Toward a treatment of diabesity: In vitro and in vivo evaluation of uncharged bromophenol derivatives as a new series of PTP1B inhibitors

Article abstract of DOI:10.1016/j.ejmech.2019.01.057

Protein tyrosine phosphatase 1B (PTP1B) has been considered as a validated biological target for type 2 diabetes treatment, but past endeavors to develop inhibitors of PTP1B into drugs have been unsuccessful. Two challenging aspects are selective inhibition and cell permeability. A structure-based strategy was employed to develop uncharged bromophenols as a new series of PTP1B inhibitors. The most potent compound 22 (LXQ46) inhibited PTP1B with an IC₅₀ value of 0.190 μM, and showed remarkable selectivity over other protein tyrosine phosphatases (PTPs, 20–200 folds). In the SPR study, increasing concentrations of compound 22 led to concentration-dependent increases in binding responses, indicating that compound 22 could bind to the surface of PTP1B via noncovalent means. By treating insulin-resistant C2C12 myotubes with compound 22, enhanced insulin and leptin signaling pathways were observed. Long-term oral administration of compound 22 reduced the blood glucose level of diabetic BKS db mice. The glucose tolerance tests (OGTT) and insulin tolerance tests (ITT) in BKS db mice showed that oral administration of compound 22 could increase insulin sensitivity. In addition, long-term oral administration of compound 22 could protect mice from obesity, which was not the result of toxicity. Our pharmacokinetics results from the rat-based assays showed that orally administered compound 22 was absorbed rapidly from the gastrointestinal tract, extensively distributed to the tissues, and rapidly eliminated from the body. All these results indicate that compound 22 could serve as a qualified agent to treat type II diabetes.

Full text of DOI:10.1016/j.ejmech.2019.01.057

Accepted Manuscript
Toward a treatment of diabesity: In vitro and in vivo evaluation of uncharged
bromophenol derivatives as a new series of PTP1B inhibitors
Xiangqian Li, Qi Xu, Chao Li, Jiao Luo, Xiuxue Li, Lijun Wang, Bo Jiang, Dayong Shi
PII:
S0223-5234(19)30078-9
DOI:
https://doi.org/10.1016/j.ejmech.2019.01.057
EJMECH 11064
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 27 December 2018
Revised Date: 23 January 2019
Accepted Date: 23 January 2019
Please cite this article as: X. Li, Q. Xu, C. Li, J. Luo, X. Li, L. Wang, B. Jiang, D. Shi, Toward a treatment
of diabesity: In vitro and in vivo evaluation of uncharged bromophenol derivatives as a new series
of PTP1B inhibitors, European Journal of Medicinal Chemistry (2019), doi: https://doi.org/10.1016/
j.ejmech.2019.01.057.
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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Toward a treatment of diabesity: in vitro and in vivo evaluation of
uncharged bromophenol derivatives as a new series of PTP1B
inhibitors
Xiangqian Lia,b, Qi Xua , Chao Lia,Jiao Luoa, Xiuxue Lia, Lijun Wanga,b, Bo Jianga,b, Dayong Shic *
a Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences,
Qingdao, China.
b Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and
Technology, Qingdao, China.
c State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
* Corresponding author: Tel. +86-0532-8289-8719; Fax: +86-0532-8289-8741: E-Mail:
shidayong@qdio.ac.cn.
Abstract
Protein tyrosine phosphatase 1B (PTP1B) has been considered as a validated biological target for type 2
diabetes treatment, but past endeavors to develop inhibitors of PTP1B into drugs have been unsuccessful. Two
challenging aspects are selective inhibition and cell permeability. A structure-based strategy was employed to
develop uncharged bromophenols as a new series of PTP1B inhibitors. The most potent compound 22
(LXQ46) inhibited PTP1B with an IC50 value of 0.190 µM, and showed remarkable selectivity over other
protein tyrosine phosphatases (PTPs, 20-200 folds). In the SPR study, increasing concentrations of compound
22 led to concentration-dependent increases in binding responses, indicating that compound 22 could bind to
the surface of PTP1B via noncovalent means. By treating insulin-resistant C2C12 myotubes with compound
22, enhanced insulin and leptin signaling pathways were observed. Long-term oral administration of
compound 22 reduced the blood glucose level of diabetic BKS db mice. The glucose tolerance tests (OGTT)
and insulin tolerance tests (ITT) in BKS db mice showed that oral administration of compound 22 could
increase insulin sensitivity. In addition, long-term oral administration of compound 22 could protect mice from
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obesity, which was not the result of toxicity. Our pharmacokinetics results from the rat-based assays showed
that orally administered compound 22 was absorbed rapidly from the gastrointestinal tract, extensively
distributed to the tissues, and rapidly eliminated from the body. All these results indicate that compound 22
could serve as a qualified agent to treat type II diabetes.
Keywords
Anti-diabetic; PTP1B inhibitor; Selectivity; BKS db mice; Toxicity.
1. Introduction
Protein tyrosine phosphatases (PTPs) are a superfamily of receptor-like, non-transmembrane proteins, whose
members are crucial modulators of tyrosine phosphorylation-dependent cellular events [1, 2]. Among the
PTPS, Protein tyrosine phosphatase 1B (PTP1B) is considered as a validated biological target to treat type 2
diabetes and obesity, owing to its regulatory role in insulin and leptin signaling [3-5]. In addition to normal
development and longevity, PTP1B-deficient mice also display improved glycemic control and increased
insulin sensitivity[6, 7]. The silencing of the PTP1B gene results in increased insulin sensitivity and resistance
to weight gain on a high-fat diet without causing any abnormality in the animals [8, 9].
Extensive efforts have successfully identified potent PTP1B inhibitors, but endeavors to develop compounds
into drugs have been largely unsuccessful [10, 11]. This situation was probably due to the highly polar nature
of the PTP1B catalytic site, which has evolved to accommodate pTyr containing two negative charges at
physiological pH[10]. Consequently, most active-site-directed PTP1B inhibitors possess a high charge density
with limited cell membrane permeability and bioavailability [12]. Numerous nanomolar nonhydrolyzable
phosphonate [13-15] and carboxylic acid [16-18] pTyr mimetics were suspended presumably due to their poor
cell permeability.
Therefore, the identification of uncharged compounds has been conducted develop new small molecule
PTP1B inhibitors. Previously, our group isolated and identified bromophenol compounds as PTP1B inhibitors
[19-21] (Figure 1). Herein, we wish to report our structure-based design and antidiabetic study of potent
uncharged PTP1B inhibitors, using these natural bromophenols as the initial lead compounds.
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Figure 1. Representative bromophenol PTP1B inhibitors in our laboratory.
2. Results and Discussions
2.1 Design of selective PTP1B inhibitors
Our previous analysis indicated that the bromophenol moiety is essential for PTP1B inhibitory activity. Two
hydroxyls of the bromophenol moiety (Figure 2a, light blue) are involved in hydrogen bonding interactions
with Ser216, Ile219, Gly220 and Arg221 in the catalytic site (site A). This group in part mimics the action of
the phosphoryl group (Figure 2a, pink) in pTyr1162 (insulin receptor kinase). Hence, natural bromophenols
were simplified to two active fragments, 3-bromo-4,5-dihydroxybenzaldehyde (1) and 2,3-dibromo-4,5-
dihydroxybenzaldehyde (2). PTP1B inhibition studies identified that compound 2 exhibited inhibitory activity
with an IC50 value of 128 µM, while compound 1 inhibited PTP1B weakly (354 µM, Figure S1). Based on
these two weak but well characterized fragments, we sought to design a series of PTP1B inhibitors to interact
with Ala27 in site B, which is a specific recognition site of PTP1B over other PTPs.
b)
a)
Gateway
Site B
Site A
c)
d)
R254
R254
A27
A27
Site B
Site A
Figure 2. Predicted binding models of PTP1B (1G1H) with (a) compound 2 (light blue) and overlay with
pTyr1162 (pink), (b) compound 4, (c) compound 11, and (d) compound 22.
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Our procedure was to construct compounds from site A toward B in a stepwise manner, in which inhibitors
could be optimized with more efficiently. An oxazole group was introduced to pass through the narrow area
between site A and B (Figure 2b). To effect the extension of the molecule, a phenyl group was introduced as a
linker to offer a favorable trajectory toward site B. Compounds 3 and 4 were synthesized and determined to
inhibit PTP1B with IC50 values of 6.68 and 4.27 µM, respectively (Table 1). Modeling suggests that the
additional 5-phenyloxazole group lies along the tunnel wall and offers an appropriate direction toward site B
(Figure 2b, Figure S1).
Table 1. Inhibitory activity of the compounds.
Comp
X
H
R1
H
R2 IC50 (µM)
H
H
H
6.68±0.5
4.27±0.2
9.13±1.6
3
4
Br
H
H
OMe
5
H
OMe Br 18.47±2.3
6
Br OMe Br 10.26±1.2
7
H
OBn
Br OBn
OPh
H
H
H
H
4.00±0.6
3.75±0.2
3.34±0.1
1.99±0.2
3.09±0.13
8
9
H
10
11
Br OPh
Na3VO4
The small hydrophobic cavity adjacent to Ala27 was next targeted; its occupation with a proper hydrophobic
group could increase inhibitor potency and selectivity. This strategy led to the design of 12-17, which contain
multiple hydrophobic groups of different sizes extending out from the para-position of the terminal phenyl ring.
The methyl group did endow compound 12 with improved inhibitory activity (IC50=0.87 µM, Table 2). When
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the large groups, such as i-propyl, t-butyl, and phenyl were incorporated, inhibitory activity showed no
improvement (or decreased efficacy). The molecular modeling predicted that the methyl group does not fully
fill this hydrophobic “hole”, but instead points to the side chain of Arg254, which could stabilize the
interactions between PTP1B and inhibitors.
Table 2. Inhibitory activity of the compounds.
Comp
12
X
Br
H
R3
Me
IC50 (µM)
0.87±0.3
7.44±0.4
3.09±1.2
2.29±0.8
2.45±0.4
3.55±0.6
1.07±0.3
2.14±0.2
3.81±0.3
0.285±0.1
0.190±0.05
3.09±0.13
i-Pr
13
Br
H
i-Pr
14
t-Bu
Ph
15
H
16
Br
H
Ph
17
OMe
OMe
EtOMe
OEt
OEt
18
Br
H
19
20
H
21
Br
22
Na3VO4
Three groups, methoxyl, ethoxyl, and methoxyethyl, were selected to optimize these interactions, leading to
the design of 18-22. These compounds contain (a) a hydrogen bond receptor that was designed to interact with
Arg254, providing an anchor site, and (b) a small flexible hydrophobic group that was expected to occupy the
hydrophobic cavity adjacent to Ala27, which is related to selectivity. Consistent with our prediction,
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compounds with the ethoxyl group at the para-position of the phenyl ring, 21 and 22, showed inhibitory
activity against PTP1B with IC50 values of 0.285 and 0.190 µM, respectively (Table 2). Modeling suggests that
the additional ethoxyl group not only optimally fills the hydrophobic hole, but also forms a hydrogen bond
with Arg254 (Figure 2d).
2.2 Compound 22 is a selective PTP1B inhibitor
Selectivity study. Selective inhibition of PTP1B over other PTPs represents another challenging aspect,
because of the high homology combined with different biological functions [22]. In vitro selectivity over PTPs
was evaluated for the most potent compounds (11, 12, 14, 19 and 22) in Table 3. Compounds 19 and 22
showed 17 to 20-fold selectivity over TCPTP, the phosphatase with the highest homolog to PTP1B. The
methoxyl and ethoxyl substituents in 19 and 22 interacted effectively with Ala27 of PTP1B, but they were less
tolerated by the Ser29 in TCPTP. Furthermore, compounds 19 and 22 also showed good selectivity over other
PTPs, such as SHP-1, SHP-2 and LAR (approximately 20-200-fold).
Table 3. Inhibition of phosphatases by selected compounds.
IC50 (µM)
Comp
PTP1B
TCPTP
PTP1B (A27S)
3.98±0.63
1.38±0.27
1.03±0.38
12.9±1.52
1.78±0.21
2.01±0.2
SHP-1
5.16±2.1
29.9±6.3
2.54±1.8
27.1±0.51
>36.8
SHP-2
7.78±0.32
>38.9
LAR
>40
1.99±0.20
5.49±1.2
11
12
14
19
22
0.87±0.28 2.55±0.46
3.09±1.23 3.02±0.28
2.14±0.16 36.42±5.3
0.190±0.05 3.81±0.64
>38.9
8.11±0.06
>37.7
>36.9
>37.7
>36.8
>36.8
Na3VO4 3.09±0.13 2.38±0.10
2.63±0.14
10.68±2.08
32.62±0.44
A27S mutant. To study the function of Ala27 in the selectivity between PTP1B and TCPTP, we applied a
site-directed A27S mutant of PTP1B to test the inhibitory activity of compounds 11, 12, 14, 19 and 22. As
expected, the substitution of Ala27 to Ser (as in the TCPTP sequence) elicited selectivity between the
derivative and the wild-type proteins. Compounds 19 and 22 exhibited lower inhibitory activity against A27S
mutant than wild-type PTP1B (6-9-fold, Table 3), while the control Na3VO4 showed no selectivity. This result
further confirmed that the capture of Ala27 is a selectivity determinant and is sufficient to confer selectivity.
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Kinetics study. Inhibition kinetics studies were carried out in the absence or presence of inhibitors with
different concentrations of pNPP. The experimental data were analyzed by the double reciprocal plot method
in order to determine the type of inhibition. As shown in Figure 3, with the increasing concentrations of
compounds 11 and 22, the Km values increased accordingly, while the Vmax values remained almost constant.
The graphs exhibited straight lines which intersect each other on the vertical axis, indicating that compounds
11 and 22 acted as competitive inhibitors.
a)
b)
Figure 3. Inhibition kinetics studies of compounds 11 and 22. (a) concentrations of compound 11 were 1
(green), 2 (blue), 4 (red), and 8 µM (black). (b) concentrations of compound 22 were 0 (green), 0.5 (blue), 1
(red), and 2 µM (black).
SPR study. A novel screening technique [23, 24] was employed to monitor the binding of PTP1B and
compounds. Using a surface plasmon resonance (SPR) biosensor, we evaluated the dynamic interaction of
small molecules with PTP1B immobilized on the sensor surface of a single chip. Association and dissociation
of inhibitors could be exhibited and analyzed with continuous response values. Compounds 11, 12, 14, 19 and
22 displayed binding affinities with the PTP1B surface, which were characterized by slow on-rates and off-
rates (Figure 4a). To determine the kinetic rate constants, increasing concentrations of compound 22 were
injected over the immobilized PTP1B surface. As shown in Figure 4b, compound 22 showed concentration-
dependent increases in binding responses to PTP1B with a KD value of 2.238×10-6 M. Increasing
concentrations of compound 22 led to concentration-dependent increases in binding responses. The SPR
studies indicated that these compounds could bind to the surface of the catalytic site in PTP1B via noncovalent
means.
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a)
b)
Figure 4. Surface plasmon resonance studies of inhibitor binding. (a) Representative sensorgrams for the
interactions of compounds 11, 12, 14, 19 and 22 (50 µM) with the PTP1B surface. (b) Sensorgrams and curve
fits (smooth lines) for the interactions of increasing concentrations of inhibitor 22 (6.25, 3.125, 1.562, 0.781,
and 0.390 µM) with the PTP1B surface, providing ka = 6.124×103 M-1 s-1, kd = 1.371×10-2 s-1, and leading to
KD = 2.238×10-6 M.
2.3 Compound 22 activates insulin and leptin signaling pathway in cells
As a critical regulator of insulin and leptin receptors, PTP1B is an ideal therapeutic target for type II
diabetes and obesity [25-27]. The activation of insulin[6, 7] and leptin signaling (JAK2-STAT3) [28, 29] is the
indirect reflection of PTP1B inhibition. Stabilization of PTP1B in an inactive, oxidized conformation by small
molecules can promote insulin and leptin signaling [30]. The role of compound 22 was also investigated in
C2C12 myotubes. As shown in Figure 5, the phosphorylation levels of IRS-1, Akt, JAK2 and STAT3 were
significantly increased in a dose-dependent manner. These results indicated that compound 22 could activate
the insulin and leptin signaling pathways in cells.
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a)
b)
Figure 5. Compound 22 activates (a) insulin and (b) JAK2-STAT3 signaling pathway. C2C12 myotubes were
treated with compound 22 for 8 h in serum-free DMEM. Then, phosphorylation levels were determined by
immunoblotting. Band density was quantified and normalized with β-actin. The results shown are means ± SD
(n = 3). *p < 0.05 versus vehicle treated control.
2.4 Oral administration of compound 22 controls body weight of BKS db mice
Since the typical symptoms of T2DM are polydipsia and polyphagia, we studied the dynamic effects of
compound 22 on food intake, water intake and body weight of BKS db mice during a treatment of five weeks.
Oral administration of compound 22 (100 mg/kg·day-1) initiated a trend toward decreasing food intake, but no
suppressive effect on the water intake (Figure 6a, b). In detail, food intake of 22-treated mice was significantly
reduced at the fourth week compared to the administered vehicle. As shown in Figure 6c, mice treated with
compound 22 maintained a steady weight during five weeks, while mice of other groups continued to increase
in weight. By the fifth week, 22-treated mice had gained approximately 15% less weight (average 7.18 g) than
the controls. The weight of the abdominal fat pad in 22-treated mice was also reduced compared with the mice
that were administered vehicle and metformin (Figure 6d). These results indicate that long-term oral
administration of 22 could protect mice from obesity.
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b)
a)
c)
d)
Figure 6. Effects of 5 weeks treatment with compound 22 (100 mg/kg·day-1) on mean (a) food intake, (b)
water intake (data are expressed as the mean ± SEM (g·day-1, n = 8)); (c) body weight and (d) abdominal fat
weight (data are expressed as the mean ± SEM (n = 8)). BKS db mice were treated with vehicle, compound 22
#
and metformin, and BKS mice were treated with vehicle. *P < 0.05 versus BKS db group; P < 0.05 versus
BKS group.
2.5 Oral administration of compound 22 ameliorates insulin sensitivity of BKS db mice
Blood glucose levels of BKS db mice were measured during the 5 weeks of treatment to further investigate
the anti-diabetic effect. Compared with BKS mice, diabetic BKS db mice exhibited hyperglycemia with blood
glucose levels of approximately 28 mM (Figure 7a). A five week treatment with compound 22 (100 mg·kg-1
body wt·day-1) showed a trend toward decreased blood glucose levels compared with vehicle. In the 22-treated
group, the blood glucose levels of BKS db mice were significantly decreased from the first week and stable
within the following four weeks. Compared to 22's rapid effect, metformin was slow-acting, there was not a
visible downregulation of glucose levels until the third week. By the fifth week, the blood glucose levels of 22
-
treated mice were similar with those of metformin-treated mice (approximately 18 mM), suggesting that
compound 22 could serve as a qualified agent to treat type II diabetes.
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b)
a)
c)
d)
Figure 7. Effects of compound 22 in BKS db mice. (a) Fasting blood glucose levels were measured at week 0,
1, 2, 3, 4 and 5 during the five-week period. (b) Blood glucose levels 120 min after a dose of oral glucose (2
g/kg). (c) ITT in the 2nd week (insulin dose, 0.75 U/kg). (d) The area under the curve (AUC) of ITT. Data are
expressed as the mean ± SEM (n = 8). *P < 0.05 versus BKS db group, #P < 0.05 versus BKS group.
We next performed oral glucose tolerance tests (OGTT) and insulin tolerance tests (ITT) in BKS db mice
treated with vehicle, metformin or 22. BKS db mice treated with compound 22 showed decreased blood
glucose levels at 120 min after a dose of oral glucose (2 g/kg) compared with the control BKS db mice (Figure
7b). Increased insulin sensitivity was observed in BKS db mice after 22 administration (Figure 7c). The area
under the curve (AUC) values of ITT in the compound 22 group were significantly lower than those in the
control group (Figure 7d).
2.6 Oral administration of compound 22 increases phosphorylation level of Akt in muscle tissues of
BKS db mice
To determine whether compound 22 improves glucose homeostasis and insulin resistance through inhibition
of PTP1B, the phosphorylated and total levels of Akt were evaluated in the muscle tissue of BKS db mice with
or without compound 22. As shown in Figure 8, the phosphorylation level of Akt in muscle of BKS db mice
were decreased, compared with the normal BKS mice. After oral administration of compound 22
,
phosphorylation level of Akt was elevated compared with the control group, indicating that compound 22
administration enhanced insulin signaling in muscle of BKS db mice.
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Figure 8. Phosphorylated and total Akt in muscle tissues of BKS db mice. Data are expressed as the mean ±
SEM (n = 3). *P < 0.05 versus BKS db group, #P < 0.05 versus BKS group.
2.7 Toxicological safety evaluation of compound 22 in vivo
To assess the safety of compound 22 for oral administration, acute and subacute toxicological evaluation
were conducted. Single doses (500, 1000 and 2000 mg/kg body wt.) elicited no significant changes in food
intake, water intake or body weight (not shown). Repetitive doses (1000 mg/kg body wt·day-) for 14 days
initiated a trend toward decreased food intake and body weight compared with vehicle, but no suppressive
effect on the water intake (Figure 9). In addition, none of the mice showed visible toxic effects, behavioral
changes or mortality during acute and subacute toxicity studies. Histological analysis by gomori staining of 22
-
treated mice livers, hearts, kidneys and lungs showed normal histological structure and normal sized cells
(Figure 10). Long-term oral administration of compound 22 could protect mice from obesity, which was not
the result of toxicity.
a)
b)
c)
Figure 9. Effects of 14 days treatment with compound 22 (1000 mg/kg·day-1) on mean (a) water intake, (b)
food intake, and (c) body weight (data are expressed as mean ± SEM (n = 10)).
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Figure 10. Histological analysis by gomori staining of livers, hearts, kidneys and lungs in the mice treated
with compound 22 (1000 mg/kg body wt·day-, 14 days) and vehicle .
2.8 Pharmacokinetics study of compound 22 in specific pathogen free rates.
The highest plasma concentration Cmax of compound 22 had a mean value of 3350 ± 707 nmol/L after i.v.
administration (5 min post dosing, 2 mg·kg-1). The mean Vss was 4.25 ± 0.47 L/kg, suggesting that compound
22 could be extensively distributed to the tissues. The plasma level of compound 22 declined rapidly during
the first 2 h (MRT 0.58 ± 0.04 h), as indicated by a short mean t1/2 of approximately 0.40 ± 0.03 h. After p.o.
administration, compound 22 was absorbed rapidly from the gastrointestinal tract (Tmax 0.5 h). The
bioavailability F of compound 22 was low, with a mean value of 8.31 ± 2.96 %.
Our pharmacokinetics results from the rat-based assays indicated that orally administered compound 22 was
absorbed rapidly from the gastrointestinal tract and extensively distributed to the tissues. In addition,
compound 22 was rapidly eliminated from the body, resulting in poor availability to systemic circulation. The
reason for this result might be that the phenolic hydroxyl groups were eliminated rapidly [31]. To circumvent
the undesirable presystemic metabolism, a slow-release formulation or a biomimetic nanocarrier approach [32]
might be employed as promising strategies to overcome this deficiency.
3. Conclusions
In summary, we have utilized a structure-based approach to design a series of non-phosphonate PTP1B
inhibitors with good specificity. When an ethoxyl group was introduced to occupy the hydrophobic pocket
containing Ala27 and Arg254, a marked inhibitory effect (22, IC50=0.190 µM) and selectivity (20-200 folds
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over other PTPs) were observed resulting from the competitive inhibition of PTP1B. Further studies on
cellular activities revealed that compound 22 increased the phosphorylation levels of IRS-1, Akt, JAK2 and
STAT3 in the C2C12 myotubes and the muscles of BKS db mice, indicating the activation of insulin and leptin
signaling pathways. Long-term oral administration of compound 22 could ameliorate insulin sensitivity,
reduced blood glucose levels (fast-acting) in BKS db mice, and protect mice from obesity, while no visible
toxic effects were observed. Orally administered compound 22 was absorbed rapidly from the gastrointestinal
tract, extensively distributed to the tissues and rapidly eliminated from the body of rat. These novel
bromophenol derivatives reported in this study could provide a possible opportunity for the development of
potent PTP1B inhibitors to treat type II diabetes.
Additional files
Additional figures, synthesis and full spectroscopic data for all new compounds can be found at Electronic
Supplementary Information (ESI).
Declarations
Funding
This work was supported by the National Natural Science Foundation of China (No. 81703354, 81773586),
Key research and development project of Shandong province (2018GSF118200, 2016ZDJS07A13), NSFC-
Shandong Joint Fund (U1706213), Key Research Program of Frontier Sciences CAS (QYZDB-SSW-
DQC014), and Aoshan Talents Program Supported by Qingdao National Laboratory for Marine Science and
Technology (2015ASTP).
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Highlights:
1. A complete process of PTP1B inhibitor identification is proposed, from
enzymatic to mouse model.
2. The difficult points in PTP1B inhibitors, selective inhibition and cell
permeability, were overcome.
3. Oral administration of 22 prevented weight gain, improved insulin
sensitivity and decreased blood glucose level in BKS db mice.