scholarly journals AQP8 is a crucial H2O2 transporter in insulin-producing RINm5F cells

Redox Biology ◽  
2021 ◽  
pp. 101962
Author(s):  
Christina Krüger ◽  
Markus Waldeck-Weiermair ◽  
Jonas Kaynert ◽  
Thomas Pokrant ◽  
Yesaswini Komaragiri ◽  
...  
Keyword(s):  
2018 ◽  
Vol 8 (3) ◽  
pp. 193 ◽  
Author(s):  
Rosa Martha Perez Gutierrez ◽  
Alethia Muñiz-Ramirez ◽  
Abraham Heriberto Garcia Campoy ◽  
Jose Maria Mota Flores ◽  
Sergio Odin Flores

Background: The health benefits of edible plants have been widely investigated and disseminated. However, only polyphenols have been found to have sufficient therapeutic potential to be considered in clinical trials. Fewer manuscripts have other applications such as prospective health benefits and disease treatment. Other components of edible plants are responsible for a range of other benefits including antimalarial, burns, flu, cancer, inflammation, diabetes, glycation, antimicrobial, prevention of neurodegeneration, analgesic, antimigraine activity, sedative activities, etc. Accordingly, the public needs to be informed of the potential edible plants have to act on different targets and maintain better control over diabetes compared to commercial drugs which can be toxic, have side effects, do not have the capacity to maintain blood glucose at normal levels, and do not protect the patient from the complications of diabetes over time. Consequently, edible plants, such as Apium graveolen, which have therapeutic targets on AGEs formation, are potentially a better alternative treatment for diabetes.Methods: The leaves of celery were extracted with methanol (CM). Polyphenols contents in CM were investigated by liquid chromatography-electrospray ionization mass. The ability of the compounds to inhibit formation of AGEs was evaluated in vitro models using formation of AGE fluorescence intensity, level of fructosamine, Nε-(carboxymethyl)lysine (CML), methylglyoxal (MG)-derived protein, and formation of amyloid cross β structure. Protein-oxidation was determined by thiol group and protein carbonyl content. Inhibition of MG-derived AGEs and MG-trapping ability were also measured. Additionally, insulin production was determined in methylglyoxal-treated pancreatic RINm5F cells assay. Results: Apigenin, kaempferol, apiin, rutin, caffeic acid, ferulic acid, chlorogenic acid, coumaroylquinic acid, and p-coumaric acid were the major polyphenols contained in CM. In all the model tests CM displayed potent AGE inhibitory activity, suggesting that CM delayed the three stages of glycation. Accordingly, the mechanisms of action of celery involving dicarbonyl trapping and breaking the crosslink structure in the AGEs formed may contribute to the protection of pancreatic RINm5F cells against MG conditions.Conclusion: These findings indicate that CM have an excellent anti-glycation effect which may be beneficial for future development of antiglycating agents for the treatment of diabetes.Keywords: Apium graveolens, anti-glycation, polyphenols methylglyoxal, insulin, pancreatic cells


2008 ◽  
Vol 197 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Hasan Kulaksiz ◽  
Evelyn Fein ◽  
Peter Redecker ◽  
Wolfgang Stremmel ◽  
Guido Adler ◽  
...  

Body iron is involved in various vital functions. Its uptake in the intestine is regulated by hepcidin, a bioactive peptide originally identified in plasma and urine and subsequently in the liver. In the present study, we provide evidence at the transcriptional and translational levels that hepcidin is also expressed in the pancreas of rat and man. Immunohistochemical studies localized the peptide exclusively to β-cells of the islets of Langerhans. Immunoelectron microscopical analyses revealed that hepcidin is confined to the insulin-storing β-cell secretory granules. As demonstrated in insulinoma-derived RINm5F cells, the expression of hepcidin in β-cells is regulated by iron. Based on the present findings we conclude that pancreatic islets are an additional source of the peptide hepcidin. The localization of this peptide to β-cells suggests that pancreatic β-cells may be involved in iron metabolism in addition to their genuine function in blood glucose regulation. In view of the various linked iron/glucose disorders in the pancreas, the present findings may provide an insight into the phenomenology of intriguing mutual relationships between iron and glucose metabolisms.


2004 ◽  
Vol 286 (3) ◽  
pp. E329-E336 ◽  
Author(s):  
Sarah M. Weber ◽  
Anna L. Scarim ◽  
John A. Corbett

Peroxisome proliferator-activated receptor (PPAR)γ agonists, such as 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2) and troglitazone, have been shown to elicit anti-inflammatory effects in pancreatic β-cells that include inhibition of cytokine-stimulated inducible nitric oxide synthase (iNOS) gene expression and production of nitric oxide. In addition, these ligands impair IL-1-induced NF-κB and MAPK as well as IFN-γ-stimulated signal transducer and activator of transcription (STAT)1 activation in β-cells. The purpose of this study was to determine if PPARγ activation participates in the anti-inflammatory actions of PGJ2 in β-cells. Pretreatment of RINm5F cells for 6 h with PGJ2 results in inhibition of IL-1-stimulated IκB degradation and IFN-γ-stimulated STAT1 phosphorylation. Overexpression of a dominant-negative (dn) PPARγ mutant or treatment with the PPARγ antagonist GW-9662 does not modulate the inhibitory actions of PGJ2 on cytokine signaling in RINm5F cells. Although these agents fail to attenuate the inhibitory actions of PGJ2 on cytokine signaling, they do inhibit PGJ2-stimulated PPARγ response element reporter activity. Consistent with the inability to attenuate the inhibitory actions of PGJ2 on cytokine signaling, neither dnPPARγ nor GW-9662 prevents the inhibitory actions of PGJ2 on IL-1-stimulated iNOS gene expression or nitric oxide production by RINm5F cells. These findings support a PPARγ-independent mechanism by which PPARγ ligands impair cytokine signaling and iNOS expression by islets.


2008 ◽  
Vol 197 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Angélica Morales ◽  
Sumiko Morimoto ◽  
Lorenza Díaz ◽  
Guillermo Robles ◽  
Vicente Díaz-Sánchez

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF) is an endothelial cell mitogen, expressed essentially in steroidogenic cells. Recently, the expression of EG-VEGF in normal human pancreas and pancreatic adenocarcinoma has been demonstrated. Epidemiologically, pancreatic carcinogenesis is more frequent in males than females, and given that androgen receptors and testosterone biotransformation have been described in pancreas, we hypothesized that testosterone could participate in the regulation of EG-VEGF expression. In this study, we investigated the regulation of EG-VEGF gene expression by testosterone in normal rat pancreatic tissue and rat insulinoma cells (RINm5F). Total RNA was extracted from rat pancreas and cultured cells. Gene expression was studied by real-time PCR and protein detection by immunohistochemistry. Serum testosterone was quantified by RIA. Results showed that EG-VEGF is expressed predominantly in pancreatic islets and vascular endothelium, as well as in RINm5F cells. EG-VEGF gene expression was lower in the pancreas of rats with higher testosterone serum levels. A similar effect that was reverted by flutamide was observed in testosterone-treated RINm5F cells. In summary, testosterone down-regulated EG-VEGF gene expression in rat pancreatic tissue and RINm5F cells. This effect could be mediated by the androgen receptor. To our knowledge, this is the first time that a direct effect of testosterone on EG-VEGF gene expression in rat pancreas and RINm5F cells is demonstrated.


Diabetologia ◽  
2004 ◽  
Vol 47 (7) ◽  
pp. 1292-1302 ◽  
Author(s):  
K. L. A. Souza ◽  
M. Elsner ◽  
P. C. F. Mathias ◽  
S. Lenzen ◽  
M. Tiedge
Keyword(s):  

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Janet Alejandra Espejel-Nava ◽  
Elisa Vega-Avila ◽  
Francisco Alarcon-Aguilar ◽  
Alejandra Contreras-Ramos ◽  
Guadalupe Díaz-Rosas ◽  
...  

Catharanthus roseus (L.) G. (C. roseus) is a medicinal plant used traditionally for diabetes mellitus control. Several compounds of an alkaloidal nature have been proposed as hypoglycemic principles. However, little attention has been paid to other compounds in this plant that could also participate in this hypoglycemic activity. This study aimed to analyze the hypoglycemic effect of a polyphenolic fraction from C. roseus, as well as its action on insulin secretion and expression in RINm5F cells. Methods. An alkaloid-free aqueous extract was obtained from C. roseus stems. The hypoglycemic effect of different doses of this extract was evaluated in normal and streptozotocin-induced diabetic mice. This extract was fractionated by bipartition, and the resultant fractions were assessed by their hypoglycemic effects. Subsequently, the fraction with the greater hypoglycemic activity was added to the RINm5F cells, and the expression and secretion of insulin were analyzed. The antioxidant activity was determined by the DPPH method and through chromatographic analysis of the most active fraction by HPLC, using an Econosphere C18 column. Results. The aqueous alkaloid-free extract of C. roseus stems significantly reduced blood glucose in normal and diabetic mice. The fractionation of this extract provided three fractions, one of which (a precipitate) showed significant reductions in glycemia at 6 h (48.1 and 64.5% in normal and diabetic mice, respectively). This precipitate contained phenolic compounds and saponins. Its chromatographic analysis showed that it is formed by several phenolic compounds; gallic acid (0.053%) and chlorogenic acid (0.216%) were identified and quantified. Conclusion. The phenolic fraction of C. roseus containing gallic acid and chlorogenic acid had a hypoglycemic effect that may be explained by an increase in insulin secretion.


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