[R03] Structure-guided approaches to prevent polymyxin-induced acute kidney injury
Ente: National Institute of Diabetes and Digestive and Kidney Diseases
Scadenza: 2028-06-30
Importo max: 123.375 EUR
Paese: US
Descrizione
Summary
The rise of multidrug-resistant (MDR) bacteria is a grave public health challenge. Polymyxin B serves as an
essential, last-line therapy for life-threatening MDR gram-negative infections, but its clinical use is constrained
by dose-limiting nephrotoxicity. Acute kidney injury (AKI) from polymyxin is driven by its uptake and
accumulation in the kidney proximal tubule, a process mediated by the endocytic receptor LRP2/megalin. The
central goal of this proposal is to uncouple polymyxin’s antimicrobial activity from its renal toxicity by defining
the structural basis for the LRP2-polymyxin interaction and identifying competitive inhibitors. The driving
hypothesis is that blocking the interaction is a feasible strategy to prevent polymyxin-induced AKI and make
this antibiotic safer for critically ill patients. To test this hypothesis, this project will characterize the LRP2-
polymyxin interaction employing two independent structural techniques and then use the structural data to
conduct an in silico screen for competitive inhibitors. Cross-linking mass spectrometry (XL-MS) will be used to
map the binding sites between polymyxin and purified, full-length endogenous human LRP2. Amine-amine
coupling of the polybasic polymyxin molecule to LRP2 will identify the receptor domains that polymyxin binds.
In a second approach, single-particle cryo-electron microscopy (cryo-EM) will visualize the LRP2-polymyxin
complex, revealing polymyxin’s binding modes to LRP2 and any drug-induced conformational changes in
LRP2. These structural insights will be used to perform an in silico screen for small-molecule inhibitors. The
most promising candidates from the in silico screen will be validated in vitro via surface plasmon resonance
(SPR) competition assays. Confirming the ability of candidate inhibitors to disrupt the LRP2-polymyxin
interaction in SPR competition assays would be proof of principle that their interaction is a druggable target.
This research is innovative in its application of cryo-EM and XL-MS techniques to study drug binding to the
complete, endogenous human LRP2 protein. It will also directly address the unanswered question of whether
LRP2-mediated polybasic drug uptake is a specific, competitively targetable process. Expected outcomes
include a detailed map of polymyxin binding sites on LRP2, the first visualization of a polybasic drug bound to
LRP2, and validated lead compounds that demonstrate in vitro inhibitory activity. This research offers a direct
path toward a novel therapy to protect kidney function during polymyxin treatment, thus addressing an urgent
clinical need in the fight against MDR infections.
Istituzione: COLUMBIA UNIVERSITY HEALTH SCIENCES
PI: ANDREW S BEENKEN
Progetto: 1R03DK149104-01
Settori: National Institute of Diabetes and Digestive and Kidney Diseases
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