DOI: 10.1002/cmdc.201600006
Communications
Antivirulence Isoquinolone Mannosides: Optimization of
the Biaryl Aglycone for FimH Lectin Binding Affinity and
Efficacy in the Treatment of Chronic UTI
Cassie Jarvis,[a] Zhenfu Han,[a] Vasilios Kalas,[b] Roger Klein,[b] Jerome S. Pinkner,[b]
Bradley Ford,[b] Jana Binkley,[b] Corinne K. Cusumano,[b] Zachary Cusumano,[d] Laurel Mydock-
McGrane,[d] Scott J. Hultgren,*[b, c] and James W. Janetka*[a, c]
Uropathogenic E. coli (UPEC) employ the mannose-binding ad-
hesin FimH to colonize the bladder epithelium during urinary
tract infection (UTI). Previously reported FimH antagonists ex-
hibit good potency and efficacy, but low bioavailability and
a short half-life in vivo. In a rational design strategy, we ob-
tained an X-ray structure of lead mannosides and then de-
signed mannosides with improved drug-like properties. We
show that cyclizing the carboxamide onto the biphenyl B-ring
aglycone of biphenyl mannosides into a fused heterocyclic
ring, generates new biaryl mannosides such as isoquinolone
22 (2-methyl-4-(1-oxo-1,2-dihydroisoquinolin-7-yl)phenyl a-d-
mannopyranoside) with enhanced potency and in vivo efficacy
resulting from increased oral bioavailability. N-Substitution of
the isoquinolone aglycone with various functionalities pro-
duced a new potent subseries of FimH antagonists. All ana-
logues of the subseries have higher FimH binding affinity than
unsubstituted lead 22, as determined by thermal shift differen-
tial scanning fluorimetry assay. Mannosides with pyridyl substi-
tution on the isoquinolone group inhibit bacteria-mediated he-
magglutination and prevent biofilm formation by UPEC with
single-digit nanomolar potency, which is unprecedented for
any FimH antagonists or any other antivirulence compounds
reported to date.
ic and healthcare burdens worldwide. UTIs predominantly af-
flict women, who have a lifetime risk of 50% for developing an
acute infection and 20% for experiencing multiple, recurrent
infections.[1] Antibiotic resistance[2] among uropathogenic
E. coli (UPEC), which account for the overwhelming majority of
UTIs, is a rising problem. In addition, the ability of UPEC to es-
tablish quiescent reservoirs may lead to the observed recalci-
trance to antibiotic therapy, as chronic bladder reservoirs may
serve as seeds for recurrent UTI and contribute to the trou-
bling nature of this disease.[3] Furthermore, a history of UTI sig-
nificantly predisposes one to recurrent UTI.[4] Thus, antibiotic-
sparing approaches, such as antivirulence strategies[5] that pre-
vent UPEC colonization, represent viable therapeutics to ad-
dress this emerging threat. UPEC express long fibrillar appen-
dages at their cell surface termed type 1 pili,[6] which are
tipped with FimH,[7] to mediate attachment to superficial facet
cells of the bladder epithelium. FimH is a two-domain adhe-
sin[8] comprised of an N-terminal lectin domain, which medi-
ates specific recognition of mannosylated receptors on the
bladder epithelium, and a C-terminal pilin domain, which an-
chors FimH to the tip of the pilus. Upon binding, FimH triggers
host cell invasion and intracellular colonization by UPEC. A pro-
portion of the UPEC population evades expulsion by escaping
into the cytoplasm and replicating to form intracellular bacteri-
al communities (IBCs), from which infection may propagate to
neighboring cells. Formation of IBCs is part of a mechanism
that allows UPEC to gain a foothold in the bladder and build
up in numbers. Targeting FimH with small-molecule[9] and mul-
tivalent carbohydrate mimetics[10] to interfere with bacterial ad-
hesion, invasion, and IBC and biofilm formation represents
a promising therapeutic strategy for combatting recurrent and
antibiotic-resistant UTIs.
Urinary tract infections (UTIs) represent the second most
common infectious disease, imposing enormous socioeconom-
[a] C. Jarvis, Dr. Z. Han, Prof. J. W. Janetka
Washington University School of Medicine
Department of Biochemistry and Molecular Biophysics
660 S. Euclid Ave., St. Louis, MO 63110 (USA)
In preliminary studies we identified biphenyl mannosides 2
and 3 (Figure 1) as promising antagonists of FimH by X-ray-
structure-based design.[11] Compound 3 exhibits good inhibi-
tion of FimH function using UPEC strain UTI89 as determined
by a hemagglutination assay (HAI=0.5 mm) and biofilm assay
(IC50 =1.35 mm). This study revealed that meta substitution on
the biphenyl B-ring with a hydrogen bond acceptor, such as
the methyl amide of 3, was optimal. Further structure–activity
relationship (SAR) studies from us and others[12] produced man-
nosides such as 5 and 6, indicating that addition of a small
substituent at the ortho position of the biphenyl A-ring leads
to marked enhancements in potency. For example, ortho-
methyl and chloro groups as with 5 and 6 were found to in-
[b] V. Kalas, R. Klein, J. S. Pinkner, Dr. B. Ford, J. Binkley, Dr. C. K. Cusumano,
Prof. S. J. Hultgren
Washington University School of Medicine
Department of Molecular Microbiology
660 S. Euclid Ave., St. Louis, MO 63110 (USA)
[c] Prof. S. J. Hultgren, Prof. J. W. Janetka
Washington University School of Medicine
Center for Women’s Infectious Disease Research (cWIDR)
660 S. Euclid Ave., St. Louis, MO 63110 (USA)
[d] Dr. Z. Cusumano, Dr. L. Mydock-McGrane
Fimbrion Therapeutics Inc.
4041 Forest Park Ave., St. Louis, MO 63108 (USA)
Supporting information for this article is available on the WWW under
ChemMedChem 2016, 11, 367 – 373
367
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim