| 1. |
- Junkunlo, Kingkamon, et al.
(författare)
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PDGF/VEGF-related receptor affects transglutaminase activity to control cell migration during crustacean hematopoiesis
- 2017
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 26:20, s. 1449-1459
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Tidskriftsartikel (refereegranskat)abstract
- The platelet-derived growth factor (PDGF) receptor, a tyrosine kinase (TK) receptor whose ligand is PDGF, is crucial in the transduction of extracellular signals into cells and mediates numerous processes, such as cell proliferation, differentiation, survival, and migration. We demonstrate the important roles of a receptor TK related to the PDGF/VEGF family protein (PVR) in controlling hematopoietic progenitor cell migration by affecting extracellular transglutaminase (TGase) activity. Pl_PVR1, GenBank accession No. KY444650, is highly expressed in hemocytes and the hematopoietic tissue (HPT). Sunitinib malate was used to block the PVF/PVR downstream pathway in HPT cell culture. The addition of Sunitinib also caused the HPT cells to increase in size and begin spreading. An increase in extracellular TGase activity on the HPT cell membrane was observed in a dose-dependent manner after treatment with Sunitinib malate. The presence of crude Ast1 provided a combinatorial beneficial effect that enhanced the number of spreading cells after inhibition of the Pl_PVR downstream signaling cascade. In addition, an increased immunoreactivity for beta-tubulin and elongation of beta-tubulin filaments were found in Pl_PVR signaling-inhibited cells. The potential roles of PVF/PVR signaling in controlling progenitor cell activity during hematopoiesis in crayfish were investigated and discussed.
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| 2. |
- Junkunlo, Kingkamon
(författare)
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Regulation of hematopoiesis in the freshwater crayfish, Pacifastacus leniusculus : role of transglutaminase
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The freshwater crayfish, Pacifastacus leniusculus, has been used as a model for studying hematopoiesis or blood cell production or hematopoiesis and immunity. The work of this thesis aims to investigate the impact of factors such as ROS signaling, Ast1, and the PVF/PVR signaling pathway in controlling stem cell behavior during hematopoiesis and specifically the role of the crosslinking enzyme transglutaminase (TGase) in regulation of hematopoiesis.The role of ROS in crayfish hematopoiesis was characterized by using the antioxidant named NAC to inhibit ROS production. Low ROS level resulted in a prolonged decrease in hemocyte numbers and a combined injection of LPS and NAC caused a slower rate of new hemocyte production. A low ROS level in cell cultures supplemented with crude Ast1 was found to inhibit cell spreading and a high extracellular TGase activity was detected on the surfaces of APC and HPT cells. We suggest that ROS serves as a prime signal to control proliferation and differentiation of progenitor cells by affecting extracellular TGase activity. We reported an inhibitory effect of Ast1 on TGase enzyme activity and on its crosslinking activity and consequently Ast1 affects the clot formation and thus coagulation by inhibiting the crosslinking activity of the TGase enzyme. Secretion of the clot protein (CP) and the production of CP filament network between spreading cells were observed in HPT cell cultures in vitro. In the presence of CP together with Ast1 in 3D-collagen-I cultures, HPT cells were found to be more elongated and they formed chains of cells throughout the surrounding matrix. In the HPT tissue, CP was located around the HPT cells or around the lobules of HPT, and thus, CP was demonstrated to be a part of ECM and to possibly function together with collagen in generating a suitable environment for HPT progenitor cells. The inhibition of PVF/PVR downstream signaling pathway by Sunitinib malate resulted in a dramatic change of cell morphology and induction of an increase cell surface area during cell culture. The addition of crude Ast1 into the cell cultures in vitro enhanced this effect. Consequently, cell migration was stimulated and a high extracellular TGase activity on HPT cell surface was found after this inhibition. In conclusion, the work in this thesis provides new insight in understanding the role of the extracellular matrix (ECM) and extracellular TGase activity in controlling stem cell activity.
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| 3. |
- Sirikharin, Ratchanok, et al.
(författare)
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Role of astakine1 in regulating transglutaminase activity
- 2017
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Ingår i: Developmental and Comparative Immunology. - : Elsevier. - 0145-305X .- 1879-0089. ; 76, s. 77-82
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Tidskriftsartikel (refereegranskat)abstract
- Transglutaminase (TGase) has been implicated in maintaining the undifferentiated stage of hematopoietic stem cells (HSC) in the crayfish Pacifastacus leniusculus. TGase activity has been reported to be regulated by astakine1, an essential crayfish cytokine for inducing new hemocyte synthesis in hematopoietic tissue (HPT). Here, the role of astakine1 in TGase activity regulation and clotting protein (CP) cross-linking was characterized. A reduction in TGase activity was observed by the addition of purified astakine1 in vitro for both endogenous crayfish TGase and a commercial purified guinea pig liver TGase. As a result, we observed that astakine1 inhibits TGase enzyme activity and acts as a non-competitive inhibitor for the TGase enzyme. Additionally, the clotting reaction was impaired in the presence of astakine1. A decrease in TGase-mediated crosslinking of ε(γ-glutamyl)-lysine bonds was also observed in the presence of astakine1. In conclusion, this study shows that astakine1 acts as an inhibitor of TGase activity and that it also affects CP cross-linking during crayfish hematopoiesis.
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