Nuclear Phosphatase Research Articles

Relaxin Modulates the Genomic Actions and Biological Effects of Estrogen in the Myometrium.

Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes.

Optimal performance objectives in the highly conserved bone morphogenetic protein signaling pathway

Throughout development, complex networks of cell signaling pathways drive cellular decision-making across different tissues and contexts. The transforming growth factor β (TGF-β) pathways, including the BMP/Smad pathway, play crucial roles in determining cellular responses. However, as the Smad pathway is used reiteratively throughout the life cycle of all animals, its systems-level behavior varies from one context to another, despite the pathway connectivity remaining nearly constant. For instance, some cellular systems require a rapid response, while others require high noise filtering. In this paper, we examine how the BMP-Smad pathway balances trade-offs among three such systems-level behaviors, or “Performance Objectives (POs)”: response speed, noise amplification, and the sensitivity of pathway output to receptor input. Using a Smad pathway model fit to human cell data, we show that varying non-conserved parameters (NCPs) such as protein concentrations, the Smad pathway can be tuned to emphasize any of the three POs and that the concentration of nuclear phosphatase has the greatest effect on tuning the POs. However, due to competition among the POs, the pathway cannot simultaneously optimize all three, but at best must balance trade-offs among the POs. We applied the multi-objective optimization concept of the Pareto Front, a widely used concept in economics to identify optimal trade-offs among various requirements. We show that the BMP pathway efficiently balances competing POs across species and is largely Pareto optimal. Our findings reveal that varying the concentration of NCPs allows the Smad signaling pathway to generate a diverse range of POs. This insight identifies how signaling pathways can be optimally tuned for each context.

P53 ensures the normal behavior and modification of G1/S-specific histone H3.1 in the nucleus.

H3.1 histone is predominantly synthesized and enters the nucleus during the G1/S phase of the cell cycle, as a new component of duplicating nucleosomes. Here, we found that p53 is necessary to secure the normal behavior and modification of H3.1 in the nucleus during the G1/S phase, in which p53 increases C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1) levels and decreases enhancer of zeste homolog 2 (EZH2) levels in the H3.1 interactome. In the absence of p53, H3.1 molecules tended to be tethered at or near the nuclear envelope (NE), where they were predominantly trimethylated at lysine 27 (H3K27me3) by EZH2, without forming nucleosomes. This accumulation was likely caused by the high affinity of H3.1 toward phosphatidic acid (PA). p53 reduced nuclear PA levels by increasing levels of CTDNEP1, which activates lipin to convert PA into diacylglycerol. We moreover found that the cytosolic H3 chaperone HSC70 attenuates the H3.1-PA interaction, and our molecular imaging analyses suggested that H3.1 may be anchored around the NE after their nuclear entry. Our results expand our knowledge of p53 function in regulation of the nuclear behavior of H3.1 during the G1/S phase, in which p53 may primarily target nuclear PA and EZH2.

Relaxin Modulates the Genomic Actions and Biological Effects of Estrogen in the Myometrium.

Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes.

TaNAC1 boosts powdery mildew resistance by phosphorylation-dependent regulation of TaSec1a and TaCAMTA4 via PP2Ac/CDPK20.

The integrity of wheat (Triticum aestivum) production is increasingly jeopardized by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), particularly amid the vicissitudes of climate change. Here, we delineated the role of a wheat transcription factor, TaNAC1, which precipitates cellular apoptosis and fortifies resistance against Bgt. Utilizing BiFC, co-immunoprecipitation, protein quantification, luciferase report assays, we determined that cytoplasmic TaNAC1-7A undergoes phosphorylation at the S184/S258 sites by TaCDPK20, facilitating its nuclear translocation. This migration appears to prime further phosphorylation by TaMPK1, thereby enhancing transcriptional regulatory activity. Notably, the apoptotic activity of phosphorylated TaNAC1-7A is negatively modulated by the nuclear protein phosphatase PP2Ac. Furthermore, activation of TaNAC1 phosphorylation initiates transcription of downstream genes TaSec1a and TaCAMTA4, through binding to the C[T/G]T[N7]A[A/C]G nucleic acid motif. Suppression of TaNAC1, TaCDPK20, and TaMPK1 in wheat compromises its resistance to Bgt strain E09, whereas overexpression of TaNAC1 and silencing of PP2Ac markedly elevate resistance levels. Our results reveal the pivotal role of TaNAC1 in basal resistance which is mediated by its effects on homotypic fusion, vacuolar protein sorting, and the expression of defense-related genes. The findings highlight the potential through targeting TaNAC1 and its regulators as a strategy for improving wheat's resistance to fungal pathogens.

Structure and mechanism of the human CTDNEP1–NEP1R1 membrane protein phosphatase complex necessary to maintain ER membrane morphology

C-terminal Domain Nuclear Envelope Phosphatase 1 (CTDNEP1) is a noncanonical protein serine/threonine phosphatase that has a conserved role in regulating ER membrane biogenesis. Inactivating mutations in CTDNEP1 correlate with the development of medulloblastoma, an aggressive childhood cancer. The transmembrane protein Nuclear Envelope Phosphatase 1 Regulatory Subunit 1 (NEP1R1) binds CTDNEP1, but the molecular details by which NEP1R1 regulates CTDNEP1 function are unclear. Here, we find that knockdown of NEP1R1 generates identical phenotypes to reported loss of CTDNEP1 in mammalian cells, establishing CTDNEP1-NEP1R1 as an evolutionarily conserved membrane protein phosphatase complex that restricts ER expansion. Mechanistically, NEP1R1 acts as an activating regulatory subunit that directly binds and increases the phosphatase activity of CTDNEP1. By defining a minimal NEP1R1 domain sufficient to activate CTDNEP1, we determine high-resolution crystal structures of the CTDNEP1-NEP1R1 complex bound to a peptide sequence acting as a pseudosubstrate. Structurally, NEP1R1 engages CTDNEP1 at a site distant from the active site to stabilize and allosterically activate CTDNEP1. Substrate recognition is facilitated by a conserved Arg residue in CTDNEP1 that binds and orients the substrate peptide in the active site. Together, this reveals mechanisms for how NEP1R1 regulates CTDNEP1 and explains how cancer-associated mutations inactivate CTDNEP1.

Ctdnep1 phosphatase is required for negative regulation of RANKL-induced osteoclast differentiation in RAW264.7 cells

Osteoclasts are multinucleated cells with bone resorption activity. Excessive osteoclast activity has been implicated in osteoporosis, rheumatoid arthritis, and bone destruction due to bone metastases from cancer, making osteoclasts essential target cells in bone and joint diseases. C-terminal domain nuclear envelope phosphatase 1 (Ctdnep1, formerly Dullard) is a negative regulator of transforming growth factor (TGF)-β superfamily signaling and regulates endochondral ossification in mesenchymal cells during skeletal development. In this study, we investigated the role of Ctdnep1 in the Receptor activator of nuclear factor-kappa B ligand (RANKL)-induced RAW264.7 osteoclast differentiation. Expression of Ctdnep1 did not change during osteoclast differentiation; Ctdnep1 protein localized to the cytoplasm before and after osteoclast differentiation. Small interfering RNA-mediated knockdown of Ctdnep1 increased tartrate-resistant acid phosphatase-positive multinucleated osteoclasts and the expression of osteoclast marker genes, including Acp5, Ctsk, and Nfatc1. Interestingly, the knockdown of Ctdnep1 increased the protein level of Nfatc1 in cells unstimulated with RANKL. Knockdown of Ctdnep1 also enhanced calcium-resorbing activity. Mechanistically, the knockdown of Ctdnep1 increased the phosphorylation of RANKL signaling components. These results suggest that Ctdnep1 negatively regulates osteoclast differentiation by suppressing the RANKL signaling pathway.

The diverging role of CDC14B: from mitotic exit in yeast to cell fate control in humans.

CDC14, originally identified as crucial mediator of mitotic exit in budding yeast, belongs to the family of dual-specificity phosphatases (DUSPs) that are present in most eukaryotes. Contradicting data have sparked a contentious discussion whether a cell cycle role is conserved in the human paralogs CDC14A and CDC14B but possibly masked due to redundancy. Subsequent studies on CDC14A and CDC14B double knockouts in human and mouse demonstrated that CDC14 activity is dispensable for mitotic progression in higher eukaryotes and instead suggested functional specialization. In this review, we provide a comprehensive overview of our current understanding of how faithful cell division is linked to phosphorylation and dephosphorylation and compare functional similarities and divergences between the mitotic phosphatases CDC14, PP2A, and PP1 from yeast and higher eukaryotes. Furthermore, we review the latest discoveries on CDC14B, which identify this nuclear phosphatase as a key regulator of gene expression and reveal its role in neuronal development. Finally, we discuss CDC14B functions in meiosis and possible implications in other developmental processes.

Research Trends in C-Terminal Domain Nuclear Envelope Phosphatase 1.

C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1, formerly Dullard) is a member of the newly emerging protein phosphatases and has been recognized in neuronal cell tissues in amphibians. It contains the phosphatase domain in the C-terminal, and the sequences are conserved in various taxa of organisms. CTDNEP1 has several roles in novel biological activities such as neural tube development in embryos, nuclear membrane biogenesis, regulation of bone morphogenetic protein signaling, and suppression of aggressive medulloblastoma. The three-dimensional structure of CTDNEP1 and the detailed action mechanisms of CTDNEP1's functions have yet to be determined for several reasons. Therefore, CTDNEP1 is a protein phosphatase of interest due to recent exciting and essential works. In this short review, we summarize the presented biological roles, possible substrates, interacting proteins, and research prospects of CTDNEP1.

Correlations of Arterial Phase CT Characteristics of Hepatocellular Carcinoma with Differentiation Degree and Expressions of PCNA and PTEN

The purpose of this study was to explore the correlations of the arterial-phase enhanced CT characteristics of hepatocellular carcinoma (HCC) with the differentiation degree and expressions of proliferating cell nuclear antigen (PCNA) and phosphatase and tensin homologue (PTEN). Seventy-nine HCC patients who underwent three-phase dynamic contrast-enhanced CT before surgery were selected to observe the arterial-phase characteristics. The degree of HCC tissue differentiation was evaluated by hematoxylin-eosin staining. PCNA and PTEN expressions were detected by immunohistochemistry. Spearman’s correlation analysis was conducted. The tumour size and vascular enhancement characteristics were negatively correlated with HCC differentiation degree and PTEN expression, and positively correlated with PCNA expression. The capsule integrity was positively correlated with HCC differentiation degree and PTEN expression, and negatively correlated with PCNA expression. The arterial-phase CT characteristics of HCC reflect the differentiation degree and expressions of PCNA and PTEN.

Regulated degradation of the inner nuclear membrane protein SUN2 maintains nuclear envelope architecture and function.

Nuclear architecture and functions depend on dynamic interactions between nuclear components (such as chromatin) and inner nuclear membrane (INM) proteins. Mutations in INM proteins interfering with these interactions result in disease. However, mechanisms controlling the levels and turnover of INM proteins remain unknown. Here, we describe a mechanism of regulated degradation of the INM SUN domain-containing protein 2 (SUN2). We show that Casein Kinase 2 and the C-terminal domain Nuclear Envelope Phosphatase 1 (CTDNEP1) have opposing effects on SUN2 levels by regulating SUN2 binding to the ubiquitin ligase Skp/Cullin1/F-BoxβTrCP (SCFβTrCP). Upon binding to phosphorylated SUN2, SCFβTrCP promotes its ubiquitination. Ubiquitinated SUN2 is membrane extracted by the AAA ATPase p97 and delivered to the proteasome for degradation. Importantly, accumulation of non-degradable SUN2 results in aberrant nuclear architecture, vulnerability to DNA damage and increased lagging chromosomes in mitosis. These findings uncover a central role of proteolysis in INM protein homeostasis.

Phosphatases are predicted to govern prolactin-mediated JAK-STAT signaling in pancreatic beta cells.

Patients with diabetes are unable to produce a sufficient amount of insulin to properly regulate their blood glucose levels. One potential method of treating diabetes is to increase the number of insulin-secreting beta cells in the pancreas to enhance insulin secretion. It is known that during pregnancy, pancreatic beta cells proliferate in response to the pregnancy hormone, prolactin (PRL). Leveraging this proliferative response to PRL may be a strategy to restore endogenous insulin production for patients with diabetes. To investigate this potential treatment, we previously developed a computational model to represent the PRL-mediated JAK-STAT signaling pathway in pancreatic beta cells. Here, we applied the model to identify the importance of particular signaling proteins in shaping the response of a population of beta cells. We simulated a population of 10 000 heterogeneous cells with varying initial protein concentrations responding to PRL stimulation. We used partial least squares regression to analyze the significance and role of each of the varied protein concentrations in producing the response of the cell. Our regression models predict that the concentrations of the cytosolic and nuclear phosphatases strongly influence the response of the cell. The model also predicts that increasing PRL receptor strengthens negative feedback mediated by the inhibitor suppressor of cytokine signaling. These findings reveal biological targets that can potentially be used to modulate the proliferation of pancreatic beta cells to enhance insulin secretion and beta cell regeneration in the context of diabetes.

SCP4-STK35/PDIK1L complex is a dual phospho-catalytic signaling dependency in acute myeloid leukemia

SUMMARYAcute myeloid leukemia (AML) cells rely on phospho-signaling pathways to gain unlimited proliferation potential. Here, we use domain-focused CRISPR screening and identify the nuclear phosphatase SCP4 as a dependency in AML, yet this enzyme is dispensable in normal hematopoietic progenitor cells. Using CRISPR exon scanning and gene complementation assays, we show that the catalytic function of SCP4 is essential in AML. Through mass spectrometry analysis of affinity-purified complexes, we identify the kinase paralogs STK35 and PDIK1L as binding partners and substrates of the SCP4 phosphatase domain. We show that STK35 and PDIK1L function catalytically and redundantly in the same pathway as SCP4 to maintain AML proliferation and to support amino acid biosynthesis and transport. We provide evidence that SCP4 regulates STK35/PDIK1L through two distinct mechanisms: catalytic removal of inhibitory phosphorylation and by promoting kinase stability. Our findings reveal a phosphatase-kinase signaling complex that supports the pathogenesis of AML.

DUSP2-mediated inhibition of tubular epithelial cell pyroptosis confers nephroprotection in acute kidney injury.

Rationale: Acute kidney injury (AKI) is pathologically characterized by renal tubular epithelial cell (RTEC) death and interstitial inflammation, while their pathogenesis remains incompletely understood. Dual-specificity phosphatase 2 (DUSP2) recently emerges as a crucial regulator of cell death and inflammation in a wide range of diseases, but its roles in renal pathophysiology are largely unknown.Methods: The expression of DUSP2 in the kidney was characterized by histological analysis in renal tissues from patients and mice with AKI. The role and mechanism of DUSP2-mediated inhibition of tubular epithelial cell pyroptosis in AKI were evaluated both in vivo and in vitro, and confirmed in RTEC-specific deletion of DUSP2 mice.Results: Here, we show that DUSP2 is enriched in RTECs in the renal tissue of both human and mouse and mainly positions in the nucleus. Further, we reveal that loss-of-DUSP2 in RTECs not only is a common feature of human and murine AKI but also positively contributes to AKI pathogenesis. Especially, RTEC-specific deletion of DUSP2 sensitizes mice to AKI by promoting RTEC pyroptosis and the resultant interstitial inflammation. Mechanistic studies show that gasdermin D (GSDMD), which mediates RTEC pyroptosis, is identified as a transcriptional target of activated STAT1 during AKI, whereas DUSP2 as a nuclear phosphatase deactivates STAT1 to restrict GSDMD-mediated RTEC pyroptosis. Importantly, DUSP2 overexpression in RTECs via adeno-associated virus-mediated gene transfer significantly ameliorates AKI.Conclusion: Our findings demonstrate a hitherto unrecognized role of DUSP2-STAT1 axis in regulating RTEC pyroptosis in AKI, highlighting that DUSP2-STAT1 axis is an attractive therapeutic target for AKI.

Roles of constitutive and signal-dependent protein phosphatase 2A docking motifs in burst attenuation of the cyclic AMP response element-binding protein

The cAMP response element-binding protein (CREB) is an important regulator of cell growth, metabolism, and synaptic plasticity. CREB is activated through phosphorylation of an evolutionarily conserved Ser residue (S133) within its intrinsically disordered kinase-inducible domain (KID). Phosphorylation of S133 in response to cAMP, Ca2+, and other stimuli triggers an association of the KID with the KID-interacting (KIX) domain of the CREB-binding protein (CBP), a histone acetyl transferase (HAT) that promotes transcriptional activation. Here we addressed the mechanisms of CREB attenuation following bursts in CREB phosphorylation. We show that phosphorylation of S133 is reversed by protein phosphatase 2A (PP2A), which is recruited to CREB through its B56 regulatory subunits. We found that a B56-binding site located at the carboxyl-terminal boundary of the KID (BS2) mediates high-affinity B56 binding, while a second binding site (BS1) located near the amino terminus of the KID mediates low affinity binding enhanced by phosphorylation of adjacent casein kinase (CK) phosphosites. Mutations that diminished B56 binding to BS2 elevated both basal and stimulus-induced phosphorylation of S133, increased CBP interaction with CREB, and potentiated the expression of CREB-dependent reporter genes. Cells from mice harboring a homozygous CrebE153D mutation that disrupts BS2 exhibited increased S133 phosphorylation stoichiometry and elevated transcriptional bursts to cAMP. These findings provide insights into substrate targeting by PP2A holoenzymes and establish a new mechanism of CREB attenuation that has implications for understanding CREB signaling in cell growth, metabolism, synaptic plasticity, and other physiologic contexts.

Melatonin Attenuates Intervertebral Disk Degeneration via Maintaining Cartilaginous Endplate Integrity in Rats.

ObjectiveThe aim of this study is to verify whether melatonin (Mel) could mitigate intervertebral disk degeneration (IVDD) in rats and to investigate the potential mechanism of it.MethodA rat acupuncture model of IVDD was established with intraperitoneal injection of Mel. The effect of Mel on IVDD was analyzed via radiologic and histological evaluations. The specific Mel receptors were investigated in both the nucleus pulposus (NP) and cartilaginous endplates (EPs). In vitro, EP cartilaginous cells (EPCs) were treated by different concentrations of Mel under lipopolysaccharide (LPS) and Luzindole conditions. In addition, LPS-induced inflammatory response and matrix degradation following nuclear factor kappa-B (NF-κB) pathway activation were investigated to confirm the potential mechanism of Mel on EPCs.ResultsThe percent disk height index (%DHI) and MRI signal decreased after initial puncture in the degeneration group compared with the control group, while Mel treatment protected disk height from decline and prevented the loss of water during the degeneration process. In the meantime, the histological staining of the Mel groups showed more integrity and well-ordered construction of the NP and EPs in both low and high concentration than that of the degeneration group. In addition, more deep-brown staining of type II collagen (Coll-II) was shown in the Mel groups compared with the degeneration group. Furthermore, in rat samples, immunohistochemical staining showed more positive cells of Mel receptors 1a and 1b in the EPs, instead of in the NP. Moreover, evident osteochondral lacuna formation was observed in rat EPs in the degeneration group; after Mel treatment, the osteochondral destruction alleviated accompanying fewer receptor activator for nuclear factor-κB ligand (RANKL) and tartrate-resistant acid phosphatase (TRAP)-stained positive cells expressed in the EPs. In vitro, Mel could promote the proliferation of EPCs, which protected EPCs from degeneration under LPS treatment. What is more, Mel downregulated the inflammatory response and matrix degradation of EPCs activated by NF-κB pathway through binding to its specific receptors.ConclusionThese results indicate that Mel protects the integrity of the EPs and attenuates IVDD by binding to the Mel receptors in the EPs. It may alleviate the inflammatory response and matrix degradation of EPCs activated by NF-κB pathway.

Transcriptome analysis of potential candidate genes and molecular pathways in colitis-associated colorectal cancer of Mkp-1-deficient mice

BackgroundThe nuclear phosphatase mitogen-activate protein kinase phosphatase-1 (MKP-1) is a key negative regulator of the innate immune response through the regulation of the biosynthesis of proinflammatory cytokines. In colorectal cancer (CRC), which is induced mainly by chronic inflammation, Mkp-1 overexpression was found in addition to disturbances in Mkp-1 functions, which may play a role in cancer development in different types of tumors. However, the potential molecular mechanisms by which Mkp-1 influences CRC development is not clear. Here, we performed global gene expression profiling of Mkp-1 KO mice using RNA sequencing (RNA-seq) to explore the role of Mkp-1 in CRC progression using transcriptome analysis.MethodsAzoxymethane/dextran sodium sulfate (AOM/DSS) mouse models were used to examine the most dramatic molecular and signaling changes that occur during different phases of CRC development in wild-type mice and Mkp-1 KO mice. Comprehensive bioinformatics analyses were used to elucidate the molecular processes regulated by Mkp-1. Differentially expressed genes (DEGs) were identified and functionally analyzed by Gene Ontology (GO), Kyoto Enrichment of Genes and Genomes (KEGG). Then, protein-protein interaction (PPI) network analysis was conducted using the STRING database and Cytoscape software.ResultsPersistent DEGs were different in adenoma and carcinoma stage (238 & 251, respectively) and in WT and MKp-1 KO mice (221& 196, respectively). Mkp-1 KO modulated key molecular processes typically activated in cancer, in particular, cell adhesion, ion transport, extracellular matrix organization, response to drug, response to hypoxia, and response to toxic substance. It was obvious that these pathways are closely associated with cancer development and metastasis. From the PPI network analyses, nine hub genes associated with CRC were identified.ConclusionThese findings suggest that MKp-1 and its hub genes may play a critical role in cancer development, prognosis, and determining treatment outcomes. We provide clues to build a potential link between Mkp-1 and colitis-associated tumorigenesis and identify areas requiring further investigation.Graphical abstract

Ctdnep1 and Eps8L2 regulate dorsal actin cables for nuclear positioning during cell migration

SummaryCells actively position their nuclei within the cytoplasm for multiple cellular and physiological functions.1, 2, 3 Consequently, nuclear mispositioning is usually associated with cell dysfunction and disease, from muscular disorders to cancer metastasis.4, 5, 6, 7 Different cell types position their nuclei away from the leading edge during cell migration.8, 9, 10, 11 In migrating fibroblasts, nuclear positioning is driven by an actin retrograde flow originated at the leading edge that drives dorsal actin cables away from the leading edge. The dorsal actin cables connect to the nuclear envelope by the linker of nucleoskeleton and cytoskeleton (LINC) complex on transmembrane actin-associated nuclear (TAN) lines.12, 13, 14 Dorsal actin cables are required for the formation of TAN lines. How dorsal actin cables are organized to promote TAN lines formation is unknown. Here, we report a role for Ctdnep1/Dullard, a nuclear envelope phosphatase,15, 16, 17, 18, 19, 20, 21, 22 and the actin regulator Eps8L223, 24, 25 on nuclear positioning and cell migration. We demonstrate that Ctdnep1 and Eps8L2 directly interact, and this interaction is important for nuclear positioning and cell migration. We also show that Ctdnep1 and Eps8L2 are involved in the formation and thickness of dorsal actin cables required for TAN lines engagement during nuclear movement. We propose that Ctdnep1-Eps8L2 interaction regulates dorsal actin cables for nuclear movement during cell migration.

Vicenin-2 inhibits the Helicobacterium pylori infection associated gastric carcinogenic events through modulation of PI3K/AKT and Nrf2 signaling in GES-1 cells.

Helicobacter pylori (H. pylori), a microbial carcinogen of Gram-negative bacteria, has been recognized to be the highest risk factor for the growthof human gastric cancer (GC). Therefore, the inhibition of thegrowth rate of H. pylori has been consideredan effective vital strategy to prevent GC development. This study highlights the inhibitory effect of vicenin-2 against H. pylori-induced gastric carcinogen signaling in human gastric epithelial cells (GES-1). In vitro cytotoxicity studies reported that 40 µM of vicenin-2 remarkably protects the gastric cells and this concentration shows 85% cell viability also does not produce toxicity. In addition, vicenin-2 prevents H. pylori-infected increased depletion of antioxidants mediated by reactive oxygen species generation, DNA damage, malondialdehyde, and nuclear fragmentation. Here, we noticed that vicenin-2 remarkably suppressed the expression range of the phosphorylated form of phosphatidylinositol 3-kinase/protein kinase B, phosphorylated p38 kinases, phosphorylated extracellular signal-regulated kinase-1, phosphorylated c-Jun N-terminal kinase, tumor necrosis factor-α, interleukin-6, cyclooxygenase-2in GES-1 infected with H. pylori. Moreover, we observed that vicenin-2 enhanced the antioxidants protein nuclear factor erythroid factor-2and phosphatase and tensin homologexpression in H. pylori-infected cells. Thus, vicenin-2 prevents the H. pylori-associated infection, and its resistance might be a potential strategyin preventing GC induced by H. pylori.

A Network Pharmacology Analysis of Cang Fu Dao Tan Formula for the Treatment of Obese Polycystic Ovary Syndrome

ObjectiveTo explore the potential molecular targets of Cang Fu Dao Tan Formula (CFDTF) in the treatment of obese polycystic ovary syndrome (PCOS) using network pharmacology and bioinformatic approaches. MethodsThe potential blood-entry active compounds and targets of CFDTF were retrieved from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and obese PCOS related gene targets were retrieved from GeneCard databases. A protein-protein interaction (PPI) network of CFDTF component-targets and obese PCOS disease- targets was constructed using STRING. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the intersection network were conducted using a Bioconductor database. ResultsIn total, 114 active compounds were screened according to oral bioavailability (OB) and drug similarity (DL), and 328 targets related to these constituents were obtained. Further, 2 559 target genes directly related to obese PCOS were obtained from the GeneCard databases, and 82 genes were obtained from the intersection of the component-target and disease-target PPI network. These genes were mainly involved in response to steroid hormones, nutrient levels and lipopolysaccharide as well as in other biological processes. Their molecular functions were mainly related to nuclear receptor activity, phosphatase binding and cytokine activity, and they were enriched in the cytoplasm, cell membrane and membrane region. ConclusionsCFDTF consists of 114 active compounds that are responsible for its pharmacodynamic effects. It mainly regulates the AGE-RAGE signaling pathway in diabetic complications, bladder cancer, and hepatitis B and in other signaling networks. These findings provide certain theoretical and scientific basis for the treatment of obese PCOS with Chinese medicine.