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Insulin-producing cells could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells.

Shi Q, Luo S, Jia H, Feng L, Lu X, Zhou L, Cai J - Nanoscale Res Lett (2013)

Bottom Line: The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy.IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm.Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Nano-Chemistry, Department of Chemistry, Jinan University, Guangzhou 510632, China. tjycai@jnu.edu.cn.

ABSTRACT

Objective: The aim of this study was to compare the difference between insulin-producing cells (IPCs) and normal human pancreatic beta cells both in physiological function and morphological features in cellular level.

Methods: The levels of insulin secretion were measured by enzyme-linked immunosorbent assay. The insulin gene expression was determined by real-time quantitative polymerase chain reaction. The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy.

Results: IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm. Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs.

Conclusions: Our results firstly revealed that the cellular ultrastructure of IPCs was closer to that of normal human pancreatic beta cells, but they still could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells.

No MeSH data available.


Gene expression analysis. Insulin gene expression by two groups of cells was 0.04 ± 0.004 for hADSCs and 0.65 ± 0.036 for IPCs; cycle threshold values of PCR assay were 14.12 ± 0.45 and 14.33 ± 0.37, respectively. Gene expression was normalized to GAPDH. The asterisk denotes P < 0.05.
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Figure 1: Gene expression analysis. Insulin gene expression by two groups of cells was 0.04 ± 0.004 for hADSCs and 0.65 ± 0.036 for IPCs; cycle threshold values of PCR assay were 14.12 ± 0.45 and 14.33 ± 0.37, respectively. Gene expression was normalized to GAPDH. The asterisk denotes P < 0.05.

Mentions: Insulin cannot be used as a differentiating medium, so the insulin that appeared in media after glucose stimulation was synthesized de novo and secreted by IPCs. Figure 1 shows that the expression of insulin gene massively increased. Insulin mRNA expression in IPCs increased 16-fold, from day 0 to day 12 (P < 0.05). To verify whether IPCs could secrete insulin as a result of sensing physiological glucose concentrations as beta cells do, we first detected the quantity of insulin secretion in different glucose concentrations and under different stimulating time frames. ELISA (Table 2) showed that beta cells and IPCs from all four donors secreted insulin after 30 min or 1 h of stimulation, with no difference existing between 30 min and 1 h of stimulation in high glucose concentrations. However, in low glucose concentrations, the amount of insulin was obviously lower than that in high-glucose stimulation for 30 min or 1 h. Interestingly, normal human pancreatic beta cells responded to low glucose concentrations after 30 min of stimulation, and the amount of insulin was similar to the amount resulting from 1 h of stimulation. On the other hand, IPCs hardly secreted any insulin (0.46 ± 0.04 μU/mL) after low-glucose stimulation for 30 min and only secreted a little insulin (1.01 ± 0.11 μU/mL) after 1 h of stimulation in low glucose concentrations. Our data illustrated that insulin secretion from both normal beta cells and IPCs were regulated by glucose. However, the amount of insulin secreted by beta cells was much higher than that by IPCs (P < 0.05).


Insulin-producing cells could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells.

Shi Q, Luo S, Jia H, Feng L, Lu X, Zhou L, Cai J - Nanoscale Res Lett (2013)

Gene expression analysis. Insulin gene expression by two groups of cells was 0.04 ± 0.004 for hADSCs and 0.65 ± 0.036 for IPCs; cycle threshold values of PCR assay were 14.12 ± 0.45 and 14.33 ± 0.37, respectively. Gene expression was normalized to GAPDH. The asterisk denotes P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585706&req=5

Figure 1: Gene expression analysis. Insulin gene expression by two groups of cells was 0.04 ± 0.004 for hADSCs and 0.65 ± 0.036 for IPCs; cycle threshold values of PCR assay were 14.12 ± 0.45 and 14.33 ± 0.37, respectively. Gene expression was normalized to GAPDH. The asterisk denotes P < 0.05.
Mentions: Insulin cannot be used as a differentiating medium, so the insulin that appeared in media after glucose stimulation was synthesized de novo and secreted by IPCs. Figure 1 shows that the expression of insulin gene massively increased. Insulin mRNA expression in IPCs increased 16-fold, from day 0 to day 12 (P < 0.05). To verify whether IPCs could secrete insulin as a result of sensing physiological glucose concentrations as beta cells do, we first detected the quantity of insulin secretion in different glucose concentrations and under different stimulating time frames. ELISA (Table 2) showed that beta cells and IPCs from all four donors secreted insulin after 30 min or 1 h of stimulation, with no difference existing between 30 min and 1 h of stimulation in high glucose concentrations. However, in low glucose concentrations, the amount of insulin was obviously lower than that in high-glucose stimulation for 30 min or 1 h. Interestingly, normal human pancreatic beta cells responded to low glucose concentrations after 30 min of stimulation, and the amount of insulin was similar to the amount resulting from 1 h of stimulation. On the other hand, IPCs hardly secreted any insulin (0.46 ± 0.04 μU/mL) after low-glucose stimulation for 30 min and only secreted a little insulin (1.01 ± 0.11 μU/mL) after 1 h of stimulation in low glucose concentrations. Our data illustrated that insulin secretion from both normal beta cells and IPCs were regulated by glucose. However, the amount of insulin secreted by beta cells was much higher than that by IPCs (P < 0.05).

Bottom Line: The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy.IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm.Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Nano-Chemistry, Department of Chemistry, Jinan University, Guangzhou 510632, China. tjycai@jnu.edu.cn.

ABSTRACT

Objective: The aim of this study was to compare the difference between insulin-producing cells (IPCs) and normal human pancreatic beta cells both in physiological function and morphological features in cellular level.

Methods: The levels of insulin secretion were measured by enzyme-linked immunosorbent assay. The insulin gene expression was determined by real-time quantitative polymerase chain reaction. The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy.

Results: IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm. Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs.

Conclusions: Our results firstly revealed that the cellular ultrastructure of IPCs was closer to that of normal human pancreatic beta cells, but they still could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells.

No MeSH data available.