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Abstract: In a phase 1 study (NCT04000165), we established proof of concept for activating pyruvate kinase (PK) in sickle cell disease (SCD) as a viable antisickling therapy. AG-348 (mitapivat), a PK activator, increased adenosine triphosphate (ATP) and decreased 2,3-diphosphoglycerate levels while patients were on treatment, in line with the mechanism of the drug. We noted that the increased hemoglobin (Hb) persisted for 4 weeks after stopping AG-348 until the end of study (EOS). Here, we investigated the pathways modulated by activating PK that may contribute to the improved red blood cell (RBC) survival after AG-348 cessation. We evaluated frozen whole blood samples taken at multiple time points from patients in the phase 1 study, from which RBC ghosts were isolated and analyzed by western blotting for tyrosine phosphorylation of band 3 (Tyr-p-bd3), ankyrin-1, and intact (active) protein tyrosine phosphatase 1B (PTP1B) levels. We observed a significant dose-dependent decrease in mean Tyr-p-bd3 from baseline in the patients, accompanied by an increase in the levels of membrane-associated ankyrin-1 and intact PTP1B, all of which returned to near baseline by EOS. Because PTP1B is cleaved (inactivated) by intracellular Ca2+-dependent calpain, we next measured the effect of AG-348 on ATP production and calpain activity and the plasma membrane Ca2+ ATPase pump-mediated efflux kinetics in HbAA and HbSS erythrocytes. AG-348 treatment increased ATP levels, decreased calpain activity, and increased Ca2+ efflux. Altogether, our data indicate that ATP increase is a key mechanism underlying the increase in hemoglobin levels upon PK activation in SCD. This trial was registered at www.clinicaltrials.gov as #NCT04000165., (Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution.)

The species Ganoderma calidophilum represents a distinct variety within the genus Ganoderma and used by the indigenous Li ethnic group as a medicinal agent for the prevention and treatment of cancer. However, the precise biological activity and role of G. calidophilum in antitumor treatment remain largely unresolved. Several lanostane triterpenoids have been isolated from G. calidophilum. The enzyme activity analysis revealed that four lanostane triterpenoids exhibited PTP1B inhibition activity, with minimal inhibition towards SHP2, SHP1, PTPN5, PTPRA, STEP and TCPTP. Molecular docking analysis demonstrated that these compounds primarily bind to the substrate recognition and entry regions of PTP1B. Further analysis indicated that among them, ganoderic aldehyde A (GAA) is a selective and non-competitive PTP1B inhibitor. GAA inhibited the proliferation, colony formation and migration of C33A and MDA-MB-231 cells in a dose-dependent manner. GAA has the capacity to induce apoptosis in a cell-type-specific manner, both in a caspase-dependent and -independent manner. PTP1B siRNA significantly reduced the cytotoxic effect of GAA, while overexpression of PTP1B significantly increased cell growth after GAA treatment. These findings confirm that PTP1B is a functional target of GAA. Research into the mechanisms of action of GAA has revealed that it could inhibit the activation of AKT by inhibiting PTP1B, while simultaneously activating p38, which promotes cell death. It is possible to develop specific PTP1B inhibitors based on the lanosterol triterpene skeleton. G. calidophilum has the potential to be developed into functional foods or drugs with the aim of preventing and treating cancer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Duchenne muscular dystrophy (DMD) is a lethal disease caused by mutations in the DMD gene that encodes dystrophin. Dystrophin deficiency also impacts muscle stem cells (MuSCs), resulting in impaired asymmetric stem cell division and myogenic commitment. Using MuSCs from DMD patients and the DMD mouse model mdx , we found that PTPN1 phosphatase expression is up-regulated and STAT3 phosphorylation is concomitantly down-regulated in DMD MuSCs. To restore STAT3-mediated myogenic signaling, we examined the effect of K884, a novel PTPN1/2 inhibitor, on DMD MuSCs. Treatment with K884 enhanced STAT3 phosphorylation and promoted myogenic differentiation of DMD patient-derived MuSCs. In MuSCs from mdx mice, K884 treatment increased the number of asymmetric cell divisions, correlating with enhanced myogenic differentiation. Interestingly, the pro-myogenic effect of K884 is specific to human and murine DMD MuSCs and is absent from control MuSCs. Moreover, PTPN1/2 loss-of-function experiments indicate that the pro-myogenic impact of K884 is mediated mainly through PTPN1. We propose that PTPN1/2 inhibition may serve as a therapeutic strategy to restore the myogenic function of MuSCs in DMD., (© 2024 Liu et al.)

Dysregulated chondrocyte metabolism is an essential risk factor for osteoarthritis (OA) progression. Maintaining cartilage homeostasis represents a promising therapeutic strategy for the treatment of OA. However, no effective disease-modifying therapy is currently available to OA patients. To discover potential novel drugs for OA, we screened a small-molecule natural product drug library and identified deapi-platycodin D3 (D-PDD3), which was subsequently tested for its effect on extracellular matrix (ECM) properties and on OA progression. We found that D-PDD3 promoted the generation of ECM components in cultured chondrocytes and cartilage explants and that intra-articular injection of D-PDD3 delayed disease progression in a trauma-induced mouse model of OA. To uncover the underlying molecular mechanisms supporting these observed functions of D-PDD3, we explored the targets of D-PDD3 via screening approach integrating surface plasmon resonance with liquid chromatography-tandem mass spectrometry. The results suggested that D-PDD3 targeted tyrosine-protein phosphatase non-receptor type 1 (PTP1B), deletion of which restored chondrocyte homeostasis and markedly attenuated destabilization of the medial meniscus induced OA. Further cellular and molecular analyses showed that D-PDD3 maintained cartilage homeostasis by directly binding to PTP1B and consequently suppressing the PKM2/AMPK pathway. These findings demonstrated that D-PDD3 was a potential therapeutic drug for the treatment of OA and that PTP1B served as a protein target for the development of drugs to treat OA. This study provided significant insights into the development of therapeutics for OA treatment, which, in turn, helped to improve the quality of life of OA patients and to reduce the health and economic burden., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Septic lung injury is an unmet clinical challenge due to its high mortality, and there is a lack of effective treatment. Accumulating evidence suggests that an uncontrolled pulmonary inflammatory response is important in the pathogenesis of lung injury in sepsis. Therefore, limiting excessive early inflammatory responses may be an effective strategy. We established a septic lung injury model using cecal ligation and puncture. Western blotting and immunofluorescence analyses were performed to assess the expression of PTP1B and endoplasmic reticulum (ER) stress and pyroptosis. Co-immunoprecipitation was used to analyze the binding of PTP1B and Src molecules. PTP1B is upregulated in both in vivo and in vitro models of septic lung injury. PTP1B directly binds to Src and aggravates inflammation by regulating the ER stress-pyroptosis axis. The inhibition of PTP1B alleviates inflammation and improves the prognosis of septic mice. Our study suggesting that PT1B inhibitors have clinical application value in the treatment of septic lung injury. This may provide a new strategy for the treatment of septic lung injury., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Formononetin (FNT) is an isoflavone known for its anti-inflammatory properties and has been shown to reduce insulin resistance in Type 2 Diabetes Mellitus (T2DM). However, its effects and the underlying mechanisms in diabetic liver injury remain largely unexplored., Methods: We established a T2DM-induced liver injury mouse model by feeding high-fat diet, followed by injecting streptozotocin. The mice were then treated with FNT and the liver function in these mice was assessed. Macrophage markers in FNT-treated T2DM mice or human THP-1 cells were evaluated using flow cytometry, RT-qPCR, and Western blotting. The expression of PTP1B and STAT6 in mouse liver tissues and THP-1 cells was analyzed. Molecular docking predicted the interaction between PTP1B and STAT6, which was validated via co-immunoprecipitation (Co-IP) and phos-tag analysis. Microscale thermophoresis (MST) assessed the binding affinity of FNT to PTP1B., Results: FNT treatment significantly ameliorated blood glucose levels, hepatocyte apoptosis, inflammatory response, and liver dysfunction in T2DM mice. Moreover, FNT facilitated M2 macrophage polarization in both T2DM mice and high glucose (HG)-induced THP-1-derived macrophages. The PTP1B/STAT6 axis, deregulated in T2DM mice, was normalized by FNT treatment, which counteracted the T2DM-induced upregulation of PTP1B and downregulation of phosphorylated STAT6. Molecular docking and subsequent analyses revealed that PTP1B binds to and dephosphorylates STAT6 at the S325A site. In contrast, FNT strongly binds to PTP1B and influences its expression at the K116A site, promoting M2 polarization of THP-1 cells via downregulation of PTP1B., Conclusion: Formononetin mitigates diabetic hepatic injury by fostering M2 macrophage polarization via the PTP1B/STAT6 axis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Uvaol (UV), a pentacyclic triterpene found in olives and virgin olive oil, is known for its anti-inflammatory and antioxidant effects in various disease models. While olive oil is reported to reduce obesity and insulin resistance, the specific impact of UV on liver lipid metabolism and its molecular mechanisms are not fully understood. In this study, hepatic lipid accumulation was measured using oil red O staining, and protein expression levels in liver cells were assessed via Western blot analysis. Apoptosis was evaluated through cell viability and caspase 3 activity assays. UV treatment reduced lipid accumulation, fatty acid uptake, apoptosis, and ER stress in palmitate-treated liver cells. Additionally, UV enhanced fatty acid oxidation. Mechanistically, increased SIRT6 expression and autophagy were observed in UV-treated cells. SIRT6-targeted siRNA or 3-methyladenine blocked the effects of UV in hyperlipidemic cells. In conclusion, UV improves SIRT6/autophagy signaling, reducing lipid deposition and apoptosis in liver cells under high lipid conditions. This in vitro study provides strong evidence for potential therapeutic strategies for hepatic steatosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitory compounds from the natural resources, two new serratane triterpenes, 3-O-dihydro-p-coumaroyltohogenol (1) and 21-O-acetyltohogenol (2), along with four known serratane triterpenes (3-6), were isolated from the whole plant of Huperzia serrata. The chemical structures of compounds 1 and 2 were determined by NMR study, HRMS analysis, and chemical modification. All isolates were evaluated for their PTP1B inhibitory activities. Among the isolates, compounds 1, 3, 5 and 6 exhibit moderate inhibitory activities against PTP1B. Kinetic studies demonstrated that they are competitive inhibitors. Molecular docking studies support these experimental results by showing that compounds 1, 3, 5 and 6 interact with the active site of PTP1B, clarifying the structure-activity relationship. This study suggests that serratane triterpenes from H. serrata have potential as starting skeletons for anti-diabetes or anti-obesity agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Metabolic associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide, characterized by excess lipid deposition. Insulin resistance (IR) serves as a fundamental pathogenic factor in MAFLD. However, currently, there are no approved specific agents for its treatment. Farrerol, a novel compound with antioxidant and anti-inflammatory effects, has garnered significant attention in recent years due to its hepatoprotective properties. Despite this, the precise underlying mechanisms of action remain unclear. In this study, a network pharmacology approach predicted protein tyrosine phosphatase non-receptor type 1 (PTPN1) as a potential target for farrerol's action in the liver. Subsequently, the administration of farrerol improved insulin sensitivity and glucose tolerance in MAFLD mice. Furthermore, farrerol alleviated lipid accumulation by binding to PTPN1 and reducing the dephosphorylation of the insulin receptor (INSR) in HepG2 cells and MAFLD mice. Thus, the phosphoinositide 3-kinase/serine/threonine-protein kinases (PI3K/AKT) signalling pathway was active, leading to downstream protein reduction. Overall, the study demonstrates that farrerol alleviates insulin resistance and hepatic steatosis of MAFLD by targeting PTPN1., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

The misregulation of protein phosphatases is a key factor in the development of many human diseases, notably cancers. Here, based on a 100 MHz quartz crystal microbalance (QCM) biosensing platform, the dephosphorylation process of phosphopeptide (P-peptide) caused by protein tyrosine phosphatase 1B (PTP1B) was monitored in real time for the first time and PTP1B activity was assayed rapidly and sensitively. The QCM chip, coated with a gold (Au) film, was used to immobilized thiol-labeled single-stranded 5'-phosphate-DNAs (P-DNA) through Au-S bond. The P-peptide, specific to PTP1B, was then connected to the P-DNA via chelation between Zr 4+ and phosphate groups. When PTP1B was injected into the QCM flow cell where the P-peptide/Zr 4+ /MCH/P-DNA/Au chip was placed, the P-peptide was dephosphorylated and released from the Au chip surface, resulting in an increase in the frequency of the QCM Au chip. This allowed the real-time monitoring of the P-peptide dephosphorylation process and sensitive detection of PTP1B activity within 6 min with a linear detection range of 0.01-100 pM and a detection limit of 0.008 pM. In addition, the maximum inhibitory ratios of inhibitors were evaluated using this proposed 100 MHz QCM biosensor. The developed 100 MHz QCM biosensing platform shows immense potential for early diagnosis of diseases related to protein phosphatases and the development of drugs targeting protein phosphatases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Protein tyrosine phosphatase non-receptor type 2 (PTPN2) has recently been recognized as a promising target for cancer immunotherapy. Despite extensive structural and functional studies of other protein tyrosine phosphatases, there is limited structural understanding of PTPN2. Currently, there are only five published PTPN2 structures and none are truly unbound due to the presence of a mutation, an inhibitor or a loop (related to crystal packing) in the active site. In this report, a novel crystal packing is revealed that resulted in a true apo PTPN2 crystal structure with an unbound active site, allowing the active site to be observed in a native apo state for the first time. Key residues related to accommodation in the active site became identifiable upon comparison with previously published PTPN2 structures. Structures of PTPN2 in complex with an established PTPN1 active-site inhibitor and an allosteric inhibitor were achieved through soaking experiments using these apo PTPN2 crystals. The increased structural understanding of apo PTPN2 and the ability to soak in inhibitors will aid the development of future PTPN2 inhibitors.

Thefruits of Gleditsia sinensis Lam. have been utilized to treat inflammatory diseases in China. Echinocystic acid (EA), one pentacyclic triterpenoid isolated from thefruits of G. sinensis, exhibits an anti-inflammatory effect. However, its anti-sepsis activity and mechanism of action, especially the protective effect against sepsis-associated acute kidney injury (SA-AKI), are not investigated yet. This study is to explore the efficacy and potential mechanism of EA on SA-AKI. EA elevated the function of multiple organs and effectively reduced the increased inflammation and apoptosis of kidney tissue and HK-2 cells. DARTS, CETSA, and molecular docking experiments revealed that EA could directly bind to protein tyrosine phosphatase 1B (PTP1B), a widespread prototype non-receptor tyrosine phosphatase. Collectively, EA can alleviate murine SA-AKI though restraining inflammation and apoptosis and may be a potential natural drug for remedying SA-AKI., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Prolonged insulin resistance is considered one of the reasons for Type 2 Diabetes Mellitus. Upregulation of Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin signalling, has been well studied as a key regulator in prognosis to insulin resistance. It has been widely studied as a desirable molecular therapeutic target. The study aimed to evaluate the efficacy of leaf extract of the medicinal plants Silybum marianum on the inhibition of PTP1B activity. It also explored the synergistic effect with extracts of Gymnema sylvestre (leaves), Momordica charantia (seeds), and Trigonella foenum graecum (seeds). The S. marianum leaves showed dose-dependent inhibition of PTP1B ranging from 9.48-47.95% (25-1000 μg mL-1). Assay with individual plant extracts showed comparatively lesser inhibition of PTP1B as compared to metformin as a control (38% inhibition). However, a synergistic effect showed nearly 45% PTP1B inhibition (higher than metformin) after the assay was done with selected four plant extracts in combination. The effect of leaf extracts of S. marianum was studied for glucose uptake efficiency in yeast cell lines which was found to be increased by 23% as compared to the control (without extract). Metformin improves glucose upake by yeast cells by ~15-31%. GC-MS analysis revealed 23 phytochemicals, some of which possessed anti-diabetic properties. A dose-dependent increase in antioxidant activity of S. marianum leaves extracts was observed (40-53%). The findings of the study highlighted the presence of various phytochemicals in leaves extracts that are effective against PTP1B inhibition and may help in reinvigorating drug development.

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.

Fluxes in human copper levels recently garnered attention for roles in cellular signaling, including affecting levels of the signaling molecule cyclic adenosine monophosphate. We herein apply an unbiased temporal evaluation of the signaling and whole genome transcriptional activities modulated by copper level fluctuations to identify potential copper sensor proteins responsible for driving these activities. We find that fluctuations in physiologically relevant copper levels modulate EGFR signal transduction and activation of the transcription factor CREB. Both intracellular and extracellular assays support Cu 1+  inhibition of the EGFR phosphatase PTPN2 (and potentially PTPN1)-via ligation to the PTPN2 active site cysteine side chain-as the underlying mechanism. We additionally show i) copper supplementation drives weak transcriptional repression of the copper importer CTR1 and ii) CREB activity is inversely correlated with CTR1 expression. In summary, our study reveals PTPN2 as a physiological copper sensor and defines a regulatory mechanism linking feedback control of copper stimulated EGFR/CREB signaling and CTR1 expression., (© 2024. The Author(s).)

Due to their low binding affinities, detecting small-molecule fragments bound to protein structures from crystallographic datasets has been a challenge. Here, we report a trove of 65 new fragment hits for PTP1B, an "undruggable" therapeutic target enzyme for diabetes and cancer. These structures were obtained from computational analysis of data from a large crystallographic screen, demonstrating the power of this approach to elucidate many (∼50% more) "hidden" ligand-bound states of proteins. Our new structures include a fragment hit found in a novel binding site in PTP1B with a unique location relative to the active site, one that links adjacent allosteric sites, and, perhaps most strikingly, a fragment that induces long-range allosteric protein conformational responses. Altogether, our research highlights the utility of computational analysis of crystallographic data, makes publicly available dozens of new ligand-bound structures of a high-value drug target, and identifies novel aspects of ligandability and allostery in PTP1B., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Nonreceptor tyrosine phosphatases (NTPs) play an important role in regulating protein phosphorylation and have been proposed as attractive therapeutic targets for cancer and metabolic diseases. We have previously identified that 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhanced STAT activation upon cytokine stimulation, leading to increased reactivation of latent HIV and effector functions of NK and CD8 T cells. Here, we demonstrate that HODHBt interacted with and inhibited the NTPs PTPN1 and PTPN2 through a mixed inhibition mechanism. We also confirm that PTPN1 and PTPN2 specifically controlled the phosphorylation of different STATs. The small molecule ABBV-CLS-484 (AC-484) is an active site inhibitor of PTPN1 and PTPN2 currently in clinical trials for advanced solid tumors. We compared AC-484 and HODHBt and found similar effects on STAT5 and immune activation, albeit with different mechanisms of action leading to varying effects on latency reversal. Our studies provide the first specific evidence to our knowledge that enhancing STAT phosphorylation via inhibition of PTPN1 and PTPN2 is an effective tool against HIV.

Tyrosine protein phosphatase non-receptor type 1 (PTP1B; also known as protein tyrosine phosphatase 1B) is a member of the protein tyrosine phosphatase (PTP) family and is a soluble enzyme that plays an essential role in different physiological processes, including the regulation of metabolism, specifically in insulin and leptin sensitivity. PTP1B is crucial in the pathogenesis of type 2 diabetes mellitus and obesity. These biological functions have made PTP1B validated as an antidiabetic and anti-obesity, and potentially anticancer, molecular target. Four main approaches aim to inhibit PTP1B: orthosteric, allosteric, bidentate inhibition, and PTPN1 gene silencing. Developing a potent and selective PTP1B inhibitor is still challenging due to the enzyme's ubiquitous expression, subcellular location, and structural properties. This article reviews the main advances in the study of PTP1B since it was first isolated in 1988, as well as recent contextual information related to the PTP family to which this protein belongs. Furthermore, we offer an overview of the role of PTP1B in diabetes and obesity, and the challenges to developing selective, effective, potent, bioavailable, and cell-permeable compounds that can inhibit the enzyme., (© 2024 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Astragalus kurdicus Boiss. roots are used in folk medicine for antidiabetic purposes. Different Astragalus plant metabolites have a notable potential for antidiabetic activity through varying mechanisms. Herein, this study is designed to assess the antidiabetic activity of Astragalus kurdicus total (AKM: methanol extract, yield: 14.53 %) and sub-extracts (AKB: n-butanol, AKC: chloroform, AKW: water, AKH: hexane extracts), utilizing a range of diabetes-related in vitro methodologies, and to investigate the chemical composition of the plant. The highest astragaloside and saponin content was seen in AKB extract. Among the measured saponins, the abundance of Astragaloside IV (27.41 μg/mg in AKM) was the highest in high-performance thin-layer chromatography (HPTLC) analysis. Furthermore, flavonoid-rich AKC was found to be mostly responsible for the high antioxidant activity. According to the results of the activity tests, AKW was the most active extract in protein tyrosine phosphatase 1 B (PTP1B), dipeptidyl peptidase IV (DPP4), and α-amylase inhibition tests (percent inhibitions are: 87.17 %, 82.4 %, and 91.49 % respectively, at 1 mg/mL). AKM and AKW demonstrated the highest efficacy in stimulating the growth of prebiotic microorganisms and preventing the formation of advanced glycation end products (AGEs). Thus, for the first time, the antidiabetic activity of A. kurdicus was evaluated from various perspectives., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Context: Obesity is related to insulin resistance, and adipose tissue-secreted TNF- α may play a role in inducing obesity. TNF- α activates inflammatory protein kinase and impairs insulin signalling., Objectives: We investigated the effect of betulinic acid on insulin resistance caused by TNF- α treatment in 3T3-L1 adipocytes., Material and Methods: 3T3-L1 was exposed to TNF- α in the presence and absence of betulinic acid. Various parameters such as glucose uptake assay, cell viability, expression of proteins involved in insulin resistance were studied., Results: Betulinic acid increased glucose uptake in TNF- α pre-treated cells and inhibited the activation of PTP1B and JNK and reduced IκB α degradation. Tyrosine phosphorylation was increased, and serine phosphorylation was decreased in IRS-1., Discussion: Betulinic acid restored TNF- α impaired insulin signalling and increased PI3K activation and phosphorylation of Akt and increased plasma membrane expression of GLUT 4, which stimulated glucose uptake concentration-dependently., Conclusion: These results suggest that betulinic acid is effective at improving TNF- α -induced insulin resistance in adipocytes via inhibiting the activation of negative regulator of insulin signalling and inflammation-activated protein kinase and may potentially improve insulin resistance.

Pueraria lobata (Willd.) Ohwi, known as kudzu and used as a "longevity powder" in China, is an edible plant which is rich in flavonoids and believed to be useful for regulating blood sugar and treating diabetes, although the modes of action are unknown. Here, a total of 53 flavonoids including 6 novel compounds were isolated from kudzu using multidimensional preparative liquid chromatography. The flavonoid components were found to lower blood sugar levels, promote urine sugar levels in mice, and reduce the urine volume. Molecular docking and in vitro assays suggested that the antidiabetic effect of kudzu was attributed to at least three targets: sodium-dependent glucose transporter 2 (SGLT2), protein tyrosine phosphatase-1B (PTP1B), and alpha-glucosidase (AG). This study suggests a possible mechanism for the antidiabetic effect that may involve the synergistic action of multiple active compounds from kudzu.

As a pivotal enzyme that regulates dephosphorylation in cell activities and participates in the insulin signaling pathway, protein tyrosine phosphatase 1B (PTP1B) is considered to be an important target for the therapy of diabetes. In this work, a rapid and efficient inhibitor screening method of PTP1B was established based on capillary electrophoresis (CE), and used for screening and evaluating the inhibition effect of Traditional Chinese Medicine on PTP1B. Response Surface Methodology was used for optimizing the conditions of analysis. After method validation, the enzyme kinetic study and inhibition test were performed. As a result, the IC 50 of PTP1B inhibitors Ⅳ and ⅩⅧ were consistent with reported values measured by a conventional method. It was found that the extracts of Astragalus membranaceus (Fisch) Bunge and Morus alba L. showed prominent inhibition on the activity of PTP1B, which were stronger than the positive controls. Meanwhile, on top of the excellent advantages of CE, the whole analysis time is less than 2 min. Thus, the results demonstrated that a fast and efficient screening method was successfully developed. This method could be a powerful tool for screening inhibitors from complex systems. It can also provide an effective basis for lead compound development in drug discovery., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Juan Gao reports financial support was provided by China Scholarship Council. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Directed cell migration is driven by the front-back polarization of intracellular signalling 1-3 . Receptor tyrosine kinases and other inputs activate local signals that trigger membrane protrusions at the front 2,4-6 . Equally important is a long-range inhibitory mechanism that suppresses signalling at the back to prevent the formation of multiple fronts 7-9 . However, the identity of this mechanism is unknown. Here we report that endoplasmic reticulum-plasma membrane (ER-PM) contact sites are polarized in single and collectively migrating cells. The increased density of these ER-PM contacts at the back provides the ER-resident PTP1B phosphatase more access to PM substrates, which confines receptor signalling to the front and directs cell migration. Polarization of the ER-PM contacts is due to microtubule-regulated polarization of the ER, with more RTN4-rich curved ER at the front and more CLIMP63-rich flattened ER at the back. The resulting ER curvature gradient leads to small and unstable ER-PM contacts only at the front. These contacts flow backwards and grow to large and stable contacts at the back to form the front-back ER-PM contact gradient. Together, our study suggests that the structural polarity mediated by ER-PM contact gradients polarizes cell signalling, directs cell migration and prolongs cell migration., (© 2024. The Author(s).)

This study describes the design, synthesis, and evaluation of a novel series of phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamide derivatives (7a-l) as dual inhibitors of α-glucosidase and protein tyrosine phosphatase 1-B (PTB-1B). The latter enzymes are two important targets in the treatment of type 2 diabetes. The in vitro obtained data demonstrated that all title compounds 7a-l were more potent than the standard inhibitor acarbose against α-glucosidase while only four derivatives (7a, 7g, 7h, and 7h) were more potent than the standard inhibitor suramin against PTP-1B. Furthermore, these data showed that the most potent α-glucosidase inhibitor was compound 7i, with sixfold higher inhibitory activity than acarbose, and the most potent PTP-1B inhibitor was compound 7a with 3.5-fold higher inhibitory activity than suramin. Kinetic studies of compounds 7i and 7a revealed that they inhibited their target enzymes in a competitive mode. The docking study demonstrated that compounds 7i and 7a well occupied the active site pockets of α-glucosidase and PTP-1B, respectively. In silico pharmacokinetic and toxicity assays of the most potent compounds were performed, and the obtained results were compared with those of the standard inhibitors., (© 2024 Deutsche Pharmazeutische Gesellschaft.)

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.

Neutrophils are rapidly recruited to sites of infection and are critical for pathogen clearance. Therapeutic use of primary neutrophils has been limited, as they have a short lifespan and are not amenable to genetic manipulation. Human induced pluripotent stem cells (iPSCs) can provide a robust source of neutrophils for infusion and are genetically tractable. However, current work has indicated that dampened intracellular signaling limits iPSC-derived neutrophil (iNeutrophil) cellular activation and antimicrobial response. Here, we show that protein tyrosine phosphatase 1B (PTP1B) inhibits intracellular signaling and dampens iNeutrophil effector function. Deletion of the PTP1B phosphatase increased PI3K and ERK signaling and was associated with increased F-actin polymerization, cell migration, and phagocytosis. In contrast, other effector functions like NETosis and reactive oxygen species production were reduced. PTP1B-deficient neutrophils were more responsive to Aspergillus fumigatus and displayed rapid recruitment and control of hyphal growth. Accordingly, depletion of PTP1B increased production of inflammatory factors including the neutrophil chemokine interleukin-8. Taken together, these findings suggest that PTP1B limits iNeutrophil motility and antimicrobial function., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

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.

Background: Spilanthes filicaulis (Schumach. & Thonn.) C. D Adam is a shrubby plant of the Asteraceae family that has medicinal benefits for the pharmaceutical and cosmetic industries., Purpose: The purpose of this study was to assess the effectiveness of Spilanthes filicaulis leaf extract in a streptozotocin (STZ)-induced rat model and the associated signaling pathways., Methods: A sample of 25 male Wistar rats was randomly assigned to groups I, II, III, IV, and V. Each group included five animals, i.e., control rats, diabetic control rats, diabetic rats treated with metformin, and diabetic rats treated with 150 mg/kg/bw and 300 mg/kg/bw of the methanolic extract of S. filicaulis leaves (MESFL). Treatment was administered for 15 successive days via oral gavage. After 15 days, the rats were evaluated for fasting blood glucose (FBG), glycated hemoglobin (HbA1c), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), lipid peroxidation (MDA), hexokinase, and glucose-6-phosphatase activities. Gene expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor gamma (PPAR-γ), kelch-like ECH-associated protein 1 (Keap1), protein tyrosine phosphatase 1B (PTP1B) and the antiapoptotic protein caspase-3 were examined., Results: MESFL was administered to diabetic rats, and changes in body weight, fasting blood glucose (FBG) and HbA1c were restored. Furthermore, in diabetic rats, S. filicaulis significantly reduced the levels of triglycerides (TGs), total cholesterol (TC), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) and significantly increased HDL. S. filicaulis improved ALT, AST, and ALP enzyme activity in diabetic rats. MDA levels decreased considerably with increasing activity of antioxidant enzymes, such as GST, SOD, CAT and GSH, in diabetic liver rats treated with S. filicaulis. Diabetic rats treated with MESFL and metformin exhibited upregulated mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Kelch-like ECH-associated protein 1 (Keap1) and protein tyrosine phosphatase 1B (PTP1B) mRNA expression in the liver was downregulated in diabetic rats treated with MESFL and metformin. In addition, MESFL downregulated the mRNA expression of caspase-3 in diabetic rats., Conclusion: It can be concluded from the data presented in this study that MESFL exerts a protective effect on diabetic rats due to its antidiabetic, antioxidant, antihyperlipidemic and antiapoptotic effects and may be considered a treatment for T2DM., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ojo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The abnormal expression of protein tyrosine phosphatase 1B (PTP1B) is highly related to several serious human diseases. Therefore, an accurate PTP1B activity assay is beneficial to the diagnosis and treatment of these diseases. In this study, a dual-mode biosensing platform that enabled the sensitive and accurate assay of PTP1B activity was constructed based on the high-frequency (100 MHz) quartz crystal microbalance (QCM) and dual-signaling electrochemical (EC) ratiometric strategy. Covalent-organic framework@gold nanoparticles@ferrocene@single-strand DNA (COF@Au@Fc-S0) was introduced onto the QCM Au chip via the chelation between Zr 4+ and phosphate groups (phosphate group of the phosphopeptide (P-peptide) on the QCM Au chip and the phosphate group of thiol-labeled single-stranded DNA (S0) on COF@Au@Fc-S0) and used as a signal reporter. When PTP1B was present, the dephosphorylation of the P-peptide led to the release of COF@Au@Fc-S0 from the QCM Au chip, resulting in an increase in the frequency of the QCM. Meanwhile, the released COF@Au@Fc-S0 hybridized with thiol/methylene blue (MB)-labeled hairpin DNA (S1-MB) on the Au NPs-modified indium-tin oxide (ITO) electrode. This caused MB to be far away from the electrode surface and Fc to be close to the electrode, leading to a decrease in the oxidation peak current of MB and an increase in the oxidation peak current of Fc. Thus, PTP1B-induced dephosphorylation of the P-peptide was monitored in real time by QCM, and PTP1B activity was detected sensitively and reliably using this innovative QCM-EC dual-mode sensing platform with an ultralow detection limit. This platform is anticipated to serve as a robust tool for the analysis of protein phosphatase activity and the discovery of drugs targeting protein phosphatase.

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 IC 50 s 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.

Olanzapine (OLA) is a highly obesogenic second-generation antipsychotic (SGA). Recently we demonstrated that, contrarily to OLA oral treatment, intraperitoneal (i.p.) administration resulted in weight loss and absence of hepatic steatosis in wild-type (WT) and protein tyrosine phosphatase 1B (PTP1B)-deficient (KO) male mice. This protection relied on two central-peripheral axes connecting hypothalamic AMPK with brown/inguinal white adipose tissue (BAT/iWAT) uncoupling protein-1 (UCP-1) and hypothalamic JNK with hepatic fatty acid synthase (FAS). Herein, we addressed OLA i.p. treatment effects in WT and PTP1B-KO female mice. Contrarily to our previous results in WT females receiving OLA orally, the i.p. treatment did not induce weight gain or hyperphagia. Molecularly, in females OLA failed to diminish hypothalamic phospho-AMPK or elevate BAT UCP-1 and energy expenditure (EE) despite the preservation of iWAT browning. Conversely, OLA i.p. treatment in ovariectomized mice reduced hypothalamic phospho-AMPK, increased BAT/iWAT UCP-1 and EE, and induced weight loss as occurred in males. Pretreatment of hypothalamic neurons with 17β-estradiol (E 2 ) abolished OLA effects on AMPK. Moreover, neither hypothalamic JNK activation nor hepatic FAS upregulation were found in WT and PTP1B-KO females receiving OLA via i.p. Importantly, this axis was reestablished upon ovariectomy. In this line, E 2 prevented OLA-induced phospho-JNK in hypothalamic neurons. These results support the role of estrogens in sex-related dimorphism in OLA treatment. This study evidenced the benefit of OLA i.p. administration in preventing its obesogenic effects in female mice that could offer clinical value., Competing Interests: Declaration of competing interest The authors declare no conflict of interest. Also, the authors declare that there are no relationships or activities that might bias, or be perceived to bias, their work., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

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., (© 2024 The Authors. Protein Science published by Wiley Periodicals LLC on behalf of The Protein Society.)

Protein tyrosine phosphatase 1B (PTP1B), a non-transmembrane phosphatase, has a major role in a variety of signalling pathways, including direct negative regulation of classic insulin and leptin signalling pathways, and is implicated in the pathogenesis of several cardiometabolic diseases and cancers. As such, PTP1B has been a therapeutic target for over two decades, with PTP1B inhibitors identified either from natural sources or developed throughout the years. Some of these inhibitors have reached phase I and/or II clinical trials in humans for the treatment of type 2 diabetes mellitus, obesity and/or metastatic breast cancer. In this Review, we summarize the cellular processes and regulation of PTP1B, discuss evidence from in vivo preclinical and human studies of the association between PTP1B and different disorders, and discuss outcomes of clinical trials. We outline challenges associated with the targeting of this phosphatase (which was, until the past few years, viewed as difficult to target), the current state of the field of PTP1B inhibitors (and dual phosphatase inhibitors) and future directions for manipulating the activity of this key metabolic enzyme., (© 2024. Springer Nature Limited.)

Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), has caused substantial economic losses to the global swine industry due to the lack of effective commercial vaccines and drugs. There is an urgent need to develop alternative strategies for PRRS prevention and control, such as antiviral drugs. In this study, we identified ursonic acid (UNA), a natural pentacyclic triterpenoid from medicinal herbs, as a novel drug with anti-PRRSV activity in vitro. Mechanistically, a time-of-addition assay revealed that UNA inhibited PRRSV replication when it was added before, at the same time as, and after PRRSV infection was induced. Compound target prediction and molecular docking analysis suggested that UNA interacts with the active pocket of PTPN1, which was further confirmed by a target protein interference assay and phosphatase activity assay. Furthermore, UNA inhibited PRRSV replication by targeting PTPN1, which inhibited IFN-β production. In addition, UNA displayed antiviral activity against porcine epidemic diarrhoea virus (PEDV) and Seneca virus A (SVA) replication in vitro. These findings will be helpful for developing novel prophylactic and therapeutic agents against PRRS and other swine virus infections., (© 2024. The Author(s).)

Forty-one 1,3,4-thiadiazolyl-containing thiazolidine-2,4-dione derivatives ( MY1-41 ) were designed and synthesized as protein tyrosine phosphatase 1B (PTP1B) inhibitors with activity against diabetes mellitus (DM). All synthesized compounds ( MY1-41 ) presented potential PTP1B inhibitory activities, with half-maximal inhibitory concentration (IC 50 ) values ranging from 0.41 ± 0.05 to 4.68 ± 0.61 μM, compared with that of the positive control lithocholic acid (IC 50 = 9.62 ± 0.14 μM). The most potent compound, MY17 (IC 50 = 0.41 ± 0.05 μM), was a reversible, noncompetitive inhibitor of PTP1B. Circular dichroism spectroscopy and molecular docking were employed to analyze the binding interaction between MY17 and PTP1B. In HepG2 cells, MY17 treatment could alleviate palmitic acid (PA)-induced insulin resistance by upregulating the expression of phosphorylated insulin receptor substrate and protein kinase B. In vivo , oral administration of MY17 could reduce the fasting blood glucose level and improve glucose tolerance and dyslipidemia in mice suffering from DM.

Background: Endothelial activation promotes the release of procoagulant extracellular vesicles and inflammatory mediators from specialized storage granules. Endothelial membrane exocytosis is controlled by phosphorylation. We hypothesized that the absence of PTP1B (protein tyrosine phosphatase 1B) in endothelial cells promotes venous thromboinflammation by triggering endothelial membrane fusion and exocytosis., Methods: Mice with inducible endothelial deletion of PTP1B (End.PTP1B-KO) underwent inferior vena cava ligation to induce stenosis and venous thrombosis. Primary endothelial cells from transgenic mice and human umbilical vein endothelial cells were used for mechanistic studies., Results: Vascular ultrasound and histology showed significantly larger venous thrombi containing higher numbers of Ly6G (lymphocyte antigen 6 family member G)-positive neutrophils in mice with endothelial PTP1B deletion, and intravital microscopy confirmed the more pronounced neutrophil recruitment following inferior vena cava ligation. RT 2 PCR profiler array and immunocytochemistry analysis revealed increased endothelial activation and adhesion molecule expression in primary End.PTP1B-KO endothelial cells, including CD62P (P-selectin) and VWF (von Willebrand factor). Pretreatment with the NF-κB (nuclear factor kappa B) kinase inhibitor BAY11-7082, antibodies neutralizing CD162 (P-selectin glycoprotein ligand-1) or VWF, or arginylglycylaspartic acid integrin-blocking peptides abolished the neutrophil adhesion to End.PTP1B-KO endothelial cells in vitro. Circulating levels of annexin V + procoagulant endothelial CD62E + (E-selectin) and neutrophil (Ly6G + ) extracellular vesicles were also elevated in End.PTP1B-KO mice after inferior vena cava ligation. Higher plasma MPO (myeloperoxidase) and Cit-H3 (citrullinated histone-3) levels and neutrophil elastase activity indicated neutrophil activation and extracellular trap formation. Infusion of End.PTP1B-KO extracellular vesicles into C57BL/6J wild-type mice most prominently enhanced the recruitment of endogenous neutrophils, and this response was blunted in VWF-deficient mice or by VWF-blocking antibodies. Reduced PTP1B binding and tyrosine dephosphorylation of SNAP23 (synaptosome-associated protein 23) resulting in increased VWF exocytosis and neutrophil adhesion were identified as mechanisms, all of which could be restored by NF-κB kinase inhibition using BAY11-7082., Conclusions: Our findings show that endothelial PTP1B deletion promotes venous thromboinflammation by enhancing SNAP23 phosphorylation, endothelial VWF exocytosis, and neutrophil recruitment., Competing Interests: Disclosures None.

PTP1B, a promising target for insulin sensitizers in type 2 diabetes treatment, can be effectively degraded using proteolysis-targeting chimera (PROTAC). This approach offers potential for long-acting antidiabetic agents. We report potent bifunctional PROTACs targeting PTP1B through the E3 ubiquitin ligase cereblon. Western blot analysis showed significant PTP1B degradation by PROTACs at concentrations from 5 nM to 5 μM after 48 h. Evaluation of five highly potent PROTACs revealed compound 75 with a longer PEG linker (23 atoms), displaying remarkable degradation activity after 48 and 72 h, with DC 50 values of 250 nM and 50 nM, respectively. Compound 75 induced selective degradation of PTP1B, requiring engagement with both the target protein and CRBN E3 ligase, in a ubiquitination and proteasome-dependent manner. It significantly reduced blood glucose AUC 0-2h to 29% in an oral glucose tolerance test and activated the IRS-1/PI3K/Akt signaling pathway in HepG2 cells, showing promise for long-term antidiabetic therapy.

Vitamin B 12 is a group of biologically active cobalamin compounds. In this study, we investigated the inhibitory effects of methylcobalamin (MeCbl) and hydroxocobalamin acetate (OHCbl Acetate) on protein tyrosine phosphatase 1B (PTP1B). MeCbl and OHCbl Acetate exhibited an IC 50 of approximately 58.390 ± 2.811 μM and 8.998 ± 0.587 μM, respectively. The K i values of MeCbl and OHCbl Acetate were 25.01 μM and 4.04 μM respectively. To elucidate the inhibition mechanism, we conducted a 500 ns Gaussian accelerated molecular dynamics (GaMD) simulation. Utilizing PCA and tICA, we constructed Markov state models (MSM) to examine secondary structure changes during motion. Our findings revealed that the α-helix at residues 37-42 remained the most stable in the PTP1B-OHCbl Acetate system. Furthermore, upon binding of OHCbl Acetate or MeCbl, the WPD loop of PTP1B moved inward to the active pocket, forming a closed conformation and potentially obstructs substrate entry. Protein-ligand interaction analysis and MM-PBSA showed that OHCbl Acetate exhibited lower binding free energy and engaged in more residue interactions with PTP1B. In summary, our study confirmed the substantial inhibitory activity of OHCbl Acetate against PTP1B, with its inhibitory potency notably surpassing that of MeCbl. We demonstrated potential molecular mechanisms of OHCbl Acetate inhibiting PTP1B., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Protein tyrosine phosphatases PTPN2 and PTPN1 (also known as PTP1B) have been implicated in a number of intracellular signaling pathways of immune cells. The inhibition of PTPN2 and PTPN1 has emerged as an attractive approach to sensitize T cell anti-tumor immunity. Two small molecule inhibitors have been entered the clinic. Here we report the design and development of compound 4, a novel small molecule PTPN2/N1 inhibitor demonstrating nanomolar inhibitory potency, good in vivo oral bioavailability, and robust in vivo antitumor efficacy., Competing Interests: Declaration of competing interest The authors are all employees of Insilico Medicine. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Protein tyrosine phosphatases (PTPs) are the group of enzymes that control both cellular activity and the dephosphorylation of tyrosine (Tyr)-phosphorylated proteins. Dysregulation of PTP1B has contributed to numerous diseases including Diabetes Mellitus, Alzheimer's disease, and obesity rendering PTP1B as a legitimate target for therapeutic applications. It is highly challenging to target this enzyme because of its highly conserved and positively charged active-site pocket motivating researchers to find novel lead compounds against it. The present work makes use of an integrated approach combining ligand-based and structure-based virtual screening to find hit compounds targeting PTP1B. Initially, pharmacophore modeling was performed to find common features like two hydrogen bond acceptors, an aromatic ring and one hydrogen bond donor from the potent PTP1B inhibitors. The dataset of compounds matching with the common pharmacophoric features was filtered to remove Pan-Assay Interference substructure and to match the Lipinski criteria. Then, compounds were further prioritized using molecular docking and top fifty compounds with good binding affinity were selected for absorption, distribution, metabolism, and excretion (ADME) predictions. The top five compounds with high solubility, absorption and permeability holding score of - 10 to - 9.3 kcal/mol along with Ertiprotafib were submitted to all-atom molecular dynamic (MD) studies. The MD studies and binding free energy calculations showed that compound M4, M5 and M8 were having better binding affinity for PTP1B enzyme with ∆G total score of - 24.25, - 31.47 and - 33.81 kcal/mol respectively than other compounds indicating that compound M8 could be a suitable lead compound as PTP1B inhibitor., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Inositol-requiring enzyme 1 (IRE1) is a transmembrane sensor that is part of a trio of sensors responsible for controlling the unfolded protein response within the endoplasmic reticulum (ER). Upon the accumulation of unfolded or misfolded proteins in the ER, IRE1 becomes activated and initiates the cleavage of a 26-nucleotide intron from human X-box-containing protein 1 (XBP1). The cleavage is mediated by the RtcB ligase enzyme, which splices together two exons, resulting in the formation of the spliced isoform XBP1s. The XBP1s isoform activates the transcription of genes involved in ER-associated degradation to maintain cellular homeostasis. The catalytic activity of RtcB is controlled by the phosphorylation and dephosphorylation of three tyrosine residues (Y306, Y316, and Y475), which are regulated by the ABL1 tyrosine kinase and PTP1B phosphatase, respectively. This study focuses on investigating the mechanism by which the PTP1B phosphatase activates the RtcB ligase using a range of advanced in silico methods. Protein-protein docking identified key interacting residues between RtcB and PTP1B. Notably, the phosphorylated Tyr306 formed hydrogen bonds and salt bridge interactions with the "gatekeeper" residues Arg47 and Lys120 of the inactive PTP1B. Classical molecular dynamics simulation emphasized the crucial role of Asp181 in the activation of PTP1B, driving the conformational change from an open to a closed state of the WPD-loop. Furthermore, QM/MM-MD simulations provided insights into the free energy landscape of the dephosphorylation reaction mechanism of RtcB, which is mediated by the PTP1B phosphatase.

Background: Neuropathic pain is a prevalent and highly debilitating condition that impacts millions of individuals globally. Neuroinflammation is considered a key factor in the development of neuropathic pain. Accumulating evidence suggests that protein tyrosine phosphatase 1B (PTP1B) plays a crucial role in regulating neuroinflammation. Nevertheless, the specific involvement of PTP1B in neuropathic pain remains largely unknown. This study aims to examine the impact of PTP1B on neuropathic pain and unravel the underlying molecular mechanisms implicated., Methods: In the current study, we evaluated the paw withdrawal threshold (PWT) of male rats following spared nerve injury (SNI) to assess the presence of neuropathic pain. To elucidate the underlying mechanisms, western blotting, immunofluorescence, and electron microscopy techniques were employed., Results: Our results showed that SNI significantly elevated PTP1B levels, which was accompanied by an increase in the expression of endoplasmic reticulum (ER) stress markers (BIP, p-PERK, p-IRE1α, and ATF6) and phosphorylated NF-κB in the spinal dorsal horn. SNI-induced mechanical allodynia was impaired by the treatment of intrathecal injection of PTP1B siRNA or PTP1B-IN-1, a specific inhibitor of PTP1B. Moreover, the intrathecal administration of PTP1B-IN-1 effectively suppressed the expression of ER stress markers (BIP, p-PERK/p-eIF2α, p-IRE1α, and ATF6), leading to the inhibition of NF-κB, microglia, and astrocytes activation, as well as a decrease in pro-inflammatory cytokines, including TNF-α, IL-6, and IL-1β. However, these effects were reversed by intrathecal administration of tunicamycin (Tm, an inducer of ER stress). Additionally, intrathecal administration of Tm in healthy rats resulted in the development of mechanical allodynia and the activation of NF-κB-mediated neuroinflammatory signaling., Conclusions: The upregulation of PTP1B induced by SNI facilitates the activation of NF-κB and glial cells via ER stress in the spinal dorsal horn. This, in turn, leads to an increase in the production of pro-inflammatory cytokines, thereby contributing to the development and maintenance of neuropathic pain. Therefore, targeting PTP1B could be a promising therapeutic strategy for the treatment of neuropathic pain., (© 2024 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Background: The overexpression of the Protein Tyrosine Phosphatase 1B (PTP1B), a key role in the development of insulin resistance, diabetes (T2DM) and obesity, seems to have a substantial impact as a negative regulator of the insulin and leptin signaling pathways. Therefore, inhibiting PTP1B is a prospective therapeutic approach for the treatment of diabetes and obesity. However, the pyrazole scaffold is expected to be of significant pharmaceutical interest due to its broad spectrum of pharmacological actions. This study aims to focus on the significance of pyrazole scaffold in medicinal chemistry, the impact of PTP1B in diabetes and the therapeutic approach of pyrazole scaffold to treat T2DM., Methods: A comprehensive analysis of the published literature in several pharmaceutical and medical databases, such as the Web of Science (WoS), PubMed, ResearchGate, ScienceDirect etc., were indeed successfully completed and classified accordingly., Results: As reviewed, the various derivatives of the pyrazole scaffold exhibited prominent PTP1B inhibitory activity. The result showed that derivatives of oxadiazole and dibenzyl amine, chloro substituents, 1, 3-diaryl pyrazole derivatives with rhodanine-3-alkanoic acid groups, naphthalene and also 1, 3, 5-triazine-1H-pyrazole-triazolothiadiazole derivatives, octyl and tetradecyl derivative, indole- and N-phenylpyrazole-glycyrrhetinic acid derivatives with trifluoromethyl group, 2,3-pyrazole ring-substituted-4,4-dimethyl lithocholic acid derivatives with 4- fluoro phenyl substituted and additional benzene ring in the pyrazole scaffold significantly inhibits PTP1B. In silico study observed that pyrazole scaffold interacted with amino acid residues like TYR46, ASP48, PHE182, TYR46, ALA217 and ILE219., Conclusion: Diabetes is a metabolic disorder that elevates the risk of mortality and severe complications. PTP1B is a crucial component in the management of diabetes and obesity. As a result, PTP1B is a promising therapeutic target for the treatment of T2DM and obesity in humans. We concluded that the pyrazole scaffold has prominent inhibitory potential against PTP1B., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

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., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Duclauxin ( 1 ) from Talaromyces sp. IQ-313 was reported as a putative allosteric modulator of human recombinant protein tyrosine phosphatase 1B (400 amino acids) ( h PTP1B 1-400 ), a validated target for the treatment of type II diabetes. Based on these findings, a one-strain-many-compound (OSMAC) experiment on the IQ-313 strain generated derivatives 5a , 6 , and 7 . Moreover, a one-/two-step semisynthetic approach guided by docking toward h PTP1B 1-400 produced 38 analogs, a series (A) incorporating a lactam functionalization at C-1 ( 8a - 15a , 36a , and 37a ) and a series (B) containing a lactam at C-1 and an extra unsaturation between C-7 and C-8 ( 5b , 11b - 37b ). In vitro evaluation and structure-activity relationship (SAR) analysis revealed that analogs from the B series are up to 10-fold more active than 1 and derivatives from the A series. Furthermore, duclauxin ( 1 ) and 36b were assessed for their potential acute toxicity, estimating their LD 50 to be higher than 300 mg/kg. Moreover, 36b significantly reduced glycemia in an insulin tolerance test in mice, suggesting that its mechanism of action is through the PTP1B inhibition.

Alzheimer's disease (AD) is a prevalently neurodegenerative disease characterized by neuronal damage which is associated with amyloid-β (Aβ) accumulation. Hederagenin is a triterpenoid saponin, exerting anti-apoptotic, anti-oxidative, anti-inflammatory, anti-tumoral, and neuroprotective activities. However, its role in AD progression is still obscure. The aim of this study was to explore the influences of hederagenin on Aβ-caused neuronal injury in vitro. Neuronal cells were treated with Aβ 25-35 (Aβ) to establish a cellular model of AD. Cell viability was assessed using cell counting kit-8 (CCK-8). Oxidative stress was evaluated by detecting reactive oxygen species (ROS) generation and superoxide dismutase (SOD) activity. Apoptosis was investigated using TUNEL staining and caspase-3 activity assays. Protein tyrosine phosphatase nonreceptor type 1 (PTPN1) was screened by bioinformatics analysis. Protein levels of PTPN1 and protein kinase B (Akt) were measured by western blotting. Hederagenin (2.5, 5, and 10 μM) alone did not affect viability of neuronal cells, but relieved Aβ-induced viability reduction. Hederagenin mitigated Aβ-induced increase in ROS accumulation and decrease in SOD activity. Hederagenin attenuated Aβ-induced increase in apoptotic rate and caspase-3 activity. PTPN1 was screened as a target of hederagenin against AD by bioinformatics analysis. Hederagenin treatment resisted Aβ-induced decrease in PTPN1 mRNA and protein levels in neuronal cells. PTPN1 silencing attenuated the suppressive functions of hederagenin in Aβ-stimulated oxidative stress and apoptosis. Hederagenin mitigated Aβ-induced Akt signaling inactivation by upregulating PTPN1 expression. In conclusion, hederagenin attenuates oxidative stress and apoptosis in neuronal cells stimulated with Aβ by promoting PTPN1/Akt signaling activation., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Interleukin 13 receptor alpha 2 (IL13Rα2) is a relevant therapeutic target in glioblastoma (GBM) and other tumors associated with tumor growth and invasion. In a previous study, we demonstrated that protein tyrosine phosphatase 1B (PTP1B) is a key mediator of the IL-13/IL13Rα2 signaling pathway. PTP1B regulates cancer cell invasion through Src activation. However, PTP1B/Src downstream signaling mechanisms that modulate the invasion process remain unclear. In the present research, we have characterized the PTP1B interactome and the PTP1B-associated phosphoproteome after IL-13 treatment, in different cellular contexts, using proteomic strategies. PTP1B was associated with proteins involved in signal transduction, vesicle transport, and with multiple proteins from the NF-κB signaling pathway, including Tenascin-C (TNC). PTP1B participated with NF-κB in TNC-mediated proliferation and invasion. Analysis of the phosphorylation patterns obtained after PTP1B activation with IL-13 showed increased phosphorylation of the transcription factor Schnurri-3 (SHN3), a reported competitor of NF-κB. SHN3 silencing caused a potent inhibition in cell invasion and proliferation, associated with a down-regulation of the Wnt/β-catenin pathway, an extensive decline of MMP9 expression and the subsequent inhibition of tumor growth and metastasis in mouse models. Regarding clinical value, high expression of SHN3 was associated with poor survival in GBM, showing a significant correlation with the classical and mesenchymal subtypes. In CRC, SHN3 expression showed a preferential association with the mesenchymal subtypes CMS4 and CRIS-B. Moreover, SHN3 expression strongly correlated with IL13Rα2 and MMP9-associated poor prognosis in different cancers. In conclusion, we have uncovered the participation of SNH3 in the IL-13/IL13Rα2/PTP1B pathway to promote tumor growth and invasion. These findings support a potential therapeutic value for SHN3., (© 2023. The Author(s).)

Diabetes mellitus (DM) is a serious global health concern affecting over 500 million people. To put it simply, it is one of the most dangerous metabolic illnesses. Insulin resistance is the root cause of 90% of all instances of diabetes, all of which are classified as Type 2 DM. Untreated, it poses a hazard to civilization since it can lead to terrifying consequences and even death. Oral hypoglycemic medicines presently available act in a variety of ways, targeting various organs and pathways. The use of protein tyrosine phosphatase 1B (PTP1B) inhibitors, on the contrary, is a novel and effective method of controlling type 2 diabetes. PTP1B is a negative insulin signaling pathway regulator; hence, inhibiting PTP1B increases insulin sensitivity, glucose absorption, and energy expenditure. PTP1B inhibitors also restore leptin signaling and are considered a potential obesity target. In this review, we have compiled a summary of the most recent advances in synthetic PTP1B inhibitors from 2015 to 2022 which have scope to be developed as clinical antidiabetic drugs., (© 2023 John Wiley & Sons Ltd.)

The inhibition of protein tyrosine phosphatases 1B (PTP1B) and N2 (PTPN2) has emerged as an exciting approach for bolstering T cell anti-tumor immunity. ABBV-CLS-484 is a PTP1B/PTPN2 inhibitor in clinical trials for solid tumors. Here we have explored the therapeutic potential of a related small-molecule-inhibitor, Compound-182. We demonstrate that Compound-182 is a highly potent and selective active site competitive inhibitor of PTP1B and PTPN2 that enhances T cell recruitment and activation and represses the growth of tumors in mice, without promoting overt immune-related toxicities. The enhanced anti-tumor immunity in immunogenic tumors can be ascribed to the inhibition of PTP1B/PTPN2 in T cells, whereas in cold tumors, Compound-182 elicited direct effects on both tumor cells and T cells. Importantly, treatment with Compound-182 rendered otherwise resistant tumors sensitive to α-PD-1 therapy. Our findings establish the potential for small molecule inhibitors of PTP1B and PTPN2 to enhance anti-tumor immunity and combat cancer., (© 2023. The Author(s).)

PTP1B plays an important role as a key negative regulator of tyrosine phosphorylation associated with insulin receptor signaling in the therapy for diabetes and obesity. In this study, the anti-diabetic activity of dianthrone derivatives from Polygonum multiflorum Thunb., as well as the structure-activity relationships, mechanism, and molecular docking were explored. Among these analogs, trans-emodin dianthrone (compound 1) enhances insulin sensitivity by upregulating the insulin signaling pathway in HepG2 cells and displays considerable anti-diabetic activity in db/db mice. By using photoaffinity labeling and mass spectrometry-based proteomics, we discovered that trans-emodin dianthrone (compound 1) may bind to PTP1B allosteric pocket at helix α6/α7, which provides fresh insight into the identification of novel anti-diabetic agents., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)