一项新的研究结果表明,科学家们通过给患糖尿病的小鼠模型提供遗传学上完全相同的健康动物胰(腺)组织中的生长细胞,可逆转小鼠的糖尿病症状。这些研究结果为糖尿病患者的治疗提出了一条新的途径。尽管组织或器官移植似乎已为糖尿病的治...一项新的研究结果表明,科学家们通过给患糖尿病的小鼠模型提供遗传学上完全相同的健康动物胰(腺)组织中的生长细胞,可逆转小鼠的糖尿病症状。这些研究结果为糖尿病患者的治疗提出了一条新的途径。尽管组织或器官移植似乎已为糖尿病的治疗提供了一个理想的武器,但这种方法却令人感到失望。据佛罗里达大学医学院的Ammon B Peck报道。展开更多
AIM: Artificial beta-cell lines may offer an abundant source of cells for the treatment of type I diabetes, but insulin secretion in beta-cells is tightly regulated in physiological conditions. The Tet-On system is a ...AIM: Artificial beta-cell lines may offer an abundant source of cells for the treatment of type I diabetes, but insulin secretion in beta-cells is tightly regulated in physiological conditions. The Tet-On system is a "gene switch" system, which can induce gene expression by administration of tetracycline (Tet) derivatives such as doxcycline (Dox). Using this system, we established 293 cells to an artificial cell line secreting insulin in response to stimulation by Dox. METHODS: The mutated proinsulin cDNA was obtained from plasmid pcDNA3.1/C-mINS by the polymerase chain reaction (PCR), and was inserted downstream from the promoter on the expression vector pTRE2, to construct a recombined expression vector pTRE2mINS. The promoter on pTRE2 consists of the tetracycline-response element and the CMV minimal promoter and is thus activated by the reverse tetracycline-controlled transactivator (rtTA) when Dox is administrated. pTRE2mINS and plasmid pTK-Hyg encoding hygromycin were co-transfected in the tet293 cells, which express rtTA stably. Following hygromycin screening, the survived cells expressing insulin were selected and enriched. Dox was used to control the expression of insulin in these cells. At the levels of mRNA and protein, the regulating effect of Dox in culture medium on the expression of proinsulin gene was estimated respectively with Northern blot, RT-PCR, and radioimmunoassay. RESULTS: From the 28 hygromycin-resistant cell strains, we selected one cell strain (tet293/Ins6) secreting insulin not only automatically, but in response to stimulation by Dox. The amount on insulin secretion was dependent on the Dox dose (0,10,100,200,400,800 and 1000 microg.L(-1)), the level of insulin secreted by the cells treated with Dox (1000 microg.L(-1)) was 241.0pU.d(-1).cell(-1) , which was 25-fold that of 9.7pU.d(-1).cell(-1) without Dox treatment. Northern blot analyses and RT-PCR further confirmed that the transcription of insulin gene had already been up-regulated after exposing tet293/Ins6 cells to Dox for 15 minutes, and was also induced in a dose-dependent manner. However, the concentration of insulin in the media did not increase significantly until 5 hours following the addition of Dox. CONCLUSION: Human proinsulin gene was transfected successfully and expressed efficiently in 293 cells, and the expression was modulated by tetracycline and its derivatives, improving the accuracy, safety, and reliability of gene therapy, suggesting that conditional establishment of artificial beta-cells may be a useful approach to develop cellular therapy for diabetes mellitus.展开更多
AIM： To examine the ability of FT-1 to affect the cell functions of PSCs and the underlying molecular mechanisms. METHODS： PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase, a...AIM： To examine the ability of FT-1 to affect the cell functions of PSCs and the underlying molecular mechanisms. METHODS： PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase, and cells between passages two and five were used. Expression of ET-1 and FT receptors was assessed by reverse transcription-PCR and immunostaining. Phosphorylation of myosin regulatory light chain （MLC）, extracellular-signal regulated kinase （FRK）, and Akt was examined by Western blotting. Contraction of PSCs was assessed on hydrated collagen lattices. Cell migration was examined using modified Boyden chambers. Ceil proliferation was assessed by measuring the incorporation of 5-bromo-2＇- deoxyuridine. RESULTS： Culture-activated PSCs expressed ETA and ETB receptors, and ET-1. ET-1 induced phosphorylation of NLC and FRK, but not Akt. ET-1 induced contraction and migration, but did not alter proliferation of PSCs. FT-1-induced contraction was inhibited by an ETA receptor antagonist BQ-123 and an ETB receptor antagonist BQ-788, whereas migration was inhibited by BQ-788 but not by BQ-123. A Rho kinase inhibitor Y-27632 abolished both contraction and migration. CONCLUSION： ET-1 induced contraction and migration of PSCs through El receptors and activation of Rho-Rho kinase. ETA and FTB receptors play different roles in the regulation of these cellular functions in response to ET-1.展开更多
AIM： To investigate the role of IFN-T inducible protein -10 （IP-10） and regulated upon activation, normal T cell expressed and secreted （RANTES） protein in acute pancreatic allograft rejection in rats. METHODS： ...AIM： To investigate the role of IFN-T inducible protein -10 （IP-10） and regulated upon activation, normal T cell expressed and secreted （RANTES） protein in acute pancreatic allograft rejection in rats. METHODS： An experimental model was established using pancreas transplantation diabetic SD rats as the recipient, induced by applying streptozocin （STZ）. Pancreas transplantation was performed with a physiologic method of portal venous and enteric drainage. Rats were divided into two groups, isograft group （group A, n = 24） and allograft group （group B, n = 24） in which either healthy SD rats or Wistar rats served as donors, respectively. Twelve diabetic or healthy SD rats were used as controls. At d 1, 4, 7, and 10 post transplantation, serum IP-10 and RANTES were assessed by ELISA and their expression in the allografts was determined by immunohistochemistry. RESULTS： In group B （allograft group）, the development of acute rejection was significantly correlated with increased serum concentration and tissue expression of IP-10 and RANTES, with a peak level at d 7 post transplantation. In contrast, there was no obvious change before and after transplantation in group A （isograft group）. CONCLUSION： Our study suggests a possible role of IP-10 and RANTES in acute rejection and early monitoring of chemokines may be helpful in predicting the outcome of pancreas transplantation.展开更多
文摘一项新的研究结果表明,科学家们通过给患糖尿病的小鼠模型提供遗传学上完全相同的健康动物胰(腺)组织中的生长细胞,可逆转小鼠的糖尿病症状。这些研究结果为糖尿病患者的治疗提出了一条新的途径。尽管组织或器官移植似乎已为糖尿病的治疗提供了一个理想的武器,但这种方法却令人感到失望。据佛罗里达大学医学院的Ammon B Peck报道。
基金the"Hundred Talents"Program of Shanghai Municipal Government,No.98BR018
文摘AIM: Artificial beta-cell lines may offer an abundant source of cells for the treatment of type I diabetes, but insulin secretion in beta-cells is tightly regulated in physiological conditions. The Tet-On system is a "gene switch" system, which can induce gene expression by administration of tetracycline (Tet) derivatives such as doxcycline (Dox). Using this system, we established 293 cells to an artificial cell line secreting insulin in response to stimulation by Dox. METHODS: The mutated proinsulin cDNA was obtained from plasmid pcDNA3.1/C-mINS by the polymerase chain reaction (PCR), and was inserted downstream from the promoter on the expression vector pTRE2, to construct a recombined expression vector pTRE2mINS. The promoter on pTRE2 consists of the tetracycline-response element and the CMV minimal promoter and is thus activated by the reverse tetracycline-controlled transactivator (rtTA) when Dox is administrated. pTRE2mINS and plasmid pTK-Hyg encoding hygromycin were co-transfected in the tet293 cells, which express rtTA stably. Following hygromycin screening, the survived cells expressing insulin were selected and enriched. Dox was used to control the expression of insulin in these cells. At the levels of mRNA and protein, the regulating effect of Dox in culture medium on the expression of proinsulin gene was estimated respectively with Northern blot, RT-PCR, and radioimmunoassay. RESULTS: From the 28 hygromycin-resistant cell strains, we selected one cell strain (tet293/Ins6) secreting insulin not only automatically, but in response to stimulation by Dox. The amount on insulin secretion was dependent on the Dox dose (0,10,100,200,400,800 and 1000 microg.L(-1)), the level of insulin secreted by the cells treated with Dox (1000 microg.L(-1)) was 241.0pU.d(-1).cell(-1) , which was 25-fold that of 9.7pU.d(-1).cell(-1) without Dox treatment. Northern blot analyses and RT-PCR further confirmed that the transcription of insulin gene had already been up-regulated after exposing tet293/Ins6 cells to Dox for 15 minutes, and was also induced in a dose-dependent manner. However, the concentration of insulin in the media did not increase significantly until 5 hours following the addition of Dox. CONCLUSION: Human proinsulin gene was transfected successfully and expressed efficiently in 293 cells, and the expression was modulated by tetracycline and its derivatives, improving the accuracy, safety, and reliability of gene therapy, suggesting that conditional establishment of artificial beta-cells may be a useful approach to develop cellular therapy for diabetes mellitus.
基金Supported by Grant-in-Aid for Encouragement of Young Scientists from Japan Society for the Promotion of Science, No. 16590572 (to AM.)by Pancreas Research Foundation of Japan, No. 01-01 (to AM.)by the Kanae Foundation for Life and Socio-Medical Science(to AM)by the Uehara Memorial Foundation (to AM)
文摘AIM： To examine the ability of FT-1 to affect the cell functions of PSCs and the underlying molecular mechanisms. METHODS： PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase, and cells between passages two and five were used. Expression of ET-1 and FT receptors was assessed by reverse transcription-PCR and immunostaining. Phosphorylation of myosin regulatory light chain （MLC）, extracellular-signal regulated kinase （FRK）, and Akt was examined by Western blotting. Contraction of PSCs was assessed on hydrated collagen lattices. Cell migration was examined using modified Boyden chambers. Ceil proliferation was assessed by measuring the incorporation of 5-bromo-2＇- deoxyuridine. RESULTS： Culture-activated PSCs expressed ETA and ETB receptors, and ET-1. ET-1 induced phosphorylation of NLC and FRK, but not Akt. ET-1 induced contraction and migration, but did not alter proliferation of PSCs. FT-1-induced contraction was inhibited by an ETA receptor antagonist BQ-123 and an ETB receptor antagonist BQ-788, whereas migration was inhibited by BQ-788 but not by BQ-123. A Rho kinase inhibitor Y-27632 abolished both contraction and migration. CONCLUSION： ET-1 induced contraction and migration of PSCs through El receptors and activation of Rho-Rho kinase. ETA and FTB receptors play different roles in the regulation of these cellular functions in response to ET-1.
基金Supported by a grant from the "135" Foundation of Jiangsu Province, No. 2003-19
文摘AIM： To investigate the role of IFN-T inducible protein -10 （IP-10） and regulated upon activation, normal T cell expressed and secreted （RANTES） protein in acute pancreatic allograft rejection in rats. METHODS： An experimental model was established using pancreas transplantation diabetic SD rats as the recipient, induced by applying streptozocin （STZ）. Pancreas transplantation was performed with a physiologic method of portal venous and enteric drainage. Rats were divided into two groups, isograft group （group A, n = 24） and allograft group （group B, n = 24） in which either healthy SD rats or Wistar rats served as donors, respectively. Twelve diabetic or healthy SD rats were used as controls. At d 1, 4, 7, and 10 post transplantation, serum IP-10 and RANTES were assessed by ELISA and their expression in the allografts was determined by immunohistochemistry. RESULTS： In group B （allograft group）, the development of acute rejection was significantly correlated with increased serum concentration and tissue expression of IP-10 and RANTES, with a peak level at d 7 post transplantation. In contrast, there was no obvious change before and after transplantation in group A （isograft group）. CONCLUSION： Our study suggests a possible role of IP-10 and RANTES in acute rejection and early monitoring of chemokines may be helpful in predicting the outcome of pancreas transplantation.
