Transcriptional profile of the immune response in the lungs of patients with active tuberculosis.
ABSTRACT Despite advances in diagnosis and treatment, Mycobacterium tuberculosis causes active disease in about 8 million people worldwide annually. The study of the interplay between the host and the pathogen at the site of infection in human TB may contribute to elucidate the pathogenesis of the disease. In this work, using macroarray technology and real-time PCR, we analyzed the modulation of 847 genes encoding immune-inflammatory mediators in BALF samples of patients affected by active pulmonary TB (PTB) and control patients affected by non-TB diseases. The data show that the PTB milieu contains a complex network of gene activation. Different genes with adhesive properties and involved in tissue repair and fibrosis were modulated. In TB patients, we observed the up-regulation of cytokines, including IFN-gamma and IFN-gamma pathway genes, of several apoptotic genes, and of potent transcriptional activators. These findings can contribute to elucidate the mechanisms of MTB pathogenicity in humans.
[show abstract] [hide abstract]
ABSTRACT: The host response to Mycobacterium tuberculosis includes macrophage activation, inflammation with increased immune effector cells, tissue necrosis, and cavity formation, and fibrosis, distortion, and bronchiectasis. To evaluate the molecular basis of the immune response in the lungs of patients with active pulmonary tuberculosis (TB), we used bronchoalveolar lavage to obtain cells at the site of infection. Affymetrix GeneChip microarrays and cDNA nylon filter microarrays interrogated gene expression in bronchoalveolar lavage (BAL) cells from 11 healthy controls and 17 patients with active pulmonary TB. We found altered gene expression for 69 genes in TB versus normal controls that included cell surface markers, cytokines, chemokines, receptors, transcription factors, and complement components. In addition, TB BAL cell gene expression patterns segregated into 2 groups: one suggestive of a T helper type 1 (Th1) cellular immune response with increased signal transducer and activator of transcription-4 (STAT-4), interferon-gamma (IFN-gamma receptor), and monokine induced by IFN-gamma (MIG) expression with increased IFN-gamma protein levels in BAL fluid; the other group displayed characteristics of Th2 immunity with increased STAT-6, CD81, and IL-10 receptor expression. We were able to demonstrate that a Th2 presentation could change to a Th1 pattern after anti-tuberculous treatment in 1 TB patient studied serially. These gene expression data support the conclusion that pulmonary TB produces a global change in the BAL cell transcriptome with manifestations of either Th1 or Th2 immunity.Tuberculosis 02/2008; 88(1):39-51. · 3.47 Impact Factor
Article: Mycobacterial stress regulation: The Dps "twin sister" defense mechanism and structure-function relationship.[show abstract] [hide abstract]
ABSTRACT: In this work, we have tried to emphasize the connection between mycobacterial growth and regulation of gene expression. Utilization of multiple carbon sources and diauxic growth helps bacteria to regulate gene expression at an optimum level so that the inhospitable conditions encountered during nutrient depletion can be circumvented. These aspects will be discussed with respect to mycobacterial growth in subsequent sections. Identification and characterization of genes induced under such conditions is helpful to understand the physiology of the bacterium. Although it is necessary to compare the total expression profile of proteins as they transit from vegetative growth to stationary phase, at times a lot of insights can be deciphered from the expression pattern of one or two proteins. We have compared the protein expression and sigma factor selectivity of two such proteins in M. smegmatis to understand the differential regulation of genes playing diverse function in the same species. Some newer insights on the structure and function of one of the Dps proteins are also explained.International Union of Biochemistry and Molecular Biology Life 12/2009; 62(1):67-77. · 3.51 Impact Factor