Unlabelled: Successful tuberculosis therapy requires treatment with an unwieldy multidrug combination for several months. Thus, there is a growing need to identify novel genetic vulnerabilities that can be leveraged to develop new, more effective antitubercular drugs. Consequently, recent efforts to optimize TB therapy have exploited Mtb chemical genetics to identify pathways influencing antibiotic efficacy, novel mechanisms of antibiotic action, and new targets for TB drug discovery.
View Article and Find Full Text PDFMycobacterium tuberculosis (Mtb) infects several lung macrophage populations, which have distinct abilities to restrict Mtb. What enables Mtb survival in certain macrophage populations is not well understood. Here we used transposon sequencing analysis of Mtb in wild-type and autophagy-deficient mouse macrophages lacking ATG5 or ATG7, and found that Mtb genes involved in phthiocerol dimycocerosate (PDIM) virulence lipid synthesis confer resistance to autophagy.
View Article and Find Full Text PDF() infection of macrophages reprograms cellular metabolism to promote lipid retention. While it is clearly known that intracellular utilize host derived lipids to maintain infection, the role of macrophage lipid processing on the bacteria's ability to access the intracellular lipid pool remains undefined. We utilized a CRISPR-Cas9 genetic approach to assess the impact of sequential steps in fatty acid metabolism on the growth of intracellular .
View Article and Find Full Text PDFThe eukaryotic GID/CTLH complex is a highly conserved E3 ubiquitin ligase involved in a broad range of biological processes. However, a role of this complex in host antimicrobial defenses has not been described. We exploited ( ) induced cytotoxicity in macrophages in a FACS based CRISPR genetic screen to identify host determinants of intracellular growth restriction.
View Article and Find Full Text PDFThe tuberculosis (TB) emergency has been a pressing health threat for decades. With the emergence of drug-resistant TB and complications from the COVID-19 pandemic, the TB health crisis is more serious than ever. Mycobacterium tuberculosis (Mtb), the causative agent of TB, requires iron for its survival.
View Article and Find Full Text PDFDiabetes mellitus increases risk for tuberculosis disease and adverse outcomes. Most people with both conditions have type 2 diabetes, but it is unknown if type 1 and type 2 diabetes have identical effects on tuberculosis susceptibility. Here we show that male mice receiving a high-fat diet and streptozotocin to model type 2 diabetes, have higher mortality, more lung pathology, and higher bacterial burden following Mycobacterium tuberculosis infection compared to mice treated with streptozotocin or high-fat diet alone.
View Article and Find Full Text PDFGenetic differences among mammalian hosts and among strains of Mycobacterium tuberculosis (Mtb) are well-established determinants of tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host-pathogen interactions. To identify host and pathogen genetic determinants of Mtb pathogenesis, we infected members of the highly diverse BXD family of strains with a comprehensive library of Mtb transposon mutants (TnSeq).
View Article and Find Full Text PDFHeterogeneity in human immune responses is difficult to model in standard laboratory mice. To understand how host variation affects Bacillus Calmette Guerin-induced (BCG-induced) immunity against Mycobacterium tuberculosis, we studied 24 unique collaborative cross (CC) mouse strains, which differ primarily in the genes and alleles they inherit from founder strains. The CC strains were vaccinated with or without BCG and challenged with aerosolized M.
View Article and Find Full Text PDFWe used a mouse model to study how Mycobacterium tuberculosis subverts host defenses to persist in macrophages despite immune pressure. CD4 T cells can recognize macrophages infected with a single bacillus in vitro. Under identical conditions, CD8 T cells inefficiently recognize infected macrophages and fail to restrict M.
View Article and Find Full Text PDFGenetic differences among mammalian hosts and ( ) strains determine diverse tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host- pathogen interactions. To identify host and pathogen genetic determinants of pathogenesis, we infected members of the BXD family of mouse strains with a comprehensive library of transposon mutants (TnSeq).
View Article and Find Full Text PDFCell-intrinsic immune mechanisms control intracellular pathogens that infect eukaryotes. The intracellular pathogen () evolved to withstand cell-autonomous immunity to cause persistent infections and disease. A potent inducer of cell-autonomous immunity is the lymphocyte-derived cytokine IFNγ.
View Article and Find Full Text PDFMycobacterium tuberculosis () is a bacterium that exclusively resides in human hosts and remains a dominant cause of morbidity and mortality among infectious diseases worldwide. Host protection against infection is dependent on the function of immunity-related GTPase clade M (IRGM) proteins. Polymorphisms in human associate with altered susceptibility to mycobacterial disease, and human IRGM promotes the delivery of into degradative autolysosomes.
View Article and Find Full Text PDFCell wall peptidoglycan is a heteropolymeric mesh that protects the bacterium from internal turgor and external insults. In many rod-shaped bacteria, peptidoglycan synthesis for normal growth is achieved by two distinct pathways: the Rod complex, comprised of MreB, RodA, and a cognate class B penicillin-binding protein (PBP), and the class A PBPs (aPBPs). In contrast to laterally growing bacteria, pole-growing mycobacteria do not encode an MreB homolog and do not require SEDS protein RodA for growth.
View Article and Find Full Text PDFThe major human genes regulating -induced immune responses and tuberculosis (TB) susceptibility are poorly understood. Although IL-12 and IL-10 are critical for TB pathogenesis, the genetic factors that regulate their expression in humans are unknown. CNBP, REL, and BHLHE40 are master regulators of IL-12 and IL-10 signaling.
View Article and Find Full Text PDFThe immunological synapse allows antigen-presenting cells (APCs) to convey a wide array of functionally distinct signals to T cells, which ultimately shape the immune response. The relative effect of stimulatory and inhibitory signals is influenced by the activation state of the APC, which is determined by an interplay between signal transduction and metabolic pathways. While pathways downstream of toll-like receptors rely on glycolytic metabolism for the proper expression of inflammatory mediators, little is known about the metabolic dependencies of other critical signals such as interferon gamma (IFNγ).
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