PROJECT SUMMARY
Multidrug-resistant Tuberculosis (MDR-TB), which accounts for ~20% of recurrent TB cases and is diagnosed in
400,000 patients each year, represents an urgent global health priority that threatens to undermine US TB
elimination strategies. Key to MDR-TB transmission is disruption and non-compliance with standard therapeutic
regimens, which are lengthy (up to 24 months) and require high daily doses of antibiotics. The goal of this project
is to develop an aerosolizable, narrow-spectrum antimicrobial biomaterial that can be paired with approved TB
antibiotics to rapidly clear pulmonary MDR-TB and dramatically shorten the course of treatment. Fundamental
to this strategy is a new class of protein-mimetic host defense peptides we have engineered de novo to undergo
instructed self-assembly within the mycolic-acid rich outer membrane of Mycobacterium tuberculosis (Mtb). We
have shown that our lead candidate, MAD1, elicits TB-specific bacteriolysis within minutes of exposure, without
collateral toxicity towards protective respiratory commensals and host lung tissue. Further, these novel peptides
synergistically enhance the activity of clinical antibiotics to achieve nanomolar anti-TB efficacy. However, these
synthetic peptides have pharmacokinetic liabilities that include rapid clearance and limited pulmonary
bioavailability, and there remain gaps in our knowledge regarding their mechanism of action when combined
with other drugs. The objectives of this application are to: (i) more deeply investigate the mode of action (MoA)
and drug interactions (e.g. synergy) of our lead compound MAD1 in Mtb, (ii) improve its ADME (absorption,
distribution, metabolism and elimination) properties and pharmacokinetic parameters through sequence
optimization and formulation into novel biomaterial aerosols, and (iii) determine the safety profile and efficacy of
lead formulations in disease-relevant preclinical models. We will accomplish these objectives over three aims.
In aim 1, artificial intelligence-guided structure-based sequence screening and recombineering assays will
optimize MAD1’s potency against Mtb and drug-resistant strains, as well as inform on MoA. Whole-genome
sequencing of resistant strains generated during these studies will characterize possible resistance mechanisms
and determine the resistance frequency. Aim 2 will develop inhalable formulations of MAD1 and antibiotics
utilizing our proprietary aerogel delivery system designed to exploit a key metabolic vulnerability of Mtb for rapid
and pathogen-specific pulmonary therapy. Combination bacteriologic studies will assess potential for synergy
towards MDR-TB and persister cells in macrophages. In aim 3, we assess the pulmonary pharmacokinetic
parameters of prioritized aerogel formulations with the goal of optimizing the lung bioavailability and
residence/clearance kinetics of the therapeutic carrier. We will evaluate the safety of therapeutic formulations
via a series of assays (histology, pulmonary function, immunogenicity) and assess in vivo efficacy in several
murine models of acute and chronic TB infection.