Profiling microRNA expression in bovine alveolar macrophages using RNA-seq.

MicroRNAs (miRNAs) are important regulators of gene expression and are known to play a key role in regulating both adaptive and innate immunity. Bovine alveolar macrophages (BAMs) help maintain lung homeostasis and constitute the front line of host defense against several infectious respiratory diseases, such as bovine tuberculosis. Little is known, however, about the role miRNAs play in these cells. In this study, we used a high-throughput sequencing approach, RNA-seq, to determine the expression levels of known and novel miRNAs in unchallenged BAMs isolated from lung lavages of eight different healthy Holstein-Friesian male calves. Approximately 80 million sequence reads were generated from eight BAM miRNA Illumina sequencing libraries, and 80 miRNAs were identified as being expressed in BAMs at a threshold of at least 100 reads per million (RPM). The expression levels of miRNAs varied over a large dynamic range, with a few miRNAs expressed at very high levels (up to 800,000RPM), and the majority lowly expressed. Notably, many of the most highly expressed miRNAs in BAMs have known roles in regulating immunity in other species (e.g. bta-let-7i, bta-miR-21, bta-miR-27, bta-miR-99b, bta-miR-146, bta-miR-147, bta-miR-155 and bta-miR-223). The most highly expressed miRNA in BAMs was miR-21, which has been shown to regulate the expression of antimicrobial peptides in Mycobacterium leprae-infected human monocytes. Furthermore, the predicted target genes of BAM-expressed miRNAs were found to be statistically enriched for roles in innate immunity. In addition to profiling the expression of known miRNAs, the RNA-seq data was also analysed to identify potentially novel bovine miRNAs. One putatively novel bovine miRNA was identified. To the best of our knowledge, this is the first RNA-seq study to profile miRNA expression in BAMs and provides an important reference dataset for investigating the regulatory roles miRNAs play in this important immune cell type.

Nanobiotechnological approaches to delivery of DNA vaccine against fungal infection.

Vaccines play an essential role in keeping humans healthy. Innovative approaches to their use include the utilization of plasmid DNA encoding sequences to express foreign antigens. DNAhsp65 from Mycobacterium leprae is suitable for this purpose due to its ability to elicit a powerful immune response. Controlled release systems represent a promising approach to delivering vaccines. In this work, we used liposomes or PLGA systems to deliver DNAhsp65 to treat the pulmonary fungal infection Paracoccidioidomycosis. Both formulations modulated a protective immune response and reduced the pulmonary fungal burden even in the groups receiving less than four times the amount of the DNAhps65 entrapped within the nanoparticles. Although both systems had the same effective therapeutic results, the advantage of the liposome formulation was that it was administered intranasally, which may be more easily accepted by patients. These systems are a great alternative to be considered as adjuvant vaccine therapy for systemic mycosis.

Intranasal vaccination with messenger RNA as a new approach in gene therapy: use against tuberculosis.

BACKGROUND: mRNAs are highly versatile, non-toxic molecules that are easy to produce and store, which can allow transient protein expression in all cell types. The safety aspects of mRNA-based treatments in gene therapy make this molecule one of the most promising active components of therapeutic or prophylactic methods. The use of mRNA as strategy for the stimulation of the immune system has been used mainly in current strategies for the cancer treatment but until now no one tested this molecule as vaccine for infectious disease. RESULTS: We produce messenger RNA of Hsp65 protein from Mycobacterium leprae and show that vaccination of mice with a single dose of 10 µg of naked mRNA-Hsp65 through intranasal route was able to induce protection against subsequent challenge with virulent strain of Mycobacterium tuberculosis. Moreover it was shown that this immunization was associated with specific production of IL-10 and TNF-alpha in spleen. In order to determine if antigen presenting cells (APCs) present in the lung are capable of capture the mRNA, labeled mRNA-Hsp65 was administered by intranasal route and lung APCs were analyzed by flow cytometry. These experiments showed that after 30 minutes until 8 hours the populations of CD11c+, CD11b+ and CD19+ cells were able to capture the mRNA. We also demonstrated in vitro that mRNA-Hsp65 leads nitric oxide (NO) production through Toll-like receptor 7 (TLR7). CONCLUSIONS: Taken together, our results showed a novel and efficient strategy to control experimental tuberculosis, besides opening novel perspectives for the use of mRNA in vaccines against infectious diseases and clarifying the mechanisms involved in the disease protection we noticed as well.

Factors associated with severe granulomatous pneumonia in Mycobacterium tuberculosis-infected mice vaccinated therapeutically with hsp65 DNA.

Resistant C57BL/6 mice infected in the lungs with Mycobacterium tuberculosis and then therapeutically vaccinated with Mycobacterium leprae-derived hsp65 DNA develop severe granulomatous pneumonia and tissue damage. Analysis of cells accumulating in the lungs of these animals revealed substantial increases in T cells secreting tumor necrosis factor alpha and CD8 cells staining positive for granzyme B. Stimulation of lung cells ex vivo revealed very high levels of interleukin-10, some of which was produced by B-1 B cells. This was probably an anti-inflammatory response, since lung pathology was dramatically worsened in B-cell gene-disrupted mice.

Effect of microbial heat shock proteins on airway inflammation and hyperresponsiveness.

Microbial heat shock proteins (hsp) have been associated with the generation and induction of Th1-type immune responses. We tested the effects of treatment with five different microbial hsp (Mycobacterium leprae, Streptococcus pneumoniae, Helicobacter pylori, bacillus Calmette-Guérin, and Mycobacterium tuberculosis) in a murine model of allergic airway inflammation and airway hyperresponsiveness (AHR). Mice were sensitized to OVA by i.p. injection and then challenged by OVA inhalation. Hsp were administered to each group by i.p. injection before sensitization and challenge. Sensitized and challenged mice developed increased serum levels of OVA-specific IgE with significant airway eosinophilia and heightened responsiveness to methacholine when compared with nonsensitized animals. Administration of M. leprae hsp prevented both development of AHR as well as bronchoalveolar lavage fluid eosinophilia in a dose-dependent manner. Treatment with M. leprae hsp also resulted in suppression of IL-4 and IL-5 production in bronchoalveolar lavage fluid, while IL-10 and IFN-gamma production were increased. Furthermore, M. leprae hsp treatment significantly suppressed OVA-specific IgE production and goblet cell hyperplasia/mucin hyperproduction. In contrast, treatment with the other hsp failed to prevent changes in airway responsiveness, lung eosinophilia, or cytokine production. Depletion of gamma/delta T lymphocytes before sensitization and challenge abolished the effect of M. leprae hsp treatment on AHR. These results indicate selective and distinctive properties among the hsp, and that M. leprae hsp may have a potential therapeutic role in the treatment of allergic airway inflammation and altered airway function.

Persistence of lymphocytic choriomeningitis virus at very low levels in immune mice.

Lymphocytic choriomeningitis virus (LCMV), strain WE, is a non-cytopathic RNA virus that is highly adapted to its natural host, the mouse. Acute infection of adult mice leads to generalized virus spread, followed by cytotoxic T lymphocyte-mediated virus clearance below the detection levels of conventional assays within 2-3 weeks. Indirect evidence had suggested that virus or viral antigen might persist in the immune mouse. Here we demonstrate LCMV-WE persistence at low levels after infection with 10(2) or 10(6) plaque-forming units, shown as viral genome, viral antigen, and replicative virus using sensitive in vitro and in vivo assays. The finding that LCMV-WE persists in the face of apparently intact immune responses resembles the situation in some viral (hepatitis B and C, HIV) and bacterial (tuberculosis, leprosy) infections in humans; the results are relevant to the understanding not only of other murine and human persistent viral infections but also of protective immunological memory by "infection immunity."

Gamma/delta cells in tissue from patients with sarcoidosis.

BACKGROUND: Because gamma/delta T lymphocytes (gamma delta cells) respond to myco-bacterial antigens in vitro and accumulate in the skin lesions of patients with certain granulomatous infections (leprosy, leishmaniasis), it was hypothesised that these cells might have a role in the pathogenesis of sarcoidosis, a disease also characterised by granuloma formation. Having failed to demonstrate an increase in gamma delta cells in the blood of patients with sarcoidosis, the aim of this study was to examine samples of bronchoalveolar lavage (BAL) fluid and biopsy tissue. METHODS: Samples from 23 patients (13 women) with newly diagnosed sarcoidosis, of mean age 31 years and median percentage of lymphocytes in the BAL fluid of 31%, were studied. Controls included normal subjects and patients with other interstitial lung diseases (ILD). Cytopreparations of BAL fluid (n = 13) and cryostat sections (five mediastinal nodes, 14 transbronchial biopsies) were stained with alkaline phosphatase-antialkaline phosphatase and monoclonal antibodies to CD3, CD4, CD8, CD25, and gamma delta T cell receptor (TCR). RESULTS: All patients had typical chest radiographs (16 stage I, four stage II, three stage III). All were Mantoux negative with negative tuberculosis cultures. Compared with normal controls and patients with other interstitial lung diseases there was no increase in gamma delta cells in the BAL fluid (sarcoidosis, 1% (range 0-4%) total cells; ILD, 1% (0-2%); controls, 0.5% (0-2%); p > 0.05, Kruskal-Wallis). Likewise, there was no increase in gamma delta cells in the transbronchial biopsy specimens (sarcoidosis, 1/high power field (hpf) (range 0-2); ILD, < 1/hpf (0-4); controls < 1/hpf (0-2); p > 0.05). gamma delta cells were rarely seen in the lymph nodes in spite of the presence of numerous granulomas. CONCLUSION: These results provide further evidence that gamma delta cells are not increased in most patients with sarcoidosis.