The EGFR phosphatase RPTPγ is a redox-regulated suppressor of promigratory signaling.

Spatially organized reaction dynamics between proto-oncogenic epidermal growth factor receptor (EGFR) and protein tyrosine phosphatases determine EGFR phosphorylation dynamics in response to growth factors and thereby cellular behavior within developing tissues. We show that the reaction dynamics of mutual inhibition between RPTPγ phosphatase and autocatalytic ligandless EGFR phosphorylation enable highly sensitive promigratory EGFR signaling responses to subnanomolar EGF levels, when < 5% receptors are occupied by EGF. EGF thereby triggers an autocatalytic phospho-EGFR reaction by the initial production of small amounts of phospho-EGFR through transient, asymmetric EGF-EGFR2 dimers. Single cell RPTPγ oxidation imaging revealed that phospho-EGFR induces activation of NADPH oxidase, which in turn inhibits RPTPγ-mediated dephosphorylation of EGFR, tilting the autocatalytic RPTPγ/EGFR toggle switch reaction towards ligandless phosphorylated EGFR. Reversibility of this reaction to EGF is maintained by the constitutive phosphatase activity of endoplasmic reticulum-associated TCPTP. This RPTPγ/EGFR reaction at the plasma membrane causes promigratory signaling that is separated from proliferative signaling induced by accumulated, liganded, phosphorylated EGF-EGFR in endosomes. Accordingly, loss of RPTPγ results in constitutive promigratory signaling from phosphorylated EGFR monomers. RPTPγ is thus a suppressor of promigratory oncogenic but not of proliferative EGFR signaling.

Transcytosis-mediated anterograde transport of TrkA receptors is necessary for sympathetic neuron development and function.

In neurons, many membrane proteins, synthesized in cell bodies, must be efficiently delivered to axons to influence neuronal connectivity, synaptic communication, and repair. Previously, we found that axonal targeting of TrkA neurotrophin receptors in sympathetic neurons occurs via an atypical transport mechanism called transcytosis, which relies on TrkA interactions with PTP1B, a protein tyrosine phosphatase. Here, we generated TrkAR685A mice, where TrkA receptor signaling is preserved, but its PTP1B-dependent transcytosis is disrupted to show that this mode of axonal transport is essential for sympathetic neuron development and autonomic function. TrkAR685A mice have decreased axonal TrkA levels in vivo, loss of sympathetic neurons, and reduced innervation of targets. The neuron loss and diminished target innervation phenotypes are specifically restricted to the developmental period when sympathetic neurons are known to rely on the TrkA ligand, nerve growth factor, for trophic support. Postnatal TrkAR685A mice exhibit reduced pupil size and eyelid ptosis, indicative of sympathetic dysfunction. Furthermore, we also observed a significant loss of TrkA-expressing nociceptive neurons in the dorsal root ganglia during development in TrkAR685A mice, suggesting that transcytosis might be a general mechanism for axonal targeting of TrkA receptors. Together, these findings establish the necessity of transcytosis in supplying TrkA receptors to axons, specifically during development, and highlight the physiological relevance of this axon targeting mechanism in the nervous system.

TRAF3 regulates STAT6 activation and T helper cell differentiation by modulating the phosphatase PTP1B.

The adaptor protein TNFR associated factor 3 (TRAF3) is a multifaceted regulator of lymphocyte biology that plays key roles in modulation of the molecular signals required for T cell activation and function. TRAF3 regulates signals mediated by the T cell receptor (TCR), costimulatory molecules, and cytokine receptors, which each drive activation of the serine/threonine kinase Akt. The impact of TRAF3 upon TCR/CD28-mediated activation of Akt, and thus on the diverse cellular processes regulated by Akt, including CD4 T cell fate decisions, remains poorly understood. We show here that TRAF3 deficiency led to impaired Akt activation, and thus to impaired in vitro skewing of CD4 T cells into the TH1 and TH2 fates. We investigated the role of TRAF3 in regulation of signaling pathways that drive TH1 and TH2 differentiation, and found that TRAF3 enhanced activation of Signal transducer and activator of transcription 6 (STAT6), thus promoting skewing toward the TH2 fate. TRAF3 promoted STAT6 activation by regulating recruitment of the inhibitory molecule Protein tyrosine phosphatase 1B (PTP1B) to the IL-4R signaling complex, in a manner that required integration of TCR/CD28- and IL-4R-mediated signals. This work reveals a new mechanism for TRAF3-mediated regulation of STAT6 activation in CD4 T cells, and adds to our understanding of the diverse roles played by TRAF3 as an important regulator of T cell biology.

LRRK1 functions as a scaffold for PTP1B-mediated EGFR sorting into ILVs at the ER-endosome contact site.

Proper control of epidermal growth factor receptor (EGFR) signaling is important for maintaining cellular homeostasis. Given that EGFR signaling occurs at the plasma membrane and endosomes following internalization, endosomal trafficking of EGFR spatiotemporally regulates EGFR signaling. In this process, leucine-rich repeat kinase 1 (LRRK1) has multiple roles in kinase activity-dependent transport of EGFR-containing endosomes and kinase-independent sorting of EGFR into the intraluminal vesicles (ILVs) of multivesicular bodies. Active, phosphorylated EGFR inactivates the LRRK1 kinase activity by phosphorylating Y944. In this study, we demonstrate that LRRK1 facilitates EGFR dephosphorylation by PTP1B (also known as PTPN1), an endoplasmic reticulum (ER)-localized protein tyrosine phosphatase, at the ER-endosome contact site, after which EGFR is sorted into the ILVs of endosomes. LRRK1 is required for the PTP1B-EGFR interaction in response to EGF stimulation, resulting in the downregulation of EGFR signaling. Furthermore, PTP1B activates LRRK1 by dephosphorylating pY944 on the contact site, which promotes the transport of EGFR-containing endosomes to the perinuclear region. These findings provide evidence that the ER-endosome contact site functions as a hub for LRRK1-dependent signaling that regulates EGFR trafficking.

A Global Analysis of the Receptor Tyrosine Kinase-Protein Phosphatase Interactome.

Receptor tyrosine kinases (RTKs) and protein phosphatases comprise protein families that play crucial roles in cell signaling. We used two protein-protein interaction (PPI) approaches, the membrane yeast two-hybrid (MYTH) and the mammalian membrane two-hybrid (MaMTH), to map the PPIs between human RTKs and phosphatases. The resulting RTK-phosphatase interactome reveals a considerable number of previously unidentified interactions and suggests specific roles for different phosphatase families. Additionally, the differential PPIs of some protein tyrosine phosphatases (PTPs) and their mutants suggest diverse mechanisms of these PTPs in the regulation of RTK signaling. We further found that PTPRH and PTPRB directly dephosphorylate EGFR and repress its downstream signaling. By contrast, PTPRA plays a dual role in EGFR signaling: besides facilitating EGFR dephosphorylation, it enhances downstream ERK signaling by activating SRC. This comprehensive RTK-phosphatase interactome study provides a broad and deep view of RTK signaling.

Conformational Rigidity and Protein Dynamics at Distinct Timescales Regulate PTP1B Activity and Allostery.

Protein function originates from a cooperation of structural rigidity, dynamics at different timescales, and allostery. However, how these three pillars of protein function are integrated is still only poorly understood. Here we show how these pillars are connected in Protein Tyrosine Phosphatase 1B (PTP1B), a drug target for diabetes and cancer that catalyzes the dephosphorylation of numerous substrates in essential signaling pathways. By combining new experimental and computational data on WT-PTP1B and ≥10 PTP1B variants in multiple states, we discovered a fundamental and evolutionarily conserved CH/π switch that is critical for positioning the catalytically important WPD loop. Furthermore, our data show that PTP1B uses conformational and dynamic allostery to regulate its activity. This shows that both conformational rigidity and dynamics are essential for controlling protein activity. This connection between rigidity and dynamics at different timescales is likely a hallmark of all enzyme function.

Protein tyrosine phosphatase 69D is a substrate of protein O-mannosyltransferases 1-2 that is required for the wiring of sensory axons in Drosophila.

Mutations in protein O-mannosyltransferases (POMTs) result in severe brain defects and congenital muscular dystrophies characterized by abnormal glycosylation of α-dystroglycan (α-Dg). However, neurological phenotypes of POMT mutants are not well understood, and the functional substrates of POMTs other than α-Dg remain unknown. Using a Drosophila model, here we reveal that Dg alone cannot account for the phenotypes of POMT mutants, and identify Protein tyrosine phosphatase 69D (PTP69D) as a gene interacting with POMTs in producing the abdomen rotation phenotype. Using RNAi-mediated knockdown, mutant alleles, and a dominant-negative form of PTP69D, we reveal that PTP69D is required for the wiring of larval sensory axons. We also found that PTP69D and POMT genes interact in this process, and that their interactions lead to complex synergistic or antagonistic effects on axon wiring phenotypes, depending on the mode of genetic manipulation. Using glycoproteomic approaches, we further characterized the glycosylation of the PTP69D transgenic construct expressed in genetic strains with different levels of POMT activity. We found that the PTP69D construct carries many O-linked mannose modifications when expressed in Drosophila with wild-type or ectopically upregulated expression of POMTs. These modifications were absent in POMT mutants, suggesting that PTP69D is a substrate of POMT-mediated O-mannosylation. Taken together, our results indicate that PTP69D is a novel functional substrate of POMTs that is required for axon connectivity. This mechanism of POMT-mediated regulation of receptor-type protein tyrosine phosphatase functions could potentially be conserved in mammals and may shed new light on the etiology of neurological defects in muscular dystrophies.

WTAP promotes proliferation of esophageal squamous cell carcinoma via m6A-dependent epigenetic promoting of PTP4A1.

Esophageal squamous cell carcinoma (ESCC) represents a frequently seen malignancy with high prevalence worldwide. Although current studies have shown that Wilms' tumor 1-associated protein (WTAP), a major part in the methyltransferase complex, is involved in various tumor pathological processes, its specific role in ESCC remains unclear. Therefore, the present work focused on exploring WTAP's function and mechanism in ESCC progression using clinical ESCC specimens, ESCC cells, and mammalian models. Firstly, we proved WTAP was significantly upregulated within ESCC, and WTAP mRNA expression showed a good diagnostic performance for ESCC. Functionally, WTAP positively regulated in-vivo and in-vitro ESCC cells' malignant phenotype through the AKT-mTOR signaling pathway. Meanwhile, WTAP positively regulated the N6-methyladenosine (m6A) modification levels in ESCC cells. Protein tyrosine phase type IVA member 1 (PTP4A1) was confirmed to be the m6A target of WTAP, and WTAP positively regulated the expression of PTP4A1. Further study revealed that PTP4A1 showed high expression within ESCC. Silencing PTP4A1 inhibited the AKT-mTOR signaling pathway to suppress ESCC cells' proliferation. Rescue experiments showed that silencing PTP4A1 partially reversed the WTAP-promoting effect on ESCC cells' proliferation ability. Mechanistically, WTAP regulated PTP4A1 expression to activate the AKT-mTOR pathway, promoting the proliferation of ESCC cells. Our study demonstrated that WTAP regulates the progression of ESCC through the m6A-PTP4A1-AKT-mTOR signaling axis and that WTAP is a potential target for diagnosing and treating ESCC.

NADPH oxidase 1 promotes hepatic steatosis in obese mice and is abrogated by augmented skeletal muscle mass.

Exercise as a lifestyle modification is a frontline therapy for nonalcoholic fatty liver disease (NAFLD), but how components of exercise attenuate steatosis is unclear. To uncouple the effect of increased muscle mass from weight loss in obesity, myostatin knockout mice were bred on a lean and obese db/db background. Myostatin deletion increases gastrocnemius (Gastrocn.) mass and reduces hepatic steatosis and hepatic sterol regulatory element binding protein 1 (Srebp1) expression in obese mice, with no impact on adiposity or body weight. Interestingly, hypermuscularity reduces hepatic NADPH oxidase 1 (Nox1) expression but not NADPH oxidase 4 (Nox4) in db/db mice. To evaluate a deterministic function of Nox1 on steatosis, Nox1 knockout mice were bred on a lean and db/db background. NOX1 deletion significantly attenuates hepatic oxidant stress, steatosis, and Srebp1 programming in obese mice to parallel hypermuscularity, with no improvement in adiposity, glucose control, or hypertriglyceridemia to suggest off-target effects. Directly assessing the role of NOX1 on SREBP1, insulin (Ins)-mediated SREBP1 expression was significantly increased in either NOX1, NADPH oxidase organizer 1 (NOXO1), and NADPH oxidase activator 1 (NOXA1) or NOX5-transfected HepG2 cells versus ?-galactosidase control virus, indicating superoxide is the key mechanistic agent for the actions of NOX1 on SREBP1. Metabolic Nox1 regulators were evaluated using physiological, genetic, and diet-induced animal models that modulated upstream glucose and insulin signaling, identifying hyperinsulinemia as the key metabolic derangement explaining Nox1-induced steatosis in obesity. GEO data revealed that hepatic NOX1 predicts steatosis in obese humans with biopsy-proven NAFLD. Taken together, these data suggest that hypermuscularity attenuates Srebp1 expression in db/db mice through a NOX1-dependent mechanism.NEW & NOTEWORTHY This study documents a novel mechanism by which changes in body composition, notably increased muscle mass, protect against fatty liver disease. This mechanism involves NADPH oxidase 1 (NOX1), an enzyme that increases superoxide and increases insulin signaling, leading to increased fat accumulation in the liver. NOX1 may represent a new early target for preventing fatty liver to stave off later liver diseases such as cirrhosis or liver cancer.

Vagal-α7 nicotinic acetylcholine receptor signaling exacerbates influenza severity by promoting lung epithelial cell infection.

The vagus nerve circuit, operating through the alpha-7 nicotinic acetylcholine receptor (α7 nAChR), regulates the inflammatory response by influencing immune cells. However, the role of vagal-α7 nAChR signaling in influenza virus infection is unclear. In particular, does vagal-α7 nAChR signaling impact the infection of alveolar epithelial cells (AECs), the primary target cells of influenza virus? Here, we demonstrated a distinct role of α7 nAChR in type II AECs compared to its role in immune cells during influenza infection. We found that deletion of Chrna7 (encoding gene of α7 nAChR) in type II AECs or disruption of vagal circuits reduced lung influenza infection and protected mice from influenza-induced lung injury. We further unveiled that activation of α7 nAChR enhanced influenza infection through PTP1B-NEDD4L-ASK1-p38MAPK pathway. Mechanistically, activation of α7 nAChR signaling decreased p38MAPK phosphorylation during infection, facilitating the nuclear export of influenza viral ribonucleoproteins and thereby promoting infection. Taken together, our findings reveal a mechanism mediated by vagal-α7 nAChR signaling that promotes influenza viral infection and exacerbates disease severity. Targeting vagal-α7 nAChR signaling may offer novel strategies for combating influenza virus infections.

Caveolin-2 in association with nuclear lamina controls adipocyte hypertrophy.

Here, we identify that Caveolin-2 (Cav-2), an integral membrane protein, controls adipocyte hypertrophy in association with nuclear lamina. In the hypertrophy stage of adipogenesis, pY19-Cav-2 association with lamin A/C facilitated the disengagement of CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) from lamin A/C and repressed Cav-2 promoter at the nuclear periphery for epigenetic activation of Cav-2, and thereby promoted C/EBPα and PPARγ-induced adipocyte hypertrophy. Stable expression of Cav-2 was required and retained by phosphorylation, deubiquitination, and association with lamin A/C for the adipocyte hypertrophy. However, obese adipocytes exhibited augmented Cav-2 stability resulting from the up-regulation of lamin A/C over lamin B1, protein tyrosine phosphatase 1B (PTP1B), and nuclear deubiquitinating enzyme (DUB), Uchl5. Our findings show a novel epigenetic regulatory mechanism of adipocyte hypertrophy by Cav-2 at the nuclear periphery.

Overexpression of forebrain PTP1B leads to synaptic and cognitive impairments in obesity.

Obesity has reached pandemic proportions and is a risk factor for neurodegenerative diseases, including Alzheimer's disease. Chronic inflammation is common in obese patients, but the mechanism between inflammation and cognitive impairment in obesity remains unclear. Accumulative evidence shows that protein-tyrosine phosphatase 1B (PTP1B), a neuroinflammatory and negative synaptic regulator, is involved in the pathogenesis of neurodegenerative processes. We investigated the causal role of PTP1B in obesity-induced cognitive impairment and the beneficial effect of PTP1B inhibitors in counteracting impairments of cognition, neural morphology, and signaling. We showed that obese individuals had negative relationship between serum PTP1B levels and cognitive function. Furthermore, the PTP1B level in the forebrain increased in patients with neurodegenerative diseases and obese cognitive impairment mice with the expansion of white matter, neuroinflammation and brain atrophy. PTP1B globally or forebrain-specific knockout mice on an obesogenic high-fat diet showed enhanced cognition and improved synaptic ultrastructure and proteins in the forebrain. Specifically, deleting PTP1B in leptin receptor-expressing cells improved leptin synaptic signaling and increased BDNF expression in the forebrain of obese mice. Importantly, we found that various PTP1B allosteric inhibitors (e.g., MSI-1436, well-tolerated in Phase 1 and 1b clinical trials for obesity and type II diabetes) prevented these alterations, including improving cognition, neurite outgrowth, leptin synaptic signaling and BDNF in both obese cognitive impairment mice and a neural cell model of PTP1B overexpression. These findings suggest that increased forebrain PTP1B is associated with cognitive decline in obesity, whereas inhibition of PTP1B could be a promising strategy for preventing neurodegeneration induced by obesity.

Schwann Cell-Derived Exosomes Induced Axon Growth after Spinal Cord Injury by Decreasing PTP-σ Activation on CSPGs via the Rho/ROCK Pathway.

Spinal cord injury (SCI) is a severe neurological condition that involves a lengthy pathological process. This process leads to the upregulation of chondroitin sulfate proteoglycans (CSPGs) by reactive glia, which impedes repair and regeneration in the spinal cord. The role of the CSPG-specific receptor protein tyrosine phosphatase-sigma (PTP-σ) in post-SCI remains largely unexplored. Exosomes have great potential in the diagnosis, prognosis, and treatment of SCI due to their ability to easily cross the blood‒brain barrier. Schwann cell-derived exosomes (SCDEs) promote functional recovery in mice post-SCI by decreasing CSPG deposition. However, the mechanism by which SCDEs decrease CSPGs after SCI remains unknown. Herein, we observed elevated levels of PTP-σ and increased CSPG deposition during glial scar formation after SCI in vivo. After SCDEs were injected into SCI mice, CSPG deposition decreased in scar tissue at the injury site, the expression of PTP-σ increased during axonal growth around the injury site, and motor function subsequently recovered. Additionally, we demonstrated that the use of both Rho/ROCK inhibitors and SCDEs inhibited the reparative effects of SCDEs on scar tissue after SCI. In conclusion, our study revealed that treatment with SCDEs targeting the Rho/ROCK signaling pathway reduced PTP-σ activation in the CSPG post-SCI, which inhibited scar tissue formation.

The mechanism of covalent inhibition of LAR phosphatase by illudalic acid.

Leukocyte antigen-related (LAR) phosphatase is a receptor-type protein tyrosine phosphatase involved in cellular signaling and associated with human disease including cancer and metabolic disorders. Selective inhibition of LAR phosphatase activity by well characterized and well validated small molecules would provide key insights into the roles of LAR phosphatase in health and disease, but identifying selective inhibitors of LAR phosphatase activity has been challenging. Recently, we described potent and selective inhibition of LAR phosphatase activity by the fungal natural product illudalic acid. Here we provide a detailed biochemical characterization of the adduct formed between LAR phosphatase and illudalic acid. A mass spectrometric analysis indicates that two cysteine residues are covalently labeled by illudalic acid and a related analog. Mutational analysis supports the hypothesis that inhibition of LAR phosphatase activity is due primarily to the adduct with the catalytic cysteine residue. A computational study suggests potential interactions between the illudalic acid moiety and the enzyme active site. Taken together, these data offer novel insights into the mechanism of inhibition of LAR phosphatase activity by illudalic acid.

Discovery and biological evaluation of novel dual PTP1B and ACP1 inhibitors for the treatment of insulin resistance.

In this study, a virtual screening pipeline comprising ligand-based and structure-based approaches was established and applied for the identification of dual PTP1B and ACP1 inhibitors. As a result, a series of benzoic acid derivatives was discovered, and compound H3 and S6 demonstrated PTP1B and ACP1 inhibitory activity, with IC50 values of 3.5 and 8.2 µM for PTP1B, and 2.5 and 5.2 µM for ACP1, respectively. Molecular dynamics simulations illustrated that H3 interacted with critical residues in the active site, such as Cys215 and Arg221 for PTP1B, and Cys17 and Arg18 for ACP1. Enzymatic kinetic research indicated that identified inhibitors competitively inhibited PTP1B and ACP1. Additionally, cellular assays demonstrated that H3 and S6 effectively increased glucose uptake in insulin-resistant HepG2 cells while displaying very limited cytotoxicity at their effective concentrations. In summary, H3 and S6 represent novel dual-target inhibitors for PTP1B and ACP1, warranting further investigation as potential agents for the treatment of diabetes.

The predictive value of coronary artery calcium score combined with traditional risk factors for obstructive coronary heart disease in young people.

OBJECTIVES: This study attempts to compare the predictive effects of several prediction models on obstructive coronary artery disease (OCAD) in young patients (30-50 years old), with a view to providing a new evaluation tool for the prediction of premature coronary artery disease (PCAD). METHODS: A total of 532 hospitalized patients aged 30-50 were included in the study.All of them underwent coronary computed tomography angiography (CCTA) for suspected symptoms of coronary heart disease.Coronary artery calcium score (CACS) combined with traditional risk factors and pre-test probability models are the prediction models to be compared in this study.The PTP model was selected from the upgraded Diamond-Forrester model (UDFM) and the Duke clinical score (DCS). RESULTS: All patients included in the study were aged 30-50 years. Among them, women accounted for 24.4%, and 355 patients (66.7%) had a CACS of 0. OCAD was diagnosed in 43 patients (8.1%). The CACS combined with traditional risk factors to predict the OCAD area under the curve of receiver operating characteristic (ROC) (AUC = 0.794,p < 0.001) was greater than the PTP models (AUCUDFM=0.6977,p < 0.001;AUCDCS=0.6214,p < 0.001). By calculating the net reclassification index (NRI) and the integrated discrimination index (IDI), the ability to predict the risk of OCAD using the CACS combined with traditional risk factors was improved compared with the PTP models (NRI&IDI > 0,p < 0.05). CONCLUSION: The predictive value of CACS combined with traditional risk factors for OCAD in young patients is better than the PTP models.

Druggable targets of protein tyrosine phosphatase Family, viz. PTP1B, SHP2, Cdc25, and LMW-PTP: Current scenario on medicinal Attributes, and SAR insights.

Protein tyrosine phosphatases (PTPs) are the class of dephosphorylation enzymes that catalyze the removal of phosphate groups from tyrosine residues on proteins responsible for various cellular processes. Any disbalance in signal pathways mediated by PTPs leads to various disease conditions like diabetes, obesity, cancers, and autoimmune disorders. Amongst the PTP superfamily, PTP1B, SHP2, Cdc25, and LMW-PTP have been prioritized as druggable targets for developing medicinal agents. PTP1B is an intracellular PTP enzyme that downregulates insulin and leptin signaling pathways and is involved in insulin resistance and glucose homeostasis. SHP2 is involved in the RAS-MAPK pathway and T cell immunity. Cdk-cyclin complex activation occurs by Cdc25-PTPs involved in cell cycle regulation. LMW-PTPs are involved in PDGF/PDGFR, Eph/ephrin, and insulin signaling pathways, resulting in certain diseases like diabetes mellitus, obesity, and cancer. The signaling cascades of PTP1B, SHP2, Cdc25, and LMW-PTPs have been described to rationalize their medicinal importance in the pathophysiology of diabetes, obesity, and cancer. Their binding sites have been explored to overcome the hurdles in discovering target selective molecules with optimum potency. Recent developments in the synthetic molecules bearing heterocyclic moieties against these targets have been explored to gain insight into structural features. The elaborated SAR investigation revealed the effect of substituents on the potency and target selectivity, which can be implicated in the further discovery of newer medicinal agents targeting the druggable members of the PTP superfamily.

Anti-diabetic and anti-inflammatory indole diterpenes from the marine-derived fungus Penicillium sp. ZYX-Z-143.

Seven new indole-diterpenoids, penpaxilloids A-E (1-5), 7-methoxypaxilline-13-ene (6), and 10-hydroxy-paspaline (7), along with 20 known ones (8-27), were isolated from the marine-derived fungus Penicillium sp. ZYX-Z-143. Among them, compound 1 was a spiro indole-diterpenoid bearing a 2,3,3a,5-tetrahydro-1H-benzo[d]pyrrolo[2,1-b][1,3]oxazin-1-one motif. Compound 2 was characterized by a unique heptacyclic system featuring a rare 3,6,8-trioxabicyclo[3.2.1]octane unit. The structures of the new compounds were established by extensive spectroscopic analyses, NMR calculations coupled with the DP4 + analysis, and ECD calculations. The plausible biogenetic pathway of two unprecedented indole diterpenoids, penpaxilloids A and B (1 and 2), was postulated. Compound 1 acted as a noncompetitive inhibitor against protein tyrosine phosphatase 1B (PTP1B) with IC50 value of 8.60 ± 0.53 µM. Compound 17 showed significant α-glucosidase inhibitory activity with IC50 value of 19.96 ± 0.32 µM. Moreover, compounds 4, 8, and 22 potently suppressed nitric oxide production on lipopolysaccharide-stimulated RAW264.7 macrophages.

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-ß1-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-ß1-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.

Clinical and radiographic outcomes following 120 consecutive patients undergoing prone transpsoas lateral lumbar interbody fusion.

PURPOSE: The prone transpsoas approach is a single-position alternative to traditional lateral lumbar interbody fusion (LLIF). Earlier prone LLIF studies have focused on technique, feasibility, perioperative efficiencies, and immediate postoperative radiographic alignment. This study was undertaken to report longer-term clinical and radiographic outcomes, and to identify learnings from experiential evolution of the prone LLIF procedure. METHODS: All consecutive patients undergoing prone LLIF for any indication at one institution were included (n = 120). Demographic, diagnostic, treatment, and outcomes data were captured via prospective institutional registry. Retrospective analysis identified 31 'pre-proceduralization' and 89 'post-proceduralization' prone LLIF approaches, enabling comparison across early and later cohorts. RESULTS: 187 instrumented LLIF levels were performed. Operative time, retraction time, LLIF blood loss, and hospital stay averaged 150 min, 17 min, 50 ml, and 2.2 days, respectively. 79% of cases were without complication. Postoperative hip flexion weakness was identified in 14%, transient lower extremity weakness in 12%, and sensory deficits in 10%. At last follow-up, back pain, worst-leg pain, Oswestry, and EQ-5D health state improved by 55%, 46%, 48%, and 51%, respectively. 99% improved or maintained sagittal alignment with an average 6.5° segmental lordosis gain at LLIF levels. Only intra-psoas retraction time differed between pre- and post-proceduralization; proceduralization saved an average 3.4 min/level (p = 0.0371). CONCLUSIONS: The largest single-center prone LLIF experience with the longest follow-up to-date shows that it results in few complications, quick recovery, improvements in pain and function, high patient satisfaction, and improved sagittal alignment at an average one year and up to four years postoperatively.