Protein Tyrosine Phosphatase 1B Inhibitors Research Articles

A novel fluorescent probe with Aggregation-Induced emission characteristics for PTP1B activity sensing and inhibitor screening

Protein tyrosine phosphatase 1B (PTP1B) is an attractive target for the treatment of metabolic diseases such as type 2 diabetes and obesity. In this study, a novel fluorescent probe with aggregation-induced emission (AIE) characteristics was designed and synthesized. Within the fluorescent probe, a tetraphenylethene core is connected to a peptide sequence that can be specifically recognized and hydrolysed by PTP1B. Due to the dephosphorylation of PTP1B, the fluorescent probe exhibited AIE in a turn-on manner, indicating PTP1B activity. This probe was successfully used to detect PTP1B activity in HepG2 cell lysates. Then, a probe-based method was applied to screen for potential PTP1B inhibitors from a natural product library, and three novel PTP1B inhibitors were discovered. These findings indicated that the proposed approach offers a new avenue for discovering potential PTP1B inhibitors.

PTP1B Modulates Carotid Plaque Vulnerability in Atherosclerosis Through Rab5-PDGFRβ-Mediated Endocytosis Disruption and Apoptosis.

Protein tyrosine phosphatase 1B (PTP1B) is a protein tyrosine phosphatase and modulates platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) signaling in vascular smooth muscle cells (VSMCs) via endocytosis. However, the related molecular pathways that participated in the interaction of endo-lysosome and the trafficking of PDGFR are largely unknown. This study aims to determine the subcellular regulating mechanism of PTP1B to the endo-lysosome degradation of PDGFR in atherosclerotic carotid plaques, thereby offering a potential therapeutic target for the stabilization of carotid plaques. The immunohistochemical staining technique was employed to assess the expression levels of both PDGFR-β and Caspase 3 in stable and vulnerable carotid plaques. Tunnel staining was utilized to quantify the apoptosis of carotid plaques. Live-cell imaging was employed to observe endocytic motility, while cell apoptosis was evaluated through Propidium Iodide staining. In an invivo experiment, ApoE-/- mice were administered a PTP1B inhibitor to investigate the impact of PTP1B on atherosclerosis. The heightened expression of PDGFR-β correlates with apoptosis in patients with vulnerable carotid plaques. At the subcellular level of VSMCs, PDGFR-β plays a pivotal role in sustaining a balanced endocytosis system motility, regulated by the expression of Rab5, a key regulator of endocytic motility. And PTP1B modulates PDGFR-β signaling via Rab5-mediated endocytosis. Additionally, disrupted endocytic motility influences the interplay between endosomes and lysosomes, which is crucial for controlling PDGFR-β trafficking. Elevated PTP1B expression induces cellular apoptosis and impedes migration and proliferation of carotid VSMCs. Ultimately, mice with PTP1B deficiency exhibit a reduction in atherosclerosis. Our results illustrate that PTP1B induces disruption in endocytosis and apoptosis of VSMCs through the Rab5-PDGFRβ pathway, suggesting a potential association with the heightened vulnerability of carotid plaques.

Exploring cutting-edge approaches in diabetes care: from nanotechnology to personalized therapeutics.

Diabetes mellitus (DM) is a persistent condition characterized by high levels of glucose in the blood due to irregularities in the secretion of insulin, its action, or both. The disease was believed to be incurable until insulin was extracted, refined, and produced for sale. In DM, insulin delivery devices and insulin analogs have improved glycemic management even further. Sulfonylureas, biguanides, alpha-glucosidase inhibitors, and thiazolidinediones are examples of newer-generation medications having high efficacy in decreasing hyperglycemia as a result of scientific and technological advancements. Incretin mimetics, dual glucose-dependent insulinotropic polypeptide, GLP-1 agonists, PPARs, dipeptidyl peptidase-4 inhibitors, anti-CD3 mAbs, glucokinase activators, and glimins as targets have all performed well in recent clinical studies. Considerable focus was placed on free FA receptor 1 agonist, protein tyrosine phosphatase-1B inhibitors, and Sparc-related modular calcium-binding protein 1 which are still being studied. Theranostics, stem cell therapy, gene therapy, siRNA, and nanotechnology are some of the new therapeutic techniques. Traditional Chinese medicinal plants will also be discussed. This study seeks to present a comprehensive analysis of the latest research advancements, the emerging trends in medication therapy, and the utilization of delivery systems in treating DM. The objective is to provide valuable insights into the application of different pharmaceuticals in the field of diabetes mellitus treatment. Also, the therapeutic approach for diabetic patients infected with COVID-19 will be highlighted. Recent clinical and experimental studies evidence the Egyptian experience. Finally, as per the knowledge of the state of the art, our conclusion and future perspective will be declared.

Virtual and in Vitro Screening Employing a Repurposing Approach Reveal 13-cis-Retinoic Acid is a PTP1B Inhibitor.

Current treatments for type 2 diabetes (T2D) mainly rely on exercise, dietary control, and anti-diabetic drugs to enhance insulin secretion and improve insulin sensitivity. However, there is a need for more therapeutic options, as approved drugs targeting different pharmacological objectives are still unavailable. One potential target that has attracted attention is the protein tyrosine phosphatase 1B (PTP1B), which negatively regulates the insulin signaling pathway. In this work, a comprehensive computational screening was carried out using cheminformatics and molecular docking on PTP1B, employing a rigorous repurposing approach. The screening involved approved drugs and compounds under research as anti-diabetics that bind to targets such as peroxisome proliferator-activated receptor gamma (PPAR-γ) and α-glucosidase. Several computational hits were then meticulously tested in vitro against PTP1B, with 13-cis-retinoic acid (3a) showing an IC50 of 0.044 mM and competitive inhibition. Molecular dynamics studies further confirmed that 3a can bind to the catalytic binding site of PTP1B. Finally, 3a is the first time it has been reported as an inhibitor of PTP1B, making it a potentially valuable candidate for further studies in D2T treatment.

Medicinal Aspects of PTP 1B Inhibitors as Anti-Breast Cancer Agents: An Overview.

Protein tyrosine phosphatase 1B (PTP1B) has gained interest as a therapeutic target for type 2 diabetes and obesity. Besides metabolic signalling, PTP1B is a positive regulator of signalling pathways linked to ErbB2-induced breast tumorigenesis. Substantial evidence proves that its overexpression is involved in breast cancer, which suggests that selective PTP1B inhibition might be effective in breast cancer treatment. Therefore, huge research is being carried out on PTP1B inhibitors and their activity against breast cancer development. To date, only two PTP1B inhibitors, viz. ertiprotafib and trodusquemine, have entered clinical trials. The discovery of selective inhibitors of PTP1B could open a new avenue in breast cancer treatment. In this review, we provide an extensive overview on the involvement of PTP1B in breast cancer, its pathophysiology, with special attention on the discovery and development of various natural as well as synthetic PTP1B inhibitors. This study will provide significant information to the researchers developing PTP1B inhibitors for breast cancer treatment.

Fucosylated Chondroitin Sulfate from Bohadschia ocellata: Structure Analysis and Bioactivities

Fucosylated chondroitin sulfate (FCS) was prepared from Bohadschia ocellata using protease hydrolysis. The structural characteristics of FCS were confirmed through chemical composition analysis using FTIR spectroscopy, 1H NMR, and 13C NMR. FCS from B. ocellata (FCS-Bo) exhibited an average molecular weight of approximately 122 kDa. The biological activities of FCS-Bo, including anticoagulant, anti-cancer, and Protein Tyrosine Phosphatase 1B (PTP1B) inhibition, were evaluated. FCS-Bo displayed potent anticoagulant properties, markedly extending activated partial thromboplastin time, prothrombin time, and thrombin time when compared to the heparin control. In anti-cancer bioactivity research, FCS-Bo efficiently inhibited colony formation in the colon cancer cell lines HCT-116, HT-29, and DLD-1, achieving inhibition rates of up to 65%. Additionally, FCS-Bo exhibited significant inhibition of PTP1B, with an IC50 as low as 0.0326 µg/mL, suggesting its potential for improving insulin sensitivity and managing conditions such as type 2 diabetes and obesity.

Identification of natural curcumins as potential dual inhibitors of PTP1B and α-glucosidase through experimental and computational study

Curcuma longa is a rich source of curcumin (1) and its major analogs, demethoxycurcumin (2), and bisdemethoxycurcumin (3), among the Curcuma species. In this study, curcumins (1–3) were purified from C. longa, and their inhibitory effects against protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase enzymes were assayed. These compounds potential inhibited PTP1B and α-glucosidase activities with IC50 values ranging from 37.8 to 72.6 μM, and 78.2–90.6 μM, respectively. In addition, density functional theory (DFT) accompanied by molecular docking (MD) were employed to analyze the ligand stability and the interaction of curcumins 1–3 with PTP1B and glucoside hydrolase proteins. The assay-based results and MD data obtained showed a high correlation, suggesting that the deterioration of enzyme activity caused by the distortion of the structural conformation of PTP1B and glucoside hydrolase may be related to the arrangement of amino acids in the protein structure. Our findings reveal the significant role of methoxylation in the variation of inhibitory effects of these curcumins against PTP1B and α-glucosidase. These in vitro and in silico activities of curcumins (1–3) against PTP1B and glucoside hydrolase have been examined and reported for the first time.

Terpenoids and steroids from aerial parts of Achillea alpina L. as PTP1B inhibitors: Kinetic analysis and molecular docking studies

Achillea alpina L. (Alpine yarrow) is a noteworthy herb in the genus Achillea with many uses in vegetables and traditionally used to treat stomach disorders. In our continuous research on the chemical constituents and biological activities of medicinal plants, ten previously undescribed terpenoids including eight eudesmane-type sesquiterpenes (1–8), one nor-eudesmane-type sesquiterpene (9), one cyclo-geraniol derivative (10), and twenty-one known compounds were isolated and structurally elucidated from the aerial parts of A. alpina. Structures and absolute configurations of the undescribed terpenoids were identified using comprehensive spectroscopic analysis (NMR, HRESI-MS, and CD data) and computational methods (ECD and NMR calculation). Enzyme inhibitory assays showed that the isolated sesquiterpene (19), triterpene (22), and sterol (26) were protein tyrosine phosphatase 1B (PTP1B) inhibitors with IC50 values ranging from 14.87 to 23.09 μM in comparison with positive control - ursolic acid, showing IC50 value of 5.93 ± 0.16 μM. Further enzyme kinetics and molecular docking studies were performed to provide valuable insights into their mechanism of action.

In Vitro and In Silico Analysis of PTP1B Inhibitors from Cleistocalyx operculatus Leaves and Their Effect on Glucose Uptake.

As part of our ongoing research on new anti-diabetic compounds from ethnopharmacologically consumed plants, two previously undescribed lupane-type triterpenoids (1 and 2) with dicarboxylic groups, an undescribed nor-taraxastane-type triterpenoid (3), and 14 known compounds (4-17) were isolated from the leaves of Cleistocalyx operculatus. Extensive spectroscopic analysis (IR, HRESIMS, 1D, and 2D NMR) was used for structure elucidation, while the known compounds were compared to reference data reported in the scientific literature. All the isolates (1-17) were evaluated for their inhibitory effects on the protein tyrosine phosphatase 1B (PTP1B) enzyme. Compounds 6, 9, and 17 showed strong PTP1B inhibitory activities. The mechanism of PTP1B inhibition was studied through enzyme kinetic experiments. A non-competitive mechanism of inhibition was determined using Lineweaver-Burk plots for compounds 6, 9, and 17. Additionally, Dixon plots were employed to determine the inhibition constant. Further insights were gained through a structure-activity relationship study and molecular docking analysis of isolated compounds with the PTP1B crystal structure. Moreover, all isolates (1-17) were tested for their stimulatory effects on the uptake of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose (2-NBDG) in differentiated 3T3-L1 adipocyte cells. Compounds 6, 13, and 17 exhibited strong glucose absorption stimulation activity in a dose-dependent manner.

Role of Alkannin in the Therapeutic Targeting of Protein-Tyrosine Phosphatase 1B and Aldose Reductase in Type 2 Diabetes: An In Silico and In Vitro Evaluation.

Alkannin is a plant-derived naphthoquinone that is isolated from the Boraginaceae family plants. In our previous studies, we found that shikonin, which is the R-enantiomer of alkannin, has potent antidiabetic activity by inhibiting the action of the aldose reductase (AR) enzyme and the protein-tyrosine phosphatase 1B (PTP1B). Therefore, in this study, we aim to explore the antidiabetic effect of alkannin targeting PTP1B and AR by employing in silico and in vitro techniques. For in silico, we used different parameters such as ADMET analysis, molecular docking, MD simulation, Root Mean Square Deviation (RMSD), protein-ligand mapping, and free binding energy calculation. The in vitro evaluation was done by assessing the inhibitory activity and enzyme kinetics of PTP1B and AR inhibition by alkannin. The in silico studies indicate that alkannin possesses favorable pharmacological properties and possesses strong binding affinity for diabetes target proteins. Hydrogen bonds (Val297, Ala299, Leu300, and Ser302) and hydrophobic interactions (Trp20, Val47, Tyr48, Trp79, Trp111, Phe122, Trp219, Val297, Cys298, Ala299, Leu300, and Leu301) are established by the compound, which potentially improves specificity and aids in the stabilization of the protein-ligand complex. The results from in vitro studies show a potent dose-dependent PTP1B inhibitory activity with an IC50 value of 19.47 μM, and toward AR it was estimated at 22.77 μM. Thus, from the results it is concluded that a low IC50 value of alkannin for both PTP1B and AR along with favorable pharmacological properties and optimal intra-molecular interactions indicates its utilization as a potential drug candidate for the management of diabetes and its end complications.

Structures of human PTP1B variants reveal allosteric sites to target for weight loss therapy.

Protein Tyrosine Phosphatase 1B (PTP1B) is a negative regulator of leptin signaling whose disruption protects against diet-induced obesity in mice. We investigated whether structural characterization of human PTP1B variant proteins might reveal precise mechanisms to target for weight loss therapy. We selected 12 rare variants for functional characterization from exomes from 997 people with persistent thinness and 200,000 people from UK Biobank. Seven of 12 variants impaired PTP1B function by increasing leptin-stimulated STAT3 phosphorylation in cells. Using room-temperature X-ray crystallography, hydrogen-deuterium exchange mass spectrometry, and computational modeling, we determined that human variants modulate the 3-dimensional structure of PTP1B through distinct allosteric conduits that energetically link distal, highly ligandable structural regions to the active site. These studies inform the design of allosteric PTP1B inhibitors for the treatment of obesity.

Luteolin-7-diglucuronide, a novel PTP1B inhibitor, ameliorates hepatic stellate cell activation and liver fibrosis in mice.

Liver fibrosis, one of the leading causes of morbidity and mortality worldwide, lacks effective therapy. The activation of hepatic stellate cells (HSCs) is the dominant event in hepatic fibrogenesis. Luteolin-7-diglucuronide (L7DG) is the major flavonoid extracted from Perilla frutescens and Verbena officinalis. Their beneficial effects in the treatment of liver diseases were well documented. In this study we investigated the anti-fibrotic activities of L7DG and the potential mechanisms. We established TGF-β1-activated mouse primary hepatic stellate cells (pHSCs) and human HSC line LX-2 as in vitro liver fibrosis models. Co-treatment with L7DG (5, 20, 50 μM) dose-dependently decreased TGF-β1-induced expression of fibrotic markers collagen 1, α-SMA and fibronectin. In liver fibrosis mouse models induced by CCl4 challenge alone or in combination with HFHC diet, administration of L7DG (40, 150 mg·kg-1·d-1, i.g., for 4 or 8 weeks) dose-dependently attenuated hepatic histopathological injury and collagen accumulation, decreased expression of fibrogenic genes. By conducting target prediction, molecular docking and enzyme activity detection, we identified L7DG as a potent inhibitor of protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 2.10 µM. Further studies revealed that L7DG inhibited PTP1B activity, up-regulated AMPK phosphorylation and subsequently inhibited HSC activation. This study demonstrates that the phytochemical L7DG may be a potential therapeutic candidate for the treatment of liver fibrosis.

Chalcone-Monoterpene Derivatives from the Buds of Cleistocalyx operculatus and Their Potential as Protein Tyrosine Phosphatase 1B Inhibitors.

Four new compounds, racemic chalcone-monoterpene hybrids (1-3) and a chalcone (9), along with nine known compounds (4-8, 10-13), have been isolated from the buds of Cleistocalyx operculatus. The chemical structures of the isolated compounds were identified through NMR data analysis and confirmed by computational methods, including electronic circular dichroism (ECD) calculations, and further synthetic approaches. Compounds 1-5 were synthesized via a Diels-Alder reaction, a process informed by biomimetic condensation studies that combined chalcones and monoterpenes. These synthetic approaches also yielded various unnatural chalcone-monoterpene derivatives (14-23). The inhibitory effects on protein tyrosine phosphatase 1B (PTP1B) of both naturally isolated and synthetically obtained compounds were evaluated. Compounds 4, 9, 13, and 16b exhibited potent PTP1B inhibitory activity, with IC50 values ranging from 0.9 ± 0.2 to 3.9 ± 0.7 μM. The enantiomers (+)-4 and (-)-16b showed enhanced activity compared to their respective enantiomers. Kinetic studies indicate that all active compounds inhibit PTP1B through mixed mechanisms, and molecular docking simulations agree with the experimental assays on PTP1B. Our results suggest that chalcone-meroterpene adducts from the buds of C.operculatus exhibit potential as antidiabetic agents, partly due to their PTP1B enzyme inhibition.

3-Benzylaminomethyl Lithocholic Acid Derivatives Exhibited Potent and Selective Uncompetitive Inhibitory Activity Against Protein Tyrosine Phosphatase 1B (PTP1B).

Protein tyrosine phosphatase 1B (PTP1B) is a promising drug target for treating type 2 diabetes (T2DM) and obesity. As a result, developing new therapies that target PTP1B is an attractive strategy for treating these diseases. Herein, we detail the synthesis of 15 lithocholic acid (LA) derivatives, each containing different benzylaminomethyl groups attached to the C3 position of the steroid skeleton. The derivatives were assessed against two forms of PTP1B enzyme (hPTP1B1-400 and hPTP1B1-285), and the most potent compounds were then tested against T-cell protein tyrosine phosphatase (TCPTP) to determine their selectivity. The results showed that compounds 6m and 6n were more potent than the reference compounds (ursolic acid, chlorogenic acid, suramin, and TCS401). Additionally, both compounds exhibited greater potency over hPTP1B1-400. Furthermore, enzyme kinetic studies on hPTP1B1-400 revealed that these two lithocholic acid derivatives have an uncompetitive inhibition against hPTP1B1-400 with K i values of 2.5 and 3.4 μM, respectively. Interestingly, these compounds were around 75-fold more selective for PTP1B over TCPTP. Finally, docking studies and molecular dynamics simulations (MDS) were conducted to determine how these compounds interact with PTP1B. The docking studies revealed hydrophobic and H-bond interactions with amino acid residues in the unstructured region. MDS showed that these interactions persisted throughout the 200 ns simulation, indicating the crucial role of the unstructured zone in the biological activity and inhibition of PTP1B.

Natural hypoglycaemic bioactives: Newer avenues and newer possibilities.

The incidences of endocrine and metabolic disorders like diabetes have increased worldwide. Several proposed molecular pathways mechanisms for the management of diabetes have been identified, but glycaemic control is still a challenging task in the drug discovery process. Most of the drug discovery processes lead to numerous scaffolds that are prominent in natural products. The review deals with the natural bioactives as an α-amylase inhibitors, α-glucosidase inhibitors, protein tyrosine phosphatase-1B inhibitors, dipeptidyl peptidase-IV inhibitors, G-protein coupled receptors-40 agonists, PPAR-γ agonists and the activators of 5'-adenosine monophosphate-activated protein kinase and glucokinase. So, in this review, we focused on the hypoglycaemic bioactives, which will assist scientific developers, traditional medicinal practitioners, and readers to discover some potent antidiabetic molecules. Strategies like chemometric approaches, scaffold hopping, and total synthesis of natural products by group modification or ring opening/closing mechanism could be useful for the development of novel hit/lead antidiabetic molecules. The study concludes that each phyto molecule inherits a potential to get explored by repurposing techniques for various antidiabetic targets and offer an alternative antidiabetic therapeutic medicinal potential.

Hovedulcates A and B, 2,3-dihydrobenzofuran derivatives isolated from the fruits of Hovenia dulcis Thunb. as potential inhibitors of PTP1B and α-glucosidase

From the fruits of Hovenia dulcis Thunb., two new 2,3-dihydrobenzofuran derivatives, named hovedulcates A and B (14 and 16), as well as 20 known compounds (1–13, 15, and 17–22) were isolated. The structures of the isolated compounds were elucidated through a combination of NMR, HR-MS, and ECD spectroscopy analyses, and reported data in the literature. The inhibitory activities of the isolated compounds (1–22) against protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase were assessed. Notably, new compounds 14 and 16 exhibited potent inhibitions of both PTP1B and α-glucosidase. The enzyme kinetics analysis was conducted to understand the inhibition mode and inhibitory constants of compounds 14 and 16 for the inhibition of PTP1B and α-glucosidase. Additionally, molecular docking simulations revealed the binding mechanisms and interactions of these compounds with the target enzymes. Our findings suggest that secondary metabolites from H. dulcis fruits are promising natural product treatments for type 2 diabetes.

Recent Developments in the Role of Protein Tyrosine Phosphatase 1B (PTP1B) as a Regulator of Immune Cell Signalling in Health and Disease.

Protein tyrosine phosphatase 1B (PTP1B) is a non-receptor tyrosine phosphatase best known for its role in regulating insulin and leptin signalling. Recently, knowledge on the role of PTP1B as a major regulator of multiple signalling pathways involved in cell growth, proliferation, viability and metabolism has expanded, and PTP1B is recognised as a therapeutic target in several human disorders, including diabetes, obesity, cardiovascular diseases and hematopoietic malignancies. The function of PTP1B in the immune system was largely overlooked until it was discovered that PTP1B negatively regulates the Janus kinase-a signal transducer and activator of the transcription (JAK/STAT) signalling pathway, which plays a significant role in modulating immune responses. PTP1B is now known to determine the magnitude of many signalling pathways that drive immune cell activation and function. As such, PTP1B inhibitors are being developed and tested in the context of inflammation and autoimmune diseases. Here, we provide an up-to-date summary of the molecular role of PTP1B in regulating immune cell function and how targeting its expression and/or activity has the potential to change the outcomes of immune-mediated and inflammatory disorders.

Protein Tyrosine Phosphatase 1B (PTP1B): A Comprehensive Review of Its Role in Pathogenesis of Human Diseases.

Overexpression of protein tyrosine phosphatase 1B (PTP1B) disrupts signaling pathways and results in numerous human diseases. In particular, its involvement has been well documented in the pathogenesis of metabolic disorders (diabetes mellitus type I and type II, fatty liver disease, and obesity); neurodegenerative diseases (Alzheimer's disease, Parkinson's disease); major depressive disorder; calcific aortic valve disease; as well as several cancer types. Given this multitude of therapeutic applications, shortly after identification of PTP1B and its role, the pursuit to introduce safe and selective enzyme inhibitors began. Regrettably, efforts undertaken so far have proved unsuccessful, since all proposed PTP1B inhibitors failed, or are yet to complete, clinical trials. Intending to aid introduction of the new generation of PTP1B inhibitors, this work collects and organizes the current state of the art. In particular, this review intends to elucidate intricate relations between numerous diseases associated with the overexpression of PTP1B, as we believe that it is of the utmost significance to establish and follow a brand-new holistic approach in the treatment of interconnected conditions. With this in mind, this comprehensive review aims to validate the PTP1B enzyme as a promising molecular target, and to reinforce future research in this direction.

Protein Tyrosine Phosphatase 1B Inhibitors of Pueraria lobata Based on the Spectrum-Effect Relationship by Q-Marker Selection.

Pueraria lobata (P. lobata), a traditional anti-diabetic medicine mainly composed of flavonoids and isoflavones, has a long history in diabetes treatment in China. However, the anti-diabetic active component is still unclear. Recently, protein tyrosine phosphatase 1B (PTP1B) has been a hot therapeutic target by negatively regulating insulin signaling pathways. In this study, the spectrum-effect relationship analysis method was first used to identify the active components of P. lobata that inhibit PTP1B. The fingerprints of 12 batches of samples were established using high-performance liquid chromatography (HPLC), and sixty common peaks were identified. Meanwhile, twelve components were identified by a comparison with the standards. The inhibition of PTP1B activity was studied in vitro by using the p-nitrophenol method, and the partial least squares discriminant analysis, grey relational analysis, bivariate correlation analysis, and cluster analysis were used to analyze the bioactive compounds in P. lobata. Peaks 6, 9 (glycitin), 11 (genistin), 12 (4'-methoxypuerarin), 25, 34, 35, 36, 53, and 59 were considered as potentially active substances that inhibit PTP1B. The in vitro PTP1B inhibitory activity was confirmed by glycitin, genistin, and 4'-methoxypuerarin. The IC50s of the three compounds were 10.56 ± 0.42 μg/mL, 16.46 ± 0.29 μg/mL, and 9.336 ± 0.56 μg/mL, respectively, indicating the obvious PTP1B inhibitory activity. In brief, we established an effective method to identify PTP1B enzyme inhibitors in P. lobata, which is helpful in clarifying the material basis of P. lobata on diabetes. Additionally, it is evident that the spectrum-effect relationship method serves as an efficient approach for identifying active compounds, and this study can also serve as a reference for screening bioactive constituents in traditional Chinese medicine.

Native dynamics and allosteric responses in PTP1B probed by high-resolution HDX-MS.

Protein tyrosine phosphatase 1B (PTP1B) is a validated therapeutic target for obesity, diabetes, and certain types of cancer. In particular, allosteric inhibitors hold potential for therapeutic use, but an incomplete understanding of conformational dynamics and allostery in this protein has hindered their development. Here, we interrogate solution dynamics and allosteric responses in PTP1B using high-resolution hydrogen-deuterium exchange mass spectrometry (HDX-MS), an emerging and powerful biophysical technique. Using HDX-MS, we obtain a detailed map of backbone amide exchange that serves as a proxy for the solution dynamics of apo PTP1B, revealing several flexible loops interspersed among more constrained and rigid regions within the protein structure, as well as local regions that exchange faster than expected from their secondary structure and solvent accessibility. We demonstrate that our HDX rate data obtained in solution adds value to estimates of conformational heterogeneity derived from a pseudo-ensemble constructed from ~200 crystal structures of PTP1B. Furthermore, we report HDX-MS maps for PTP1B with active-site versus allosteric small-molecule inhibitors. These maps suggest distinct and widespread effects on protein dynamics relative to the apo form, including changes in locations distal (>35 Å) from the respective ligand binding sites. These results illuminate that allosteric inhibitors of PTP1B can induce unexpected changes in dynamics that extend beyond the previously understood allosteric network. Together, our data suggest a model of BB3 allostery in PTP1B that combines conformational restriction of active-site residues with compensatory liberation of distal residues that aid in entropic balancing. Overall, our work showcases the potential of HDX-MS for elucidating aspects of protein conformational dynamics and allosteric effects of small-molecule ligands and highlights the potential of integrating HDX-MS alongside other complementary methods, such as room-temperature X-ray crystallography, NMR spectroscopy, and molecular dynamics simulations, to guide the development of new therapeutics.