Shp1 protein tyrosine phosphatase function in the early development of the hematopoietic system of zebrafish
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE172292 | GEO | 2021/04/30
REPOSITORIES: GEO
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Project description:Deficiency in the protein-tyrosine phosphatase SHP1/PTPN6 is linked with hematological malignancies and chronic inflammatory diseases. Here we exploited the embryonic and larval stages of zebrafish as an animal model to study ptpn6 function in the sole context of innate immunity. We show that ptpn6 knockdown induces a spontaneous inflammation-associated phenotype at the late larval stage, which was microbe-independent and enhanced instead of suppressed by glucocorticoids. When challenged with Salmonella typhimurium or Mycobacterium marinum at earlier stages of development, the innate immune system was hyperactivated to a contra-productive level that impaired the control of these pathogenic bacteria. These results demonstrate the crucial regulatory function of ptpn6 in preventing host-detrimental effects of inflammation by imposing a tight control over the level of innate immune response activation. This microarray study was designed to determine the effect of morpholino knockdown of the ptpn6 gene on the innate immune response of zebrafish embryos during infection with Salmonella typhimurium. Three independent infection experiments were performed using mixed egg clutches of wild type zebrafish, which were a cross of the AB and TL strains. Each experiment consisted of the following four treatment groups: (1) uninfected control embryos, (2) S. typhimurium-infected control embryos, (3) uninfected ptpn6 knockdown embryos, and (4) S. typhimurium-infected ptpn6 knockdown embryos. Knockdown of ptpn6 was performed by micro-injecting embryos at the 1-2 cell stage with the ptpn6 morpholino, and control embryos were mock-injected with buffer. Embryos were grown at 28.5M-bM-^@M-^S30M-BM-0C in egg water and manually dechorionated at 24 hours post fertilization (hpf). Subsequently, embryos were infected at 28 hpf by micro-injecting 200-250 colony forming units (CFU) of S. typhimurium SL1027 bacteria into the caudal vein, or were mock-injected with buffer as a control. After injections embryos were transferred into fresh egg water and incubated for 8 h at 28M-BM-0C. After the incubation period, pools of 15-20 embryos per treatment group were snap-frozen in liquid nitrogen and RNA was isolated for microarray analysis. All treatment groups were analyzed using a common reference approach.
2012-12-31 | E-GEOD-34930 | biostudies-arrayexpress
Project description:Deficiency in the protein-tyrosine phosphatase SHP1/PTPN6 is linked with hematological malignancies and chronic inflammatory diseases. Here we exploited the embryonic and larval stages of zebrafish as an animal model to study ptpn6 function in the sole context of innate immunity. We show that ptpn6 knockdown induces a spontaneous inflammation-associated phenotype at the late larval stage, which was microbe-independent and enhanced instead of suppressed by glucocorticoids. When challenged with Salmonella typhimurium or Mycobacterium marinum at earlier stages of development, the innate immune system was hyperactivated to a contra-productive level that impaired the control of these pathogenic bacteria. These results demonstrate the crucial regulatory function of ptpn6 in preventing host-detrimental effects of inflammation by imposing a tight control over the level of innate immune response activation.
2012-12-31 | GSE34930 | GEO
Project description:Hematopoietic stem cell (HSC) function is regulated by activation of receptor tyrosine kinases (RTKs). Receptor protein tyrosine phosphatases (PTPs) counterbalance RTK signaling; however, the functions of receptor PTPs in HSCs remain incompletely understood. We found that a receptor PTP, PTP?, was substantially overexpressed in mouse and human HSCs compared with more mature hematopoietic cells. Competitive transplantation of bone marrow cells from PTP?-deficient mice revealed that the loss of PTP? substantially increased long-term HSC-repopulating capacity compared with BM cells from control mice. While HSCs from PTP?-deficient mice had no apparent alterations in cell-cycle status, apoptosis, or homing capacity, these HSCs exhibited increased levels of activated RAC1, a RhoGTPase that regulates HSC engraftment capacity. shRNA-mediated silencing of PTP? also increased activated RAC1 levels in wild-type HSCs. Functionally, PTP?-deficient BM cells displayed increased cobblestone area-forming cell (CAFC) capacity and augmented transendothelial migration capacity, which was abrogated by RAC inhibition. Specific selection of human cord blood CD34?CD38?CD45RA?lin? PTP?? cells substantially increased the repopulating capacity of human HSCs compared with CD34?CD38?CD45RA?lin? cells and CD34?CD38?CD45RA?lin?PTP?? cells. Our results demonstrate that PTP? regulates HSC functional capacity via RAC1 inhibition and suggest that selecting for PTP?-negative human HSCs may be an effective strategy for enriching human HSCs for transplantation.
| S-EPMC4382260 | biostudies-literature
Project description:Hematopoietic tyrosine phosphatase (HePTP) is one of three members of the kinase interaction motif (KIM) phosphatase family which also includes STEP and PCPTP1. The KIM-PTPs are characterized by a 15 residue sequence, the KIM, which confers specific high-affinity binding to their only known substrates, the MAP kinases Erk and p38, an interaction which is critical for their ability to regulate processes such as T cell differentiation (HePTP) and neuronal signaling (STEP). The KIM-PTPs are also characterized by a unique set of residues in their PTP substrate binding loops, where 4 of the 13 residues are differentially conserved among the KIM-PTPs as compared to more than 30 other class I PTPs. One of these residues, T106 in HePTP, is either an aspartate or asparagine in nearly every other PTP. Using multiple techniques, we investigate the role of these KIM-PTP specific residues in order to elucidate the molecular basis of substrate recognition by HePTP. First, we used NMR spectroscopy to show that Erk2-derived peptides interact specifically with HePTP at the active site. Next, to reveal the molecular details of this interaction, we solved the high-resolution three-dimensional structures of two distinct HePTP-Erk2 peptide complexes. Strikingly, we were only able to obtain crystals of these transient complexes using a KIM-PTP specific substrate-trapping mutant, in which the KIM-PTP specific residue T106 was mutated to an aspartic acid (T106D). The introduced aspartate side chain facilitates the coordination of the bound peptides, thereby stabilizing the active dephosphorylation complex. These structures establish the essential role of HePTP T106 in restricting HePTP specificity to only those substrates which are able to interact with KIM-PTPs via the KIM (e.g., Erk2, p38). Finally, we describe how this interaction of the KIM is sufficient for overcoming the otherwise weak interaction at the active site of KIM-PTPs.
| S-EPMC2908255 | biostudies-literature
Project description:MAP kinases regulate essential cellular events, including cell growth, differentiation and inflammation. The solution structure of a complete MAPK-MAPK-regulatory protein complex, p38α-HePTP, was determined, enabling a comprehensive investigation of the molecular basis of specificity and fidelity in MAPK regulation. Structure determination was achieved by combining NMR spectroscopy and small-angle X-ray scattering data with a new ensemble calculation-refinement procedure. We identified 25 residues outside of the HePTP kinase interaction motif necessary for p38α recognition. The complex adopts an extended conformation in solution and rarely samples the conformation necessary for kinase deactivation. Complex formation also does not affect the N-terminal lobe, the activation loop of p38α or the catalytic domain of HePTP. Together, these results show how the downstream tyrosine phosphatase HePTP regulates p38α and provide for fundamentally new insights into MAPK regulation and specificity.
| S-EPMC3657131 | biostudies-literature
Project description:Protein tyrosine phosphatases (PTPs) have only recently become the focus of attention in the search for novel drug targets despite the fact that they play vital roles in numerous cellular processes and are implicated in many human diseases. The hematopoietic protein tyrosine phosphatase (HePTP) is often found dysregulated in preleukemic myelodysplastic syndrome (MDS), as well as in acute myelogenous leukemia (AML). Physiological substrates of HePTP include the mitogen-activated protein kinases (MAPKs) ERK1/2 and p38. Specific modulators of HePTP catalytic activity will be useful for elucidating mechanisms of MAPK regulation in hematopietic cells, and may also provide treatments for hematopoietic malignancies such as AML. Here we report the discovery of phenoxyacetic acids as inhibitors of HePTP. Structure-activity relationship (SAR) analysis and in silico docking studies reveal the molecular basis of HePTP inhibition by these compounds. We also show that these compounds are able to penetrate cell membranes and inhibit HePTP in human T lymphocytes.
| S-EPMC3077561 | biostudies-literature
Project description:Shp1 protein tyrosine phosphatase function in the early development of the hematopoietic system of zebrafish
| PRJNA722846 | ENA
Project description:Hematopoietic tyrosine phosphatase (HePTP) regulates orthogonal MAP kinase signaling cascades by dephosphorylating both extracellular signal-regulated kinase (ERK) and p38. HePTP recognizes a docking site (D-recruitment site, DRS) on its targets using a conserved N-terminal sequence motif (D-motif). Using solution nuclear magnetic resonance spectroscopy and isothermal titration calorimetry, we compare, for the first time, the docking interactions of HePTP with ERK2 and p38?. Our results demonstrate that ERK2-HePTP interactions primarily involve the D-motif, while a contiguous region called the kinase specificity motif also plays a key role in p38?-HePTP interactions. D-Motif-DRS interactions for the two kinases, while similar overall, do show some specific differences.
| S-EPMC3548032 | biostudies-literature
Project description:The hematopoietic protein tyrosine phosphatase (HePTP) is implicated in the development of blood cancers through its ability to negatively regulate the mitogen-activated protein kinases (MAPKs) ERK1/2 and p38. Small-molecule modulators of HePTP activity may become valuable in treating hematopoietic malignancies such as T cell acute lymphoblastic leukemia (T-ALL) and acute myelogenous leukemia (AML). Moreover, such compounds will further elucidate the regulation of MAPKs in hematopoietic cells. Although transient activation of MAPKs is crucial for growth and proliferation, prolonged activation of these important signaling molecules induces differentiation, cell cycle arrest, cell senescence, and apoptosis. Specific HePTP inhibitors may promote the latter and thereby may halt the growth of cancer cells. Here, we report the development of a small molecule that augments ERK1/2 and p38 activation in human T cells, specifically by inhibiting HePTP. Structure-activity relationship analysis, in silico docking studies, and mutagenesis experiments reveal how the inhibitor achieves selectivity for HePTP over related phosphatases by interacting with unique amino acid residues in the periphery of the highly conserved catalytic pocket. Importantly, we utilize this compound to show that pharmacological inhibition of HePTP not only augments but also prolongs activation of ERK1/2 and, especially, p38. Moreover, we present similar effects in leukocytes from mice intraperitoneally injected with the inhibitor at doses as low as 3 mg/kg. Our results warrant future studies with this probe compound that may establish HePTP as a new drug target for acute leukemic conditions.
| S-EPMC3288537 | biostudies-literature
Project description:Protein tyrosine phosphatase receptor-ζ1 (PTPRZ1) is a transmembrane tyrosine phosphatase receptor highly expressed in embryonic stem cells. In the present work, gene expression analyses of Ptprz1-/- and Ptprz1+/+ mice endothelial cells and hearts pointed to an unidentified role of PTPRZ1 in heart development through the regulation of heart-specific transcription factor genes. Echocardiography analysis in mice identified that both systolic and diastolic functions are affected in Ptprz1-/- compared with Ptprz1+/+ hearts, based on a dilated left ventricular (LV) cavity, decreased ejection fraction and fraction shortening, and increased angiogenesis in Ptprz1-/- hearts, with no signs of cardiac hypertrophy. A zebrafish ptprz1-/- knockout was also generated and exhibited misregulated expression of developmental cardiac markers, bradycardia, and defective heart morphogenesis characterized by enlarged ventricles and defected contractility. A selective PTPRZ1 tyrosine phosphatase inhibitor affected zebrafish heart development and function in a way like what is observed in the ptprz1-/- zebrafish. The same inhibitor had no effect in the function of the adult zebrafish heart, suggesting that PTPRZ1 is not important for the adult heart function, in line with data from the human cell atlas showing very low to negligible PTPRZ1 expression in the adult human heart. However, in line with the animal models, Ptprz1 was expressed in many different cell types in the human fetal heart, such as valvar, fibroblast-like, cardiomyocytes, and endothelial cells. Collectively, these data suggest that PTPRZ1 regulates cardiac morphogenesis in a way that subsequently affects heart function and warrant further studies for the involvement of PTPRZ1 in idiopathic congenital cardiac pathologies.NEW & NOTEWORTHY Protein tyrosine phosphatase receptor ζ1 (PTPRZ1) is expressed in fetal but not adult heart and seems to affect heart development. In both mouse and zebrafish animal models, loss of PTPRZ1 results in dilated left ventricle cavity, decreased ejection fraction, and fraction shortening, with no signs of cardiac hypertrophy. PTPRZ1 also seems to be involved in atrioventricular canal specification, outflow tract morphogenesis, and heart angiogenesis. These results suggest that PTPRZ1 plays a role in heart development and support the hypothesis that it may be involved in congenital cardiac pathologies.
| S-EPMC8754060 | biostudies-literature