scholarly journals LIM-Homeodomain Transcription Factor Isl-1 Mediates Kisspeptin's Effect on Insulin Secretion in Mice

2014 ◽  
Vol 28 (8) ◽  
pp. 1276-1290 ◽  
Author(s):  
Juan Chen ◽  
Rui Fu ◽  
Yan Cui ◽  
Jirong Pan ◽  
Yushan Li ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Insulin Secretion ◽  
Pancreatic Islet ◽  
Islet Cells ◽  
Direct Action ◽  
Janus Kinase ◽  
Homeodomain Transcription Factor ◽  
Lim Homeodomain

Kisspeptin and the G protein-coupled receptor 54 (GPR54) are highly abundant in the pancreas. In addition, circulating kisspeptin directly influences insulin secretion through GPR54. However, the mechanisms by which kisspeptin affects insulin release are unclear. The LIM-homeodomain transcription factor, Isl-1, is expressed in all pancreatic islet cells and is involved in regulating both islet development and insulin secretion. We therefore investigated potential interactions between kisspeptin and Isl-1. Our results demonstrate that Isl-1 and GPR54 are coexpressed in mouse pancreatic islet β-cells and NIT cells. Both in vitro and in vivo results demonstrate that kisspeptin-54 (KISS-54) inhibits Isl-1 expression and insulin secretion and both the in vivo and in vitro effects of KISS-54 on insulin gene expression and secretion are abolished when an Isl-1-inducible knockout model is used. Moreover, our results demonstrate that the direct action of KISS-54 on insulin secretion is mediated by Isl-1. Our results further show that KISS-54 influences Isl-1 expression and insulin secretion through the protein kinase C-ERK1/2 pathway. Conversely, insulin has a feedback loop via the Janus kinase-phosphatidylinositol 3-kinase pathway regulating kisspeptin expression and secretion. These findings are important in understanding mechanisms of insulin secretion and metabolism in diabetes.

Dietary fatty acids modify insulin secretion of rat pancreatic islet cells in vitro

2002 ◽  
Vol 25 (5) ◽  
pp. 436-441 ◽  
Author(s):  
F. J. Tinahones ◽  
A. Pareja ◽  
F. J. Soriguer ◽  
J. M. Gómez-Zumaquero ◽  
F. Cardona ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Insulin Secretion ◽  
Pancreatic Islet ◽  
Islet Cells ◽  
Dietary Fatty Acids ◽  
Pancreatic Islet Cells ◽  
Rat Pancreatic Islet

scholarly journals Loss-of-Function Mutation of the Galanin Gene Is Associated with Perturbed Islet Function in Mice

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3190-3196 ◽  
Author(s):  
Bo Ahrén ◽  
Giovanni Pacini ◽  
David Wynick ◽  
Nils Wierup ◽  
Frank Sundler
Keyword(s):  
Insulin Secretion ◽  
Islet Cells ◽  
Insulin Response ◽  
Tolerance Test ◽  
Glucose Disposal ◽  
Islet Function ◽  
Loss Of Function ◽  
Euglycemic Hyperinsulinemic Clamp

Abstract The neuropeptide galanin is expressed in sympathetic nerve terminals that surround islet cells and inhibits insulin secretion. To explore its role for islet function, we studied mice with a loss-of-function mutation in the galanin gene [galanin knockout (KO) mice]. Intravenous 2-deoxy-glucose, which activates both the sympathetic and parasympathetic branches of the autonomic nervous system, caused an initial (1–5 min) inhibition of insulin secretion that was impaired in galanin KO mice (P = 0.027), followed by a subsequent stimulation of insulin secretion that was augmented in galanin KO mice (P < 0.01). Similar effects were seen after chemical sympathectomy by 6-hydroxydopamine. In contrast, galanin KO mice had a reduced insulin response to glucose, both in vivo (P < 0.001) and in isolated islets (P < 0.001), and to arginine, both in vivo (P = 0.012) and in vitro (P = 0.018). During an iv glucose tolerance test, galanin KO mice had impaired glucose disposal (P = 0.005) due to a reduced insulin response (P < 0.001) and a reduced insulin-independent glucose elimination (glucose effectiveness; P = 0.040). Insulin sensitivity, as judged by a euglycemic, hyperinsulinemic clamp technique, was slightly increased in galanin KO mice (P = 0.032). We conclude that 1) galanin may contribute to sympathetic influences inhibiting insulin secretion in mice, and 2) galanin KO mice have a reduced glucose-induced insulin secretion.

scholarly journals Perilipin2 down-regulation in β cells impairs insulin secretion under nutritional stress and damages mitochondria

2020 ◽  
Author(s):  
Akansha Mishra ◽  
Siming Liu ◽  
Joseph Promes ◽  
Mikako Harata ◽  
William Sivitz ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Function ◽  
Islet Cells ◽  
Cell Metabolism ◽  
Nutritional Stress ◽  
Β Cells ◽  
Β Cell ◽  
Down Regulation

Perilipin 2 (PLIN2) is the lipid droplet (LD) protein in β cells that increases under nutritional stress. Down-regulation of PLIN2 is often sufficient to reduce LD accumulation. To determine whether PLIN2 positively or negatively affects β cell function under nutritional stress, PLIN2 was down-regulated in mouse β cells, INS1 cells, and human islet cells. β cell specific deletion of PLIN2 in mice on a high fat diet reduced glucose-stimulated insulin secretion (GSIS) in vivo and in vitro. Down-regulation of PLIN2 in INS1 cells blunted GSIS after 24 h incubation with 0.2 mM palmitic acids. Down-regulation of PLIN2 in human pseudoislets cultured at 5.6 mM glucose impaired both phases of GSIS, indicating that PLIN2 is critical for GSIS. Down-regulation of PLIN2 decreased specific OXPHOS proteins in all three models and reduced oxygen consumption rates in INS1 cells and mouse islets. Moreover, we found that PLIN2 deficient INS1 cells increased the distribution of a fluorescent oleic acid analog to mitochondria and showed signs of mitochondrial stress as indicated by susceptibility to fragmentation and alterations of acyl-carnitines and glucose metabolites. Collectively, PLIN2 in β cells have an important role in preserving insulin secretion, β cell metabolism and mitochondrial function under nutritional stress.

scholarly journals The β-cell specific transcription factor Nkx6.1 inhibits glucagon gene transcription by interfering with Pax6

2007 ◽  
Vol 403 (3) ◽  
pp. 593-601 ◽  
Author(s):  
Benoit R. Gauthier ◽  
Yvan Gosmain ◽  
Aline Mamin ◽  
Jacques Philippe
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Gene Transcription ◽  
Promoter Activity ◽  
Islet Cells ◽  
Gene Activation ◽  
Physical Interaction ◽  
Specific Expression

The transcription factor Nkx6.1 is required for the establishment of functional insulin-producing β-cells in the endocrine pancreas. Overexpression of Nkx6.1 has been shown to inhibit glucagon gene expression while favouring insulin gene activation. Down-regulation resulted in the opposite effect, suggesting that absence of Nkx6.1 favours glucagon gene expression. To understand the mechanism by which Nkx6.1 suppresses glucagon gene expression, we studied its effect on the glucagon gene promoter activity in non-islet cells using transient transfections and gel-shift analyses. In glucagonoma cells transfected with an Nkx6.1-encoding vector, the glucagon promoter activity was reduced by 65%. In BHK21 cells, Nkx6.1 inhibited by 93% Pax6-mediated activation of the glucagon promoter, whereas Cdx2/3 and Maf stimulations were unaltered. Although Nkx6.1 could interact with both the G1 and G3 element, only the former displayed specificity for Nkx6.1. Mutagenesis of the three potential AT-rich motifs within the G1 revealed that only the Pax6-binding site preferentially interacted with Nkx6.1. Chromatin immunoprecipitation confirmed interaction of Nkx6.1 with the glucagon promoter and revealed a direct competition for binding between Pax6 and Nkx6.1. A weak physical interaction between Pax6 and Nkx6.1 was detected in vitro and in vivo suggesting that Nkx6.1 predominantly inhibits glucagon gene transcription through G1-binding competition. We suggest that cell-specific expression of the glucagon gene may only proceed when Nkx6.1, in combination with Pdx1 and Pax4, are silenced in early α-cell precursors.

scholarly journals LIM-homeodomain Transcription Factor Isl-1 Mediates the Effect of Leptin on Insulin Secretion in Mice

2013 ◽  
Vol 288 (17) ◽  
pp. 12395-12405 ◽  
Author(s):  
Juan Chen ◽  
Rui Fu ◽  
Yan Cui ◽  
Yu-shan Li ◽  
Ji-rong Pan ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Insulin Secretion ◽  
Homeodomain Transcription Factor ◽  
Lim Homeodomain

scholarly journals Intrapancreatic MSC transplantation facilitates pancreatic islet regeneration

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rahul Khatri ◽  
Sebastian Friedrich Petry ◽  
Thomas Linn
Keyword(s):  
Stem Cells ◽  
Growth Factor ◽  
Pancreatic Islet ◽  
Nude Mice ◽  
Direct Contact ◽  
Islet Cells ◽  
Physical Contact ◽  
Min6 Cells

Abstract Background Type 1 diabetes mellitus (T1D) is characterized by the autoimmune destruction of the pancreatic β cells. The transplantation of mesenchymal stromal/stem cells (MSC) was reported to rescue the damaged pancreatic niche. However, there is an ongoing discussion on whether direct physical contact between MSC and pancreatic islets results in a superior outcome as opposed to indirect effects of soluble factors released from the MSC entrapped in the lung microvasculature after systemic administration. Hence, MSC were studied in direct contact (DC) and indirect contact (IDC) with murine pancreatic β cell line MIN6-cells damaged by nitrosourea derivative streptozotocin (STZ) in vitro. Further, the protective and antidiabetic outcome of MSC transplantation was evaluated through the intrapancreatic route (IPR) and intravenous route (IVR) in STZ-induced diabetic NMRI nude mice. Methods MSC were investigated in culture with STZ-damaged MIN6-cells, either under direct contact (DC) or separated through a semi-permeable membrane (IDC). Moreover, multiple low doses of STZ were administered to NMRI nude mice for the induction of hyperglycemia. 0.5 × 106 adipose-derived mesenchymal stem cells (ADMSC) were transferred through direct injection into the pancreas (IPR) or the tail vein (IVR), respectively. Bromodeoxyuridine (BrdU) was injected for the detection of proliferating islet cells in vivo, and real-time polymerase chain reaction (RT-PCR) was employed for the measurement of the expression of growth factor and immunomodulatory genes in the murine pancreas and human MSC. Phosphorylation of AKT and ERK was analyzed with Western blotting. Results The administration of MSC through IPR ameliorated hyperglycemia in contrast to IVR, STZ, and non-diabetic control in a 30-day window. IPR resulted in a higher number of replicating islet cells, number of islets, islet area, growth factor (EGF), and balancing of the Th1/Th2 response in vivo. Physical contact also provided a superior protection to MIN6-cells from STZ through the AKT and ERK pathway in vitro in comparison with IDC. Conclusion Our study suggests that the physical contact between MSC and pancreatic islet cells is required to fully unfold their protective potential.

scholarly journals Paired-Type Homeodomain Transcription Factors Are Imported into the Nucleus by Karyopherin 13

2004 ◽  
Vol 24 (11) ◽  
pp. 4824-4834 ◽  
Author(s):  
Jonathan E. Ploski ◽  
Monee K. Shamsher ◽  
Aurelian Radu
Keyword(s):  
Transcription Factor ◽  
In Vitro Assays ◽  
Nuclear Localization Sequence ◽  
Amino Acid Residues ◽  
Homeodomain Transcription Factor ◽  
Permeabilized Cells ◽  
Localization Sequence ◽  
Direct Binding

ABSTRACT We report that the paired homeodomain transcription factor Pax6 is imported into the nucleus by the Karyopherin β family member Karyopherin 13 (Kap13). Pax6 was identified as a potential cargo for Kap13 by a yeast two-hybrid screen. Direct binding of Pax6 to Kap13 was subsequently confirmed by in vitro assays with recombinant proteins, and binding in vivo was shown by coimmunoprecipitation. Ran-dependent import of Pax6 by Kap13 was shown to occur by using a digitonin-permeabilized cells assay. Kap13 binds to Pax6 via a nuclear localization sequence (NLS), which is located within a segment of 80 amino acid residues that includes the homeodomain. Kap13 showed reduced binding to Pax6 when either region located at each end of the homeodomain (208 to 214 and 261 to 267) was deleted. The paired-type homeodomain transcription factor family includes more than 20 members. All members contain a region similar to the NLS found in Pax6 and are therefore likely to be imported by Kap13. We confirmed this hypothesis for Pax3 and Crx, which bind to and are imported by Kap13.

Monolayer cultures of pancreatic islet cells from adult rats: effect of 2-deoxyglucose

1988 ◽  
Vol 118 (2) ◽  
pp. 173-NP ◽  
Author(s):  
M. Aoki ◽  
S. Kagawa ◽  
T. Yamamura ◽  
A. Matsuoka ◽  
J. Utsunomiya
Keyword(s):  
Insulin Secretion ◽  
B Cells ◽  
Pancreatic Islet ◽  
Cell Function ◽  
Islet Cells ◽  
Pancreatic Tissue ◽  
Pancreatic Islet Cells ◽  
Adult Rats ◽  
Monolayer Cultures

ABSTRACT Techniques for the monolayer culture of pancreatic islet cells from adult rats and the responsiveness of B cells are described. Whole pancreatic tissue was enzymatically dispersed and then cultured for 30 days in tissue culture medium 199 containing 5·5 mmol glucose/l, with or without 1 mmol 2-deoxyglucose/l. In the absence of 2-deoxyglucose, the responsiveness of B cells diminished to almost zero by day 15 and islets degenerated. In contrast, addition of 2-deoxyglucose to the medium resulted in a selective degeneration of fibroblasts, yielding monolayers that consisted mostly of islet cells. In this stationary system in which monolayers of islet cells were maintained in medium with 2-deoxyglucose, insulin secretion from B cells on days 15 and 30 increased in a dose-dependent fashion in response to increasing concentrations of glucose, leucine and 2-ketoisocaproate. Similarly, when exposed to 16·7 mmol glucose/l, perifused B cells showed a biphasic pattern of insulin secretion on day 15. Addition of 10 μmol forskolin/l and 200 nmol 12-O-tetradecanoyl phorbol13-acetate/l remarkably enhanced this response. Likewise, the response to 10 mmol leucine/l or 10 mmol 2-ketoisocaproate/l was biphasic. These results suggest that these monolayer cultures retain the functional properties of the adult rat pancreas, and may be useful not only as a model for the in-vitro study of B cell function, but also for implantation. J. Endocr. (1988) 118, 173–178

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