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− | + | Ein internalin (InlA) to enter human enterocyte-like epithelial cell line Caco- | |
+ | Ein internalin (InlA) to enter human enterocyte-like epithelial cell line Caco-2 and some other epithelial cells51. In sharp contrast, we obtain here that ACT-mediated bacterial internalisation doesn't necessarily call for a toxin-receptor interaction, as both the virulent parental B. pertussis BP18323 bacteria and also the non-virulent ACT-coated bacteria (BP18323H- strain), and also ACT-coated latex beads are similarly taken up by CHO-K1 cells, a non-phagocytic cell line that will not express the ACT receptor, the 2 integrin CD11b/CD18. Constant with this, it was observed that ACT itself is internalized each by receptor-bearing cells32 and by cells thatScientific RepoRts | 5:13774 | DOi: ten.1038/srepwww.nature.com/scientificreports/do not express the CD11b/CD18 toxin-receptor32, suggesting that the hydrophobic-amphipathic nature of ACT is sufficient to allow productive attachment to a range of host cell membranes. Consistent together with the notion that bacterial uptake demands host cytoskeleton rearrangements like F-actin or microtubules52 we observe here that the cell actin cytoskeleton is prominently remodeled upon contact with parental B. pertussis, having a visible destruction of actin filaments and also the formation of membrane protrusions. An incredibly similar impact, that is certainly concentration dependent, is also observed upon incubation of CHO-K1 cells with purified ACT, hence suggesting that the toxin itself triggers the expected signals to rearrange the actin filaments. Restructuring from the cell actin cytoskeleton can be brought on by diverse signaling events. Modifications in the intracellular Ca2+ and cAMP-mediated signalling have already been involved in perturbations on the actin cytoskeleton homeostasis in diverse cells53,54. ACT generates rises in cAMP levels in the cytosol on the target cells17 and induces intracellular Ca2+ rises45, hence each components might be involved within the effects on the cytoskeleton observed here. In assistance of this we observe a vital reduction in bacterial entry under conditions in which the ACT-induced Ca2+-influx is inhibited. We come across that ACT-coated bacteria follow a cholesterol-dependent, caveolae-dependent entry pathway in which bacteria-containing vesicles show markers of early and late endosomes (Cav-1-positive, Rab-5and Rab-7-positive) but appear to avoid ulterior fusion with lysosomes (LAMP-1-negative for all tested occasions). This mechanism is element from the virulence tactics of several invasive bacteria, enabling them to evade intracellular death43. Our observations are in agreement with earlier research indicating that B. pertussis survives in non-acidic compartments of human macrophages11 or in respiratory epithelial cells41. We show evidences that internalisation of ACT-coated bacteria shares a number of functions with all the endocytosis from the purified toxin, namely the requirement for Ca2+-influx and also the involvement of tyrosine kinases32. This suggests that a equivalent widespread entry route is activated and is involved in both processes. Tyrosine kinases are crucial signaling molecules involved in diverse processes of nucleated cells. In the internalisation of the purified ACT by the CHO-K1 cells we found that phosphorylation of crucial elements in the endocytic machinery involved inside the caveolae-mediated ACT uptake is required32. Lately, tyrosine kinases have already been involved in F-actin restructuring at the Listeria monocytogenes entry site55, suggesting that these signaling proteins can be important collaborators in bacterial internali. |
รุ่นแก้ไขเมื่อ 16:48, 8 กันยายน 2564
Ein internalin (InlA) to enter human enterocyte-like epithelial cell line Caco- Ein internalin (InlA) to enter human enterocyte-like epithelial cell line Caco-2 and some other epithelial cells51. In sharp contrast, we obtain here that ACT-mediated bacterial internalisation doesn't necessarily call for a toxin-receptor interaction, as both the virulent parental B. pertussis BP18323 bacteria and also the non-virulent ACT-coated bacteria (BP18323H- strain), and also ACT-coated latex beads are similarly taken up by CHO-K1 cells, a non-phagocytic cell line that will not express the ACT receptor, the 2 integrin CD11b/CD18. Constant with this, it was observed that ACT itself is internalized each by receptor-bearing cells32 and by cells thatScientific RepoRts | 5:13774 | DOi: ten.1038/srepwww.nature.com/scientificreports/do not express the CD11b/CD18 toxin-receptor32, suggesting that the hydrophobic-amphipathic nature of ACT is sufficient to allow productive attachment to a range of host cell membranes. Consistent together with the notion that bacterial uptake demands host cytoskeleton rearrangements like F-actin or microtubules52 we observe here that the cell actin cytoskeleton is prominently remodeled upon contact with parental B. pertussis, having a visible destruction of actin filaments and also the formation of membrane protrusions. An incredibly similar impact, that is certainly concentration dependent, is also observed upon incubation of CHO-K1 cells with purified ACT, hence suggesting that the toxin itself triggers the expected signals to rearrange the actin filaments. Restructuring from the cell actin cytoskeleton can be brought on by diverse signaling events. Modifications in the intracellular Ca2+ and cAMP-mediated signalling have already been involved in perturbations on the actin cytoskeleton homeostasis in diverse cells53,54. ACT generates rises in cAMP levels in the cytosol on the target cells17 and induces intracellular Ca2+ rises45, hence each components might be involved within the effects on the cytoskeleton observed here. In assistance of this we observe a vital reduction in bacterial entry under conditions in which the ACT-induced Ca2+-influx is inhibited. We come across that ACT-coated bacteria follow a cholesterol-dependent, caveolae-dependent entry pathway in which bacteria-containing vesicles show markers of early and late endosomes (Cav-1-positive, Rab-5and Rab-7-positive) but appear to avoid ulterior fusion with lysosomes (LAMP-1-negative for all tested occasions). This mechanism is element from the virulence tactics of several invasive bacteria, enabling them to evade intracellular death43. Our observations are in agreement with earlier research indicating that B. pertussis survives in non-acidic compartments of human macrophages11 or in respiratory epithelial cells41. We show evidences that internalisation of ACT-coated bacteria shares a number of functions with all the endocytosis from the purified toxin, namely the requirement for Ca2+-influx and also the involvement of tyrosine kinases32. This suggests that a equivalent widespread entry route is activated and is involved in both processes. Tyrosine kinases are crucial signaling molecules involved in diverse processes of nucleated cells. In the internalisation of the purified ACT by the CHO-K1 cells we found that phosphorylation of crucial elements in the endocytic machinery involved inside the caveolae-mediated ACT uptake is required32. Lately, tyrosine kinases have already been involved in F-actin restructuring at the Listeria monocytogenes entry site55, suggesting that these signaling proteins can be important collaborators in bacterial internali.