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Soares, Ângela Maria Victoriano De Campos - One of the best experts on this subject based on the ideXlab platform.
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Efeito inibidor da deferoxamina sobre a sobrevivência do Paracoccidioides brasiliensis em monócitos humanos: reversão por holotransferrina e não por Apotransferrina
Instituto de Medicina Tropical, 2005Co-Authors: Dias-melicio, Luciane Alarcão, Calvi, Sueli Aparecida, Peraçoli, Maria Terezinha Serrão, Soares, Ângela Maria Victoriano De CamposAbstract:The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (Apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent.Os mecanismos utilizados pelo Paracoccidioides brasiliensis para sobreviver em células fagocitárias ainda não estão elucidados. O metabolismo celular férrico é muito importante para o crescimento de inúmeros patógenos intracelulares cuja capacidade de se multiplicarem em fagócitos mononucleares é dependente da disponibilidade intracelular do íon ferro. Assim, o objetivo deste trabalho foi investigar o papel do ferro intracelular sobre a capacidade do P. brasiliensis sobreviver em monócitos humanos. O tratamento de monócitos com deferoxamina, uma droga quelante, diminuiu a sobrevivência de leveduras do fungo de forma dose-dependente. O efeito inibidor da deferoxamina sobre a sobrevivência do P. brasiliensis foi revertido por transferrina saturada com ferro (holotransferrina) mas não por transferrina insaturada (Apotransferrina). Estes resultados sugerem que a sobrevivência do P. brasiliensis em monócitos humanos é dependente do íon ferro
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Inhibitory effect of deferoxamine on Paracoccidioides brasiliensis survival in human monocytes: reversal by holotransferrin not by Apotransferrin
Instituto de Medicina Tropical, 2005Co-Authors: Dias-melicio, Luciane Alarcão, Calvi, Sueli Aparecida, Peraçoli, Maria Terezinha Serrão, Soares, Ângela Maria Victoriano De CamposAbstract:The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (Apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent
Sungjong Hong - One of the best experts on this subject based on the ideXlab platform.
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paragonimus westermani molecular cloning expression and characterization of a recombinant yolk ferritin
Experimental Parasitology, 2002Co-Authors: Shinyong Kang, Sungjong HongAbstract:Abstract Ferritin is an intracellular protein involved in iron metabolism. A cDNA PwYF-1 cloned from the adult Paragonimus westermani cDNA library encoded a putative polypeptide of 216 amino acids homologous with ferritins of vertebrates and invertebrates. Fe-binding motifs identified in PwYF-1 polypeptide were conserved and predicted to form a ferroxidase center. PwYF-1 polypeptide contained an extended peptide of 45 amino acids at its C-terminus. Recombinant PwYF-1 protein, expressed and purified from Escherichia coli, showed iron-uptake ability and ferroxidase activity. Ferroxidase activity of recombinant PwYF-1 protein was reactivated by secondary addition of Apotransferrin to assay mixture. Mouse immune serum raised against the recombinant PwYF-1 protein recognized specifically 24 kDa protein from adult P. westermani lysate. PwYF-1 protein was localized to vitelline follicles and the eggs of P. westermani. Collectively, PwYF-1 protein was identified as a P. westermani yolk ferritin. Abbreviations: PwYF-1, Paragonimus westermani yolk ferritin-1; PCR, polymerase chain reaction; MTPBS, mouse tonicity phosphate-buffered saline; Ni–NTA, nickel–nitrilotriacetic acid
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paragonimus westermani molecular cloning expression and characterization of a recombinant yolk ferritin
Experimental Parasitology, 2002Co-Authors: Tae Yun Kim, Sungjong Hong, Shinyong Kang, Il Jung Joo, Seung Yull ChoAbstract:Ferritin is an intracellular protein involved in iron metabolism. A cDNA PwYF-1 cloned from the adult Paragonimus westermani cDNA library encoded a putative polypeptide of 216 amino acids homologous with ferritins of vertebrates and invertebrates. Febinding motifs identified in PwYF-1 polypeptide were conserved and predicted to form a ferroxidase center. PwYF-1 polypeptide contained an extended peptide of 45 amino acids at its C-terminus. Recombinant PwYF-1 protein, expressed and purified from Escherichia coli, showed iron-uptake ability and ferroxidase activity. Ferroxidase activity of recombinant PwYF-1 protein was reactivated by secondary addition of Apotransferrin to assay mixture. Mouse immune serum raised against the recombinant PwYF-1 protein recognized specifically 24 kDa protein from adult P. westermani lysate. PwYF-1 protein was localized to vitelline follicles and the eggs of P. westermani. Collectively, PwYF-1 protein was identified as a P. westermani yolk ferritin.
Zm Qian - One of the best experts on this subject based on the ideXlab platform.
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Apotransferrin is internalized and distributed in the same way as holotransferrin in K562 cells
细胞生理学杂志, 2004Co-Authors: Wang K, Yuan L, Yz Chang, Zm QianAbstract:Transferrin (Tf), a naturally existing protein, has received considerable attention in the area of drug targeting since it is biodegradable, non-toxic, and nonimmunogenic. The efficient cellular uptake of Tf shows it has potential in the delivery of anti-cancer drugs, proteins, and therapeutic genes into proliferating malignant cells that overexpress transferrin receptor (TfR). In human serum, about 30% of Tf exists in the iron-saturated form (Fe-2-Tf) and the remainder exists as Apotransferrin (apo-Tf). Understanding the uptake of apo-Tf by cells will provide key insights into studies on Tf-mediated drug delivery. In the present study, we investigated visually the transport of apo-Tf into K562 cells and its intracellular localization by laser-scanning confocal microscopy (LSCM) and flow cytometry analysis (FCA). It was found that, like Fe-2-Tf, apo-Tf can be taken up into the cells. The process is time- and temperature-dependent, competitively inhibited by Fe-2-Tf, and significantly abolished by pronase pretreatment. Visual evidence showed that the transport of apo-Tf into K562 cells is a TfR-mediated process. Furthermore, the investigations using optical-slicing technique demonstrated that the distribution of apo-Tf is similar to that of Fe-2-Tf, both appearing in the perinuclear region in ball-in-bowl shape.Cell BiologyPhysiologySCI(E)11ARTICLE145-5420
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Apotransferrin is internalized and distributed in the same way as holotransferrin in K562 cells
2004Co-Authors: Wang K, Yuan L, Ke Y, Cz Chang, Zm QianAbstract:Transferrin (Tf), a naturally existing protein, has received considerable attention in the area of drug targeting since it is biodegradable, non-toxic, and non-immunogenic. The efficient cellular uptake of Tf shows it has potential in the delivery of anti-cancer drugs, proteins, and therapeutic genes into proliferating malignant cells that overexpress transferrin receptor (TfR). In human serum, about 30% of Tf exists in the iron-saturated form (Fe 2-Tf) and the remainder exists as Apotransferrin (apo-Tf). Understanding the uptake of apo-Tf by cells will provide key insights into studies on Tf-mediated drug delivery. In the present study, we investigated visually the transport of apo-Tf into K562 cells and its intracellular localization by laser-scanning confocal microscopy (LSCM) and flow cytometry analysis (FCA). It was found that, like Fe2-Tf, apo-Tf can be taken up into the cells. The process is time- and temperature-dependent, competitively inhibited by Fe2-Tf, and significantly abolished by pronase pretreatment. Visual evidence showed that the transport of apo-Tf into K562 cells is a TfR-mediated process. Furthermore, the investigations using optical-slicing technique demonstrated that the distribution of apo-Tf is similar to that of Fe2-Tf, both appearing in the perinuclear region in ball-in-bowl shape.Department of Applied Biology and Chemical Technolog
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Complexation of ytterbium to human transferrin and its uptake by K562 cells
european journal of biochemistry, 2002Co-Authors: Ti Zhang, Yuan L, Yy Zhao, Wang K, Sc Yan, Zhang L, Hz Sun, Zm QianAbstract:There is an increasing interest in the use of lanthanides in medicine. However, the mechanism of their accumulation in cells is not well understood. Lanthanide cations are similar to ferric ions with regard to transferrin binding, suggesting transferrin-receptor mediated transport is possible; however, this has not yet been confirmed. In order to clarify this mechanism, we investigated the binding of Yb3+ to Apotransferrin by UV-Vis spectroscopy and stopped-flow spectrophotometry, and found that Yb3+ binds to Apotransferrin at the specific iron sites in the presence of bicarbonate. The apparent binding constants of these sites showed that the affinity of Yb3+ is lower than that of Fe3+ and binding of Yb3+ in the N-lobe is kinetically favored while the C-lobe is thermodynamically favored. The first Yb3+ bound to the C-lobe quantitatively with a Yb/Apotransferrin molar ratio of < 1, whereas the binding to the other site is weaker and approaches completeness by a higher molar ratio only. As demonstrated by (1) H NMR spectra, Yb3+ binding disturbed the conformation of Apotransferrin in a manner similar to Fe3+ . Flow cytometric studies on the uptake of fluorescein isothiocyanate labeled Yb3+ -bound transferrin species by K562 cells showed that they bind to the cell receptors. Laser scanning confocal microscopic studies with fluorescein isothiocyanate labeled Yb3+ -bound transferrin and propidium iodide labeled DNA and RNA in cells indicated that the Yb3+ entered the cells. The Yb3+ -transferrin complex inhibited the uptake of the fluorescein labeled ferric-saturated transferrin (Fe-2 -transferrin) complex into K562 cells. The results demonstrate that the complex of Yb3+ -transferrin complex was recognized by the transferrin receptor and that the transferrin-receptor-mediated mechanism is a possible pathway for Yb3+ accumulation in cells.Biochemistry & Molecular BiologySCI(E)0246082-609026
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Complexation of ytterbium to human transferrin and its uptake by K562 cells
'Wiley', 2002Co-Authors: Tl Zhang, Yuan L, Yy Zhao, Wang K, Sc Yan, Zm Qian, Sun H, Zhang LAbstract:There is an increasing interest in the use of lanthanides in medicine. However, the mechanism of their accumulation in cells is not well understood. Lanthanide cations are similar to ferric ions with regard to transferrin binding, suggesting transferrin-receptor mediated transport is possible; however, this has not yet been confirmed. In order to clarify this mechanism, we investigated the binding of Yb3+ to Apotransferrin by UV-Vis spectroscopy and stopped-flow spectrophotometry, and found that Yb3+ binds to Apotransferrin at the specific iron sites in the presence of bicarbonate. The apparent binding constants of these sites showed that the affinity of Yb3+ is lower than that of Fe3+ and binding of Yb3+ in the N-lobe is kinetically favored while the C-lobe is thermodynamically favored. The first Yb3+ bound to the C-lobe quantitatively with a Yb/Apotransferrin molar ratio of < 1, whereas the binding to the other site is weaker and approaches completeness by a higher molar ratio only. As demonstrated by 1H NMR spectra, Yb3+ binding disturbed the conformation of Apotransferrin in a manner similar to Fe3+. Flow cytometric studies on the uptake of fluorescein isothiocyanate labeled Yb3+-bound transferrin species by K562 cells showed that they bind to the cell receptors. Laser scanning confocal microscopic studies with fluorescein isothiocyanate labeled Yb3+-bound transferrin and propidium iodide labeled DNA and RNA in cells indicated that the Yb3+ entered the cells. The Yb3+-transferrin complex inhibited the uptake of the fluorescein labeled ferric-saturated transferrin (Fe2-transferrin) complex into K562 cells. The results demonstrate that the complex of Yb3+-transferrin complex was recognized by the transferrin receptor and that the transferrin-receptor-mediated mechanism is a possible pathway for Yb3+ accumulation in cells.link_to_subscribed_fulltex
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Complexation of ytterbium to human transferrin and its uptake by K562 cells
Wiley-Blackwell, 2002Co-Authors: Tl Zhang, Yuan L, Yy Zhao, Wang K, Sc Yan, Zhang L, Sun H, Zm QianAbstract:There is an increasing interest in the use of lanthanides in medicine. However, the mechanism of their accumulation in cells is not well understood. Lanthanide cations are similar to ferric ions with regard to transferrin binding, suggesting transferrin-receptor mediated transport is possible; however, this has not yet been confirmed. In order to clarify this mechanism, we investigated the binding of Yb3+ to Apotransferrin by UV-Vis spectroscopy and stopped-flow spectrophotometry, and found that Yb3+ binds to Apotransferrin at the specific iron sites in the presence of bicarbonate. The apparent binding constants of these sites showed that the affinity of Yb3+ is lower than that of Fe3+ and binding of Yb3+ in the N-lobe is kinetically favored while the C-lobe is thermodynamically favored. The first Yb3+ bound to the C-lobe quantitatively with a Yb/Apotransferrin molar ratio of < 1, whereas the binding to the other site is weaker and approaches completeness by a higher molar ratio only. As demonstrated by 1H NMR spectra, Yb3+ binding disturbed the conformation of Apotransferrin in a manner similar to Fe3+. Flow cytometric studies on the uptake of fluorescein isothiocyanate labeled Yb3+-bound transferrin species by K562 cells showed that they bind to the cell receptors. Laser scanning confocal microscopic studies with fluorescein isothiocyanate labeled Yb3+-bound transferrin and propidium iodide labeled DNA and RNA in cells indicated that the Yb3+ entered the cells. The Yb3+-transferrin complex inhibited the uptake of the fluorescein labeled ferric-saturated transferrin (Fe2-transferrin) complex into K562 cells. The results demonstrate that the complex of Yb3+-transferrin complex was recognized by the transferrin receptor and that the transferrin-receptor-mediated mechanism is a possible pathway for Yb3+ accumulation in cells.Department of Applied Biology and Chemical Technolog
Dias-melicio, Luciane Alarcão - One of the best experts on this subject based on the ideXlab platform.
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Efeito inibidor da deferoxamina sobre a sobrevivência do Paracoccidioides brasiliensis em monócitos humanos: reversão por holotransferrina e não por Apotransferrina
Instituto de Medicina Tropical, 2005Co-Authors: Dias-melicio, Luciane Alarcão, Calvi, Sueli Aparecida, Peraçoli, Maria Terezinha Serrão, Soares, Ângela Maria Victoriano De CamposAbstract:The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (Apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent.Os mecanismos utilizados pelo Paracoccidioides brasiliensis para sobreviver em células fagocitárias ainda não estão elucidados. O metabolismo celular férrico é muito importante para o crescimento de inúmeros patógenos intracelulares cuja capacidade de se multiplicarem em fagócitos mononucleares é dependente da disponibilidade intracelular do íon ferro. Assim, o objetivo deste trabalho foi investigar o papel do ferro intracelular sobre a capacidade do P. brasiliensis sobreviver em monócitos humanos. O tratamento de monócitos com deferoxamina, uma droga quelante, diminuiu a sobrevivência de leveduras do fungo de forma dose-dependente. O efeito inibidor da deferoxamina sobre a sobrevivência do P. brasiliensis foi revertido por transferrina saturada com ferro (holotransferrina) mas não por transferrina insaturada (Apotransferrina). Estes resultados sugerem que a sobrevivência do P. brasiliensis em monócitos humanos é dependente do íon ferro
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Inhibitory effect of deferoxamine on Paracoccidioides brasiliensis survival in human monocytes: reversal by holotransferrin not by Apotransferrin
Instituto de Medicina Tropical, 2005Co-Authors: Dias-melicio, Luciane Alarcão, Calvi, Sueli Aparecida, Peraçoli, Maria Terezinha Serrão, Soares, Ângela Maria Victoriano De CamposAbstract:The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (Apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent
Ângela Maria Victoriano De Campos Soares - One of the best experts on this subject based on the ideXlab platform.
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Inhibitory effect of deferoxamine on Paracoccidioides brasiliensis survival in human monocytes: reversal by holotransferrin not by Apotransferrin Efeito inibidor da deferoxamina sobre a sobrevivência do Paracoccidioides brasiliensis em monócitos humanos: reversão por holotransferrina e não por Apotransferrina
Universidade de São Paulo, 2005Co-Authors: Luciane Alarcão Dias-melicio, Sueli Aparecida Calvi, Maria Terezinha Serrão Peraçoli, Ângela Maria Victoriano De Campos SoaresAbstract:The mechanisms used by Paracoccidioides brasiliensis to survive into phagocytic cells are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Thus, the objective of this paper was to investigate the role of intracellular iron in regulating the capacity of P. brasiliensis yeast cells to survive within human monocytes. Treatment of monocytes with deferoxamine, an iron chelator, suppressed the survival of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by nonsaturated transferrin (Apotransferrin). These results strongly suggest that P. brasiliensis survival in human monocytes is iron dependent.Os mecanismos utilizados pelo Paracoccidioides brasiliensis para sobreviver em células fagocitárias ainda não estão elucidados. O metabolismo celular férrico é muito importante para o crescimento de inúmeros patógenos intracelulares cuja capacidade de se multiplicarem em fagócitos mononucleares é dependente da disponibilidade intracelular do íon ferro. Assim, o objetivo deste trabalho foi investigar o papel do ferro intracelular sobre a capacidade do P. brasiliensis sobreviver em monócitos humanos. O tratamento de monócitos com deferoxamina, uma droga quelante, diminuiu a sobrevivência de leveduras do fungo de forma dose-dependente. O efeito inibidor da deferoxamina sobre a sobrevivência do P. brasiliensis foi revertido por transferrina saturada com ferro (holotransferrina) mas não por transferrina insaturada (Apotransferrina). Estes resultados sugerem que a sobrevivência do P. brasiliensis em monócitos humanos é dependente do íon ferro