6 research outputs found
Synthesis, Structure, and SAR of Tetrahydropyran-Based LpxC Inhibitors
In
the search for novel Gram-negative agents, we performed a comprehensive
search of the AstraZeneca collection and identified a tetrahydropyran-based
matrix metalloprotease (MMP) inhibitor that demonstrated nanomolar
inhibition of UDP-3-<i>O</i>-(acyl)-<i>N</i>-acetylglucosamine
deacetylase (LpxC). Crystallographic studies in <i>Aquifex aeolicus</i> LpxC indicated the tetrahydropyran engaged in the same hydrogen
bonds and van der Waals interactions as other known inhibitors. Systematic
optimization of three locales on the scaffold provided compounds with
improved Gram-negative activity. However, the optimization of LpxC
activity was not accompanied by reduced inhibition of MMPs. Comparison
of the crystal structure of the native product, UDP-3-<i>O</i>-(acyl)-glucosamine, in <i>Aquifex aeolicus</i> to the
structure of a tetrahydropyran-based inhibitor indicates pathways
for future optimization
Boosting Intracellular Delivery of Lipid Nanoparticle-Encapsulated mRNA
Intracellular
delivery of mRNA holds great potential for vaccineā and therapeutic discovery and development.
Despite increasing recognition of the utility of lipid-based nanoparticles
(LNPs) for intracellular delivery of mRNA, particle engineering is
hindered by insufficient understanding of endosomal escape, which
is believed to be a main limiter of cytosolic availability and activity
of the nucleic acid inside the cell. Using a series of CRISPR-based
genetic perturbations of the lysosomal pathway, we have identified
that late endosome/lysosome (LE/Ly) formation is essential for functional
delivery of exogenously presented mRNA. Lysosomes provide a spatiotemporal
hub to orchestrate mTOR signaling and are known to control cell proliferation,
nutrient sensing, ribosomal biogenesis, and mRNA translation. Through
modulation of the mTOR pathway we were able to enhance or inhibit
LNP-mediated mRNA delivery. To further boost intracellular delivery
of mRNA, we screened 212 bioactive lipid-like molecules that are either
enriched in vesicular compartments or modulate cell signaling. Surprisingly,
we have discovered that leukotriene-antagonists, clinically approved
for treatment of asthma and other lung diseases, enhance intracellular
mRNA delivery in vitro (over 3-fold, <i>p</i> < 0.005)
and in vivo (over 2-fold, <i>p</i> < 0.005). Understanding
LNP-mediated intracellular delivery will inspire the next generation
of RNA therapeutics that have high potency and limited toxicity
Pharmacodynamic Profiling of a Siderophore-Conjugated Monocarbam in Pseudomonas aeruginosa: Assessing the Risk for Resistance and Attenuated Efficacy
SAR and Structural Analysis of Siderophore-Conjugated Monocarbam Inhibitors of <i>Pseudomonas aeruginosa</i> PBP3
A main challenge in the development
of new agents for the treatment
of <i>Pseudomonas aeruginosa</i> infections is the identification
of chemotypes that efficiently penetrate the cell envelope and are
not susceptible to established resistance mechanisms. Siderophore-conjugated
monocarbams are attractive because of their ability to hijack the
bacteriaās iron uptake machinery for transport into the periplasm
and their inherent stability to metallo-Ī²-lactamases. Through
development of the SAR we identified a number of modifications to
the scaffold that afforded active anti-<i>P. aeruginosa</i> agents with good physicochemical properties. Through crystallographic
efforts we gained a better understanding into how these compounds
bind to the target penicillin binding protein PBP3 and factors to
consider for future design
Identification through structure-based methods of a bacterial NAD+-dependent DNA ligase inhibitor that avoids known resistance mutations
Discovery of Efficacious Pseudomonas aeruginosa-Targeted Siderophore-Conjugated Monocarbams by Application of a Semi-mechanistic Pharmacokinetic/Pharmacodynamic Model
To identify new agents
for the treatment of multi-drug-resistant Pseudomonas
aeruginosa, we focused on siderophore-conjugated
monocarbams. This class of monocyclic Ī²-lactams are stable to
metallo-Ī²-lactamases and have excellent P. aeruginosa activities due to their ability to exploit the iron uptake machinery
of Gram-negative bacteria. Our medicinal chemistry plan focused on
identifying a molecule with optimal potency and physical properties
and activity for in vivo efficacy. Modifications to the monocarbam
linker, siderophore, and oxime portion of the molecules were examined.
Through these efforts, a series of pyrrolidinone-based monocarbams
with good P. aeruginosa cellular activity
(P. aeruginosa MIC<sub>90</sub> = 2
Ī¼g/mL), free fraction levels (>20% free), and hydrolytic
stability
(<i>t</i><sub>1/2</sub> ā„ 100 h) were identified.
To differentiate the lead compounds and enable prioritization for
in vivo studies, we applied a semi-mechanistic pharmacokinetic/pharmacodynamic
model to enable prediction of in vivo efficacy from in vitro data