The insulin factory: a tour of the plant surroundings and a visit to the assembly line

Orci, Lelio

doi:10.1007/bf00281987

Cited by 174 publications

(139 citation statements)

References 56 publications

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“…Insulin degradation is a prominent feature of a normal liver cell. 25 What induced the formation of storage granules in the HUH7-ins cells, and for that matter, the transfected HEP G2 cells, is unknown. Such information is highly relevant in understanding how to make a substitute b cell since it is the storage of insulin in such granules that allows the b cell to secrete insulin so rapidly when needed.…”

Section: Discussionmentioning

confidence: 99%

Function of a genetically modified human liver cell line that stores, processes and secretes insulin

Tuch

Szymańska

et al. 2003

Gene Ther

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An alternative approach to the treatment of type I diabetes is the use of genetically altered neoplastic liver cells to synthesize, store and secrete insulin. To try and achieve this goal we modified a human liver cell line, HUH7, by transfecting it with human insulin cDNA under the control of the cytomegalovirus promoter. The HUH7-ins cells created were able to synthesize insulin in a similar manner to that which occurs in pancreatic b cells. They secreted insulin in a regulated manner in response to glucose, calcium and theophylline, the dose-response curve for glucose being near-physiological. Perifusion studies showed that secretion was rapid and tightly controlled. Removal of calcium resulted in loss of glucose stimulation while addition of brefeldin A resulted in a 30% diminution of effect, indicating that constitutive release of insulin occurred to a small extent. Insulin was stored in granules within the cytoplasm. When transplanted into diabetic immunoincompetent mice, the cells synthesized, processed, stored and secreted diarginyl insulin in a rapid regulated manner in response to glucose.Constitutive release of insulin also occurred and was greater than regulated secretion. Blood glucose levels of the mice were normalized but ultimately became subnormal due to continued proliferation of cells. Examination of the HUH7-ins cells as well as the parent cell line for b cell transcription factors showed the presence of NeuroD but not PDX-1. PC1 and PC2 were also present in both cell types. Thus, the parent HUH7 cell line possessed a number of endocrine pancreatic features that reflect the common endodermal ancestry of liver and pancreas, perhaps as a result of ontogenetic regression of the neoplastic liver cell from which the line was derived. Introduction of the insulin gene under the control of the CMV promoter induced changes in these cells to make them function to some extent like pancreatic b cells. Our results support the view that neoplastic liver cells can be induced to become substitute pancreatic b cells and become a therapy for the treatment of type I diabetes.

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Section: Discussionmentioning

confidence: 99%

Function of a genetically modified human liver cell line that stores, processes and secretes insulin

Tuch

Szymańska

et al. 2003

Gene Ther

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“…The maturation of secretory granules involves not only progressive acidification and prohormone conversion but also the loss of the clathrin coat [71,72]. Clathrin is removed from coated vesicles by disassembly mediated by an ATP-dependent uncoating enzyme [73] shown to be a member of the 70 kDa family of stress proteins [74].…”

Section: Protein Secretory Pathways: a General Outline Leader And Leamentioning

confidence: 99%

“…Most recently, Leblond et al [151] [55][56][57][58]61,71]. Clathrin assembly depends upon the association of specialized adaptor proteins (adaptins, or assembly proteins) [158,159] Although alluded to earlier [162], it was in 1967 that Steiner provided the first direct evidence for the processing of a highermolecular-mass precursor, proinsulin, into a smaller, biologically active peptide hormone, insulin [163,164].…”

Section: The Example Of the Secretograninsmentioning

confidence: 99%

“…Note that these sequences would be suitable for conversion by furin [233,237]. When PC2 was expressed in Xenopus oocytes, it was found that the pro-region was initially cleaved at Lys-ArgArg-Arg8l to yield an intermediate of 71 kDa, which was further cleaved to a 68 kDa form only after secretion [269]. This unusual processing pattern may be peculiar to this particular, and same cleavage site was identified in CHO cells expressing a mutant Sorting and processing of secretory proteins 11 unnatural, setting.…”

Section: Pc1/pc3 and Pc2mentioning

confidence: 99%

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Sorting and processing of secretory proteins

Halban

Irminger

1994

Biochemical Journal

307

226

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“…Differences in the degree of B-cell granulation have been often described by histologists who examined pancreatic sections in aldehyde fuchsin stain [40]. The form of the stored hormone can also differ from one cell to another, as indicated by the presence of proinsulin-rich cells adjacent to the more numerous insulinrich cells [51]. The variation in insulin content of individual cells was also evident from the differences in the cellular fluorescence intensity after an immunostain for insulin.…”

Section: Coexistence Of Functionally Diverse B-cell Subpopulationsmentioning

confidence: 99%

The biosociology of pancreatic B cells

1987

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The insulin factory: a tour of the plant surroundings and a visit to the assembly line

Cited by 174 publications

References 56 publications

Function of a genetically modified human liver cell line that stores, processes and secretes insulin

Function of a genetically modified human liver cell line that stores, processes and secretes insulin

Sorting and processing of secretory proteins

The biosociology of pancreatic B cells

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