Protein tyrosine phosphatase 1B regulates migration of ARPE-19 cells through EGFR/ERK signaling pathway

AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for α-smooth muscle actin (α-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. α-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, α-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.

Structural Insight into the Design on Oleanolic Acid Derivatives as Potent Protein Tyrosine Phosphatase 1B Inhibitors

Oleanolic acid derivatives act as newer protein tyrosine phosphatase 1B （PTP-1B） inhibitors for type 2 diabetes mellitus （T2DM）. In order to understand the structural requirement of PTP-1B inhibitors, 52 oleanolic acid derivatives were divided into a training set （34 compounds） and a test set （18 compounds）. The highly reliable and predictive 3D-QSAR models were constructed by CoMFA, CoMSIA and topomer CoMFA methods, respectively. The results showed that the cross validated coefficient （q2） and non-cross-validated coefficient （R2） were 0.554 and 0.999 in the CoMFA model, 0.675 and 0.971 in the CoMSIA model, and 0.628 and 0.939 in the topomer CoMFA model, which suggests that three models are robust and have good exterior predictive capabilities. Furthermore, ten novel inhibitors with much higher inhibitory potency were designed. Our design strategy was that （i） the electronegative substituents （Cl, -CH2OH, OH and -CH2Cl） were introduced into the double bond of ring C, （ii） the hydrogen bond acceptor groups （C≡N and N atom）, electronegative groups （C≡N, N atom, -COOH and -COOCH3） and bulky substituents （C6H5N） were connected to the C-3 position, which would result in generating potent and selective PTP-1B inhibitors. We expect that the results in this paper have the potential to facilitate the process of design and to develop new potent PTP-1B inhibitors.

Synthesis and protein tyrosine phosphatase 1B inhibition activities of two new synthetic bromophenols and their methoxy derivatives

3-bromo-4,5-bis（2,3-dibromo-4,5-dihydroxybenzyl）-l,2-benzenediol （1） is a natural bromophenol isolated from the red algae Rhodomela confervoides that exhibits significant inhibition against protein tyrosine phosphatase 1B （PTP1B）. Based on its activity, we synthesized two new synthetic bromophenols and their methoxy derivatives from vanillin using the structure of natural bromophenol 1 as a scaffold. The structures of these bromophenols were elucidated from H NMR, 13C NMR, and high resolution electron ionization mass spectrometry as 2,3-dibromo-1-（2＇-bromo-6＇-（3＂,4＂-dimethoxybenzyl）- 3 ＇,4 ＇-dimethoxybenzyl）-4,5 -dimethoxybenzene （2）, 2,3-dibromo- 1 -（2 ＇-bromo-6＇-（2 ＂-bromo-4＂,5 ＂-dimethoxy- benzyl）-3＇,4＇-dimethoxybenzyl）-4,5-dimethoxybenzene （3）, 3,4-dibromo-5-（2＇-bromo-6＇-（2＂-bromo-4＂,5＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （4） and 3,4-dibromo-5-（2＇-bromo-6＇-（3＂,4＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （5）. PTP1B inhibition activities of these compounds were evaluated using a colorimetric assay, and compounds 3 and 4 demonstrated interesting activity against PTP1B.

POM analysis and computational interactions of 8-hydroxydiospyrin inside active site of protein tyrosine phosphatase 1B

Proteintyrosine phosphatase 1B(PTP1B)inhibitionis consideredas a potentialtherapeuticfor the treatmentof cancer,type2 diabetes,andobesity.Inour presentwork,weinvestigatedtheanti-diabeticpotentialof8-hydroxydiospyrin(8-HDN)from D.lotus against the PTP1B enzyme.It showed significant inhibitory activity of PTP1B with an IC 50 value of 18.37±0.02μM.A detailed molecular docking study was carried out to analyze the binding orientation,binding energy,and mechanism of inhibition.A comparative investigation of 8-HDN in the catalytic,as well as the allosteric site of PTP1B,was performed.Binding energy data showed that compound 8-HDN is more selective for the allosteric site and hence avoids the problems associated with catalytic site inhibition.The inhibition mechanism of 8-HDN can be further investigated as an active lead compound against PTP1B by using in vitro and in vivo models.

Inactivation of Protein Tyrosine Phosphatase 1B （PTP1B） Activity by the Aqueous Partition of Guava Leaf Extract

Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B （protein tyrosine phosphatase 1b） was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.

Bioactive chemical constituents from the marine-derived fungus Cladosporium sp.DLT-5

A new isochromanone,cladosporinisochromanone(1),accompanied by 15 known compounds(2–16)were obtained from secondary metabolites produced by marine-derived fungus Cladosporium sp.DLT-5.NMR and HRESIMS spectra elucidation determined the planar structure of 1.Subsequent electronic circular dichroism(ECD)experiment assigned the absolute configuration of 1.Compounds 1,2,4–6,and 10 displayed different degrees of neuroprotective activities on human neuroblastoma cells SH-SY5Y.Five compounds(1,3–5,and 13)emerged resistance to protein tyrosine phosphatase 1B(PTP1B),further kinetic analysis and molecular docking study indicated that the most potent compound 13(IC50value of 10.74±0.61μmol/L)was found as a noncompetitive inhibitor for PTP1B.Surface plasmon resonance(SPR)and molecular docking studies also demonstrated the interaction between compound 12 and Niemann-Pick C1 Like 1(NPC1L1),which has been identified as significant therapeutic target for hypercholesteremia.In addition,compounds 3,6,and 14 showed attractive inhibitory activity against the phytopathogenic fungi:Colletotrichum capsici.Therefore,library of Cladosporium metabolites is enriched and new active uses of known compounds are explored.

Pachymic acid exerts antitumor activities by modulating the Wnt/β-catenin signaling pathway via targeting PTP1B

Objective:To determine the inhibitory effects of pachymic acid on lung adenocarcinoma(LUAD)cells and elucidate its underlying mechanism.Methods:CCK-8,wound healing,Transwell,Western blot,tube formation,and immunofluorescence assays were carried out to measure the effects of various concentrations of pachymic acid on LUAD cell proliferation,metastasis,angiogenesis as well as autophagy.Subsequently,molecular docking technology was used to detect the potential targeted binding association between pachymic acid and protein tyrosine phosphatase 1B(PTP1B).Moreover,PTP1B was overexpressed in A549 cells to detect the specific mechanisms of pachymic acid.Results:Pachymic acid suppressed LUAD cell viability,metastasis as well as angiogenesis while inducing cell autophagy.It also targeted PTP1B and lowered PTP1B expression.However,PTP1B overexpression reversed the effects of pachymic acid on metastasis,angiogenesis,and autophagy as well as the expression of Wnt3a andβ-catenin in LUAD cells.Conclusions:Pachymic acid inhibits metastasis and angiogenesis,and promotes autophagy in LUAD cells by modulating the Wnt/β-catenin signaling pathway via targeting PTP1B.

Inhibition of protein tyrosine phosphatase 1B activity by triterpenes isolated from Aceriphyllum rossii

An organic layer prepared from the seed of Aceriphyllum rossii was studied to identify the active compounds for protein tyrosine phosphatase 1B（PTP1B） inhibition.Bioassay guided fractionation resulted in the isolation of PTP1B inhibitory activity of triterpenes（1-4）.These four compounds were identified as aceriphyllic acid C（1）,aceriphyllic acid D（2）,aceriphyllic acid E（3） and aceriphyllic acid F（4）.The isolated 1-4 compounds inhibited PTP1B with IC50 values ranged from（2.1±1.5） μmol/L to（11.2±2.5） μmol/L.Kinetic analysis of PTP1B inhibition by aceriphyllic acid C（1） and aceriphyllic acid D（2） suggested that oleanane-type triterpenes inhibited PTP1B activity in a mixed-type manner.

Inhibition of protein tyrosine phosphatase 1B by triterpenes isolated from Potentilla discolor Bge

Seven oleanene triterpenes were isolated from the roots of Potentilla discolor Bge and their structures were identified as 3-oxoolean-12-en-27-oic acid（1）, gypsogenic acid（2）, 3α-hydroxyolean-12-en-27-oic acid（3）, 3β-hydroxyolean-12-en-27-oic acid（4）, aceriphyllic acid A（5）, aceriphyllic acid A methyl ester（6）, and oleanolic acid（7）. Compounds 1–7 inhibited protein tyrosine phosphatase 1B（PTP1B） activity, with IC50 values ranging from（7.5±0.5） to（22.7±0.5） μmol/L. Among the isolates, compounds 1, 2, 3 and 7 from the Potentilla discolor Bge were found to exhibit selective PTP1 B inhibitory activity.

Novel and emerging diabetes mellitus drug therapies for the type 2 diabetes patient

Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide variety of diabetes therapies is available, yet limited efficacy, adverse effects, cost, contraindications, renal dosage adjustments, inflexible dosing schedules and weight gain significantly limit their use. In addition, many patients in the United States fail to meet the therapeutic HbA1c goal of 【 7% set by the American Diabetes Association. As such new and emerging diabetes therapies with different mechanisms of action hope to address some of these drawbacks to improve the patient with type 2 diabetes. This article reviews new and emerging classes, including the sodium-glucosecotransporter-2 inhibitors, 11β-Hydroxysteroid dehydrogenase type 1 inhibitors, glycogen phosphorylase inhibitors; protein tyrosine phosphatase 1B inhibitors, G Protein-Coupled receptor agonists and glucokinase activators. These emerging diabetes agents hold the promise of providing benefit of glucose lowering, weight reduction, low hypoglycemia risk, improve insulin sensitivity, pancreatic β cell preservation, and oral formulation availability. However, further studies are needed to evaluate their safety profile, cardiovascular effects, and efficacy durability in order to determine their role in type 2 diabetes management.

Extraction and PTP1B inhibitory activity of bromophenols from the marine red alga Symphyocladia latiuscula

Previously, we had characterized several structurally interesting brominated phenols from the marine red alga Symphyocladia latiuscula collected from various sites. However, Phytochemical investigations on this species collected from the Weihai coastline of Shandong Province remains blank. Therefore, we characterized the chemical constituents of individuals of this species collected from the region. Eight bromophenols were isolated and identified. Using detailed spectroscopic techniques and comparisons with published data, these compounds were identified as 2,3-dibromo-4,5-dihydroxybenzyl methyl ether (1), 3,5-dibromo-4-hydroxybenzoic acid (2), 2,3,6-tribromo-4,5-dihydroxymethylbenzene (3), 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (4), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (5), bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (6), 1,2-bis(2,3,6-tribromo-4,5-dihydroxyphenyl)-ethane (7), and 1-(2,3,6-tribromo-4,5-dihydroxybenzyl)-pyrrolidin-2-one (8). Among these compounds, 1 and 2 were isolated for the first time from S. latiuscula. Each compound was evaluated on the ability to inhibit protein tyrosine phosphatase 1B (PTP1B), which is a potential therapeutic target in the treatment of type 2 diabetes. Bromophenols 5, 6, and 7 showed strong activities with IC50 values of 3.9, 4.3, and 3.5 μmol/L, respectively. This study provides further evidence that bromophenols are predominant among the chemical constituents of Symphyocladia, and that some of these compounds may be candidates for the development of anti-diabetes drugs.

Synthesis of mangiferin derivates and study their potent PTP1B inhibitory activity

Protein tyrosine phosphatase 1 B （PTP1 B） has received considerable attention from the drug industry as a potential treatment for diabetes mellitus. Mangiferin has been reported to possess significant antidiabetic activity. Based on the previous study, eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity. Some of them displayed good inhibitory activity on PTP1B.

Protein tyrosine phosphatase 1B expression contributes to the development of breast cancer

The protein tyrosine phosphatase 1B（PTP1B）is an important regulator of metabolism.The relationship between PTP1B and tumors is quite complex.The purpose of this study is to explore the expression pattern and role of PTP1B in breast cancer.The expression of PTP1B was detected in 67 samples of breast cancer tissue by Western blot.Cell growth assay,Transwell migration assay,and Scratch motility assay were used to examine the proliferation and migration of MCF-7 with and without PTP1B.The total levels and phosphorylated levels of signal transduction and activator of transcription 3（STAT3）and the expression of C-C motif chemokine ligand 5（CCL5）were also examined by Western blot.PTP1B was overexpressed in over 70%of breast cancer tissues,correlating with patients with estrogen receptor（ER）-negative,progesterone receptor（PR）-negative,and human epidermal growth factor receptor 2（HER2）-positive tumors.The data also showed that both tumor size and lymph node metastasis were significantly higher in patients with a higher level of PTP1B.The proliferation and migration of MCF-7 cells were found to be inhibited after knocking down the gene of PTP1B.Our data also showed that PTP1B could up-regulate the dephosphorylated level of STAT3,which could increase the expression of CCL5.These phenomena indicated that PTP1B may play a crucial role in the development of breast cancer.

Isoprenylated Flavonoids with PTP1B Inhibition from Macaranga denticulata

Three new C-methylated and isoprenylated chalcone derivatives,dentichalcones A–C(1–3),together with six known compounds(4–9),were isolated from the twigs and leaves of Macaranga denticulata.Their structures were elucidated by spectroscopic analysis,including 1D,2D NMR,and MS data.The known compounds,(2E)-1-(5,7-dihydroxy-2,2,6-trimethyl-2H-benzopyran-8-yl)-3-(4-methoxyphenyl)-2-propen-1-one(4),(2E)-1-(5,7-dihydroxy-2,2-dimethyl-2H-benzopyran-8-yl)-3-phenyl-2-propen-1-one(5),laxichalcone(6),macarangin(7),bonanniol A(8),and bonannione A(9),showed inhibitory activities against protein tyrosine phosphatase 1B(PTP1B)in vitro.Graphical Abstract Three new C-methylated and isoprenylated chalcone derivatives,dentichalcones A–C(1–3),together with six known compounds,were isolated from the twigs and leaves of Macaranga denticulata.Some compounds showed inhibitory activities against PTP1B in vitro.

Protein Tyrosine Phosphatase 1B Inhibitors from Plantago asiatica

Objective To identify the active compounds for protein tyrosine phosphatase 1B(PTP1B) from the seeds of Plantago asiatica.Methods Bioassay-guided fractionation resulted in the isolation of iridoid glucosides(1-5) with PTP1B inhibitory activity.Results Five compounds were identified as desacetylhookerioside(1),melittoside(2),geniposidic acid(3),10-O-acetyl-geniposidic acid(4),and alpinoside(5).Conclusion Isolated compounds 35 inhibit PTP1B with IC50 values ranged from(16.3 ± 1.1) to(19.8 ± 1.2) μmol/L.

A key role for PTP1B in dendritic cell maturation, migration, and T cell activation

Dendritic cells(DC)are the major antigen-presenting cells bridging innate and adaptive immunity,a function they perform by converting quiescent DC to active,mature DC with the capacity to activate naı¨ve T cells.They do this by migrating from the tissues to the T cell area of the secondary lymphoid tissues.Here,wedemonstrate thatmyeloid cell-specific genetic deletion of PTP1B(LysM PTP1B)leads to defects in lipopolysaccharide-driven bone marrow-derivedDC(BMDC)activation associated with increased levels of phosphorylated Stat3.We showthatmyeloid cell-specific PTP1Bdeletion also causes decreased migratory capacity of epidermal DC,aswell as reduced CCR7 expression and chemotaxis to CCL19 by BMDC.PTP1B deficiency in BMDC also impairs their migration in vivo.Further,immature LysM PTP1B BMDC display fewer podosomes,increased levels of phosphorylated Src at tyrosine 527,and loss of Src localization to podosome puncta.In co-culture with T cells,LysM PTP1B BMDC establish fewer and shorter contacts than control BMDC.Finally,LysMPTP1BBMDCfail to present antigen to T cells as efficiently as controlBMDC.These data provide first evidence for a key regulatory role for PTP1B in mediating a central DC function of initiating adaptive immune responses in response to innate immune cell activation.

Enantiomeric pairs of meroterpenoids from Rhododendron fastigiatum

Five pairs of optically pure meroterpenoid enantiomers(1 a/1 b-5 a/5 b)and two known compounds(6 and 7)were isolated from Rhododendron fastigiatum.Compounds 1 a/1 b-5 a/5 b were resolved from naturally scalemic mixtures by chiral HPLC.Their structures were elucidated by spectroscopic methods,X-ray crystallographic experiments,and ECD analyses.Compounds 1 a/1 b,2 a/2 b,3 b,4 a/4 b,and 5 a/5 b were new meroterpenoids with different polycyclic systems.Two enantiomeric pairs(2 a/2 b and 3 a/3 b),6,and 7 exhibited inhibitory effects on protein tyrosine phosphatase 1 B(PTP1 B)in vitro.