scholarly journals Timing of neuronal death in trkA, trkB and trkC mutant embryos reveals developmental changes in sensory neuron dependence on Trk signalling

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 3255-3261 ◽  
Author(s):  
L.G. Pinon ◽  
L. Minichiello ◽  
R. Klein ◽  
A.M. Davies
Keyword(s):  
Neuronal Death ◽  
Tyrosine Kinases ◽  
Marked Decrease ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Embryonic Mouse ◽  
Target Field ◽  
Significant Difference

The sensory neurons of the embryonic mouse trigeminal ganglion are supported in culture by different neurotrophins at successive stages of development. Initially the neurons survive in response to BDNF and NT3 and later switch to becoming NGF-dependent (Buchman, V. I. and Davies, A. M. (1993), Development 118, 989–1001). To determine if this in vitro switch in neurotrophin responsiveness is physiologically relevant, we studied the timing of neuronal death in the trigeminal ganglia of embryos that are homozygous for null mutations in the trkA, trkB and trkC genes, which encode receptor tyrosine kinases for NGF, BDNF and NT3, respectively. In wild-type embryos, the number of pyknotic nuclei increased from E11 to peak between E13 and E14, and decreased gradually at later ages, becoming negligible by birth. Neuronal death in the trigeminal ganglia of trkA−/− embryos also peaked between E13 and E14, but was almost threefold greater than in wild-type embryos at this stage. Whereas there was no significant difference between the number of pyknotic nuclei in trkA−/− and wild-type embryos at E11 and E12, there was a substantial increase in the number of pyknotic nuclei in the trigeminal ganglia of trkB−/− at these earlier stages. Counts of the total number of neurons in E13 trigeminal ganglia revealed a marked decrease in trkB−/− but not trkA−/− or trkC−/− embryos. Consistent with the later onset of excessive neuronal death in trkA−/− embryos, there was a marked decrease in the neuronal complement of the trigeminal ganglia of trkA−/− embryos at E15. These results demonstrate that TrkB signalling is required for the in vivo survival of many trigeminal neurons during the early stages of target field innervation before they become NGF-dependent.

Optimisation of EGFR TKI efficiency in the therapeutic scheme of EGFR wild-type lung cancer.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e18532-e18532
Author(s):  
Mathilde Cabart ◽  
Judith Raimbourg ◽  
Lisenn Lalier ◽  
Jaafar Bennouna ◽  
Francois Vallette
Keyword(s):  
Lung Cancer ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Wild Type ◽  
Short Term ◽  
Egfr Ligands ◽  
Egfr Mutated ◽  
Egfr Tki

e18532 Background: EGFR tyrosine kinase inhibitors (EGFR TKI) have improved the therapeutic care of lung cancer patients but only a small sub-population of patients, namely those harboring EGFR-mutated tumors, benefit from this therapy. The observation that EGFR TKI enhance prognosis and quality of life in all patients when used as second line or maintenance treatment impelled us into the search of potential markers of the optimal introduction kinetics of EGFR TKI in the therapeutic scheme. Methods: We used lung cancer cell lines harboring either wild-type or mutated EGFR (NCI-H1650, NCI-H1975) to study the consequences of cisplatin treatment in vitro on the consecutive sensitivity to erlotinib. Results: Sub-lethal cisplatin pretreatment (3µM) enhances erlotinib toxicity in EGFR wild-type, but not EGFR mutated cells (A549 IC50 drops from 28 to 15µM for short-term or 12µM for long-term exposure). This correlates with EGFR activation following short-term or prolonged cisplatin treatment through the secretion of EGFR ligands. This activation of EGFR is concomitant to the decrease in other receptor tyrosine kinases phosphorylation including Met. Conclusions: The sensitivity of EGFR wild-type lung cancer cells to erlotinib in vitro is enhanced by cisplatin pretreatment. We identified potential markers of this sensitization, namely EGFR ligands, which serum level might be predicitive of the optimal efficiency of EGFR TKI. In vivo validation of these markers is under investigation. The concomitant decrease in other receptor tyrosine kinases phosphorylation suggests that the targeting of other receptor tyrosine kinases might potentiate EGFR TKI efficiency.

scholarly journals Regions of the Herpes Simplex Virus Type 1 Latency-Associated Transcript That Protect Cells from Apoptosis In Vitro and Protect Neuronal Cells In Vivo

2002 ◽  
Vol 76 (2) ◽  
pp. 717-729 ◽  
Author(s):  
Maryam Ahmed ◽  
Martin Lock ◽  
Cathie G. Miller ◽  
Nigel W. Fraser
Keyword(s):  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Exon 1 ◽  
Induced Apoptosis ◽  
Simplex Virus ◽  
In Cells

ABSTRACT Recent studies have suggested that the latency-associated transcript (LAT) region of herpes simplex virus type 1 (HSV-1) is effective at blocking virus-induced apoptosis both in vitro and in the trigeminal ganglia of acutely infected rabbits (Inman et al., J. Virol. 75:3636–3646, 2001; Perng et al., Science 287:1500–1503, 2000). By transfecting cells with a construct expressing the Pst-Mlu segment of the LAT, encompassing the LAT exon 1, the stable 2.0-kb intron, and 5′ part of exon 2, we confirmed that this region was able to diminish the onset of programmed cell death initiated by anti-Fas and camptothecin treatment. In addition, caspase 8-induced apoptosis was specifically inhibited in cells expressing the Pst-Mlu LAT fragment. To further delineate the minimal region of LAT that is necessary for this antiapoptotic function, LAT mutants were used in our cotransfection assays. In HeLa cells, the plasmids lacking exon sequences were the least effective at blocking apoptosis. However, similar to previous work (Inman et al., op. cit.), our data also indicated that the 5′ end of the stable 2.0-kb LAT intron appeared to contribute to the promotion of cell survival. Furthermore, cells productively infected with the 17N/H LAT mutant virus, a virus deleted in the LAT promoter, exon 1, and about half of the intron, exhibited a greater degree of DNA fragmentation than cells infected with wild-type HSV-1. These data support the finding that the exon 1 and 2.0-kb intron region of the LAT transcription unit display an antiapoptotic function both in transfected cells and in the context of the virus infection in vitro. In trigeminal ganglia of mice acutely infected with the wild-type virus, 17, and 17ΔSty, a virus lacking most of exon 1, apoptosis was not detected in cells that were positive for virus particles. However, dual staining was observed in cells from mice infected with 17N/H virus, indicating that the LAT antiapoptotic function demonstrated in cells transfected by LAT-expressing constructs may also play a role in protecting cells from virus-induced apoptosis during acute viral infection in vivo.

scholarly journals Ectopic EphA4 Receptor Induces Posterior Protrusions via FGF Signaling in Xenopus Embryos

2004 ◽  
Vol 15 (4) ◽  
pp. 1647-1655 ◽  
Author(s):  
Eui Kyun Park ◽  
Neil Warner ◽  
Yong-Sik Bong ◽  
David Stapleton ◽  
Ryu Maeda ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Sh2 Domain ◽  
Binding Motif ◽  
Eph Receptors ◽  
Fgf Signaling ◽  
Wild Type ◽  
Sam Domain ◽  
Xenopus Embryos

The Eph family of receptor tyrosine kinases regulates numerous biological processes. To examine the biochemical and developmental contributions of specific structural motifs within Eph receptors, wild-type or mutant forms of the EphA4 receptor were ectopically expressed in developing Xenopus embryos. Wild-type EphA4 and a mutant lacking both the SAM domain and PDZ binding motif were constitutively tyrosine phosphorylated in vivo and catalytically active in vitro. EphA4 induced loss of cell adhesion, ventro-lateral protrusions, and severely expanded posterior structures in Xenopus embryos. Moreover, mutation of a conserved SAM domain tyrosine to phenylalanine (Y928F) enhanced the ability of EphA4 to induce these phenotypes, suggesting that the SAM domain may negatively regulate some aspects of EphA4 activity in Xenopus. Analysis of double mutants revealed that the Y928F EphA4 phenotypes were dependent on kinase activity; juxtamembrane sites of tyrosine phosphorylation and SH2 domain-binding were required for cell dissociation, but not for posterior protrusions. The induction of protrusions and expansion of posterior structures is similar to phenotypic effects observed in Xenopus embryos expressing activated FGFR1. Furthermore, the budding ectopic protrusions induced by EphA4 express FGF-8, FGFR1, and FGFR4a. In addition, antisense morpholino oligonucleotide-mediated loss of FGF-8 expression in vivo substantially reduced the phenotypic effects in EphA4Y928F expressing embryos, suggesting a connection between Eph and FGF signaling.

scholarly journals CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Rachel Vaivoda ◽  
Christine Vaine ◽  
Cassandra Boerstler ◽  
Kristy Galloway ◽  
Peter Christmas
Keyword(s):  
Weight Loss ◽  
Mouse Model ◽  
Immune Regulation ◽  
Complement Component ◽  
Wild Type ◽  
Eicosanoid Synthesis ◽  
Colonic Tissue ◽  
Significant Difference

CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4(LTB4). CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type andCyp4f18knockout neutrophils using anin vitroassay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9–2.25-fold in knockout cells compared to wild-type (P< 0.01). This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxisin vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type andCyp4f18knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores thein vivochallenges of CYP knockout studies.

Interleukin 27 inhibits atherosclerosis via immunoregulation of macrophages in mice

2013 ◽  
Vol 305 (3) ◽  
pp. H420-H429 ◽  
Author(s):  
Tetsuaki Hirase ◽  
Hiromitsu Hara ◽  
Yoshiyuki Miyazaki ◽  
Noriko Ide ◽  
Ai Nishimoto-Hazuku ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Macrophage Activation ◽  
Density Lipoprotein ◽  
Cell Polarization ◽  
High Cholesterol Diet ◽  
Wild Type ◽  
Interleukin 27 ◽  
Significant Difference

Chronic inflammation in arterial wall that is driven by immune cells and cytokines plays pivotal roles in the development of atherosclerosis. Interleukin 27 (IL-27) is a member of the IL-12 family of cytokines that consists of IL-27p28 and Epstein-Barr virus induced gene 3 (EBI3) and has anti-inflammatory properties that regulate T cell polarization and cytokine production. IL-27-deficient ( Ldlr−/− Ebi3−/−) and IL-27 receptor-deficient ( Ldlr−/− WSX-1−/−) Ldlr−/− mice were generated and fed with a high-cholesterol diet to induce atherosclerosis. Roles of bone marrow-derived cells in vivo and macrophages in vitro were studied using bone marrow reconstitution by transplantation and cultured peritoneal macrophages, respectively. We demonstrate that mice lacking IL-27 or IL-27 receptor are more susceptible to atherosclerosis compared with wild type due to enhanced accumulation and activation of macrophages in arterial walls. The number of circulating proinflammatory Ly6Chi monocytes showed no significant difference between wild-type mice and mice lacking IL-27 or IL-27 receptor. Administration of IL-27 suppressed the development of atherosclerosis in vivo and macrophage activation in vitro that was indicated by increased uptake of modified low-density lipoprotein and augmented production of proinflammatory cytokines. These findings define a novel inhibitory role for IL-27 in atherosclerosis that regulates macrophage activation in mice.

scholarly journals Loss of Synchronized Retinal Phagocytosis and Age-related Blindness in Mice Lacking αvβ5 Integrin

2004 ◽  
Vol 200 (12) ◽  
pp. 1539-1545 ◽  
Author(s):  
Emeline F. Nandrot ◽  
Yoonhee Kim ◽  
Scott E. Brodie ◽  
Xiaozhu Huang ◽  
Dean Sheppard ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Early Morning ◽  
Wild Type ◽  
Photoreceptor Outer Segment ◽  
Rpe Cells ◽  
Age Related

Daily phagocytosis by the retinal pigment epithelium (RPE) of spent photoreceptor outer segment fragments is critical for vision. In the retina, early morning circadian photoreceptor rod shedding precedes synchronized uptake of shed photoreceptor particles by RPE cells. In vitro, RPE cells use the integrin receptor αvβ5 for particle binding. Here, we tested RPE phagocytosis and retinal function in β5 integrin–deficient mice, which specifically lack αvβ5 receptors. Retinal photoresponses severely declined with age in β5−/− mice, whose RPE accumulated autofluorescent storage bodies that are hallmarks of human retinal aging and disease. β5−/− RPE in culture failed to take up isolated photoreceptor particles. β5−/− RPE in vivo retained basal uptake levels but lacked the burst of phagocytic activity that followed circadian photoreceptor shedding in wild-type RPE. Rhythmic activation of focal adhesion and Mer tyrosine kinases that mediate wild-type retinal phagocytosis was also completely absent in β5−/− retina. These results demonstrate an essential role for αvβ5 integrin receptors and their downstream signaling pathways in synchronizing retinal phagocytosis. Furthermore, they identify the β5−/− integrin mouse strain as a new animal model of age-related retinal dysfunction.

scholarly journals GENE-21. ROLE OF POT1 MUTATION IN GLIOMA PROLIFERATION AND SEXUAL DIVERGENCE OF SURVIVAL

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi102-vi102
Author(s):  
Ali Jalali ◽  
Kwanha Yu ◽  
Vivek Beechar ◽  
Deepika Mehra ◽  
Brittney Lozzi ◽  
...  
Keyword(s):  
Sex Differences ◽  
Immune Surveillance ◽  
Tumor Grade ◽  
The Cancer Genome Atlas ◽  
Mouse Tumor ◽  
Wild Type ◽  
Embryonic Mouse ◽  
Tumor Sphere

Abstract Germline POT1 mutations are associated with risk of several cancers including glioma. In The Cancer Genome Atlas, we found that the level of POT1 gene expression in tumors is associated with overall survival in IDH wild-type glioma independent of age and tumor grade (P=0.036). To assess if POT1 expression in a native mouse model of IDH wild-type glioma (referred to as C3 tumors) affects survival, we targeted both mouse POT1 orthologs (Pot1a/Pot1b) in C3 tumors using CRISPR/Cas9, generating C5 tumors. Interestingly, we noted a sexual divergence of survival, with female C5 mice dying faster than males (P=0.0034), whereas C3 mice show no sexual divergence in survival. To assess the genes and pathways underlying this divergence, we performed RNAseq profiling on C3 and C5 tumors and normalized the sex differences in the C5 profile for baseline sex differences in the C3 profile. Compared to males, female C5 tumors had lower enrichment of numerous gene sets related to immune surveillance. To specifically assess the effects of glioma-associated human POT1 variants, we expressed these variants in a mouse tumor sphere culture. We noted that expression of POT1-G95C variant increased the rate of sphere formation in vitro. In vivo expression of this variant in embryonic mouse brain during the gliogenic period increased the proliferative rate as assessed by BrdU uptake (P=0.008). These findings suggest a potential role for human POT1 variants in growth and proliferation of glial progenitor cells as well as glioma tumor cells. Additionally, the sexual divergence of survival in C5 tumors points to a differential interaction between POT1 loss and sex in regulation of immune response to these tumors.

scholarly journals Prothrombotic Phenotype of a Protein S Mutant Lacking Anticoagulant Activity

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2098-2098
Author(s):  
Stephanie Springborn ◽  
Sourav Ghosh ◽  
Marie L Schulte ◽  
Carla Rothlin ◽  
Brian R Branchford
Keyword(s):  
Platelet Activation ◽  
Tyrosine Kinases ◽  
Protein C ◽  
Receptor Tyrosine Kinases ◽  
Anticoagulant Activity ◽  
Protein S ◽  
Mutant Form ◽  
Wild Type ◽  
Significant Difference

Abstract Protein S is a vitamin K-dependent protein that plays an important role in balancing pro- and anti-thrombotic responses to vascular injury. On one hand, it circulates bound to activated protein C, functioning as an anticoagulant complex that downregulates the activities of coagulation factors V and VIII. On the other hand, protein S is a ligand for platelet TYRO3 and MERTK, which, along with the third paralog AXL, constitute the TAM family of receptor tyrosine kinases that functions to potentiate the action of platelet-activating agonists, ultimately resulting in activation of the α IIbβ3 integrin. The relative importance of these two activities in vivo, however, is not known. To better understand the importance of the TYRO3/MERTK-stimulating ability of protein S and thus gain additional insight into its role in platelet activation, we used CRISPR/Cas9 technology to generate mice with a D136A mutant form of protein S that lacks the ability to bind protein C and function as an anticoagulant, while retaining its ability to bind platelet-activating TAM receptors - hereafter termed Pros1 D136A mice. Since homozygosity for this variant was embryonically lethal, all assays were carried out in wild-type animals and their heterozygous littermates comprising a wild-type Pros1 allele and an allele encoding Pros1 D136A. Though there was no significant difference between Pros1 D136A mice and their wild-type littermates in either a collagen/epinephrine-induced pulmonary embolism model or in tail vein bleeding times, platelets from Pros1 D136A mice accumulated at the injury site to a significantly greater degree following in vivo laser injury to the cremaster muscle microvasculature. Taken together with the embryonic phenotype of Pros1 D136A homozygous mice, these data support the notion that protein S can function to augment platelet responsiveness. Further studies on this and other ligands for the TAM family of receptor tyrosine kinases should provide additional insights into their roles in physiological platelet activation. Disclosures Branchford: Bio Products Laboratory: Honoraria; Novo Nordisk: Honoraria.

scholarly journals The Effectiveness of Candidate Probiotic Bacteria to Control Vibriosis Disease

2017 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Mulyati Mulyati ◽  
Suryati Suryati ◽  
Irfani Baga
Keyword(s):  
Survival Rate ◽  
Sea Water ◽  
Challenge Test ◽  
Probiotic Bacteria ◽  
Pathogenicity Test ◽  
Inhibitory Ability ◽  
Significant Difference ◽  
Portunid Crab

The study aims to isolate, characterize, and examine probiotic bacteria's inhibitory ability against Vibrio harveyi bacteria, both in-vitro and in vivo. Methods used in the study consist of 1) An Isolation of Candidate Probiotic Bacteria, 2) An Antagonistic Test of Candidate Probiotic Bacteria in vitro, 3) An Identification of Bacteria, 4) A Pathogenicity Test of Candidate Probiotic Bacteria, 5) An Antagonistic Test of Candidate Probiotic Bacteria against V. harveyi in vivo. According to the isolation of candidate probiotic bacteria, there are 18 isolated candidate probiotic. After being tested for its inhibitory ability in vitro, there are 8 isolates with zone of inhibition as follows: isolate MM 7 from intestine (22 mm), isolate MM 6 from intestine (12 mm), isolate MM 10 from sea water (10 mm), isolate MM 5 from intestine (9 mm), isolate MM 4 from intestine (8 mm), isolate MM 3 from intestine (7 mm), isolate MM 2.2 from intestine (7 mm), isolate MM 2.1 from intestine (7 mm). Eight genera of the candidate probiotic bacteria is derived from Portunid crab, they are Staphylococcus, Streptococcus, bacillus, vibrio, Alcaligenes, Lactobacillus, micrococcus. Before proceeding the V. harveyi bacterial challenge test in vivo, three potential isolates consisting of MM6, MM7 and MM10 as the probiotic bacteria are pathogenicity-tested against V. harveyi. The survival rate of Portunid crab on pathogenicity test using MM6, MM7 and MM10 generates 91.11-100%, while the control generates 100% survival rate. Variance analysis result through post-hoc Tukey's Honest Significant Difference (HSD) test at 95% confidence interval indicates that isolate MM7 and MM10 are significantly able to increase hatchling Portunid crab's survival rate.

scholarly journals Arabidopsis Disulfide Reductase, Trx-h2, Functions as an RNA Chaperone under Cold Stress

2021 ◽  
Vol 11 (15) ◽  
pp. 6865
Author(s):  
Eun Seon Lee ◽  
Joung Hun Park ◽  
Seong Dong Wi ◽  
Ho Byoung Chae ◽  
Seol Ki Paeng ◽  
...  
Keyword(s):  
Cold Stress ◽  
Wild Type ◽  
Rna Chaperone ◽  
E Coli ◽  
Cold Sensitive ◽  
Thioredoxin H ◽  
Functional Rnas

The thioredoxin-h (Trx-h) family of Arabidopsis thaliana comprises cytosolic disulfide reductases. However, the physiological function of Trx-h2, which contains an additional 19 amino acids at its N-terminus, remains unclear. In this study, we investigated the molecular function of Trx-h2 both in vitro and in vivo and found that Arabidopsis Trx-h2 overexpression (Trx-h2OE) lines showed significantly longer roots than wild-type plants under cold stress. Therefore, we further investigated the role of Trx-h2 under cold stress. Our results revealed that Trx-h2 functions as an RNA chaperone by melting misfolded and non-functional RNAs, and by facilitating their correct folding into active forms with native conformation. We showed that Trx-h2 binds to and efficiently melts nucleic acids (ssDNA, dsDNA, and RNA), and facilitates the export of mRNAs from the nucleus to the cytoplasm under cold stress. Moreover, overexpression of Trx-h2 increased the survival rate of the cold-sensitive E. coli BX04 cells under low temperature. Thus, our data show that Trx-h2 performs function as an RNA chaperone under cold stress, thus increasing plant cold tolerance.

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