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Paolo Pozzilli - One of the best experts on this subject based on the ideXlab platform.
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beta Cell gene expression and functional characterisation of the human Insulinoma Cell Line cm
Journal of Endocrinology, 1999Co-Authors: M G Baroni, L Monetini, M Mark, B Stoehrer, Maria Gisella Cavallo, Paolo PozzilliAbstract:Animal Insulinoma Cell Lines are widely used to study physiological and pathophysiological mechanisms involved in glucose metabolism and to establish in vitro models for studies on ‚-Cells. In contrast, human Insulinoma Cell Lines are rarely used because of diYculties in obtaining and culturing them for long periods. The aim of our study was to investigate, under diVerent experimental conditions, the capacity of the human Insulinoma Cell Line CM to retain ‚-Cell function, particularly the expression of constitutive ‚-Cell genes (insulin, the glucose transporters GLUT1 and GLUT2, glucokinase), intraCellular and secreted insulin, ‚-Cell granules, and cAMP content. Results showed that CM Cells from an early-passage express specific ‚-Cell genes in response to glucose stimulation, in particular the insulin and GLUT genes. Such capacity is lost at later passages when Cells are cultured at standard glucose concentrations. However, if cultured at lower glucose concentration (0·8 mM) for a longer time, CM Cells re-acquire the capacity to respond to glucose stimulation, as shown by the increased expression of ‚-Cell genes (insulin, GLUT2, glucokinase). Nonetheless, insulin secretion could not be restored under such experimental conditions despite the presence of intraCellular insulin, although cAMP response to a potent activator of adenylate cyclase, forskolin, was present indicating a viable system. In conclusion, these data show that the human Insulinoma Cell Line CM, at both early-passage and late-passage, posseses a functional glucose-signalling pathway and insulin mRNA expression similar to normal ‚-Cells, representing, therefore, a good model for studies concerning the signalling and expression of ‚-Cells. Furthermore, we have previously shown that it is also a good model for immunological studies. In this respect it is important to note that the CM Cell Line is one of the very few existing human ‚-Cell Lines in long-term culture.
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t Cell reactivity to human Insulinoma Cell Line cm antigens in patients with type 1 diabetes
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38 kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity.In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferatio...
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T Cell reactivity to human Insulinoma Cell Line (CM) antigens in patients with type 1 diabetes.
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity. In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferation was measured using Cells from 32 patients with type 1 diabetes (19 of recent onset and 13 at 3 to 22 months from diagnosis) and 27 age-matched control subjects. A significant increase in T Cell proliferation to CM Cells grown in high glucose conditions (11 mM) (p < 0.05) was found in type 1 diabetic patients compared to controls. No significant differences were observed when using CM Cells cultured at the low glucose concentration. Furthermore, the response to both extracts of CM Cells was independent of disease duration (p = 0.6 for both CM Cells cultured at 0.8 and 11 mM glucose). These data indicate that T Cell reactivity to homogenates of CM Cells is detectable in patients with type 1 diabetes and suggest that this human Insulinoma Cell Line is an interesting potential source of beta Cell material for immunological studies of autoimmune diabetes.
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Glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors-α-mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P
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glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors α mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P<0.001). These results suggest a protective effect of glutathione on beta-Cell cytotoxicity induced by tumor necrosis factor-α and encourage the use of glutathione in trials aimed at reducing the beta-Cell damage occurring in insulin-dependent diabetes.
Maria Gisella Cavallo - One of the best experts on this subject based on the ideXlab platform.
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beta Cell gene expression and functional characterisation of the human Insulinoma Cell Line cm
Journal of Endocrinology, 1999Co-Authors: M G Baroni, L Monetini, M Mark, B Stoehrer, Maria Gisella Cavallo, Paolo PozzilliAbstract:Animal Insulinoma Cell Lines are widely used to study physiological and pathophysiological mechanisms involved in glucose metabolism and to establish in vitro models for studies on ‚-Cells. In contrast, human Insulinoma Cell Lines are rarely used because of diYculties in obtaining and culturing them for long periods. The aim of our study was to investigate, under diVerent experimental conditions, the capacity of the human Insulinoma Cell Line CM to retain ‚-Cell function, particularly the expression of constitutive ‚-Cell genes (insulin, the glucose transporters GLUT1 and GLUT2, glucokinase), intraCellular and secreted insulin, ‚-Cell granules, and cAMP content. Results showed that CM Cells from an early-passage express specific ‚-Cell genes in response to glucose stimulation, in particular the insulin and GLUT genes. Such capacity is lost at later passages when Cells are cultured at standard glucose concentrations. However, if cultured at lower glucose concentration (0·8 mM) for a longer time, CM Cells re-acquire the capacity to respond to glucose stimulation, as shown by the increased expression of ‚-Cell genes (insulin, GLUT2, glucokinase). Nonetheless, insulin secretion could not be restored under such experimental conditions despite the presence of intraCellular insulin, although cAMP response to a potent activator of adenylate cyclase, forskolin, was present indicating a viable system. In conclusion, these data show that the human Insulinoma Cell Line CM, at both early-passage and late-passage, posseses a functional glucose-signalling pathway and insulin mRNA expression similar to normal ‚-Cells, representing, therefore, a good model for studies concerning the signalling and expression of ‚-Cells. Furthermore, we have previously shown that it is also a good model for immunological studies. In this respect it is important to note that the CM Cell Line is one of the very few existing human ‚-Cell Lines in long-term culture.
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t Cell reactivity to human Insulinoma Cell Line cm antigens in patients with type 1 diabetes
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38 kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity.In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferatio...
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T Cell reactivity to human Insulinoma Cell Line (CM) antigens in patients with type 1 diabetes.
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity. In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferation was measured using Cells from 32 patients with type 1 diabetes (19 of recent onset and 13 at 3 to 22 months from diagnosis) and 27 age-matched control subjects. A significant increase in T Cell proliferation to CM Cells grown in high glucose conditions (11 mM) (p < 0.05) was found in type 1 diabetic patients compared to controls. No significant differences were observed when using CM Cells cultured at the low glucose concentration. Furthermore, the response to both extracts of CM Cells was independent of disease duration (p = 0.6 for both CM Cells cultured at 0.8 and 11 mM glucose). These data indicate that T Cell reactivity to homogenates of CM Cells is detectable in patients with type 1 diabetes and suggest that this human Insulinoma Cell Line is an interesting potential source of beta Cell material for immunological studies of autoimmune diabetes.
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Glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors-α-mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P
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glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors α mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P<0.001). These results suggest a protective effect of glutathione on beta-Cell cytotoxicity induced by tumor necrosis factor-α and encourage the use of glutathione in trials aimed at reducing the beta-Cell damage occurring in insulin-dependent diabetes.
Jean-claude Carel - One of the best experts on this subject based on the ideXlab platform.
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Destruction of conditional Insulinoma Cell Lines in NOD mice: a role for autoimmunity.
Diabetologia, 2003Co-Authors: Pierre Cattan, D. Rottembourg, Sandra Cottet, Isabelle Tardivel, Philippe Dupraz, Christian Boitard, Bernard Thorens, Jean-claude CarelAbstract:Aims/Hypothesis βTC-tet (H2k) is a conditional Insulinoma Cell Line derived from transgenic mice expressing a tetracycLine-regulated oncogene. Transgenic expression of several proteins implicated in the apoptotic pathways increase the resistance of βTC-tet Cells in vitro. We tested in vivo the sensitivity of the Cells to rejection and the protective effect of genetic alterations in NOD mice.
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expression of functional human epstein barr virus c3d receptor cr2 cd21 on Insulinoma Cell Line induction of tumor rejection but not diabetes in syngeneic rats
Diabetes, 1991Co-Authors: Jean-claude Carel, William L. Chick, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
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Expression of functional human Epstein-Barr virus/C3d receptor ([CR2] CD21) on Insulinoma Cell Line. Induction of tumor rejection but not diabetes in syngeneic rats.
Diabetes, 1991Co-Authors: Jean-claude Carel, Chick Wl, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
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Expression of functional human Epstein-Barr virus/C3d receptor ([CR2] CD21) on Insulinoma Cell Line. Induction of tumor rejection but not diabetes in syngeneic rats.
Diabetes, 1991Co-Authors: Jean-claude Carel, Chick Wl, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
P E Lacy - One of the best experts on this subject based on the ideXlab platform.
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expression of functional human epstein barr virus c3d receptor cr2 cd21 on Insulinoma Cell Line induction of tumor rejection but not diabetes in syngeneic rats
Diabetes, 1991Co-Authors: Jean-claude Carel, William L. Chick, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
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Expression of functional human Epstein-Barr virus/C3d receptor ([CR2] CD21) on Insulinoma Cell Line. Induction of tumor rejection but not diabetes in syngeneic rats.
Diabetes, 1991Co-Authors: Jean-claude Carel, Chick Wl, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
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Expression of functional human Epstein-Barr virus/C3d receptor ([CR2] CD21) on Insulinoma Cell Line. Induction of tumor rejection but not diabetes in syngeneic rats.
Diabetes, 1991Co-Authors: Jean-claude Carel, Chick Wl, V. Michael Holers, Dan R Littman, P E LacyAbstract:We stably expressed human complement receptor 2 ([CR2] CD21 C3d/Epstein-Barr virus [EBV] receptor) on the rat Insulinoma Cell Line RINm5F with a recombinant retroviral vector. CR2-expressing RINm5F Cells secreted 78–33% less insulin than parental Cells or Cells transduced with an antisense vector and could be infected with high-titer EBV. We tested whether human CR2 expression on RINm5F Cells would affect tumorigenesis after transplantation to syngeneic New England Deaconess Hospital rats. Non-CR2–expressing antisense-transduced RINm5F Cells rapidly grew tumors and caused hypoglycemia, hyperinsuLinemia, and the death of the animals after 15.7 ± 0.7 days. CR2-expressing RINm5F Cells were infiltrated by mononuclear Cells at an early stage and eventually caused noninfiltrated tumors and the death of the animals after 33.0 ± 0.4 days. These tumors were CR2− and are believed to have arisen from a minor CR2− population of tumor Cells. The pancreatic islets were histologically normal at all time points. We conclude that expression of a xenoantigen on a rat Insulinoma Cell Line induces an immune response in syngeneic rats but does not result in breakage of tolerance to parental or revertant Cells.
L Monetini - One of the best experts on this subject based on the ideXlab platform.
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beta Cell gene expression and functional characterisation of the human Insulinoma Cell Line cm
Journal of Endocrinology, 1999Co-Authors: M G Baroni, L Monetini, M Mark, B Stoehrer, Maria Gisella Cavallo, Paolo PozzilliAbstract:Animal Insulinoma Cell Lines are widely used to study physiological and pathophysiological mechanisms involved in glucose metabolism and to establish in vitro models for studies on ‚-Cells. In contrast, human Insulinoma Cell Lines are rarely used because of diYculties in obtaining and culturing them for long periods. The aim of our study was to investigate, under diVerent experimental conditions, the capacity of the human Insulinoma Cell Line CM to retain ‚-Cell function, particularly the expression of constitutive ‚-Cell genes (insulin, the glucose transporters GLUT1 and GLUT2, glucokinase), intraCellular and secreted insulin, ‚-Cell granules, and cAMP content. Results showed that CM Cells from an early-passage express specific ‚-Cell genes in response to glucose stimulation, in particular the insulin and GLUT genes. Such capacity is lost at later passages when Cells are cultured at standard glucose concentrations. However, if cultured at lower glucose concentration (0·8 mM) for a longer time, CM Cells re-acquire the capacity to respond to glucose stimulation, as shown by the increased expression of ‚-Cell genes (insulin, GLUT2, glucokinase). Nonetheless, insulin secretion could not be restored under such experimental conditions despite the presence of intraCellular insulin, although cAMP response to a potent activator of adenylate cyclase, forskolin, was present indicating a viable system. In conclusion, these data show that the human Insulinoma Cell Line CM, at both early-passage and late-passage, posseses a functional glucose-signalling pathway and insulin mRNA expression similar to normal ‚-Cells, representing, therefore, a good model for studies concerning the signalling and expression of ‚-Cells. Furthermore, we have previously shown that it is also a good model for immunological studies. In this respect it is important to note that the CM Cell Line is one of the very few existing human ‚-Cell Lines in long-term culture.
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t Cell reactivity to human Insulinoma Cell Line cm antigens in patients with type 1 diabetes
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38 kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity.In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferatio...
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T Cell reactivity to human Insulinoma Cell Line (CM) antigens in patients with type 1 diabetes.
Autoimmunity, 1999Co-Authors: L Monetini, Maria Gisella Cavallo, M. Russo, Robin Thorpe, F Barone, L. Valente, Barry Walker, Paolo PozzilliAbstract:Autoimmune (type 1) diabetes mellitus results from a progressive destruction of insulin secreting beta Cells operated by T lymphocytes in pancreatic islets. Circulating autoreactive T Cells to specific beta Cell antigens are detected in patients with type 1 diabetes. To date, several beta Cell autoantigens have been identified in this disease (GAD, IA-2, 38kD secretory protein, insulin, ICA69 etc.), however, it is possible that also other unidentified self molecules contribute to trigger beta Cell autoimmunity. In this study we used the human Insulinoma Cell Line CM as source of beta Cell antigens to detect reactive T lymphocytes in patients with type 1 diabetes mellitus. This Cell Line has been previously shown to express a number of recognized beta Cell antigens. Since the expression of several beta Cell antigens is affected by glucose stimulation we tested two preparations of CM Cells cultured under different conditions containing low (0.8 mM) and high glucose concentration (11 mM). T Cell proliferation was measured using Cells from 32 patients with type 1 diabetes (19 of recent onset and 13 at 3 to 22 months from diagnosis) and 27 age-matched control subjects. A significant increase in T Cell proliferation to CM Cells grown in high glucose conditions (11 mM) (p < 0.05) was found in type 1 diabetic patients compared to controls. No significant differences were observed when using CM Cells cultured at the low glucose concentration. Furthermore, the response to both extracts of CM Cells was independent of disease duration (p = 0.6 for both CM Cells cultured at 0.8 and 11 mM glucose). These data indicate that T Cell reactivity to homogenates of CM Cells is detectable in patients with type 1 diabetes and suggest that this human Insulinoma Cell Line is an interesting potential source of beta Cell material for immunological studies of autoimmune diabetes.
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Glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors-α-mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P
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glutaihione protects a human Insulinoma Cell Line from tumor necrosis factors α mediated cytotoxicity
International Journal of Clinical & Laboratory Research, 1997Co-Authors: Maria Gisella Cavallo, L Monetini, P Beales, M. Russo, F Barone, L. Valente, Paolo PozzilliAbstract:It is postulated that glutathione acting as a free oxygen radical scavenger may protect beta-Cells from cytokine-mediated cytotoxicity in insulin-dependent diabetes. In this study the effect of glutathione in preventing the cytotoxic damage mediated by tumor necrosis factor-a in vitro towards a human beta-Cell Line (CM Insulinoma) was investigated. CM Cells were exposed in vitro to tumor necrosis factor-α, tumor necrosis factor-α plus glutathione or glutathione alone at different concentrations. The resulting cytotoxicity was measured using a colorimetric assay. Glutathione significantly reduced the cytotoxicity mediated by tumor necrosis factor-α in a dose-dependent fashion (P<0.001). These results suggest a protective effect of glutathione on beta-Cell cytotoxicity induced by tumor necrosis factor-α and encourage the use of glutathione in trials aimed at reducing the beta-Cell damage occurring in insulin-dependent diabetes.