Research
I. Metabolic remodeling required for tuberculosis infection.
Mycobacterium tuberculosis (Mtb) is a causative agent of tuberculosis (TB), faces a particularly unique challenge in that it resides within human. Evolutionarily, Mtb is capable of entering into a state of a slowed or arrested replication (e.g., a non-replicating state). The majority of TB patients harbor this non-replicating (NR) form of Mtb that is asymptomatic and tolerant to most clinically relevant TB antibiotics. Eoh laboratory is thus focused on expanding our knowledge of the specific metabolic reprograms used by Mtb to complete its pathogenic lifecycle as a source of new antibiotic targets.
- Metabolic activities essential for the transition between a replicating and non-replicating form of Mtb. Mtb spends the majority of its lifetime in a state of slowed or arrested replication while remaining poised to reenter cell cycle. Remarkably, Mtb evolutionarily achieves the capacity to remodel its metabolism to complete the lifecycle.
• First, Eoh laboratory will assess the metabolic reprogramming associated with transitioning between non-replicating latency and a actively replicating form. To this aim, Eoh laboratory uses the isotopic tracing Liquid Chromatography Mass Spectrometry (LC-MS) metabolomics.
• Second, metabolic reprogramming during the transition state requires biochemical/molecular bases but these are still undefined. Eoh laboratory thus studies the regulatory mechanisms; (i) post-translational modification of target enzymes, (ii) allosteric regulation, and (iii) condition-dependent switched interactive partners. - Products of various stages of Mtb pathogenic cycle at the interaction with host immune system. Host immune system acts as an internal shield against invading Mtb. Thus, intervention in the host cell responses against Mtb infection should promise to expand therapeutic option.
• Invading Mtb interacts with host immune cells through either physical contact or indirect modulation of signaling cascades with secreted mediators. Eoh laboratory thus seeks to establish the repertoires of key candidates by using LC-MS based glycolipidome and secreted metabolome.
The studies will lead to a better understanding of Mtb chemistry, metabolism, and pathogenicity. This could facilitate to the discovery of conceptually novel antibiotic targets and diagnostic biomarkers to improve the quality of current TB control.
To achieve these goals, Eoh laboratory seeks to uncover the metabolic adaptive topology of Mtb as well as many infectious agents used to adapt various environmental stresses using the multiomics technique.
II. New antibiotic development targeting the Latent Tuberculosis Infection (LTBI).
Tuberculosis chemotherapy often fails to sterilize Mtb resulting in individuals at high risk of relapse TB and multidrug resistance. Taking advantage of in vitro biochemical stresses and LC-MS metabolomics, we have developed in vitro biofilm or hypoxia culture models to mimic the in vivo latent or persistent infection. Investigating the mechanistic bases underlying Mtb persistence during chronic and latent TB infection will identify points of vulnerability, which could be targeted to clear these bacilli that escape current TB chemotherapy. These models are also being used to study the host immune components that control latent TB infection and uncover new chemotherapy and pathogenic lifecycle of TB.
III. Trehalose-catalytic shift: a new drug target against Latent Tuberculosis Infection.
Eoh laboratory demonstrated that our in vitro M. tuberculosis culture was enriched with latent TB infection and conducted the multiomics profiling. Eoh laboratory observed that trehalose metabolism was significantly altered. A shift in the trehalose carbon fluxes was associated with increased biosynthesis of glycolysis (GL) and pentose phosphate pathway (PPP) intermediates with a concomitant depletion in the biosynthesis of cell wall glycolipids such as trehalose dimycolate (TDM). This shift is termed trehalose-catalytic shift to sustain energy and redox balance of latent Mtb adaptation. TreS deficient Mtb mutants lack the trehalose-catalytic shift activity, thereby resulting in failing to form mature persisters and being hypersensitive to all TB antibiotics. We apply the multiomics integration, CRISPRi target gene knock-down, chemoenzymatic synthesis, and structural biology to screen for TreS inhibitory compounds to discover new TB chemotherapy.
IV. KSHV infection mediated tumorigenesis.
Cellular metabolism is a highly regulated system that safeguards the homeostasis of our body. Metabolic aberrance is often associated with pathological consequences including cancer, infectious diseases, and neuron degenerative diseases. We use oncogenic Kaposi’s sarcoma associated herpesvirus (KSHV) in either 2D- or 3D- culture de novo infection model and LC-MS metabolomics to understand KSHV infection mediated metabolic aberrance in host cells as a trigger of tumorigenic pathogenesis. The outcome of this approach often suggests a new therapeutic options to target Kaposi’s sarcoma and primary effusion lymphoma (PEL) tumor.