scholarly journals β-Cell Lines Derived from Transgenic Cpefat/Cpefat Mice Are Defective in Carboxypeptidase E and Proinsulin Processing*

Endocrinology ◽  
1997 ◽  
Vol 138 (11) ◽  
pp. 4883-4892 ◽  
Author(s):  
Oleg Varlamov ◽  
Lloyd D. Fricker ◽  
Hisasi Furukawa ◽  
Donald F. Steiner ◽  
Stephen H. Langley ◽  
...  
Keyword(s):  
Cell Lines ◽  
Β Cell ◽  
Carboxypeptidase E ◽  
Proinsulin Processing

scholarly journals Effects of Carboxypeptidase E Overexpression on Insulin mRNA Levels, Regulated Insulin Secretion, and Proinsulin Processing of Pituitary GH3 Cells Transfected with a Furin-Cleavable Human Proinsulin cDNA

2002 ◽  
Vol 11 (8) ◽  
pp. 803-811 ◽  
Author(s):  
Luca Polastri ◽  
Francesca Galbiati ◽  
Franco Folli ◽  
Alberto M. Davalli
Keyword(s):  
Insulin Secretion ◽  
Cell Lines ◽  
Secretory Granules ◽  
Gh3 Cells ◽  
Soluble Form ◽  
Mrna Levels ◽  
Carboxypeptidase E ◽  
Proinsulin Processing ◽  
Membrane Bound ◽  
Overexpressing Cell

We recently developed two rat pituitary GH3 cell clones engineered to secrete human insulin (InsGH3). InsGH3 cells convert proinsulin into mature insulin, which is partially stored into a readily releasable pool of secretory granules. The efficiency of these processes, however, is relatively low in these cells, either in vitro or in vivo. This study was aimed at determining whether carboxypeptidase E (Cpe) overexpression can increase proinsulin processing and regulated secretion by InsGH3 clones. Indeed, in its membrane-bound form Cpe works as sorting receptor for the regulated secretory pathway of many hormones while, in its soluble form, Cpe takes part to the late step of insulin maturation. We obtained two Cpe-overexpressing cell lines from two different InsGH3 clones (InsGH3/C1 and C7). In the Cpe-overexpressing cell lines, derived from InsGH3 of clone 1 (InsGH3/C1-HACpe), in which the membrane-bound form of exogenous Cpe is accounted for by 90% of total Cpe immunoreactivity, we observed an increase in proinsulin gene expression, and in basal and stimulated insulin secretion compared with the original clone. In contrast, in the Cpe-overexpressing cell line derived from InsGH3 of clone 7 (InsGH3/C7-HACpe), where the exogenous membrane-bound form was only 60% of total Cpe, we detected a decrease in basal insulin release and a modest, albeit significant, increase in intracellular proinsulin processing. In conclusion, Cpe overexpression can increase regulated insulin secretion and proinsulin processing in InsGH3 cells; however, such improvements appear quantitatively and qualitatively modest.

scholarly journals Inside the Insulin Secretory Granule

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 515
Author(s):  
Mark Germanos ◽  
Andy Gao ◽  
Matthew Taper ◽  
Belinda Yau ◽  
Melkam A. Kebede
Keyword(s):  
Secretory Granules ◽  
Β Cells ◽  
Β Cell ◽  
Proinsulin Processing ◽  
Membrane Bound ◽  
Golgi Network ◽  
Insulin Secretory Granule ◽  
Insulin Storage ◽  
Cellular Stimulation

The pancreatic β-cell is purpose-built for the production and secretion of insulin, the only hormone that can remove glucose from the bloodstream. Insulin is kept inside miniature membrane-bound storage compartments known as secretory granules (SGs), and these specialized organelles can readily fuse with the plasma membrane upon cellular stimulation to release insulin. Insulin is synthesized in the endoplasmic reticulum (ER) as a biologically inactive precursor, proinsulin, along with several other proteins that will also become members of the insulin SG. Their coordinated synthesis enables synchronized transit through the ER and Golgi apparatus for congregation at the trans-Golgi network, the initiating site of SG biogenesis. Here, proinsulin and its constituents enter the SG where conditions are optimized for proinsulin processing into insulin and subsequent insulin storage. A healthy β-cell is continually generating SGs to supply insulin in vast excess to what is secreted. Conversely, in type 2 diabetes (T2D), the inability of failing β-cells to secrete may be due to the limited biosynthesis of new insulin. Factors that drive the formation and maturation of SGs and thus the production of insulin are therefore critical for systemic glucose control. Here, we detail the formative hours of the insulin SG from the luminal perspective. We do this by mapping the journey of individual members of the SG as they contribute to its genesis.

Adenoviral infection or deferoxamine? Two approaches to overexpress VEGF in β-cell lines

2009 ◽  
Vol 17 (6) ◽  
pp. 415-422 ◽  
Author(s):  
Allan Langlois ◽  
William Bietiger ◽  
Marie-Christine Sencier ◽  
Elisa Maillard ◽  
Michel Pinget ◽  
...  
Keyword(s):  
Cell Lines ◽  
Β Cell ◽  
Adenoviral Infection

Differential activation of ER stress and apoptosis in response to chronically elevated free fatty acids in pancreatic β-cells

2008 ◽  
Vol 294 (3) ◽  
pp. E540-E550 ◽  
Author(s):  
Elida Lai ◽  
George Bikopoulos ◽  
Michael B. Wheeler ◽  
Maria Rozakis-Adcock ◽  
Allen Volchuk
Keyword(s):  
Er Stress ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Human Islets ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Min6 Cells ◽  
Relative Contribution ◽  
Induced Apoptosis

Chronic exposure to elevated saturated free fatty acid (FFA) levels has been shown to induce endoplasmic reticulum (ER) stress that may contribute to promoting pancreatic β-cell apoptosis. Here, we compared the effects of FFAs on apoptosis and ER stress in human islets and two pancreatic β-cell lines, rat INS-1 and mouse MIN6 cells. Isolated human islets cultured in vitro underwent apoptosis, and markers of ER stress pathways were elevated by chronic palmitate exposure. Palmitate also induced apoptosis in MIN6 and INS-1 cells, although the former were more resistant to both apoptosis and ER stress. MIN6 cells were found to express significantly higher levels of ER chaperone proteins than INS-1 cells, which likely accounts for the ER stress resistance. We attempted to determine the relative contribution that ER stress plays in palmitate-induced β-cell apoptosis. Although overexpressing GRP78 in INS-1 cells partially reduced susceptibility to thapsigargin, this failed to reduce palmitate-induced ER stress or apoptosis. In INS-1 cells, palmitate induced apoptosis at concentrations that did not result in significant ER stress. Finally, MIN6 cells depleted of GRP78 were more susceptible to tunicamycin-induced apoptosis but not to palmitate-induced apoptosis compared with control cells. These results suggest that ER stress is likely not the main mechanism involved in palmitate-induced apoptosis in β-cell lines. Human islets and MIN6 cells were found to express high levels of stearoyl-CoA desaturase-1 compared with INS-1 cells, which may account for the decreased susceptibility of these cells to the cytotoxic effects of palmitate.

scholarly journals Transcription of the gene encoding TNF-α is increased by IL-1β in rat and human islets and β-cell lines

2014 ◽  
Vol 62 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Susan J. Burke ◽  
Danhong Lu ◽  
Tim E. Sparer ◽  
Michael D. Karlstad ◽  
J. Jason Collier
Keyword(s):  
Cell Lines ◽  
Human Islets ◽  
Β Cell ◽  
Gene Encoding ◽  
Tnf Α

IGF-II, IGF-binding proteins and IGF receptors in pancreatic β-cell lines

1997 ◽  
Vol 152 (3) ◽  
pp. 455-464 ◽  
Author(s):  
L E L Katz ◽  
A Bhala ◽  
E Camron ◽  
S E Nunn ◽  
R L Hintz ◽  
...  
Keyword(s):  
Cell Lines ◽  
Binding Proteins ◽  
Conditioned Media ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Igf Binding Proteins ◽  
Igf Receptors ◽  
Igf I ◽  
Igf Binding ◽  
Hit Cells

The IGFs are mitogenic agents which are closely linked to regulatory processes in carbohydrate metabolism. Because limited information is available on the occurrence of the IGF system in the pancreatic β-cell milieu, we evaluated the presence of IGFs, IGF receptors, and IGF-binding proteins (IGFBPs) in the β-cell lines βTC3 and HIT T-15. Serum-free conditioned media (SFCM) from βTC3 cells contained IGF-II at concentrations greater than 100 ng/ml. High (15 kDa) and low (7·5 kDa) molecular weight IGF-II were detected both by column chromatography followed by RIA and by immunoblotting. GH (10–1000 ng/ml) conditioning of βTC3 cells stimulated IGF-II secretion in a dose-dependent manner. IGF-II mRNA was detected in βTC3 cells using Northern blots, and also showed a GH-dependent relationship. IGF-II peptide was detected in SFCM from HIT cells, albeit at lower concentrations. To evaluate the presence of IGF receptors in β-cell lines, affinity cross-linking studies were performed on βTC3 cells, demonstrating type I IGF receptors which bound iodinated IGF-II with high affinity, iodinated IGF-I with lesser affinity, and had minimal appreciable binding to iodinated insulin. Type II IGF receptors were not detected. SFCM from βTC3 and HIT cells was subjected to Western ligand blotting, which disclosed the presence of two major IGFBPs of 29 kDa and 24 kDa, characteristic of IGFBP-2 and IGFBP-4. The identity of the specific IGFBPs was confirmed by immunoprecipitation and Northern blotting. Varying the glucose concentration had no significant effect on the levels of IGFBPs, nor did preconditioning with GH, IGF-I, IGF-II, insulin, or glucagon. Levels of both IGFBPs in βTC3 cell-conditioned media increased in the presence of dexamethasone at concentrations of 10−6 m or greater. In summary, we present evidence that β-cell lines comprise an environment for GH and IGF action. We speculate that IGFs, their receptors and binding proteins function as a complex interactive system which regulates β-cell growth and function. Journal of Endocrinology (1997) 152, 455–464

Presence of GAWK-like immunoreactivity (LI) in insulin-secreting clonal β-cell lines

1993 ◽  
Vol 47 (1) ◽  
pp. 110
Author(s):  
M.J. Salahuddin ◽  
R.N. Kulkarni ◽  
M.A. Ghatei ◽  
S.R Bloom
Keyword(s):  
Cell Lines ◽  
Β Cell

Pancreatic β-Cell Lines

1999 ◽  
pp. 21-46 ◽  
Author(s):  
Shanta J. Persaud
Keyword(s):  
Cell Lines ◽  
Pancreatic Β Cell ◽  
Β Cell

scholarly journals Establishment of new clonal pancreatic β-cell lines (MIN6-K) useful for study of incretin/cyclic adenosine monophosphate signaling

2010 ◽  
pp. no-no ◽  
Author(s):  
Masahiro Iwasaki ◽  
Kohtaro Minami ◽  
Tadao Shibasaki ◽  
Takashi Miki ◽  
Jun-ichi Miyazaki ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Pancreatic Β Cell ◽  
Β Cell

scholarly journals Overexpression of lactate dehydrogenase A attenuates glucose-induced insulin secretion in stable MIN-6 β-cell lines

FEBS Letters ◽  
1998 ◽  
Vol 430 (3) ◽  
pp. 213-216 ◽  
Author(s):  
Chao Zhao ◽  
Guy A Rutter
Keyword(s):  
Insulin Secretion ◽  
Lactate Dehydrogenase ◽  
Cell Lines ◽  
Β Cell
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