Calcium influx activates adenylyl cyclase 8 for sustained insulin secretion in rat pancreatic beta cells

Dou, Hongwei; Wang, Changhe; Wu, Xi; Yao, Lei; Zhang, Xiaoyu; Teng, Susanto; Xu, Hua‐Dong; Liu, Bin; Wu, Qihui; Zhang, Quanfeng; Hu, Meiru; Wang, Yeshi; Wang, Li; Wu, Yi; Shang, Shujiang; Kang, Xinjiang; Zheng, Lianghong; Zhang, Jin; Raoux, Matthieu; Lang, Jochen; Li, Qing; Su, Jing; Yu, Xiao; Chen, Liangyi; Zhou, Zhuan

doi:10.1007/s00125-014-3437-z

Cited by 40 publications

(43 citation statements)

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“…The kinase inhibitor H-89 had been reported not to alter the effect of glucose in intact islets [32]. However, recent pharmacological data from mouse [2], rat [33] and human islets [28,34] are in line with our observations. Previously reported differences may be due to the timing of drug addition as they are less evident once glucoseinduced effects are installed [2].…”

Section: Discussionsupporting

confidence: 91%

Multilevel control of glucose homeostasis by adenylyl cyclase 8

et al. 2014

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Aims/hypothesis Nutrient homeostasis requires integration of signals generated by glucose metabolism and hormones. Expression of the calcium-stimulated adenylyl cyclase ADCY8 is regulated by glucose and the enzyme is capable of integrating signals from multiple pathways. It may thus have an important role in glucose-induced signalling and glucose homeostasis. Methods We used pharmacological and genetic approaches in beta cells to determine secretion and calcium metabolism. Furthermore, Adcy8 knockout mice were characterised. Results In clonal beta cells, inhibitors of adenylyl cyclases or their downstream targets reduced the glucose-induced increase in cytosolic calcium and insulin secretion. This was reproduced by knock-down of ADCY8, but not of ADCY1. These agents also inhibited glucose-induced increase in cytosolic calcium and electrical activity in primary beta cells and similar effects were observed after ADCY8 knock-down.Moreover, insulin secretion was diminished in islets from Adcy8 knockout mice. These mice were glucose intolerant after oral or intraperitoneal administration of glucose whereas their levels of glucagon-like peptide-1 remained unaltered. Finally, we knocked down ADCY8 in the ventromedial hypothalamus to evaluate the need for ADCY8 in the central regulation of glucose homeostasis. Whereas mice fed a standard diet had normal glucose levels, high-fat diet exacerbated glucose intolerance and knock-down mice were incapable of raising their plasma insulin levels. Finally we confirmed that ADCY8 is expressed in human islets. Conclusions/interpretations Collectively, our findings demonstrate that ADCY8 is required for the physiological activation of glucose-induced signalling pathways in beta cells, for glucose tolerance and for hypothalamic adaptation to a high-fat diet via regulation of islet insulin secretion.Electronic supplementary material The online version of this article (doi:10.1007/s00125-014-3445-z) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

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Section: Discussionsupporting

confidence: 91%

Multilevel control of glucose homeostasis by adenylyl cyclase 8

et al. 2014

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“…However, although the insulin secretion of islets isolated from Sst-Cre +/-Cul4b fl/Y mice was still much lower than that of their WT littermates after SNX482 treatment, this difference was eliminated after nicardipine treatment ( Figure 3D). These data are in agreement with the observed somatostatin secretion patterns and reinforce the conclusion that L-type calcium channels in pancreatic δ cells are key components mediating the increased somatostatin secretion and impaired glucose metabolism in Sst In addition to intracellular calcium, the second messenger cAMP, the G q -PLC pathway, and kinase signaling are actively involved in hormone secretion from pancreatic islets (5,13,(39)(40)(41). Therefore, we preincubated the islets with several inhibitors, including cAMP-PKA signaling inhibitors Rp-CAMPs and H89, G q -PLC inhibitor U73122, MEK inhibitor U0126, and adenyl cyclase (AC) inhibitor 2′,5′-dideoxyadenosine (DDA), and we examined glucose-induced somatostatin secretion patterns ciency in the pancreatic β cells of Ins2-Cre +/-Cul4b fl/Y mice did not significantly affect insulin and somatostatin secretion levels in response to high glucose relative to trends found for Ins2-Cre +/-mice (Supplemental Figure 3, A and B).…”

Section: Cul4b Ablation In Pancreatic δ Cells Other Than β Cells Caussupporting

confidence: 89%

“…L-type calcium channels are responsible for the influx of extracellular calcium during hormone secretion. We therefore measured high glucose-and high potassium-induced calcium signals in iso- In addition to intracellular calcium, the second messenger cAMP, the G q -PLC pathway, and kinase signaling are actively involved in hormone secretion from pancreatic islets (5,13,(39)(40)(41). Therefore, we preincubated the islets with several inhibitors, including cAMP-PKA signaling inhibitors Rp-CAMPs and H89, G q -PLC inhibitor U73122, MEK inhibitor U0126, and adenyl cyclase (AC) inhibitor 2′,5′-dideoxyadenosine (DDA), and we examined glucose-induced somatostatin secretion patterns ciency in the pancreatic β cells of Ins2-Cre +/-Cul4b fl/Y mice did not significantly affect insulin and somatostatin secretion levels in response to high glucose relative to trends found for Ins2-Cre +/-mice (Supplemental Figure 3, A and B).…”

Section: The Journal Of Clinical Investigation R E S E a R C H A R T mentioning

confidence: 99%

A cullin 4B-RING E3 ligase complex fine-tunes pancreatic δ cell paracrine interactions

Cui

Yang

et al. 2017

Journal of Clinical Investigation

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Figure 1. CUL4B deficiency in pancreatic δ cells impairs glucose metabolism. (A and B)Western blots and quantitative data for CUL4A and CUL4B protein levels in islets from 12-week-old diabetic db/db mice and their heterozygous littermates (db/+). n = 6 mice per group. Representative Western blots from at least 3 independent experiments are shown. (C) Immunostaining for CUL4B (green) and somatostatin (SST, red) in pancreatic sections from db/db and db/+ mice. Scale bar: 100 μm. n = 6 mice per group; 4-7 random areas were selected from each islet section, and 10 sections were randomly selected from each mouse. Insulininduced decreases in blood glucose levels were significantly lower in Sst-Cre +/-Cul4b fl/Y mice than in their WT littermates, and they did not return to baseline levels at the 2-hour time point, whereas the levels of their WT littermates did (n = 9-11). *P < 0.05; **P < 0.01; ***P < 0.001. db/db mice were compared with their db/+ littermates, and Sst-Cre +/-Cul4b fl/Y mice were compared with their WT littermates. Error bars in F represent mean ± SD; other bars represent mean ± SEM. All data were analyzed using 1-way ANOVA. The Journal of Clinical Investigation R E S E A R C H A R T I C L E2 6 3 3 jci.orgVolume 127 Number 7 July 2017mental Figure 1E). Immunofluorescence also showed no significant differences in islet or β or δ cell numbers between +/-mice, the knockout mice exhibited increased glucose levels after 2 hours of feeding following a 16-hour fast ( Figure 1G). Accordingly, during a glucose tolerance test, the blood glucose levels of Sst-Cre +/-Cul4b fl/Y mice were 33% and 30% higher at 30 minutes and 120 minutes, respectively, than those of the control group consisting of both Sst-Cre +/-and Cul4b fl/Y mice ( Figure 1H). In addition, during the insulin tolerance test, the blood glucose levels of Sst-Cre +/-Cul4b fl/Y mice unexpectedly decreased more dramatically and rapidly than those of the Sst-Cre +/-control mice in response to insulin stimulation ( Figure 1I). Insulin and somatostatin content as well as kidney, brain, heart, liver, and stomach weights were not found to be significantly different between the mice was 140% and 40% higher than that of Sst-Cre +/-mice at 5 minutes and 60 minutes, respectively ( Figure 2H). In contrast to the results found for the Sst-Cre +/-Cul4b fl/Y mice, CUL4B defistrated that CRL4 ubiquitinates WD repeat-containing protein 5 (WDR5), a core subunit of H3K4 methyltransferase complexes, for degradation in the nucleus, thereby promoting increased H3K4 methylation levels (30). However, whether CUL4B or its E3 ligase complex CRL4B-PRC2 participates in the functioning or development of Langerhans islets has not been studied. In this study, we found that CUL4B expression levels are decreased in db/db mice. Therefore, we crossed mice expressing Cre under the insulin II promotor (Ins2-Cre) and mice expressing Cre under the somatostatin promoter (Sst-Cre) with Cul4b fl/fl mice to characterize CUL4B functions in specific cell types of the islet circuit. Although In...

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“…Intracellular calcium concentrations were measured to determine a possible influence of AAGP on glucosestimulated calcium influx (34). No significant differences in calcium influx were observed between groups (AUC: Tac 2 209.4, Tac + 221.6, Tac+AAGP 208.7 fF/treatment/ 2 s; P .…”

Section: Tac Effect On Islet Intracellular Calcium Responses and Exocmentioning

confidence: 98%

Antiaging Glycopeptide Protects Human Islets Against Tacrolimus-Related Injury and Facilitates Engraftment in Mice

et al. 2015

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Clinical islet transplantation has become an established treatment modality for selected patients with type 1 diabetes. However, a large proportion of transplanted islets is lost through multiple factors, including immunosuppressant-related toxicity, often requiring more than one donor to achieve insulin independence. On the basis of the cytoprotective capabilities of antifreeze proteins (AFPs), we hypothesized that supplementation of islets with synthetic AFP analog antiaging glycopeptide (AAGP) would enhance posttransplant engraftment and function and protect against tacrolimus (Tac) toxicity. In vitro and in vivo islet Tac exposure elicited significant but reversible reduction in insulin secretion in both mouse and human islets. Supplementation with AAGP resulted in improvement of islet survival (Tac + vs. Tac+AAGP, 31.5% vs. 67.6%, P < 0.01) coupled with better insulin secretion (area under the curve: Tac + vs. Tac+AAGP, 7.3 vs. 129.2 mmol/L/60 min, P < 0.001). The addition of AAGP reduced oxidative stress, enhanced insulin exocytosis, improved apoptosis, and improved engraftment in mice by decreasing expression of interleukin (IL)-1b, IL-6, keratinocyte chemokine, and tumor necrosis factor-a. Finally, transplant efficacy was superior in the Tac+AAGP group and was similar to islets not exposed to Tac, despite receiving continuous treatment for a limited time. Thus, supplementation with AAGP during culture improves islet potency and attenuates long-term Tac-induced graft dysfunction.

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Calcium influx activates adenylyl cyclase 8 for sustained insulin secretion in rat pancreatic beta cells

Cited by 40 publications

References 45 publications

Multilevel control of glucose homeostasis by adenylyl cyclase 8

Multilevel control of glucose homeostasis by adenylyl cyclase 8

A cullin 4B-RING E3 ligase complex fine-tunes pancreatic δ cell paracrine interactions

Antiaging Glycopeptide Protects Human Islets Against Tacrolimus-Related Injury and Facilitates Engraftment in Mice

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