phenotype (CD40 and CD80) was significantly elevated. Although macrophages were activated in the NTM-PD group T cell activity was unaltered. Notably, expression of the costimulatory molecule CD28 was decreased in NTM-PD. IHC analysis showed that T cells expressing Foxp3 or TIM-3, which facilitate the regulatory functions of T cells, were increased. From these, NTM-PD exhibits distinct immunologic signatures characterized by the activation of macrophages without T cell activation.
Project description:Background: Patients with cystic fibrosis (CF) have an elevated lifetime risk of infection and disease caused by nontuberculous mycobacteria (NTM). Currently, there is no method to predict whether patients with cystic fibrosis will develop disease related to non-tuberculous mycobacteria. In non cystic fibrosis populations, several genetic susceptibility factors have been described. In this study, we examined whether patients with cystic fibrosis demonstrate a similar pattern of genetic susceptibility and explored host immune-related biomarkers predictive of NTM pulmonary disease (NTM-PD). Methods: We evaluated whole blood gene expression using bulk RNA-seq in a cohort of CF patients at the time of first isolation of NTM. Differential gene expression was compared in patients who did (n = 12) vs. did not (n= 30) develop NTM-PD following first NTM growth. Results: No differences in demographics or composition of white blood cell sample populations at the time of sample collection were identified between groups. There were no significant differences in the expression of genes previously reported to confer susceptibility to NTM-PD in non-CF populations. However, CF patients who went on to develop NTM-PD had higher expression of genes involved in the interferon ( and ), tumor necrosis factor, and IL6 STAT3 JAK pathways. Conclusion: Patients with CF who develop NTM-PD have increased expression of genes involved in innate immunity, in contrast to non-CF populations where these responses seem to be suppressed.
Project description:Aging has a significant impact on the immune system, leading to a gradual decline in immune function and changes in the body's ability to respond to bacterial infections. Non-tuberculous mycobacteria (NTM), also known as atypical mycobacteria or environmental mycobacteria, are commonly found in soil, water, and various environmental sources. While many NTM species are considered opportunistic pathogens, some can cause significant infections, particularly in individuals with compromised immune systems, such as the elderly. When mycobacteria enter the body, macrophages are among the first immune cells to encounter them, and attempt to engulf mycobacteria through a process called phagocytosis. Some NTM species, including Mycobacterium avium (M.avium) can survive and replicate within macrophages. However, little is known about the interaction between NTM and macrophages in the elderly. In this study, we investigated the mouse bone marrow-derived macrophage (BMMs) response to M. avium serotype 4, one of the main NTM species in patients with pulmonary NTM diseases. Our results demonstrated that old mouse BMMs have an increased level of intracellular iron and are more susceptible to M. avium serotype 4 infection compared to young mouse BMMs. The whole-cell proteomic analysis indicated a dysregulated expression of iron homeostasis-associated proteins in old mouse BMMs regardless of mycobacterial infection. Deferoxamine, an iron chelator, significantly rescued mycobacterial killing and phagolysosome maturation in old mouse BMMs. Therefore, our data indicate that an intracellular iron overload improves NTM survival within macrophages, and suggest a potential application of iron chelating drugs as a host-directed therapy for pulmonary NTM infection in the elderly
Project description:Nontuberculous mycobacterial pulmonary diseases (NTM-PD) are becoming increasingly prevalent and incident, and heightened antibiotic resistance presents a considerable challenge to clinicians. Despite this, our understanding of the factor(s) contributing to host defense against NTM-PD remains incomplete. Herein, we report that the myeloid autophagy-related gene (ATG) 7 promotes host protective responses against NTM-PD by mitigating excessive pathological inflammation, oxidative stress, and cell death associated with neutrophil infiltration. Patients with NTM-PD displayed a notable reduction in ATG7 expression in peripheral blood mononuclear cells and in necrotic lesions at disease sites. Mice with deletion of Atg7 specifically in myeloid cells (Atg7 cKO) exhibited a significant increase in lung bacterial load during infection. Spatial and bulk RNA-seq analyses, as well as biological experiments, revealed heightened myeloid cell infiltration, excessive inflammation, and mitochondrial damage in Atg7 cKO lung tissues. Furthermore, myeloid Atg7-deficient mice showed upregulated apoptosis, necrosis, and GSDME-associated cell death, along with the formation of neutrophil extracellular traps, in the lung tissues during NTM-PD. However, Atg7-deficient macrophages showed only marginal differences in inflammation and cell death in vitro during NTM infection. Our findings demonstrate that myeloid ATG7 plays a major role in non-cell-autonomous protection against NTM-PD by alleviating neutrophil-associated pathological inflammation and cell death.
Project description:We sought to elucidate the differentially expressed host factors in bronchoalveolar lavage cells (BALc) from nontuberculous mycobacteria (NTM)-infected subjects by studying the host transcriptome in during infection. A heatmap was created from the normalized expression of selected genes that showed statistically significant differential expression between NTM-infected and uninfected subjects. Genes with similar expression patterns were grouped and the most highly expressed genes are shown. One of the most differentially expressed gene in the NTM-infected group was the CFD (complement factor D) gene. Of note, a statistically significant three-fold increase in expression of the CAMP gene, encoding the LL-37 peptide was observed in the NTM-infected subject group (padj=0.05).
Project description:Non-tuberculous Mycobacteria (NTM) are a group of emerging bacterial pathogens that have been identified in cystic fibrosis (CF) patients with microbial lung infections. The treatment of NTM infection in CF patients is challenging due to the natural resistance of NTM species to many antibiotics. Mycobacterium abscessus (M. abscessus) is one of the most common NTM strains found in the airway of CF patients. In our current study, we characterized the extracellular vesicles (EVs) released by drug-sensitive M. abscessus untreated or treated with clarithromycin, one of the well-known anti-NTM drugs. Our data show that clarithromycin treatment increases mycobacterial protein trafficking into EVs as well as the secretion of EVs in M. abscessus culture. Additionally, EVs released by clarithromycin-treated M. abscessus increase M. abscessus resistance to clarithromycin when compared to EVs from untreated M. abscessus. EV proteomic analysis further indicates that EVs released by clarithromycin-treated M. abscessus carry an increased level of 50S ribosomal subunits, the target of clarithromycin. Taken together, our results suggest that mycobacterial EVs play an important role in increasing M. abscessus resistance to clarithromycin treatment.
Project description:This study aims to comprehensively investigate the immunological responses associated with non-tuberculous mycobacterial pulmonary disease (NTM-PD). We evaluated immune-related gene expression profiles using nCounter assays on peripheral blood mononuclear cell samples from 18 patients diagnosed with NTM-PD, comparing them with samples from 6 healthy controls.