Epithelial cell proliferation and islet neogenesis in IFN-g transgenic mice

Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 33-46 ◽  
Author(s):  
D. Gu ◽  
N. Sarvetnick

We have identified a model system for the study of pancreatic islet development and regeneration in transgenic mice bearing the interferon-gamma (IFN-g) gene expressed in the pancreatic islets. Previous studies showed that the locally produced IFN-g causes lymphocyte infiltration and islet cell destruction. Here we demonstrate that new islet cells are formed continuously from duct cells as evidenced by (1) the dramatic proliferation of duct cells, (2) the appearance of primitive cells and (3) their subsequent differentiation to endocrine cells. The IFN-g induced islet neogenesis is similar to embryonic islet morphogenesis and offers a model system for studying factors modulating islet development. Additionally, the duct cells occasionally transdifferentiate to gastrointestinal-like cell types and hepatocytes. These results underscore the lymphokine's ability to initiate a complex ‘transdifferentiation’ pathway, providing a window for understanding lineage interrelationships within a terminally differentiated structure.

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 245-252 ◽  
Author(s):  
B.H. Upchurch ◽  
G.W. Aponte ◽  
A.B. Leiter

The islets of Langerhans contain four distinct endocrine cell types producing the hormones glucagon, insulin, somatostatin and pancreatic polypeptide. These cell lineages are thought to arise from a common, multipotential progenitor cell whose identity has not been well established. The pancreatic and intestinal hormone, peptide YY, has been previously identified in glucagon-producing cells in islets; however, transgenic mice expressing Simian Virus 40 large T antigen under the control of the peptide YY gene expressed the oncoprotein in beta, delta and pancreatic polypeptide cells, and occasionally developed insulinomas, suggesting relationships between peptide YY-producing cells and several islet cell lineages. The four established pancreatic islet cell types were examined for coexpression of peptide YY in islets of normal and transgenic mice throughout development. Peptide YY immunoreactivity was identified in the earliest endocrine cells in the fetal pancreas and was coexpressed in each islet cell type during development. Peptide YY showed a high degree of co-localization with glucagon- and insulin-producing cells in early pancreatic development, but by adulthood, peptide YY was expressed in less than half of the alpha cells and was no longer expressed in beta cells. Peptide YY was also coexpressed with somatostatin and pancreatic polypeptide when these cell types first appeared, but most delta and pancreatic polypeptide cells continued to express peptide YY throughout development. The use of conditions that distinguish peptide YY from the related peptides, pancreatic polypeptide and neuropeptide Y, as well as the ability of the peptide YY gene to direct expression of a reporter gene in islets of transgenic mice, establishes expression of peptide YY in the earliest pancreatic endocrine cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1157-1163 ◽  
Author(s):  
B.H. Upchurch ◽  
B.P. Fung ◽  
G. Rindi ◽  
A. Ronco ◽  
A.B. Leiter

The hormone peptide YY is produced by endocrine cells in the pancreas, ileum and colon. We have previously shown that peptide YY is coexpressed in all four islet cell types in the murine pancreas when they first appear, suggesting a common peptide YY-producing progenitor. In the colon, peptide YY has been frequently identified in glucagon-expressing L-type endocrine cells. Characterization of colonic endocrine tumors in transgenic mice expressing simian virus 40 large T antigen under the control of the peptide YY gene 5′ flanking region revealed tumor cells producing not only peptide YY and glucagon, but also neurotensin, cholecystokinin, substance P, serotonin, secretin, and gastrin. This suggested that multiple enteroendocrine lineages were related to peptide YY-producing cells. Subsequent examination of the ontogeny of colonic endocrine differentiation in nontransgenic mice revealed that peptide YY was the first hormone to appear during development, at embryonic day 15.5. Between embryonic days 16.5 and 18.5, cells expressing glucagon, cholecystokinin, substance P, serotonin, secretin, neurotensin, gastrin and somatostatin first appeared and peptide YY was coexpressed in each cell type at this time. Peptide YY coexpression continued in a significant fraction of most enteroendocrine cell types throughout fetal and postnatal development and into adulthood, with the exception of serotonin-producing cells. This latter population of cells expanded dramatically after birth with rare coexpression of peptide YY. These studies indicate that expression of peptide YY is an early event in colonic endocrine differentiation and support the existence of a common progenitor for all endocrine cells in the colon.


1996 ◽  
Vol 149 (1) ◽  
pp. 145-154 ◽  
Author(s):  
K Josefsen ◽  
J P Stenvang ◽  
H Kindmark ◽  
P-O Berggren ◽  
T Horn ◽  
...  

Abstract Studies of individual cell types in the islets of Langerhans are complicated by the cells' functional coupling by gap junctions and paracrine interaction. Access to purified alpha and beta cells is therefore desirable. We present a simplified and optimized method for fluorescence-activated cell sorting of endocrine pancreatic rat islets. For dispersion of the islets, dispase was superior to trypsin, as the number of vital single cells was higher (1·1 ± 0·1 × 103 vs 0·6 ± 0·1 × 103/islet, P<0·05). The purity of the sorted cells was 96·7 ± 1·2% for the non-beta cells and 97·8 ± 0·6% for the beta cells (numbers in percentages of endocrine cells). In culture, isolated beta cells, non-beta cells and mixtures of beta and non-beta cells formed aggregates, but not at low temperature (4 °C) and not in medium with low serum content (2%). Finally, in pure beta cell aggregates, glucose stimulated changes in cytoplasmic free Ca2+ concentration although both glucose- and arginine-induced insulin secretion was much reduced. We conclude that alpha cells are necessary for insulin secretion but not for glucose sensing. Journal of Endocrinology (1996) 149, 145–154


1995 ◽  
Vol 4 (4) ◽  
pp. 371-383 ◽  
Author(s):  
Lawrence Rosenberg

During embryogenesis, islet cells differentiate from primitive duct-like cells. This process leads to the formation of islets in the mesenchyme adjacent to the ducts. In the postnatal period, any further expansion of the pancreatic endocrine cell mass will manifest itself either by a limited proliferation of the existing islet cells, or by a reiteration of ontogenetic development. It is the latter, cell transformation by a process of differentiation from a multipotential cell, that will be referred to in this review as islet neogenesis. To better appreciate the mechanisms underlying islet cell neogenesis, some of the basic concepts of developmental biology will be reviewed. Considerable discussion is devoted to the subject of transdifferentiation, a change in a cell or in its progeny from one differentiated phenotype to another, where the change includes both morphological and functional phenotypic markers. While in vitro studies with fetal and neonatal pancreata strongly suggest that new islet tissue is derived from ductal epithelium, what is not established is whether the primary cell is a committed endocrine cell or duct-like cell capable of transdifferentiation. Next, research in the field of β-cell neogenesis is surveyed, in preparation for the examination of whether there is a physiological means of inducing islet cell regeneration, and whether the new islet mass will function in a regulated manner to reverse or stabilize a diabetic state? Our belief is that the pancreas retains the ability to regenerate a functioning islet cell mass in the postnatal period, and that the process of cell transformation leading to islet neogenesis is mediated by growth factors that are intrinsic to the gland. Furthermore, it is our contention that these factors act directly or indirectly on a multipotential cell, probably associated with the ductular epithelium, to induce endocrine cell differentiation. In other words, new islet formation in the postnatal period reiterates the normal ontogeny of islet cell development. These ideas will be fully developed in a discussion of the Partial Duct Obstruction (PDO) Model.


Development ◽  
1979 ◽  
Vol 52 (1) ◽  
pp. 23-38
Author(s):  
Ann Andrew ◽  
Beverley Kramer

To determine whether or not any pancreatic islet cell type arises from rhombencephalic levels of neurectoderm, lengths of presumptive rhombencephalon (containing potential neural crest) of Black Australorp chick embryos at 6- to 9-somite stages were replaced isotopically and isochronically by neural tube of Japanese quail embryos. Some transplants included mesencephalic regions. In some cases various levels of the rhombencephalon were deleted and not replaced. The quail nuclear marker was detected in cranial ganglia in operated embryos sacrificed at 3¾ days of incubation and in enteric ganglia and cells accompanying some pancreatic nerves, in embryos killed at 7 days of incubation. This provided evidence of normal migration of crest cells from the grafts. Dopa was administered to the younger embryos, which were submitted to the formaldehyde-induced fluorescence procedure to demonstrate APUD (Amine Precursor Uptake and Decarboxylation) cells. No pancreatic APUD cells exhibited the quail nuclear marker. In 9- to 11-day embryos, A and B cells were identified by specific light and electron microscopic features. None showed the quail marker. The marker was also absent from those D cells seen and from cells of an as yet unidentified type, but not enough of these were found to warrant a conclusion. All islet cell types were found in embryos from which various levels of the rhombencephalon had been deleted. It is concluded that at least A and B islet cells are not derived from the rhombencephalic neurectoderm and probably not from mesencephalic levels. Their most likely origin remains the endoderm, which was the accepted source until recently


2021 ◽  
Vol 11 ◽  
Author(s):  
Eva Bru-Tari ◽  
Daniel Oropeza ◽  
Pedro L. Herrera

The β-cell regeneration field has shown a strong knowledge boost in the last 10 years. Pluripotent stem cell differentiation and direct reprogramming from other adult cell types are becoming more tangible long-term diabetes therapies. Newly generated β-like-cells consistently show hallmarks of native β-cells and can restore normoglycemia in diabetic mice in virtually all recent studies. Nonetheless, these cells still show important compromises in insulin secretion, cell metabolism, electrical activity, and overall survival, perhaps due to a lack of signal integration from other islet cells. Mounting data suggest that diabetes is not only a β-cell disease, as the other islet cell types also contribute to its physiopathology. Here, we present an update on the most recent studies of islet cell heterogeneity and paracrine interactions in the context of restoring an integrated islet function to improve β-cell replacement therapies.


1996 ◽  
Vol 44 (8) ◽  
pp. 809-817 ◽  
Author(s):  
M Jackerott ◽  
A Oster ◽  
L I Larsson

Exhaustive characterizations of antisera to the structurally related peptides pancreatic polypeptide (PP), neuropeptide Y (NPY), and peptide YY (PYY) enabled us to establish the developmental pattern of these peptides in rat and mouse pancreas. PYY was the earliest detectable peptide and was present in all early appearing endocrine cell types. NPY appeared later and occurred exclusively in a subpopulation of insulin cells, whereas PP cells arose latest. At the earliest stage studied, all endocrine cells stored PYY. Most of these cells also contained glucagon. Subsequently, the endocrine cells comprised glucagon+PYY cells and glucagon+PYY+insulin cells. Later, cells storing either only insulin or insulin+PYY appeared. Quantitations of the relative numbers of these cell populations during development were consistent with a precursor role of triple-positive (insulin+glucagon+PYY) cells. Moreover, bromodeoxyuridine (BrdU) injections at E15.5 showed that a large percentage of triple-positive cells were in S-phase and therefore were actively dividing, whereas almost no pure insulin cells or insulin+PYY cells synthesized DNA at this time. These results suggest that PYY-positive endocrine cells may represent precursors for mature islet cells.


Scientifica ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-22 ◽  
Author(s):  
Paolo Meda

The islets of Langerhans collectively form the endocrine pancreas, the organ that is soley responsible for insulin secretion in mammals, and which plays a prominent role in the control of circulating glucose and metabolism. Normal function of these islets implies the coordination of different types of endocrine cells, noticeably of the beta cells which produce insulin. Given that an appropriate secretion of this hormone is vital to the organism, a number of mechanisms have been selected during evolution, which now converge to coordinate beta cell functions. Among these, several mechanisms depend on different families of integral membrane proteins, which ensure direct (cadherins, N-CAM, occludin, and claudins) and paracrine communications (pannexins) between beta cells, and between these cells and the other islet cell types. Also, other proteins (integrins) provide communication of the different islet cell types with the materials that form the islet basal laminae and extracellular matrix. Here, we review what is known about these proteins and their signaling in pancreaticβ-cells, with particular emphasis on the signaling provided by Cx36, given that this is the integral membrane protein involved in cell-to-cell communication, which has so far been mostly investigated for effects on beta cell functions.


Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1873-1881 ◽  
Author(s):  
D. Gu ◽  
M.S. Lee ◽  
T. Krahl ◽  
N. Sarvetnick

We examined the spectrum of intermediate cell types in the regenerating pancreas as duct epithelial cells progressed through their differentiation pathway to become mature endocrine cells. The model used was transgenic mice in which the pancreatic islets continue to grow during adulthood, unlike normal mice whose islet cell formation ceases early in life. Because the intermediate cells migrated into islet-like clusters at specific locations, we propose a specific pathway for islet development. Endocrine cells are derived from duct cells co-expressing a duct cell antigen, carbonic anhydrase II (CA II) and an exocrine enzyme, amylase. The CA II/amylase cells become amylase/endocrine intermediate cells as they exited from their lumenal location. The abluminal amylase/endocrine cells continue to differentiate to multihormone-bearing young endocrine cells, which migrated to form clusters with other differentiating endocrine cells.


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