Browsing by Author "Mahlobo, Precious Zama"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    The host response to infection with pathogenic and non–pathogenic mycobacteria: a proteomics approach
    (Stellenbosch : Stellenbosch University, 2018-12) Mahlobo, Precious Zama; Baker, Bienyameen; Wiid, Ian; Leisching, Gina; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Molecular Biology and Human Genetics.
    ENGLISH ABSTRACT: Tuberculosis (TB) continues to be a major health problem worldwide. In 2017, 1.6 million TB associated deaths were reported (WHO, 2017). The etiological agent of TB disease is Mycobacterium tuberculosis (Mtb), and is a highly successful pathogen due to its ability to persist in the host. The immune system uses the non-specific innate immunity as the first line of defence against invading pathogens. The interplay between macrophages and mycobacteria is not yet fully understood. Mass spectrometry is one of the most effective tools for identification and quantitation of proteins from complex mixtures of biological samples. It has been shown that mycobacteria cultured in detergent medium and detergent-free medium induce differential macrophage host response. Following on a study that identified differentially expressed genes using high-throughput RNA sequencing, we aimed to identify and quantify protein expression of murine bone marrow derived macrophages infected with non-pathogenic mycobacteria, Mycobacterium smegmatis, Mycobacterium bovis BCG, and pathogenic mycobacteria, Mycobacterium tuberculosis H37Rv and Mycobacterium tuberculosis R179 grown in a detergent-free medium. The differential proteomes of C57Bl/6 cells in response to Mtb infection, were analysed at 12 hours post infection using liquid-chromatography-tandem mass spectrometry (LC-MS/MS). Four proteins MYH9, TLN1, AHNAK and GAL-3 were expressed by pathogenic mycobacteria. Moreover, corresponding genes (Myh9, Tln1, Gal-3, and Ahnak) of the differentially expressed proteins were quantified by using quantitative PCR (qPCR) to monitor and analyse gene expression at later time points, 12, 24 & 96 hours post-infection. At the later time points, Myh9, Tln1 and Ahnak, were down-regulated indicating that these genes are only expressed at an early stage (up to 24 hours post-infection) of mycobacterial infection; while Lgal-3 was up-regulated by all slow growers (BCG, H37Rv & R179) at 96 hours post-infection. Galectin 3 is a binding protein known to control the survival of Mtb during infection. The significance of this protein can be further investigated in TB patients and healthy controls.