scholarly journals Critical role of WNK1 in MYC-dependent early mouse thymocyte development

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Robert Köchl ◽  
Lesley Vanes ◽  
Miriam Llorian Sopena ◽  
Probir Chakravarty ◽  
Harald Hartweger ◽  
...  
Keyword(s):  
Critical Role ◽  
Ion Homeostasis ◽  
Thymocyte Development ◽  
Double Positive ◽  
Mouse Thymocyte ◽  
Proliferation And Differentiation ◽  
Tcr Signals ◽  
And Migration ◽  
Early Mouse

WNK1, a kinase that controls kidney salt homeostasis, also regulates adhesion and migration in CD4+ T cells. Wnk1 is highly expressed in thymocytes, and since migration is important for thymocyte maturation, we investigated a role for WNK1 in mouse thymocyte development. We find that WNK1 is required for the transition of double negative (DN) thymocytes through the β-selection checkpoint and subsequent proliferation and differentiation into double positive (DP) thymocytes. Furthermore, we show that WNK1 negatively regulates LFA1-mediated adhesion and positively regulates CXCL12-induced migration in DN thymocytes. Despite this, migration defects of WNK1-deficient thymocytes do not account for the developmental arrest. Instead, we show that in DN thymocytes WNK1 transduces pre-TCR signals via OXSR1 and STK39 kinases, and the SLC12A2 ion co-transporter that are required for post-transcriptional upregulation of MYC and subsequent proliferation and differentiation into DP thymocytes. Thus, a pathway regulating ion homeostasis is a critical regulator of thymocyte development.

scholarly journals Critical role of WNK1 in MYC-dependent early thymocyte development

2020 ◽  
Author(s):  
Robert Köchl ◽  
Lesley Vanes ◽  
Miriam Llorian Sopena ◽  
Probir Chakravarty ◽  
Harald Hartweger ◽  
...  
Keyword(s):  
Critical Role ◽  
Ion Homeostasis ◽  
Thymocyte Development ◽  
Double Positive ◽  
Developmental Arrest ◽  
Proliferation And Differentiation ◽  
Tcr Signals ◽  
And Migration ◽  
Salt Homeostasis

AbstractWNK1, a kinase that controls kidney salt homeostasis, also regulates adhesion and migration in CD4+ T cells. Wnk1 is highly expressed in thymocytes, and since migration is important for thymocyte maturation, we investigated a role for WNK1 in thymocyte development. We find that WNK1 is required for the transition of double negative (DN) thymocytes through the β-selection checkpoint and subsequent proliferation and differentiation into double positive (DP) thymocytes. Furthermore, we show that WNK1 negatively regulates LFA1-mediated adhesion and positively regulates CXCL12-induced migration in DN thymocytes. Despite this, migration defects of WNK1-deficient thymocytes do not account for the developmental arrest. Instead, we show that in DN thymocytes WNK1 transduces pre-TCR signals via OXSR1 and STK39 kinases and the SLC12A2 ion co-transporter that are required for post-transcriptional upregulation of MYC and subsequent proliferation and differentiation into DP thymocytes. Thus, a pathway regulating ion homeostasis is a critical regulator of thymocyte development.

scholarly journals Author response: Critical role of WNK1 in MYC-dependent early mouse thymocyte development

2020 ◽  
Author(s):  
Robert Köchl ◽  
Lesley Vanes ◽  
Miriam Llorian Sopena ◽  
Probir Chakravarty ◽  
Harald Hartweger ◽  
...  
Keyword(s):  
Critical Role ◽  
Author Response ◽  
Thymocyte Development ◽  
Mouse Thymocyte ◽  
Early Mouse

Exosomal miR-214-5p Released from Glioblastoma Cells Modulates Inflammatory Response of Microglia after Lipopolysaccharide Stimulation through Targeting CXCR5

2019 ◽  
Vol 18 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Jian-kai Yang ◽  
Hong-jiang Liu ◽  
Yuanyu Wang ◽  
Chen Li ◽  
Ji-peng Yang ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Critical Role ◽  
Luciferase Reporter ◽  
Clinical Prognosis ◽  
Direct Target ◽  
And Migration ◽  
High Level ◽  
Cxcr5 Expression ◽  
Proliferation And Migration

Background and Objective: Exosomes communicate inter-cellularly and miRNAs play critical roles in this scenario. MiR-214-5p was implicated in multiple tumors with diverse functions uncovered. However, whether miR-214-5p is mechanistically involved in glioblastoma, especially via exosomal pathway, is still elusive. Here we sought to comprehensively address the critical role of exosomal miR-214-5p in glioblastoma (GBM) microenvironment.Methods:The relative expression of miR-214-5p was determined by real-time PCR. Cell viability and migration were measured by MTT and transwell chamber assays, respectively. The secretory cytokines were measured with ELISA kits. The regulatory effect of miR-214-5p on CXCR5 expression was interrogated by luciferase reporter assay. Protein level was analyzed by Western blot.Results:We demonstrated that miR-214-5p was aberrantly overexpressed in GBM and associated with poorer clinical prognosis. High level of miR-214-5p significantly contributed to cell proliferation and migration. GBM-derived exosomal miR-214-5p promoted inflammatory response in primary microglia upon lipopolysaccharide challenge. We further identified CXCR5 as the direct target of miR-214- 5p in this setting.Conclusion:Overexpression of miR-214-5p in GBM modulated the inflammatory response in microglia via exosomal transfer.

scholarly journals Functional modulation of PTH1R activation and signalling by RAMP2

2021 ◽  
Author(s):  
Katarina Nemec ◽  
Hannes Schihada ◽  
Gunnar Kleinau ◽  
Ulrike Zabel ◽  
Eugene O. Grushevskyi ◽  
...  
Keyword(s):  
Homology Modelling ◽  
Critical Role ◽  
Ion Homeostasis ◽  
Optical Biosensors ◽  
Dependent Manner ◽  
Activated State ◽  
Class B ◽  
Receptor Activity Modifying Proteins ◽  
G Protein Coupled

Receptor-activity-modifying proteins (RAMPs) are ubiquitously expressed membrane proteins that associate with different G protein-coupled receptors (GPCRs) including the parathyroid hormone 1 receptor (PTH1R), a class B GPCR, and an important modulator of mineral ion homeostasis and bone metabolism. However, it is unknown whether and how RAMP proteins may affect PTH1R function. Using different optical biosensors to measure the activation of PTH1R and its downstream signalling, we describe here that RAMP2 acts as a specific allosteric modulator of PTH1R, shifting PTH1R to a unique pre-activated state that permits faster activation in a ligand-specific manner. Moreover, RAMP2 modulates PTH1R downstream signalling in an agonist-dependent manner, most notably increasing the PTH-mediated Gi3 signalling sensitivity. Additionally, RAMP2 increases both PTH- and PTHrP-triggered β-arrestin2 recruitment to PTH1R. Employing homology modelling we describe the putative structural molecular basis underlying our functional findings. These data uncover a critical role of RAMPs in the activation and signalling of a GPCR that may provide a new venue for highly specific modulation of GPCR function and advanced drug design.

scholarly journals Critical role of integrin CD11c in splenic dendritic cell capture of missing-self CD47 cells to induce adaptive immunity

2018 ◽  
Vol 115 (26) ◽  
pp. 6786-6791 ◽  
Author(s):  
Jiaxi Wu ◽  
Huaizhu Wu ◽  
Jinping An ◽  
Christie M. Ballantyne ◽  
Jason G. Cyster
Keyword(s):  
Critical Role ◽  
T Cell Proliferation ◽  
Cell Capture ◽  
Antigen Uptake ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Missing Self

CD11c, also known as integrin alpha X, is the most widely used defining marker for dendritic cells (DCs). CD11c can bind complement iC3b and mediate phagocytosis in vitro, for which it is also referred to as complement receptor 4. However, the functions of this prominent marker protein in DCs, especially in vivo, remain poorly defined. Here, in the process of studying DC activation and immune responses induced by cells lacking self-CD47, we found that DC capture of CD47-deficient cells and DC activation was dependent on the integrin-signaling adaptor Talin1. Specifically, CD11c and its partner Itgb2 were required for DC capture of CD47-deficient cells. CD11b was not necessary for this process but could partially compensate in the absence of CD11c. Mice with DCs lacking Talin1, Itgb2, or CD11c were defective in supporting T-cell proliferation and differentiation induced by CD47-deficient cell associated antigen. These findings establish a critical role for CD11c in DC antigen uptake and activation in vivo. They may also contribute to understanding the functional mechanism of CD47-blockade therapies.

scholarly journals Survivin Loss in Thymocytes Triggers p53-mediated Growth Arrest and p53-independent Cell Death

2004 ◽  
Vol 199 (3) ◽  
pp. 399-410 ◽  
Author(s):  
Hitoshi Okada ◽  
Chris Bakal ◽  
Arda Shahinian ◽  
Andrew Elia ◽  
Andrew Wakeham ◽  
...  
Keyword(s):  
Cell Death ◽  
Critical Role ◽  
Cell Receptor ◽  
Thymocyte Development ◽  
Double Positive ◽  
Developmental Defects ◽  
Cycle Arrest ◽  
Tightly Coupled ◽  
Early Embryonic Stage ◽  
P53 Inactivation

Because survivin-null embryos die at an early embryonic stage, the role of survivin in thymocyte development is unknown. We have investigated the role by deleting the survivin gene only in the T lineage and show here that loss of survivin blocks the transition from CD4− CD8− double negative (DN) thymocytes to CD4+ CD8+ double positive cells. Although the pre–T cell receptor signaling pathway is intact in survivin-deficient thymocytes, the cells cannot respond to its signals. In response to proliferative stimuli, cycling survivin-deficient DN cells exhibit cell cycle arrest, a spindle formation defect, and increased cell death. Strikingly, loss of survivin activates the tumor suppressor p53. However, the developmental defects caused by survivin deficiency cannot be rescued by p53 inactivation or introduction of Bcl-2. These lines of evidence indicate that developing thymocytes depend on the cytoprotective function of survivin and that this function is tightly coupled to cell proliferation but independent of p53 and Bcl-2. Thus, survivin plays a critical role in early thymocyte development.

Gimap4 accelerates T-cell death

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 591-599 ◽  
Author(s):  
Silke Schnell ◽  
Corinne Démollière ◽  
Paul van den Berk ◽  
Heinz Jacobs
Keyword(s):  
Cell Death ◽  
T Cell ◽  
Critical Role ◽  
T Cell Development ◽  
Cell Receptor ◽  
Cell Physiology ◽  
Double Positive ◽  
Pkc Activation ◽  
Null Mutant Mouse

Gimap4, a member of the newly identified GTPase of the immunity-associated protein family (Gimap), is strongly induced by the pre–T-cell receptor in precursor T lymphocytes, transiently shut off in double-positive thymocytes, and reappears after TCR-mediated positive selection. Here, we show that Gimap4 remains expressed constitutively in the cytosol of mature T cells. A C-terminal IQ domain binds calmodulin in the absence of calcium, and conserved PKC phosphorylation motifs are targets of concanavalin A (ConA)– or PMA/ionomycin-induced PKC activation. To address the role of Gimap4 in T-cell physiology, we completed the genomic organization of the gimap4 locus and generated a Gimap4-null mutant mouse. Studies in these mice revealed no critical role of Gimap4 in T-cell development but in the regulation of apoptosis. We have found that Gimap4 accelerates the execution of programmed cell death induced by intrinsic stimuli downstream of caspase-3 activation and phosphatidylserine exposure. Apoptosis directly correlates with the phosphorylation status of Gimap4.

scholarly journals Critical role of Src-Syk-PLCγ2 signaling in megakaryocyte migration and thrombopoiesis

Blood ◽  
2010 ◽  
Vol 116 (5) ◽  
pp. 793-800 ◽  
Author(s):  
Alexandra Mazharian ◽  
Steve G. Thomas ◽  
Tarvinder S. Dhanjal ◽  
Christopher D. Buckley ◽  
Steve P. Watson
Keyword(s):  
Kinase Inhibitor ◽  
Tyrosine Phosphatase ◽  
Critical Role ◽  
Src Family Kinases ◽  
Surface Glycoprotein ◽  
Platelet Recovery ◽  
Glycoprotein Vi ◽  
Syk Kinase ◽  
And Migration

Migration of megakaryocytes (MKs) from the proliferative osteoblastic niche to the capillary-rich vascular niche is essential for proplatelet formation and platelet release. In this study, we explore the role of surface glycoprotein receptors and signaling proteins in regulating MK migration and platelet recovery after immune-induced thrombocytopenia. We show that spreading and migration of mouse primary bone marrow–derived MKs on a fibronectin matrix are abolished by the Src family kinases inhibitor PP1, the Syk kinase inhibitor R406 and the integrin αIIbβ3 antagonist lotrafiban. We also demonstrate that these responses are inhibited in primary phospholipase C γ2 (PLCγ2)–deficient MKs. Conversely, MK spreading and migration were unaltered in the absence of the collagen receptor, the glycoprotein VI–FcRγ-chain complex. We previously reported a correlation between a defect in MK migration and platelet recovery in the absence of platelet endothelial cell adhesion molecule-1 and the tyrosine phosphatase CD148. This correlation also holds for mice deficient in PLCγ2. This study identifies a model in which integrin signaling via Src family kinases and Syk kinase to PLCγ2 is required for MK spreading, migration, and platelet formation.

scholarly journals CDK6 kinase activity is required for thymocyte development

Blood ◽  
2011 ◽  
Vol 117 (23) ◽  
pp. 6120-6131 ◽  
Author(s):  
Miaofen G. Hu ◽  
Amit Deshpande ◽  
Nicolette Schlichting ◽  
Elisabeth A. Hinds ◽  
Changchuin Mao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Gene ◽  
Kinase Activity ◽  
Thymocyte Development ◽  
Hematopoietic Stem ◽  
Notch Target Gene ◽  
Target Gene Expression ◽  
Lymphoid Malignancies ◽  
Proliferation And Differentiation

Abstract Cyclin-dependent kinase-6 (CDK6) is required for early thymocyte development and tumorigenesis. To mechanistically dissect the role of CDK6 in thymocyte development, we generated and analyzed mutant knock-in mice and found that mice expressing a kinase-dead Cdk6 allele (Cdk6K43M) had a pronounced reduction in thymocytes and hematopoietic stem cells and progenitor cells (Lin−Sca-1+c-Kit+ [LSK]). In contrast, mice expressing the INK4-insensitive, hyperactive Cdk6R31C allele displayed excess proliferation in LSK and thymocytes. However, this is countered at least in part by increased apoptosis, which may limit progenitor and thymocyte expansion in the absence of other genetic events. Our mechanistic studies demonstrate that CDK6 kinase activity contributes to Notch signaling because inactive CDK6 kinase disrupts Notch-dependent survival, proliferation, and differentiation of LSK, with concomitant alteration of Notch target gene expression, such as massive up-regulation of CD25. Further, knockout of CD25 in Cdk6K43M mice rescued most defects observed in young mice. These results illustrate an important role for CDK6 kinase activity in thymocyte development that operates partially through modulating Notch target gene expression. This role of CDK6 as a downstream mediator of Notch identifies CDK6 kinase activity as a potential therapeutic target in human lymphoid malignancies.

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