Novel Isoxazole Derivatives with Potent FXR Agonistic Activity Prevent Acetaminophen-Induced Liver Injury

Article abstract of DOI:10.1021/acsmedchemlett.8b00423

Acetaminophen misuse is a leading cause of acute liver failure and liver transplantation for which therapy is poorly effective. FXR ligands have shown effective in reducing liver injury in several experimental and clinical settings. In this Letter, we have elaborated on the structure of GW4064, the first nonsteroidal agonist for FXR, to identify novel isoxazoles endowed with FXR agonistic activity and improved ADME properties. The pharmacological characterization and molecular docking studies for the structure-activity rationalization allowed the identification of several FXR agonists with nanomolar potency in transactivation and SRC-1 recruitment assays. This characterization resulted in the identification of a potent FXR agonist, compound 20 that was orally active, and rescued mice from acute liver failure caused by acetaminophen overdose in a FXR-dependent manner.

Full text of DOI:10.1021/acsmedchemlett.8b00423

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Letter
Novel isoxazole derivatives with potent FXR agonistic
activity prevent acetaminophen induced liver injury
Valentina Sepe, Silvia Marchianò, Claudia Finamore, Giuliana Baronissi, Francesco Saverio Di
Leva, Adriana Carino, Michele Biagioli, Chiara Fiorucci, Chiara Cassiano, Maria Chiara Monti,
Federica Del Gaudio, Ettore Novellino, Vittorio Limongelli, Stefano Fiorucci, and Angela Zampella
ACS Med. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acsmedchemlett.8b00423 • Publication Date (Web): 06 Dec 2018
Downloaded from http://pubs.acs.org on December 6, 2018
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Novel isoxazole derivatives with potent FXR agonistic activity
prevent acetaminophen induced liver injury
Valentina Sepe,1 Silvia Marchianò,2 Claudia Finamore,1 Giuliana Baronissi,1 Francesco Saverio Di
Leva1§, Adriana Carino,2 Michele Biagioli,2 Chiara Fiorucci,2 Chiara Cassiano,4 Maria Chiara Monti,4
Federica del Gaudio,4 Ettore Novellino,1 Vittorio Limongelli,1,3 Stefano Fiorucci2§ and Angela
Zampella1§*
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1Department of Pharmacy, University of Naples "Federico II", via D. Montesano 49, 80131 Naples, Italy.
2Department of Surgery and Biomedical Sciences, Nuova Facoltà di Medicina, Perugia, Italy
3Università della Svizzera Italiana (USI), Faculty of Biomedical Sciences, Institute of Computational Science - Center for
Computational Medicine in Cardiology, Via G. Buffi 13, CH-6900 Lugano, Switzerland.
4Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, Salerno, Italy.
KEYWORDS: FXR agonists, bile acid receptors, trisubstituted isoxazole scaffold, liver diseases, acetaminophen,
hepatotoxicity.
ABSTRACT: Acetaminophen misuse is a leading cause of acute liver failure and liver transplantation for which therapy is poorly
effective. FXR ligands have shown effective in reducing liver injury in several experimental and clinical settings. In this report, we
have elaborated on the structure of GW4064, the first non-steroidal agonist for FXR, to identify novel isoxazoles endowed with FXR
agonistic activity and improved ADME properties. The pharmacological characterization and molecular docking studies for the
structure-activity rationalization allowed the identification of several FXR agonists with nanomolar potency in transactivation and
SRC-1 recruitment assays. This characterization resulted in the identification of a potent FXR agonist, compound 20 that was orally
active, and rescued mice from acute liver failure caused by acetaminophen overdose in a FXR-dependent manner.
Apart from their function in facilitating the absorption of dietary
A
R=OH R1=H
CDCA (1)
lipids by the small intestine, bile acids regulate their own
synthesis, secretion, transport, storage, metabolism, and
toxicity, by activating a family of receptors known as bile acid
activated receptors. This family includes both G-protein
coupled receptors and nuclear receptors such as the farnesoid X
receptor (FXR). FXR is a bile acid sensor, with primary bile
acids, i.e. chenodeoxycholic acid (CDCA, 1) in humans, and
cholic acid (CA) in mouse, and the corresponding taurine or
glycine amide conjugates (Figure 1A), serving as natural
ligands.1,2
FXR is expressed by entero-hepatic tissues including liver,
gallbladder, intestine, and by the kidney, governing bile acid
homeostasis by repressing bile acid synthesis and uptake while
increasing their urinary excretion, as protective mechanism in
conditions of impaired biliary excretion (cholestasis).3 In
addition, FXR activation plays functional roles in regulating
glucose4 and lipid metabolism5,6 and exerting robust anti-
inflammatory activity in intestine7 and in the liver,8 and is
considered a validated target for the treatment of liver diseases,
such as cholestasis, liver fibrosis,9 steatohepatitis (NASH),10,11
diabetes,12 as well as obesity,13 metabolic syndrome,14 and
inflammatory bowel disease.15
O
R=OH R1=OH CA
Bile acids BAs
R2=OH
R1
12
R=H R1=H
LCA
24
R2
R=H R1=OH DCA
SO3Na
Tauro-conjugated BAs
R2=NH
R2=NH
7
3
HO
R
H
Glyco-conjugated BAs
COONa
COOH
O
N
O
COOH
Cl
O
O
N
B
COOH
Cl
Cl
Cl
HO
OH
Cl
Cl
H
GW4064 (3)
6-ECDCA/OCA (2)
Px-102
COOH
S
O
O
OCF3
LJN452/tropifexor/LMB763
N
N
N
F
Figure 1. A) Endogenous bile acids; B) FXR agonists in advanced
clinical trials
These molecules cover diverse chemical spaces that should be
included in two large families, steroidal and non-steroidal
scaffolds. Figure 1B highlights FXR agonists currently in
advanced pre-clinical and clinical trials. Within the two above
mentioned families, the semisynthetic CDCA derivative
obeticholic acid (INT747/6-ECDCA/OCA, 2),19 represents the
first-in-class of FXR ligands approved for the treatment of
UDCA-resistant patients with primary biliary cholangitis
(PBC), recently progressed in Phase III trials on NASH patients.
Hence, FXR agonists are of great pharmacological interest and
several small molecule agonists have been described.16,17,18
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On the other hand, GW4064 (3) is a first in class of non-
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In contrast, nitrile 6 and alcohol 7 exhibited similar activity to
GW4064. The efficacy of compounds 6 and 7 is highly
influenced by the position of the non-acidic substituent on the
terminal aromatic ring (compare 6 vs 13 and 7 vs 12) with p-
substituted derivatives showing a comparable efficacy than
GW4064 in SRC-1 recruitment assay (see Table 1).
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steroidal FXR ligands representing the prototype of isoxazole-
type FXR agonists20 endowed with an efficacy of 140% versus
CDCA. Several reports over the years have elaborated on the
GW4064 chemical space to address the limited bioavailability
as well as the stilbene-mediated photo-instability. Thus,
medicinal chemistry protocols have been mainly focused on the
linker between the largely conserved trisubstituted isoxazole
core and the terminal acidic entity, affording to the
identification of a large family of isoxazole derivatives.16,17
Among these, Px-102 and LJN452 (tropifexor, LMB763),21,22
with a trans-cyclopropyl and an 8-azabicyclo[3.2.1]-octane ring
as linker, respectively, represent elegant solutions to the poor
GW4064 ADME profile. Both molecules have recently
progressed into Phase II clinical trial in patients with NASH.
The challenge of the present work is to find novel isoxazole-
type FXR agonists of similar efficacy with the additional
requirement of improved ADME properties. Thus, several
modifications have been introduced on the oxymethylene at C-
4 while maintaining the central isoxazole core, with the
isopropyl group at C-5 and the 2,6-dicloro-substituted phenyl
moiety at C-3. The structures of the newly identified FXR
agonists are shown in Table 1. Pharmacological experiments
resulted in the identification of several compounds endowed
with selective agonistic activity toward FXR and notably to the
identification of compound 20, which combines the good
pharmacokinetic properties with the distinct ability to
specifically bind and regulate FXR activity in vivo, and to
rescue mice from acute liver failure caused by acetaminophen
overdose in a FXR-dependent manner.
Of interest, in the above subset of simplified derivatives, the
replacement of the COOH moiety with the methyl sulfonate
isoster produces compound 9, with a promising efficacy (167%
vs 1, 109% vs 2) and, thus, opening up, in this class of
molecules, possibilities for minimizing phase II metabolism in
vivo. Elongation at C-4 isoxazole chemical space by
introduction of an additional substituted aromatic ring resulted
in an opposite behavior with the carboxylic group on the
terminal aryl moiety resulting a mandatory hallmark for
effective FXR agonists. In a cross comparison between the
carboxylic acid bearing derivatives, the exact position of the
acid moiety on the terminal aromatic ring produces a negligible
effect on SRC-1 recruitment with the meta-derivative 24
slightly more effective than the para isomer 20. Of interest, the
above efficacy in SRC-1 recruitment is not affected by the
conformational freedom around the two aromatic rings with the
constrained derivative 16 showing comparable efficacy than
compound 24.
Alpha Screen results were confirmed by transactivation assay
on HepG2 cells transiently transfected with hFXR with the
relative potency of all series investigated by a detailed
measurement of concentration-response curves. As reported in
Table 1, the best match in term of efficacy and potency
outcomes for compounds 6, 16, 20 and 24, with compound 20
as the most potent derivative found in this screening (EC50
0.30±0.006 μM, efficacy 149%). Besides, even if less potent
than GW4064 in FXR transactivation, these compounds
showed a similar efficacy in SRC-1 recruitment with respect of
GW4064 as reported in Table 1. Thus, compound 20 represents
the most promising compound of the series considering its
efficacy in the recruitment of the coactivator SRC-1 very close
to GW4064 (Table 1) and pharmacokinetics profile (see below
for details).
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The synthetic procedures for the preparation of compounds 4-
24 and Scheme S1 are reported and detailed in the
Supplementary Information (SI).
FXR agonistic activities are reported in Table 1. Efficacy of
compounds 4-24 was firstly evaluated on FXR in a cell-free
Alpha Screen assay in comparison with reference compounds
1-3.
First, fragmentation of GW4064 (3) structure resulted in a
general drop in activity respect to 6-ECDCA and GW4064 with
dramatic effects operated by the presence of the carboxyl group
on the terminal aromatic group (compounds 8 and 13).
Table 1. FXR agonistic activity of 4-24
2
R1
3
O
N
1
6
O
4
R2
5
Cl
Cl
b
Compound
R1
R2
Eff (% Ref.)a
EC50
vs CDCA
-
vs ECDCA
61±16
-
101±15
69±7
CDCA (1)
6-ECDCA (2)
GW4064 (3)
4
5
6
7
8
-
-
-
H
H
H
H
H
-
-
-
H
20
0.5
0.02
165±7
166±15
114±7
136±7
151±6
164±18
43±18
167±7
120±6
93±17
76±20
1.59±0.35
3.59±1.08
0.81±0.20
2.93±1.09
6.67±1.7
1.09±0.1
2.06±0.26
10.17±0.84
4.37±0.72
COOMe
CN
CH2OH
COOH
SO2CH3
H
83±7
92±6
100±8
26±18
102±7
73±6
56±17
46±20
9
H
10
11
12
COOMe
CN
CH2OH
H
H
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COOH
H
H
67±18
125±3
40±18
64±3
19.74±0.31
2.8±0.36
1
2
3
4
COOMe
15
H
121±2
61±2
0.83±0.06
5
CH2OH
6
7
8
9
16
17
18
19
20
21
22
23
H
H
H
H
H
H
H
H
175±3
115±3
56±1
50±2
63±4
91±13
36±3
56±5
63±14
1.4±0.32
COOH
O
92±1
0.73±0.07
0.94±0.02
0.74±0.02
0.30±0.006
1.15±0.37
5.4±0.51
COOMe
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O
83±2
CN
O
103±4
CH2OH
O
149±12
COOH
O
97±3
COOMe
O
117±5
CN
O
124±14
0.67±0.038
CH2OH
O
24
H
191±4
130±4
0.46±0.033
COOH
aAlpha Screen coactivator recruitment assay measuring a direct interaction of FXR with SRC-1; ligands were tested at 5 μM. Eff (%) is
the maximum efficacy of the compound relative to CDCA and/or 6-ECDCA set alternatively as 100%. Results are expressed as mean of
three independent measurements ± standard error. bTransactivation assays on HepG2 cells. EC50 values (μM) were calculated from at least
three experiments. Results are expressed as mean ± SEM.
Therefore, we have decided to perform docking studies to shed
light on its binding mode to the ligand binding domain (LBD)
of FXR. The most occurring top scored docking pose shows that
the ligand’s 3-(2,6-dichlorophenyl)-5-isopropylisoxazole
moiety occupies the hydrophobic cavity of the LBD defined by
helices H3, H5, H6, H7, H11 and H12 (Figure 2A). Herein, the
ligand engages favorable van der Waals contacts with the
residues Phe284, Leu287, Phe329, Ile352, Trp454, and Leu465.
In addition, the isoxazole ring forms a hydrogen bond with the
protonated His447 of H10 and -stacking interactions with
Trp469 of H12. These ligand/protein interactions are able to
stabilize in the LBD of FXR the cation- interaction formed by
the latter two residues (i.e., His447 and Trp469) that has been
reported to favor the receptor conformation responsible for the
recruitment of the coactivator partner, activating gene
transcription.23,24,25 On the other side of the binding site, the
carboxylic group of compound 20 H-binds with the backbone
atoms of Met265 and forms a salt bridge with the side chain of
Arg331 at H5. The latter is the strongest interaction between 20
and FXR, thus acting as ligand anchor point in the LBD. It is
worth noting that a similar ionic interaction with Arg331 has
been previously reported to stabilize the binding of bile acid
derivatives to FXR.23 Finally, the ligand’s p-
(phenoxymethyl)phenoxymethyl linker forms a number of
hydrophobic contacts with residues such as Met265, Leu287,
Met290, Ile335, and Ile352, contributing to stabilize the ligand
binding conformation.
The elucidation of the binding mode of 20 allowed the
rationalization of the different efficacy values of the other
derivatives of the series reported in Table 1. From the structural
point of view, the compounds of the series differ for the distance
of the isoxazole ring from the terminal functional group and the
nature of the latter. Compounds endowed with the
biphenyloxymethyl and the p-(phenoxymethyl)phenoxymethyl
linker like compound 20 and presenting diverse terminal groups
such as –COOH, –CH2OH, –COOCH3 and –CN, can similarly
interact with Arg331 thanks to both the flexibility of the
ligand’s linker and the arginine side chain (see Figure S1).
As a result, the derivatives with para and meta substituted
terminal groups display comparable efficacy (i.e., 20 vs 24).
However, less polar terminal functional groups like –COOCH3
(9 and 21) weaken the interaction with Arg331, thus reducing
the ligand-induced recruitment of the coactivator (i.e., lower
efficacy). On the other hand, the terminal functional group of
compounds endowed with the shorter phenoxymethyl linker (4
to 8, 10 to 13, and 8) poorly interacts with Arg331, while it is
placed close by hydrophobic residues like Ile335, Met265 and
Met290 and the polar His294 (see Figure S2). This explains
why in these compounds the presence of polar but not charged
terminal functional groups leads to ligands with higher efficacy
(see 5, 6, 7 and 9 vs 8).
Finally, considering the structural similarity between 20 and
GW4064, we deemed important to compare the docking pose
of 20 with the X-ray binding conformation of GW4064.23 The
overlap of the two binding modes in the LBD of FXR shows a
common pattern of interaction with the receptor in which the
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ACS Medicinal Chemistry Letters
two ligands similarly occupy the LBD, thus allowing the proper
interaction with His447 and Arg331 (Figure 2B).
The physicochemical parameters of a subset of the above
mentioned analogs were assessed by LC-MS analysis (Table 2).
Page 4 of 7
carcinoma cell line HepG2 by RT-PCR, with GW4064 (10 μM)
as reference compound. Among the three selected hits,
compounds 20 and 24 at 5 μM concentration were more potent
than GW4064 in the induction of SHP mRNA expression
(Figure S3 in the SI). Because this gene is endowed with a
canonical FXR-responsive element in the promoter, this result
is fully consistent with the nature of compounds 20 and 24 as
potent FXR agonists. Of interest, the above potency is
independent from the position of the carboxylic unit on the
terminal aromatic ring. Further, the in vitro profile of
compounds 20 and 24 was expanded to common off targets for
bile acid receptor ligands. Compounds 20 and 24 were unable
to induce LXRα/LXRβ and PPARγ transactivation on HepG2
cells (Figure S3, SI). Moreover, compounds 4-24 were
demonstrated inactive toward GPBAR1 (Figure S4, SI).
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Figure 2. (A) Docking pose of 20 (cyan sticks) in the FXR LBD
crystal structure. The receptor is shown as gray ribbons, with amino
acids important for ligand binding highlighted as sticks. Non polar
hydrogens are omitted for clarity. Hydrogen bonds are shown as
dashed black lines. (B) Superposition between the predicted
binding mode of 20 and the crystallographic pose of GW4064
(yellow sticks).
Collectively, compound 20 combines the high efficacy in the
recruitment of SRC-1 at FXR, fully comparable to GW4064
(Table 1), with an excellent metabolic stability (Table 2), while
the low aqueous solubility might raise concerns over its oral
bioavailability in vivo. Thus, to evaluate the in vivo intestinal
absorption, mice were administered with compound 20 for three
days by o.s. or by i.p and hepatic expression of target genes, i.e.
SHP and BSEP, measured by RT-PCR.
As expected, compound 6 suffers of very low aqueous
solubility, whereas 9 gains in polarity respect to GW4064 (3).
The comparison between the carboxylic acid derivatives 16, 20
and 24, isomeric for the position of the carboxylic unit on the
terminal aromatic ring is of interest. Compound 24, bearing the
acid in the 3-position relative to the oxymethylene linker, as
well as the corresponding constrained derivative 16, exhibited
improved aqueous solubility compared to the corresponding 4-
position isomer, compound 20.
These results were further challenged by assessing the
metabolic stability by in vitro incubation with rat liver
microsomes. Compounds 16, 20 and 24 showed moderate
clearances, significantly lower than the starting lead GW4064
(3) and the steroidal reference compound 6-ECDCA (2), with
half-lives greater than 1 h for compounds 20 and 24.
Figure 3. Mice were administered with 10 mg/kg of 20, daily by
gavage (o.s.) or i.p. for 3 days. Total RNA extracted from liver was
used to evaluate by quantitative real-time PCR the relative mRNA
expression of (A) SHP and (B) BSEP. The data are normalized to
GADPH mRNA. Results are the meanꢀ±ꢀSEM of four mice per
group.
Table 2. In vitro pharmacokinetics for selected derivatives
b
c
Compound
Solubilitya
(µM)
Clint
t (min)
½
%
6-ECDCA (2)
>200
109
56
21
41
8
27
48
3
The data shown in Figure 3 demonstrate that both genes were
upregulated following administration of 20 either by o.s or by
i.p., thus demonstrating that 20 is absorbed in the intestine and
transported to the liver.
GW4064 (3)
152
3
6
299
112
53
In vivo acetaminophen (APAP) liver toxicity. APAP is one
of the most prescribed drugs worldwide. Though safe at
therapeutic doses, APAP overdosing causes severe liver injury
which results in acute liver failure.26 Currently, APAP overdose
is the leading cause of acute liver failure in the United States
and most of Europe and represents a major indication for liver
transplantation. At therapeutic doses, APAP is metabolized in
the liver by phase II conjugation enzymes and transformed in
the corresponding sulfate and glucoronate derivatives, with
only a small amount being converted into the cytotoxic Michael
acceptor N-acetyl-p-quinoneimine (NAPQI), which in turn is
rapidly detoxified by glutathione (GSH) conjugation. However,
excessive NAPQI formation, resulting from APAP overdose,
saturates phase II conjugation pathways, leading to formation
of large amounts of the toxic NAPQI metabolite,27 depletion of
hepatic GSH and binding to cellular proteins with consequently
increased oxidative stress and mitochondrial damage. Because
therapy for APAP-induced acute liver toxicity remains
9
>200
75
21
44
72
66
26
56
67
62
16
20
24
44
32
>200
35
aAqueous solubility at pH 7.4; bReported as µL/min/mg protein;
cPercentage of compound remaining in solution after 40 min
incubation. Each measurement has been repeated in triplicate and
SD < 5%.
Finally, compounds 6 and 9 showed a very low metabolic
stability in vitro, with only 3% and 26% of unmodified
molecule remaining after 40 min, respectively, and these data
rule out the pharmacological potential of these compounds.
To gain insights into the agonism and to support target
engagement for compounds 16, 20 and 24, the effect in
modulating SHP, a FXR target gene, was assessed in a liver
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suboptimal, we have decided to investigate whether FXR
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agonism might rescue from acute liver failure caused in mice
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by APAP overdosing. For this purpose, C57Bl6 mice were
administered a single dose of 500 mg/kg APAP.
Figure 4. Compound 20 rescues mice form acute liver injury caused by APAP overdose. Serum levels of (A) AST and (B) ALT; (C)
Hematoxylin and eosin (H&E) staining on mice liver tissues; Relative mRNA levels of (D) Ugt1a1, (E) Ugt2b1 and (F) Sult1a1 in liver; (G)
Hepatic levels of GSH, (H) Hepatic SOD Activity and (I) Hepatic levels of MDA; (J) Effects of 20 APAP metabolic disposition with mouse
plasma contents (nM) of APAP, APAP-glucuronide and APAP-sulfate. Each value represents the mean ± SEM of 5-8 animals per group.*p
< 0.01.
Twenty four hours later, surviving mice were sacrificed and
blood and liver sections collected. As illustrated in Figure 4A-
B, while treating mice with APAP resulted in a severe liver
injury with ~50 fold increase of AST and ALT plasma levels
(p<0.01 versus naïve mice), this pattern was completely
reversed by treating mice with compound 20 at the dose of 30
mg/kg (p<0.01 versus APAP alone). A similar pattern of
protection was observed in mice administered GW4064 (data
not shown). At the histopathology analysis we found that
compound 20 was highly effective in rescuing mice from liver
necrosis caused by APAP (Figure 4C). To gain insights on the
molecular mechanism that supports protection afforded by
compound 20, we have then examined the effect that this agent
on enzymes involved in xenobiotic metabolism.28 As shown in
Figure 4D-F, exposure to APAP results in a dramatic
downregulation of the expression of glucuronosyltransferases
(Ugt1a1 and Ugt2b1) and sulfotransferase family 1A member 1
(Sult1a1) (p<0.01). These three genes encode for Phase II
enzymes involved in xenobiotics detoxification and are known
for being FXR regulated genes. The results of these
investigations demonstrated that compound 20 effectively
restores the expression of Phase II genes. Consistent with these
findings, compound 20 effectively reestablished the liver levels
of glutathione and super-oxide dismutase (SOD) (Figure 4G
and H, p<0.01). In addition, compound 20 reduced the level of
lipid peroxidation in mice administered with APAP, as
indicated by changes of malonildialdehyde (MDA) levels in the
liver of various experimental groups (Figure 5I, p<0.01).
APAP and its main Phase II conjugates (APAP-glucoronate and
APAP-sulfate) in plasma were measured by LC-MS/MS and
the relative concentrations are shown in Figure 5J. Plasma
APAP concentration reached ~1000 nM, in response to APAP
treatment. Treatment with compound 20 slightly decreased
APAP plasma concentration (615 nM) while enhanced the
concentration of APAP metabolites, APAP-glucuronide and
APAP-sulfate, thereby indicating that compound 20 increases
APAP metabolism by the liver.
In conclusion, in this report, elaboration on GW4064 chemical
space afforded the identification of several FXR agonists with
nanomolar potency in transactivation and SRC-1 recruitment
assays. This study resulted in the identification of compound
20, an orally active FXR agonist that rescues mice from acute
toxicity caused by APAP.
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the ACS
Publications website.
Synthesis, experimental procedures, docking poses of 9, 16 and 24
1
in FXR-LBD, Figure S3 and S4, H and 13C NMR of compounds
4-24 (PDF).
AUTHOR INFORMATION
Corresponding Author
*Prof. Angela Zampella; e-mail: angela.zampella@unina.it
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Mencarelli, A.; Renga, B.; D’Amore, C.; Santorelli, C.;
Author Contributions
Graziosi, L.; Bruno, A.; Monti, M. C.; Distrutti, E.; Cipriani, S.;
Donini, A.; Fiorucci, S. Dissociation of intestinal and hepatic activities
of FXR and LXRα supports metabolic effects of terminal ileum
interposition in rodents. Diabetes 2013, 62, 3384-3393.
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§These authors equally contributed to this work
Notes
The authors declare no competing financial interest.
(13)
Moschetta, A.; Bookout, A. L.; Mangelsdorf, D. J.
Prevention of cholesterol gallstone disease by FXR agonists in a mouse
model. Nat. Med. 2004, 10, 1352-1358.
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ACKNOWLEDGMENT
This work was supported by a grant from University of Naples
Federico II "Finanziamento della Ricerca in Ateneo (DR/2016/341,
February 2016)" and the Swiss National Science Foundation
(Project N. 200021_163281). V.L. also thanks the COST action
CA15135 (Multi-target paradigm for innovative ligand
identification in the drug discovery process MuTaLig) for the
support.
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metabolic syndrome? Trends Pharmacol. Sci. 2007, 28, 236-243.
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Cariou, B.; Staels, B. FXR: a promising target for the
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receptors in immunity and inflammation. Curr. Mol. Med. 2010, 10,
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Gege, C.; Kinzel, O.; Steeneck, C.; Schulz, A.; Kremoser,
C. Knocking on FXR’s Door: the “hammerhead”-structure series of
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ABBREVIATIONS
ADME, absorption, distribution, metabolism, and excretion;
APAP, Acetaminophen; CDCA, chenodeoxycholic acid; Clint,
intrinsic clearance; FXR-LBD, Farnesoid X Receptor, Ligand
Binding Domain; GPBAR1, membrane G-protein coupled bile acid
receptor; GSH, glutathione; LXRα/LXRβ, liver X receptor α or β;
(17)
treatment of metabolic diseases. J. Med. Chem. 2016, 59, 6553-6579.
(18) Sepe, V.; Distrutti, E.; Fiorucci, S.; Zampella, A. Farnesoid
Xu Y. Recent progress on bile acid receptor modulators for
X receptor modulators 2014-present: a patent review. Expert Opin.
Ther. Pat. 2018, 28, 351-364.
NAPQI,
N-acetyl-p-quinoneimine;
NASH,
Nonalcoholic
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Pellicciari, R.; Fiorucci, S.; Camaioni, E.; Clerici, C.;
steatohepatitis; PPARγ, Peroxisome proliferator-activated receptor
gamma; SRC-1, steroid receptor coactivator-1.
Costantino, G.; Maloney, P. R.; Morelli, A.; Parks, D. J.; Willson, T.
M. 6-alpha-etyl-chenodeoxycholic acid (6-ECDCA), a potent and
selective FXR agonist endowed with anticholestatic activity. J. Med.
Chem. 2002, 45, 3569-3572.
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