Project description:Genetically distinct lineages of Mycobacterium tuberculosis differ in their virulence, transmissibility, and immune evasion capacity. The modern Lineage 2-Beijing (L2-B) clade of Mtb, which is highly prevalent in Asia and now globally distributed, is associated with resistance to the bacille Calmette Guerin (BCG) vaccine. Using a murine BCG vaccination model followed by aerosol challenge with geographically matched L2-B or Lineage 4 clinical isolates, we examined how L2-B circumvents vaccine-induced immunity. BCG-trained alveolar macrophages showed impaired control of L2-B growth in vitro. Spatial transcriptomic profiling of infected lungs revealed broad transcriptional reprogramming, including selective suppression of pathways essential for macrophage activation and trained innate immunity. Similar immune dysregulation was observed in peripheral blood from BCG-vaccinated household contacts of L2-B smear-positive TB patients. Together, these findings define mechanisms by which L2-B evades immune control, highlight key components of BCG-induced protection, and support re-evaluation of current TB vaccine strategies.
Project description:We examined the microRNA profiles of THP-1 macrophages upon the MTB infection of (1) Beijing/W and non-Beijing/W clinical strains, and (2) susceptible and multidrug-resistant (MDR-) MTB strains. THP-1 cells were induced differentiation into a macrophage phenotype. Then cells were infected with three MDR (INHR, RIFR) Beijing/W, three sensitive (INHS, RIFS) Beijing/W, three MDR(INHR, RIFR) non-Beijing/W, and three sensitive (INHS, RIFS) non-Beijing/W strains. Total RNA were extracted and transfered into cDNA for miRNA profile analysis. Non-infected cells were used as control.
Project description:We examined the microRNA profiles of THP-1 macrophages upon the MTB infection of (1) Beijing/W and non-Beijing/W clinical strains, and (2) susceptible and multidrug-resistant (MDR-) MTB strains.
Project description:Background. The Beijing family of Mycobacterium tuberculosis is dominant in countries in East Asia. Genomic polymorphisms are a source of diversity within the M.tuberculosis genome and may account for the variation of virulence among M.tuberculosis isolates. To date there are no studies that have examined the genomic composition of M.tuberculosis isolates from the high TB-burden country, Myanmar. Methodology/Principle findings. Twenty-two M.tuberculosis isolates from Myanmar were screened on whole-genome arrays containing genes from M.tuberculosis H37Rv, M.tuberculosis CDC1551 and M.bovis AF22197. Screening identified 198 deletions or extra regions in the clinical isolates compared to H37Rv. Twenty-two regions differentiated between Beijing and non-Beijing isolates and were verified by PCR on an additional 40 isolates. Six regions (Rv0071-0074 [RD105], Rv1572-1576c [RD149], Rv1585c-1587c[RD149], MT1798-Rv1755c [RD152], Rv1761c [RD152] and Rv0279c) were deleted in Beijing isolates, of which 4 (Rv1572-1576c, Rv1585c-1587c, MT1798-Rv1755c and Rv1761c) were variably deleted among ST42 isolates, indicating a closer relationship between the Beijing and ST42 lineages. The TbD1 region, Mb1582-Mb1583 was deleted in Beijing and ST42 isolates. One M.bovis gene of unknown function, Mb3184c was present in all isolates, except 11 of 13 ST42 isolates. The CDC1551 gene, MT1360 coding for a putative adenylate cyclase, was present in all Beijing and ST42 isolates (except 1). The pks15/1 gene, coding for a putative virulence factor, was intact in all Beijing and non-Beijing isolates, except in ST42 and ST53 isolates. Conclusion. This study describes previously unreported deletions/extra regions in Beijing and non-Beijing M.tuberculosis isolates. The modern and highly frequent ST42 lineage showed a closer relationship to the hypervirulent Beijing lineage than to the ancient non-Beijing lineages. The pks15/1 gene was disrupted only in modern non-Beijing isolates. This is the first report of an in-depth analysis on the genomic diversity of M.tuberculosis isolates from Myanmar. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-66
Project description:The identification of multidrug resistant (MDR), extensively and totally drug resistant Mycobacterium tuberculosis (Mtb), in vulnerable sites such as Mumbai, is a grave threat to the control of tuberculosis. The current study aimed at explaining the rapid expression of MDR in Directly Observed Treatment Short Course (DOTS) compliant patients, represents the first study comparing global transcriptional profiles of 3 pairs of clinical Mtb isolates, collected longitudinally at initiation and completion of DOTS. While the isolates were drug susceptible (DS) at onset and MDR at completion of DOTS, they exhibited identical DNA fingerprints at both points of collection. The whole genome transcriptional analysis was performed using total RNA from H37Rv and 3 locally predominant spoligotypes viz. MANU1, CAS and Beijing, hybridized on MTBv3 (BuG@S) microarray, and yielded 36, 98 and 45 differentially expressed genes respectively. Genes encoding transcription factors (sig, rpoB), cell wall biosynthesis (emb genes), protein synthesis (rpl) and additional central metabolic pathways (ppdK, pknH, pfkB) were found to be down regulated in the MDR isolates as compared to the DS isolate of the same genotype. Up regulation of drug efflux pumps, ABC transporters, trans-membrane proteins and stress response transcriptional factors (whiB) in the MDR isolates was observed. The data indicated that Mtb, without specific mutations in drug target genes may persist in the host due to additional mechanisms like drug efflux pumps and lowered rate of metabolism. Furthermore this population of Mtb, which also showed reduced DNA repair activity, would result in selection and stabilization of spontaneous mutations in drug target genes, causing selection of a MDR strain in the presence of drug pressures. Efflux pump such as drrA may play a significant role in increasing fitness of low level drug resistant cells and assist in survival of Mtb till acquisition of drug resistant mutations with least fitness cost. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-134]
Project description:Transcriptional profile comparison among Beijing and non-Beijing M. tuberculosis isolates. Three M. tuberculosis strains were compared. The laboratory reference strain, H37Rv, belongs to the Euro-American or lineage 4. Two clinical isolates of the East-Asian or lineage 2: 98_1663 is a pre-Beijing or Group 1 isolate, and HN878 is a Beijing or Group 5 isolate. Three replicates were performed for each comparison using two different biological samples.