Discovery of Novel Retigabine Derivatives as Potent KCNQ4 and KCNQ5 Channel Agonists with Improved Specificity

Article abstract of DOI:10.1021/acsmedchemlett.8b00315

Recent research suggests that KCNQ isoforms, particularly the KCNQ4 and KCNQ5 subtypes expressed in smooth muscle cells, are involved in both establishing and maintaining resting membrane potentials and regulating smooth muscle contractility. Retigabine (

Full text of DOI:10.1021/acsmedchemlett.8b00315

Subscriber access provided by University of South Dakota
Letter
Discovery of novel retigabine derivatives as potent KCNQ4
and KCNQ5 channel agonists with improved specificity
Lei Wang, Gua-Hua Qiao, Hai-Ning Hu, Zhao-Bing Gao, and Fa-Jun Nan
ACS Med. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acsmedchemlett.8b00315 • Publication Date (Web): 19 Dec 2018
Downloaded from http://pubs.acs.org on December 21, 2018
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 7
ACS Medicinal Chemistry Letters
1
2
3
4
5
6
7
8
9
Discovery of novel retigabine derivatives as potent KCNQ4 and
KCNQ5 channel agonists with improved specificity
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Lei Wang,†,§,∥ Guan-Hua Qiao,†,§,∥ Hai-Ning Hu,† Zhao-Bing Gao,†,* Fa-Jun Nan†,*
† State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia
Medica, Chinese Academy of Sciences, Shanghai, 201203, China
§ University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, P. R. China
∥ These authors contributed equally
KEYWORDS: KCNQ channel; retigabine; subtype selectivity; agonist.
ABSTRACT: Recent research suggests that KCNQ isoforms, particularly the KCNQ4 and KCNQ5 subtypes expressed in
smooth muscle cells, are involved in both establishing and maintaining resting membrane potentials and regulating
smooth muscle contractility. Retigabine (RTG) is a first-in-class antiepileptic drug that potentiates neuronal KCNQ potas-
sium channels, but poor subtype selectivity limits its further application as a pharmacological tool. In this study, we im-
proved the subtype specificity of retigabine by altering the N-1/3 substituents and discovered several compounds that
show better selectivity for KCNQ4/KCNQ5 channels. Among these compounds, 10g is highly selective for
KCNQ4/KCNQ5 channels without potentiating KCNQ1/KCNQ2 channels. These results are an advance in the exploration
of small molecule modifiers that selectively activate different KCNQ isoforms. The developed compounds could also serve
as new pharmacological tools for elucidating the function of KCNQ channels natively expressed in various tissues.
The Kv7 (KCNQ) subfamily of voltage-gated potassium
channels consists of 5 members (KCNQ1-5) and plays im-
portant roles in many excitable cells, such as neurons,
cardiac myocytes and vascular smooth muscle cells.1-4
KCNQ1 is the most divergent and is primarily expressed in
cardiac tissues. The KCNQ2–5 subtypes are predominantly
found in various central and peripheral neurons.5-6 Specif-
ically, the KCNQ2/3 heterotetramers are considered to be
the molecular basis for generating M currents that exert
inhibitory control over neuronal firing.7 Therefore, the
neuronal KCNQ2/3 channels represent interesting targets
for the treatment of diseases that involve altered neuronal
excitability, such as epilepsy and chronic pain.8-11 The
small molecule retigabine (RTG, Figure 1) is an anticon-
vulsant drug, and it activates KCNQ2-KCNQ5 channels.12-13
However, the poor subtype selectivity of retigabine leads
to undesirable side effects, such as urinary retention,
which limit its clinical use.14-15
pharmacological KCNQ channel modulators have sup-
ported the crucial role of these channels in regulating
smooth muscle contractility.21-23 Therefore, recent reports
have refocused attention on the smooth muscle isoforms
of KCNQ channels. It is worth noting that most of the
visceral tissues that have been tested show high expres-
sion of the KCNQ4 and KCNQ5 subtypes, which suggests
that KCNQ4/KCNQ5 channels could be potential targets
for visceral smooth muscle-related diseases such as irrita-
ble bowel syndrome and overactive bladder syndrome.24
To date, no compounds that selectively activate KCNQ4
and KCNQ5 channels without activating neuronal
KCNQ2/KCNQ3 channels have been developed for clinical
use.
By introducing a CF3 group at the 4-position of the
benzylamine moiety and a fluorine atom at the 3-position
of the aniline ring of retigabine, Thanos Tzounopoulos et
al. generated SF0034 and RL648_81 as new KCNQ2/3-
specific activators, which are more potent and more selec-
tive than retigabine.25-26 During our previous studies on
KCNQ modulators, P-RTG, an RTG derivative that incor-
porates a propargyl group at the N-1 position, did not
show any changes in potentiation potency, subtype selec-
tivity or molecular determinants on KCNQ channels com-
pared to RTG.27 In addition, we found that certain chemi-
cal modifications at the N-1 and N-3 positions of retiga-
bine gave rise to a KCNQ4 and KCNQ5 channel agonist
with improved subtype specificity (compound 1, Figure
It has also been suggested that KCNQ isoforms ex-
pressed in smooth muscle cells are involved in establish-
ing and maintaining the resting membrane potential as
well as in regulating smooth muscle contractility. KCNQ
channels has been identified in multiple smooth muscle
cells, including: vascular smooth muscle such as thoracic
artery, carotid artery, femoral artery, and portal vein; and
visceral smooth muscle such as gastrointestinal smooth
muscle, bladder detrusor, respiratory smooth muscle, and
uterine smooth muscle.16-20 Experiments using an array of
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
1).28 This compound activated the current of the KCNQ4
Page 2 of 7
currents. As demonstrated in Figures 2B and D, 6e en-
hanced KCNQ4 currents in a concentration-dependent
manner. The EC50 of 6e for KCNQ4 was determined to be
0.89 ± 0.16 μM. In contrast, 6e (1-30 μM) did not affect the
current amplitude of homomeric KCNQ2 currents (Figure
2A) at similar concentrations. In fact, 6e at a concentra-
tion of 30 μM slightly activated KCNQ2 currents by 2% ±
0.9%.
1
2
3
4
5
6
7
8
and KCNQ5 channels at a concentration of 10 μM by 2.12-
and 1.49-fold, respectively. Meanwhile, compound 1 inhib-
ited the current of the KCNQ2 channel by 70%. This en-
couraged us to further explore this class of retigabine de-
rivatives to improve KCNQ4 and KCNQ5 selectivity. Here,
we report the synthesis of a series of N-1- and N-3-
substituted retigabine derivatives via structural modifica-
tion of 1 and the evaluation of their activity toward differ-
ent KCNQ channel subtypes. We found several com-
pounds that selectively activate KCNQ4 and KCNQ5
channels without activating KCNQ2 channels. These re-
sults therefore provide hope for the further development
of subtype-specific KCNQ channel agonists.
Table 1. Structures of the N-1 derivatives 6a-f and their ef-
9
fects on KCNQ2, 4, and 5 channels.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
a
I/I0
Cpds
1
R1
KCNQ2
KCNQ4
KCNQ5
0.30±0.00 2.21±0.15
0.87±0.06 1.85±0.25
0.66±0.16 3.63±0.24
0.85±0.04 2.36±0.60
1.19±0.06 1.49±0.08
0.94±0.05 5.68±1.11
1.26±0.03 1.54±0.21
1.49±0.24
Figure 1. Structures of RTG and 1.
6a
6b
6c
1.36±0.13
1.37±0.10
1.28±0.16
1.05±0.05
3.20±0.27
1.13±0.03
First, compounds 6a-f were synthesized to evaluate
the effect of various substituents at the N-1 position of 1.
All compounds were synthesized according to Scheme 1.
Compound 3 was synthesized from the commercially
available compound 2 and 4-fluorobenzaldehyde via a
reductive amination reaction. Compound 3 was then cata-
lytically hydrogenated over Pd/C. Intermediately, com-
pound 4 was treated with ethyl chloroformate to give 5.
The reaction of compound 5 with the appropriate al-
kyl bromide reagent produced 6a–f.
6d
6e
6f
With these N-1-substituted analogues in hand, their ef-
fects on the KCNQ2, 4, and 5 channels were first assessed.
Electrophysiology experiments were conducted using the
whole-cell patch clamp technique, and compound effects
on the amplitude of the outward current (I/I0) were ana-
lyzed. I0 is the amplitude of the outward current in the
absence of a compound. I is the amplitude of the outward
current in the presence of a compound. Compounds re-
sulting in I/I0>1 were defined as activators, while com-
pounds that gave I/I0<1 were defined as inhibitors. All
compounds were tested at a concentration of 10 μM, and
the testing voltage was -10 mV unless otherwise stated. As
shown in Table 1, the results indicate that N-1 substitution
is important for activation and subtype selectivity.
Branching on the allylic group (providing increased length
and steric hindrance) had a detrimental effect on KCNQ2
inhibition, but the ability to activate KCNQ4 and KCNQ5
channels was retained. Among the newly synthesized de-
rivatives, the N-1 propargyl-substituted compound 6e dis-
played the best agonist potency. At a concentration of 10
μM, 6e caused 5.68-fold and 3.20-fold increases in the
KCNQ4 and KCNQ5 channels, respectively. However,
there was no significant change in the outward current
when we applied 6e to KCNQ2 channels; for comparison,
RTG increased KCNQ2 currents by 1.5-fold (Figure 2C). To
determine the specific potency of 6e on the KCNQ2 and
KCNQ4 channels, the concentration-response relation-
ship of 6e was established for the KCNQ2 and KCNQ4
[a]
The testing concentration was 10 μM. Each compound was
tested in more than four cells.
Figure 2. The effect of 6e on KCNQ2 and KCNQ4 channels.
(A and B) The representative current traces of KCNQ2 (A)
ACS Paragon Plus Environment

Page 3 of 7
ACS Medicinal Chemistry Letters
and KCNQ4 (B) channels activated by 6e using different drug
clamp technique. The depolarized voltage ranged from -
90 mV to +60 mV in 10 mV increments as described in
Figure 3A. Except for KCNQ1 and KCNQ2, the outward
currents of all KCNQ subtypes were potentiated by extra-
cellular treatment with 10 μM 6e (Figures 3B and 4C). The
provided histogram illustrates that the current amplitude
produced by 6e decreased in the following order: KCNQ4
1
2
3
4
5
6
7
8
concentrations as indicated are shown. (C) A histogram plot-
ting 6e and RTG effect on KCNQ2 currents measured at -10
mV (n ≥ 4). (D) The concentration-response relationships of
6e on homomeric KCNQ4 currents. The Hill coefficient was
0.33.
To determine the specificity of 6e on other KCNQ sub-
types, we individually expressed and then tested KCNQ1
to KCNQ5 in CHO-K1 cells using the whole cell voltage-
>
KCNQ5
>
KCNQ3
(1.6-fold).
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Scheme 1. Synthesis of the N-1/3 retigabine derivatives 6a-f, 8a-l, 10a-h and 13. Reagents and conditions: a) 4-
Fluorobenzaldehyde, cat. p-TsOH, toluene, 120°C, 77.2%; b) NaBH4, 1,4-dioxane:MeOH (4:1), rt, 94%; c) H2, Pd/C, MeOH, rt,
100%; d) Ethyl chloroformate, DIPEA, 1,4-dioxane, rt, 90%; e) R1Br, DIPEA, 60°C, DMF; f) Boc2O, NaHCO3, H2O:THF (1:2), rt,
85%; g) 3-Bromo-1-propyne, DIPEA, 600C, DMF, 90%; h) TFA, DCM, 0°C; i) ClCOOR2, DIPEA, 1,4-dioxane, rt; j) Ethyl chlo-
roformate, DIPEA, 1,4-dioxane, rt, 50%; k) ClCOOR3, DIPEA, 1,4-dioxane, rt; l) 3-Bromo-1-propyne, DIPEA, 60°C, DMF, 85%; m)
Boc2O, DMAP, THF, 80C, 35%; n) Zn, NH4Cl, MeOH, H2O, reflux; and o) Ethyl chloroformate, DIPEA, rt, 60% over two steps.
Figure 3. The subtype selectivity of 6e for KCNQ channels. (A) In the voltage protocol, cells were held at -80 mV and stepped to
a series of voltages ranging from -90 to +60 mV in 10 mV increments for a 1500 ms pulse followed by stepping to -120 mV for 500
ms. (B) Histogram showing the effects of 6e on different subtypes of KCNQ with currents measured at -10 mV and +60 mV. (C)
Whole-cell currents of CHO cells transfected individually with KCNQ1 to KCNQ5 were recorded in the absence (left panels) and
presence (right panels) of 10 μM 6e.
Next, the N-1 propargyl substituent was maintained,
and the N-2 and N-3 substituents were varied. Two new
series of N-2- and N-3-substitued analogues (8 and 10)
were prepared via a similar synthetic strategy (Scheme 1).
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Page 4 of 7
Compound 4 was treated with Boc2O to give 7. The reac-
were better agonists than cycloalkane- and arene-
substituted compounds. Among these compounds, the
bis-tertiary butyl-substituted compound 8g displayed the
best agonist potency and selectivity.
1
2
3
4
5
6
7
8
tion of compound 7 with 3-bromo-1-propyne produced 8g.
Deprotection of 8g followed by treatment with the appro-
priate chloroformate gave the final compounds 8a-f and
8h-l. Deprotection of 8g followed by treatment with ethyl
chloroformate formed intermediate 9. Compounds 10
were synthesized in the same way from 9.
Accordingly, the two new series of synthesized com-
pounds (8 and 10) were assessed for their effects on the
KCNQ2, 4, and 5 channels, and the results are shown in
Table 2. When R2 and R3 remained the same, the effects of
the substituents were determined from compounds 8a-l.
The identities of the functional groups at N-2 and N-3
were very important. For the alkyl substituted compounds
8a-j, a critical difference was observed between the activi-
ty of the methyl and tertiary butyl analogues (8a and 8g)
and the rest of the analogues; 8a and 8g behaved as weak
activators, while the others inhibited the KCNQ2 channel.
Changing the length or steric hindrance of the chain
caused an ambiguous effect on the activation of KCNQ4
and KCNQ5. In general, alkane-substituted compounds
When R2 was maintained as ethyl and the R3 group was
varied, the effects of substituents can be seen by compar-
ing compounds 10a-h. Unlike compounds 8 and with the
exception of 10a, which was a weak inhibitor of KCNQ2,
compounds 10 had no agonist activity on KCNQ2 and dis-
played significant activator potency on the KCNQ4 and
KCNQ5 channels. Increasing the length or steric hin-
drance of the alkyl chain had beneficial effects on com-
pound activity (10a vs 10c vs 10e and 10e vs 10f vs 10g).
Among the compounds in this series, the N-2 ethyl, N-3
tertiary butyl-substituted compound 10g exhibited the
best agonist potency. In addition, an N-2 and N-3 substit-
uent exchanged compound (13) of 10g was designed and
synthesized (Scheme 1). Compound 13 displayed agonist
activities comparable to that of 10g, and the activity of 13
toward KCNQ4 was even greater than that of 10g.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Table 2. Structures of N-2/3 derivatives 8, 10, and 13 and their effects on the KCNQ2, 4, and 5 channels.
a
I/I0
Cpds
R2
R3
KCNQ2
1.37±0.11
KCNQ4
4.77±0.44
2.21±0.11
KCNQ5
2.89±0.07
5.26±0.53
2.75±0.84
3.11±0.93
4.13±1.09
1.73±0.10
5.32±0.39
2.55±0.38
1.33±0.23
1.25±0.14
1.16±0.04
3.57±0.31
3.34±0.54
4.67±0.69
5.809±0.62
5.71±0.34
3.62±0.31
4.84±0.32
4.58±0.32
2.57±0.67
4.59±0.56
8a
8b
8c
8d
8e
Me
Allyl
nPr
iPr
Me
Allyl
nPr
iPr
nBu
0.67±0.02
0.78±0.04
0.35±0.04
0.77±0.02
0.83±0.04
1.00±0.09
0.64±0.03
0.26±0.06
0.21±0.05
0.91±0.02
1.25±0.01
0.61±0.05
0.96±0.04
1.07±0.027
0.94±0.06
1.06±0.03
1.04±0.04
1.16±0.04
0.97±0.15
1.07±0.06
2.58±0.56
1.33±0.06
2.75±0.40
1.52±0.17
3.05±0.74
1.51±0.04
1.21±0.09
0.88±0.07
1.22±0.05
3.02±0.28
2.56±0.47
3.68±0.36
3.947±0.89
5.01±0.83
4.16±0.60
5.19±0.64
6.37±0.84
1.27±0.03
7.71±0.50
nBu
8f
8g
iBu
tBu
iBu
tBu
8h
8i
8j
8k
8l
cyclopropyl
cyclobutyl
cyclopentyl
cyclopropyl
cyclobutyl
cyclopentyl
Ph
Ph
Bn
Et
Et
Et
Et
Et
Et
Et
Bn
Me
Allyl
nPr
iPr
nBu
iBu
tBu
Bn
10a
10b
10c
10d
10e
10f
10g
10h
13
Et
tBu
Et
[a] The testing concentration was 10 μM. Each compound was tested in more than four cells.
Compounds 8g, 10g and 13 were selected for further
KCNQ4 and KCNQ5 with EC50 values of 0.78 and 1.68 μM,
respectively. Then, the evaluation of 10g against all other
subtypes was completed (Figure 4). To characterize the
activation of KCNQ2/3 heteromeric channels by 10g, we
generated a r-KCNQ2/3 tandem construct (see experi-
mental section). Unfortunately, we observed a maximum
increase of approximately 1.50-fold in the outward cur-
rents of the KCNQ3 and KCNQ2/3 channels. Notably, at a
testing based on their potent activation of the KCNQ4
and KCNQ5 channels. The concentration-response rela-
tionships of 8g, 10g and 13 were then established for the
KCNQ4 and KCNQ5 currents. Analysis of the dose-
response curves revealed that the EC50 values of the se-
lected compounds ranged from 0.78 to 2.43 μM (Table 3).
Compound 10g displayed the best agonist potency against
ACS Paragon Plus Environment

Page 5 of 7
ACS Medicinal Chemistry Letters
similar concentration range (1-30 μM), 10g did not affect
the current amplitude of homomeric KCNQ2 currents.
Compound 10g actually slightly inhibited KCNQ2 cur-
rents at higher concentrations (30 μM) (Figure 4), making
its effect on the KCNQ channels more specific than that
of RTG.
dependent activation curves of the KCNQ2 and KCNQ4
channels (data shown in supplementary Table 1). Particu-
larly at -60 mV or at more negative membrane potentials,
the drug 10g does not induce channel opening (data
shown in supplementary Figure 5). We speculated that
the RTG-induced G-V shift should be sensitive to struc-
ture alterations around N-1, N-2 and N-3 and that the ma-
jor influence of this class of compounds is on the current
amplitude.
1
2
3
4
5
6
7
8
9
Table 3. Potency (EC50, μM) of RTG, 8g, 10g and 13
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
against KCNQ4, KCNQ5 and KCNQ2
RTG
8g
10g
13
KCNQ4 5.90±0.18 2.03±0.14 0.78±0.14 1.42±0.04
KCNQ5 3.45±0.28 2.43±0.17 1.68±0.12 1.37± 0.11
KCNQ2 2.17±0.07
>30
>30
>30
The previously reported KCNQ activators have low or
no selectivity for KCNQ2-5 channels. Their undesirable
side effects are likely due to poor KCNQ2-5 channel selec-
tivity, and nonselective KCNQ modulators may be likely
to cause side effects when used clinically. Recently, cer-
tain compounds have been reported to be selective for
either KCNQ4, 5 or KCNQ2 channels. For example,
fasudil did not affect KCNQ2 and KCNQ2/3 currents but
enhanced KCNQ4 and KCNQ4/5 channels29, while it orig-
inally acted as a potent rho-kinase inhibitor to suppress
proliferation/migration and induce apoptosis in urothelial
cancer cells.30 AaTXKβ(2–64), a peptide activator isolated
from scorpion toxin, increased the maximal currents in
homomeric KCNQ4 and heteromeric KCNQ2/3 channels
but showed no effect on homomeric KCNQ3 channels.31
In this study, we synthesized a series of selective activa-
tors for KCNQ4 and KCNQ5 channels based on the struc-
tural core of RTG, an approved anti-epileptic drug.
Among these newly synthesized derivatives, compound
10g was found to be the most potent activator of KCNQ4
and KCNQ5 and exhibited EC50 values of 0.78 and 1.68
μM, respectively, with no enhancement of the current
amplitude for KCNQ2. This result provides a new plat-
form for developing selective KCNQ modulators. On the
other hand, as a KCNQ4,5-selective probe compound, 10g
will be a useful tool for elucidating the mechanism of the
interaction between the compounds and channels and for
determining the contributions of different KCNQ channel
subtypes in various tissues. The slight increase in the
outward currents of the KCNQ3 and KCNQ2/3 channels
will be an issue in regard to possible side effects; thus,
additional experiments are needed to clarify these results.
Therefore, experiments are in progress in our lab to fur-
ther improve the compound specificity.
Figure 4. Dose-response curves of 10g on different KCNQ
isoforms. (A) Representative traces of homomeric KCNQ1-
KCNQ5 channels and heteromeric KCNQ2/3 channels, be-
fore and after application of 10 μM 10g. (B) Dose-response
relationship of 10g on homomeric KCNQ1-KCNQ5 channels
and heteromeric KCNQ2/3 channels.
Investigation of the influence of an activator on V1/2 is
very important for fully understanding the effects of an
activator on channels. The effects of 6e and 10g on volt-
age-dependent activation were then analyzed. As de-
scribed previously13, the current-voltage curves suggest
that one effect of RTG is to produce a 20-30 mV negative
shift in the KCNQ current activation curve. However,
unlike RTG, 6e and 10g only slightly affected the voltage-
Supporting Information
Experimental procedures and characterization data for new
compounds. This material is available free of charge via the
Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Authors
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Page 6 of 7
their contribution to spontaneous activity. Br. J. Pharmacol.
2013, 169, 1290–1304.
* Email: fjnan@simm.ac.cn (F. N)
* Email: zbgao@simm.ac.cn (Z. G)
1
2
3
4
5
6
7
8
15. Rodea, F.; Svaløab, J.; Sheykhzadeb, M.; Rønna, L. C. B.
Functional effects of the KCNQ modulators retigabine and
XE991 in the rat urinary bladder. Eur. J. Pharmacol. 2010,
638, 121–127.
16. Yeung, S. Y.; Pucovský, V.; Moffatt, J. D.; Saldanha, L.;
Schwake, M.; Ohya, S.; Greenwood, I. A. Molecular
expression and pharmacological identification of a role for
Kv7 channels in murine vascular reactivity. Br. J. Pharmacol.
2007, 151, 758–770.
ACKNOWLEDGMENTS
This work was supported by grants from the National Natu-
ral Science Foundation of China (NO. 81773707) and the Sci-
ence and Technology Commission of Shanghai Municipality
(NO. 16431901700 and NO. 15431901500).
ABBREVIATIONS
9
17. Jepps, T. A.; Greenwood, I. A.; Moffatt, J. D.; Sanders, K. M.;
Ohya, S. Molecular and functional characterization of Kv7
K+ channel in murine gastrointestinal smooth muscles. Am.
J. Physiol. Gastrointest. Liver. Physiol. 2009, 297, 107–115.
18. Bientinesi, R.; Mancuso, C.; Martire, M.; Bassi, P. F.; Sacco,
E.; Currò, D. Kv7 channels in the human detrusor: channel
modulator effects and gene and protein expression. Naunyn
Schmiedebergs Arch. Pharmacol. 2017, 390, 127–137.
19. Brueggemann, L. I.; Kakad, P. P.; Love, R. B.; Solway, J.;
Dowell, M. L.; Cribbs, L. L.; Byron, K. L. Kv7 potassium
channels in airway smooth muscle cells: signal transduction
Cpds, compounds. p-TsOH, p-Toluenesulfonic acid. DIPEA,
N,N-Diisopropylethylamine. DMF, N,N-Dimethylformamide.
Boc2O, Di-tert-butyl dicarbonate. DCM, Dichloromethane.
rt, Room temperature. DMAP, 4-(Dimethylamino)pyridine.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
REFERENCES
1.
Robbins, J. KCNQ potassium channels: physiology,
pathophysiology, and pharmacology. Pharmacol. Ther.
2001, 90, 1–19.
2. Brown, D. A.; Passmore, G. M. Neural KCNQ (Kv7)
channels. Br. J. Pharmacol. 2009, 156, 1185–1195.
3. Greenwood, I. A.; Ohya, S. New tricks for old dogs: KCNQ
expression and role in smooth muscle. Br. J. Pharmacol.
2009, 156, 1196–1203.
4. Stott, J. B.; Jepps, T. A.; Greenwood, I. A. Kv7 potassium
channels: a new therapeutic target in smooth muscle
disorders, Drug. Discov. Today. 2014, 19, 413–424.
5. Wang, Q.; Curran, M. E.; Splawski, I.; Burn, T. C.;
Millholland, J. M.; VanRaay, T. J.; Shen, J.; Timothy, K. W.;
Vincent, G. M.; Jager, T. de; Schwartz, P. J.; Towbin, J. A.;
Moss, A. J.; Atkinson, D. L.; Landes, G. M.; Connors, T. D.;
Keating, M. T. Positional cloning of a novel potassium
channel gene: KVLQT1 mutations cause cardiac
arrhythmias. Nat. Genet. 1996, 12, 17–23.
6. Wei, A. D.; Butler, A. G.; Salkoff, L. B. KCNQ-like potassium
channels in C. elegans: Conserved properties and
modulation. J. Biol. Chem. 2005, 280, 21337–21345.
7. Wang, H. S.; Pan, Z.; Shi, W.; Brown, B. S.; Wymore, R. S.;
Cohen, I. S.; Dixon, J. E.; McKinnon, D. KCNQ2 and KCNQ3
potassium channel subunits: molecular correlates of the M-
channel. Science. 1998, 282, 1890–1893.
8. Xiong, Q. J.; Gao, Z. B.; Wang, W.; Li, M. Activation of Kv7
(KCNQ) voltage-gated potassium channels by synthetic
compounds. Trends. Pharmacol. Sci. 2008, 29, 99–107.
9. Wulff, H.; Castle, N. A.; Pardo, L. A. Voltage-gated
potassium channels as therapeutic targets. Nat. Rev. Drug.
Discov. 2009, 8, 982–1001.
10. Wickenden, A. D.; McNaughton-Smith, G. Kv7 channels as
targets for the treatment of pain. Curr. Pharm. Des. 2009,
15, 1773–1798.
11. Zheng, Y. M.; Xu, H. Y.; Zhan, L.; Zhou, X. D.; Chen, X. Q.;
Gao, Z. B. Activation of peripheral KCNQ channels relieves
gout pain. Pain. 2015, 156, 1025–1035.
12. Main, M. J.; Cryan, J. E.; Dupere, J. R. B.; Cox, B.; Clare, J. J.;
Burbidge, S. A. Modulation of KCNQ2/3 potassium
channels by the novel anticonvulsant retigabine. Mol.
Pharmacol. 2002, 58, 253–262.
13. Tatulian, L.; Delmas, P.; Abogadie, F. C.; Brown, D. A.
Activation of expressed KCNQ potassium currents and
native neuronal M-type potassium currents by the anti-
convulsant drug retigabine. J. Neurosci. 2001, 21, 5535–5545.
14. Anderson, U. A.; Carson, C.; Johnston, L.; Joshi, S.; Gurney,
A. M.; McCloskey, K. D. Functional expression of KCNQ
(Kv7) channels in guinea pig bladder smooth muscle and
intermediates
and
pharmacological
targets
for
bronchodilator therapy. Am. J. Physiol. Lung. Cell. Mol.
Physiol. 2012, 302, 120–132.
20. Evseev, A. I.; Semenov, I.; Archer, C. R.; Medina, J. L.; Dube,
P. H.; Shapiro, M. S.; Brenner, R. Functional effects of
KCNQ K+ channels in airway smooth muscle. Front. Physiol.
2013, 4, 277–287.
21. McCallumm, L. A.; Pierce, S. L.; England, S. K.; Greenwood,
I. A.; Tribe, R. M. The contribution of Kv7 channels to
pregnant mouse and human myometrial contractility. J.
Cell. Mol. Med. 2011, 15, 577–586.
22. Yeung, S. Y.; Schwake, M.; Pucovský, V.; Greenwood, I. A.
Bimodal effects of the Kv7 channel activator retigabine on
vascular K+ currents. Br. J. Pharmacol. 2008, 155, 62–72.
23. Zhong, X. Z.; Harhun, M. I.; Olesen, S. P.; Ohya, S.; Moffatt,
J. D.; Cole, W. C.; Greenwood, I. A. Participation of KCNQ
(Kv7) potassium channels in myogenic control of cerebral
arterial diameter. J. Physiol. 2010, 588, 3277–3293.
24. Haick, J. M.; Byron, K. L. Novel treatment strategies for
smooth muscle disorders: Targeting Kv7 potassium
channels. Pharmacol. Ther. 2016, 165, 14-25.
25. Kalappa, B. I.; Soh, H.; Duignan, K. M.; Furuya, T.; Edwards,
S.; Tzingounis, A. V.; Tzounopoulos, T. Potent KCNQ2/3-
specific channel activator suppresses in vivo epileptic
activity and prevents the development of tinnitus. J.
Neurosci. 2015, 35, 8829-8842.
26. Kumar, M.; Reed, N.; Liu, R.; Aizenman, E.; Wipf, P.;
Tzounopoulos, T. Synthesis and evaluation of potent
KCNQ2/3-specific channel activators. Mol. Pharmacol. 2016,
89, 667-677.
27. Zhou, P. Z.; Zhang, Y. M.; Xu, H. Y.; Chen, F.; Chen, X. Q.; Li,
X. Y.; Pi, X. P.; Wang, L. P.; Zhan, L.; Nan, F. J.; Gao, Z. B. P-
Retigabine: An N-Propargyled Retigabine with Improved
Brain Distribution and Enhanced Antiepileptic Activity. Mol.
Pharmacol. 2015, 87, 31–38.
28. Hu, H. N.; Zhou, P. Z.; Chen, F.; Li, M.; Nan, F.J.; Gao, Z. B.
Discovery of a retigabine derivative that inhibits KCNQ2
potassium channels. Acta. Pharmacol. Sin. 2013, 34, 1359–
1366.
29. Zhang, X.; An, H. l.; Li, J. W.; Zhang, Y. Y.; Liu, Y.; Jia, Z. F.;
Zhang, W.; Chu, L.; Zhang, H. L. Selective activation of
vascular Kv7.4/Kv7.5 K+ channels by fasudil contributes to
its vasorelaxant effect. Br. J. Pharmacol. 2016, 173, 3480–
3491.
30. Abe, H.; Kamai, T.; Hayashi, K.; Anzai, N.; Shirataki, H.;
Mizuno, T.; Yamaguchi, Y.; Masuda, A.; Yuki, H.; Betsunoh,
ACS Paragon Plus Environment

Page 7 of 7
ACS Medicinal Chemistry Letters
H.; Yashi, M.; Fukabori, Y.; Yoshida, K. The Rho-kinase
31. Landoulsi, Z.; Miceli, F.; Palmese, A.; Amoresano, A.;
Marino, G.; Ayeb, M. E.; Taglialatela, M.; Benkhalifa, R.
Subtype-selective activation of Kv7 channels by AaTXKβ(2–
64), a novel toxin variant from the Androctonus australis
Scorpion Venom. Mol. Pharmacol. 2013, 84, 763–773.
inhibitor HA-1077 suppresses proliferation/migration and
induces apoptosis of urothelial cancer cells. BMC cancer.
2014, 14, 412–423.
1
2
3
4
5
Insert Table of Contents artwork here
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment