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Cardiovascular Research Jun 2024SCUBE2 (Signal peptide-CUB-epidermal growth factor-like domain-containing protein 2) is a secreted or membrane-bound protein originally identified from endothelial cells...
AIMS
SCUBE2 (Signal peptide-CUB-epidermal growth factor-like domain-containing protein 2) is a secreted or membrane-bound protein originally identified from endothelial cells (ECs). Our previous work showed that SCUBE2 forms a complex with E-cadherin and stabilizes epithelial adherens junctions (AJs) to promote epithelial phenotypes. However, it remains unclear whether SCUBE2 also interacts with vascular endothelial (VE)-cadherin and modulates EC barrier function. In this study, we investigated whether and how SCUBE2 in ECs regulates vascular barrier maintenance.
METHODS AND RESULTS
We showed that SCUBE2 colocalized and interacted with VE-cadherin and VE-protein tyrosine phosphatase (VE-PTP) within EC AJs. Furthermore, SCUBE2 knockdown disrupted EC AJs and increased EC permeability. Expression of EC SCUBE2 was suppressed at both mRNA and protein levels via the nuclear factor-κB (NF-κB) signaling pathway in response to pro-inflammatory cytokines or permeability-inducing agents. In line with these findings, EC-specific deletion of Scube2 (EC-KO) in mice impaired baseline barrier function and worsened vascular leakiness of peripheral capillaries after local injection of histamine or vascular endothelial growth factor. EC-KO mice were also sensitive to pulmonary vascular hyperpermeability and leukocyte infiltration in response to acute endotoxin- or influenza virus-induced systemic inflammation. Meanwhile, EC-specific SCUBE2-overexpressing mice were protected from these effects. Molecular studies suggested that SCUBE2 acts as a scaffold molecule enabling VE-PTP to dephosphorylate VE-cadherin, which prevents VE-cadherin internalization and stabilizes EC AJs. As such, loss of SCUBE2 resulted in hyperphosphorylation of VE-cadherin at tyrosine 685, which led to its endocytosis, thus destabilizing EC AJs and reducing barrier function. All of these effects were exacerbated by inflammatory insults.
CONCLUSIONS
We found that SCUBE2 contributes to vascular integrity by recruiting VE-PTP to dephosphorylate VE-cadherin and stabilize AJs, thereby promoting EC barrier function. Moreover, our data suggest that genetic overexpression or pharmacological upregulation of SCUBE2 may help to prevent vascular leakage and edema in inflammatory diseases.
PubMed: 38870316
DOI: 10.1093/cvr/cvae132 -
Nucleic Acids Research May 2024Bud27 is a prefoldin-like protein that participates in transcriptional regulation mediated by the three RNA polymerases in Saccharomyces cerevisiae. Lack of Bud27...
Bud27 is a prefoldin-like protein that participates in transcriptional regulation mediated by the three RNA polymerases in Saccharomyces cerevisiae. Lack of Bud27 significantly affects RNA pol III transcription, although the involved mechanisms have not been characterized. Here, we show that Bud27 regulates the phosphorylation state of the RNA pol III transcriptional repressor, Maf1, influences its nuclear localization, and likely its activity. We demonstrate that Bud27 is associated with the Maf1 main phosphatase PP4 in vivo, and that this interaction is required for proper Maf1 dephosphorylation. Lack of Bud27 decreases the interaction among PP4 and Maf1, Maf1 dephosphorylation, and its nuclear entry. Our data uncover a new nuclear function of Bud27, identify PP4 as a novel Bud27 interactor and demonstrate the effect of this prefoldin-like protein on the posttranslational regulation of Maf1. Finally, our data reveal a broader effect of Bud27 on PP4 activity by influencing, at least, the phosphorylation of Rad53.
PubMed: 38864693
DOI: 10.1093/nar/gkae414 -
Frontiers in Cardiovascular Medicine 2024Protein phosphatase 2A (PP2A) is a serine/threonine-selective holoenzyme that controls Ca homeostasis and contractility of the heart via dephosphorylation of regulatory...
BACKGROUND
Protein phosphatase 2A (PP2A) is a serine/threonine-selective holoenzyme that controls Ca homeostasis and contractility of the heart via dephosphorylation of regulatory proteins. In some genetically modified mouse models with increased arrhythmogenicity, a reduced expression of the regulatory subunit B56α of PP2A was found as a concomitant effect. Whether there is a general correlation between the abundance of B56α and the promotion of cardiac arrhythmogenesis remains unclear.
METHODS
The aim of this study was therefore to investigate the role of PP2A-B56α in the propensity for arrhythmic activity in the heart. The experimental analysis of this question has been addressed by using a mouse model with deletion of the PP2A-B56α gene, (KO), in comparison to wild-type animals (WT). Evidence for arrhythmogenicity was investigated in whole animal, isolated heart and cardiomyocytes by ECG, recording of monophasic action potential (MAP) induced by programmed electrical stimulation (PES), measurement of Ca transients under increased pacing frequencies and determination of total K channel currents ( ).
RESULTS
ECG measurements showed a prolongation of QT time in KO vs. WT. KO mice exhibited a higher rate of premature ventricular contractions in the ECG. MAP measurements in Langendorff-perfused KO hearts showed increased episodes of ventricular tachyarrhythmia induced by PES. However, the KO hearts showed values for MAP duration that were similar to those in WT hearts. In contrast, KO showed more myocardial cells with spontaneous arrhythmogenic Ca transient events compared to WT. The whole-cell patch-clamp technique applied to ventricular cardiomyocytes revealed comparable peak potassium channel current densities between KO and WT.
CONCLUSION
These findings support the assumption that a decrease or even the loss of PP2A-B56α leads to an increased propensity of triggered arrhythmias. This could be based on the increased spontaneous Ca tansients observed.
PubMed: 38863902
DOI: 10.3389/fcvm.2024.1419597 -
Analytical Chemistry Jun 2024The abnormal expression of protein tyrosine phosphatase 1B (PTP1B) is highly related to several serious human diseases. Therefore, an accurate PTP1B activity assay is...
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 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.
Topics: Protein Tyrosine Phosphatase, Non-Receptor Type 1; Quartz Crystal Microbalance Techniques; Gold; Electrochemical Techniques; Humans; Metal-Organic Frameworks; Ferrous Compounds; Metallocenes; DNA, Single-Stranded; Metal Nanoparticles; Biosensing Techniques; Zirconium; Enzyme Assays
PubMed: 38863215
DOI: 10.1021/acs.analchem.4c01604 -
Nature Communications Jun 2024Missions into Deep Space are planned this decade. Yet the health consequences of exposure to microgravity and galactic cosmic radiation (GCR) over years-long missions on...
Missions into Deep Space are planned this decade. Yet the health consequences of exposure to microgravity and galactic cosmic radiation (GCR) over years-long missions on indispensable visceral organs such as the kidney are largely unexplored. We performed biomolecular (epigenomic, transcriptomic, proteomic, epiproteomic, metabolomic, metagenomic), clinical chemistry (electrolytes, endocrinology, biochemistry) and morphometry (histology, 3D imaging, miRNA-ISH, tissue weights) analyses using samples and datasets available from 11 spaceflight-exposed mouse and 5 human, 1 simulated microgravity rat and 4 simulated GCR-exposed mouse missions. We found that spaceflight induces: 1) renal transporter dephosphorylation which may indicate astronauts' increased risk of nephrolithiasis is in part a primary renal phenomenon rather than solely a secondary consequence of bone loss; 2) remodelling of the nephron that results in expansion of distal convoluted tubule size but loss of overall tubule density; 3) renal damage and dysfunction when exposed to a Mars roundtrip dose-equivalent of simulated GCR.
Topics: Animals; Space Flight; Humans; Mice; Cosmic Radiation; Rats; Male; Kidney; Kidney Diseases; Weightlessness; Astronauts; Mice, Inbred C57BL; Proteomics; Female; Mars; Weightlessness Simulation
PubMed: 38862484
DOI: 10.1038/s41467-024-49212-1 -
ChemMedChem Jun 2024The Eyes Absent (EYA) family of developmental proteins, often in partnership with the sine oculis (SIX) homeobox proteins, promote cancer metastasis and recurrence in...
The Eyes Absent (EYA) family of developmental proteins, often in partnership with the sine oculis (SIX) homeobox proteins, promote cancer metastasis and recurrence in numerous tumor types. In addition to being a transcriptional coactivator, EYA2 is a Tyr phosphatase that dephosphorylates H2AX which leads to repair instead of apoptosis upon DNA damage and ERβ which inhibits the anti-tumor transcriptional activity of ERβ. The SIX members of the EYA-SIX complex are difficult to target, therefore, we targeted the EYA2 to promote cell death and prevent cancer progression. We conducted structural optimization of a previously discovered allosteric inhibitor of EYA2, 9987, using the combination of in silico modeling, biochemical and cell-based assays. A new series of compounds was developed with significantly improved cellular activity and physiochemical properties desirable for brain targets. Specifically, compound 2e showed >30 fold improvement in the medulloblastoma cell line D458, relative to 9987, while maintaining potent and selective inhibitory activity against EYA2 Tyr phosphatase activity and a good multiparameter optimization score for central nervous system drugs.
PubMed: 38861151
DOI: 10.1002/cmdc.202400179 -
Methods in Molecular Biology (Clifton,... 2024Phosphoglycolate phosphatase (PGLP) dephosphorylates 2-phosphoglycolate to glycolate that can be further metabolized to glyoxylate by glycolate oxidase (GOX) via an...
Phosphoglycolate phosphatase (PGLP) dephosphorylates 2-phosphoglycolate to glycolate that can be further metabolized to glyoxylate by glycolate oxidase (GOX) via an oxidative reaction that uses O and releases HO. The oxidation of o-dianisidine by HO catalyzed by a peroxidase can be followed in real time by an absorbance change at 440 nm. Based on these reactions, a spectrophotometric method for measuring PGLP activity using a coupled reaction with recombinant Arabidopsis thaliana GOX is described. This protocol has been used successfully with either purified PGLP or total soluble proteins extracted from Arabidopsis rosette leaves.
Topics: Recombinant Proteins; Arabidopsis; Alcohol Oxidoreductases; Phosphoric Monoester Hydrolases; Glycolates; Enzyme Assays; Hydrogen Peroxide; Oxidation-Reduction; Plant Leaves; Arabidopsis Proteins; Spectrophotometry
PubMed: 38861076
DOI: 10.1007/978-1-0716-3802-6_3 -
WEE Family Kinase Inhibitors Combined with Sorafenib Can Selectively Inhibit HCC Cell Proliferation.Current Cancer Drug Targets Jun 2024Sorafenib is currently the first choice for the treatment of patients with advanced hepatocellular carcinoma, but its therapeutic effect is still limited.
BACKGROUND
Sorafenib is currently the first choice for the treatment of patients with advanced hepatocellular carcinoma, but its therapeutic effect is still limited.
OBJECTIVES
This study aims to examine whether WEE family kinase inhibitors can enhance the anticancer effect of sorafenib.
METHODS
We analyzed the expression levels of PKMYT1 kinase and WEE1 kinase in HCC, studied the inhibitory effect of PKMYT1 kinase inhibitor RP-6306, WEE1 kinase inhibitor adavosertib combined with sorafenib on the proliferation of HCC cells, and detected the effect of drug combination on CDK1 phosphorylation.
RESULTS
We found that PKMYT1 and WEE1 were upregulated in HCC and were detrimental to patient survival. Cell experiments showed that both RP-6306 and adavosertib (1-100 μM) inhibited the proliferation of HCC cell lines in a dose-dependent manner alone, and the combination of the two drugs had a synergistic effect. In HCC cell lines, sorafenib combined with RP-6306 or adavosertib showed a synergistic antiproliferation effect and less toxicity to normal cells. Sorafenib combined with RP-6306 and adavosertib further inhibited the proliferation of HCC cells and caused complete dephosphorylation of CDK1.
CONCLUSION
Taken together, our findings provide experimental evidence for the future use of sorafenib in combination with RP-6306 or adavosertib for the treatment of HCC.
PubMed: 38860904
DOI: 10.2174/0115680096298370240520093003 -
Acta Physiologica (Oxford, England) Jun 2024Calcineurin, protein phosphatase 2B (PP2B) or protein phosphatase 3 (PP3), is a calcium-dependent serine/threonine protein phosphatase. Calcineurin is widely expressed... (Review)
Review
Calcineurin, protein phosphatase 2B (PP2B) or protein phosphatase 3 (PP3), is a calcium-dependent serine/threonine protein phosphatase. Calcineurin is widely expressed in the kidney and regulates renal Na and K transport. In the thick ascending limb, calcineurin plays a role in inhibiting NKCC2 function by promoting the dephosphorylation of the cotransporter and an intracellular sorting receptor, called sorting-related-receptor-with-A-type repeats (SORLA), is involved in modulating the effect of calcineurin on NKCC2. Calcineurin also participates in regulating thiazide-sensitive NaCl-cotransporter (NCC) in the distal convoluted tubule. The mechanisms by which calcineurin regulates NCC include directly dephosphorylation of NCC, regulating Kelch-like-3/CUL3 E3 ubiquitin-ligase complex, which is responsible for WNK (with-no-lysin-kinases) ubiquitination, and inhibiting Kir4.1/Kir5.1, which determines NCC expression/activity. Finally, calcineurin is also involved in regulating ROMK (Kir1.1) channels in the cortical collecting duct and Cyp11 2 expression in adrenal zona glomerulosa. In summary, calcineurin is involved in the regulation of NKCC2, NCC, and inwardly rectifying K channels in the kidney, and it also plays a role in modulating aldosterone synthesis in adrenal gland, which regulates epithelial-Na-channel expression/activity. Thus, application of calcineurin inhibitors (CNIs) is expected to abrupt calcineurin-mediated regulation of transepithelial Na and K transport in the kidney. Consequently, CNIs cause hypertension, compromise renal K excretion, and induce hyperkalemia.
PubMed: 38860527
DOI: 10.1111/apha.14189 -
Cell Communication and Signaling : CCS Jun 2024Interleukin 33 (IL-33) is a crucial inflammatory factor that functions as an alarm signal in endometriosis (EMs). Epithelial-mesenchymal transition (EMT), a process...
OBJECTIVES
Interleukin 33 (IL-33) is a crucial inflammatory factor that functions as an alarm signal in endometriosis (EMs). Epithelial-mesenchymal transition (EMT), a process related to inflammatory signals, intracellular reactive oxygen species (ROS) production, and lipid peroxidation, have been proposed as potential mechanisms that contribute to the development and progression of EMs. IL-33 is highly upregulated in the ectopic milieu. Moreover, ectopic endometrial cells constitutively express interleukin-33 receptor ST2 (IL-33R). However, the role of IL-33/ST2 in the EMT of EMs remains largely unknown. In this study, we aimed to mechanistically determine the role of IL-33/ST2 in EMs-associated fibrosis.
MATERIALS AND METHODS
We established a non-lethal oxidative stress model to explore the conditions that trigger IL-33 induction. We performed α-smooth muscle actin (α-SMA) protein detection, cell counting kit-8 (CCK-8) assays, and scratch assays to analyze the impact of IL-33 on primary endometrial stromal cells (ESCs) proliferation and invasion. Clinical samples from patients with or without EMs were subjected to immunohistochemical (IHC) and and immunofluorescence(IF) staining to assess the clinical relevance of IL-33 receptor ST2 and EMT-related proteins. Furthermore, we used the ectopic human endometrial epithelial cell line 12Z and normal human epithelial cell line EEC to evaluate the effects of IL-33 on Wnt/β-catenin signaling. The effect of IL-33 on EMT-associated fibrosis was validated in vivo by intraperitoneal injections of IL-33 and antiST2.
RESULTS
We observed that ectopic milieu, characterized by ROS, TGF-β1, and high level of estrogen, triggers the secretion of IL-33 from ectopic ESCs. Ectopic endometrial lesions exhibited higher level of fibrotic characteristics and ST2 expression than that in the normal endometrium. Exogenous recombinant human (rhIL-33) enhanced ESC migration and survival. Similarly, 12Z cells displayed a higher degree of EMT characteristics with elevated expression of CCN4 and Fra-1, downstream target genes of the WNT/β-catenin pathway, than that observed in EECs. Conversely, blocking IL-33 with neutralizing antibodies, knocking down ST2 or β-catenin with siRNA, and β-catenin dephosphorylation abolished its effects on EMT promotion. In vivo validation demonstrated that IL-33 significantly promotes EMs-related fibrosis through the activation of Wnt/β-catenin signaling.
CONCLUSION
Our data strongly support the vital role of the IL-33/ST2 pathway in EMs-associated fibrosis and emphasize the importance of the EMT in the pathophysiology of fibrosis. Targeting the IL-33/ST2/Wnt/β-catenin axis may hold promise as a feasible therapeutic approach for controlling fibrosis in EMs.
Topics: Female; Endometriosis; Interleukin-33; Epithelial-Mesenchymal Transition; Humans; Interleukin-1 Receptor-Like 1 Protein; beta Catenin; Animals; Phosphorylation; Mice; Endometrium; Adult; Cell Proliferation; Cell Movement; Signal Transduction
PubMed: 38858740
DOI: 10.1186/s12964-024-01683-x