SerpinB1 improves insulin sensitivity

2016 ◽  
Vol 9 (411) ◽  
pp. ec10-ec10
Author(s):  
Annalisa M. VanHook

Pancreatic β cells adjust the secretion of insulin in response to acute changes in plasma glucose concentration. These cells also compensate for long-term changes in insulin sensitivity by adjusting their activity or numbers, or both (see Tarasov and Rorsman). In addition to being insulin resistant, mice lacking the liver insulin receptor (LIRKO mice) also exhibit β cell hyperplasia that depends on factors released from the liver. Using a proteomic approach, El Ouaamari etal. found that the abundance of the protease inhibitor serpinB1 was greater in liver extracts, liver explant–conditioned medium, and serum from LIRKO mice than in those from wild-type mice. SerpinB1 abundance correlated inversely with insulin sensitivity in human patients with risk factors for type 2 diabetes. Recombinant human serpinB1 stimulated the proliferation of β cells in cultured mouse and human islets in a dose-dependent manner. Elastase is a protease inhibited by serpinB1, and forms of serpinB1 that do not inhibit elastase activity did not stimulate proliferation of cultured mouse β cells. Compounds that inhibit elastase also promoted the proliferation of cultured mouse β cells. In mice, elastase inhibitors stimulated the proliferation of both endogenous β cells and the β cells of human islet grafts. Furthermore, overexpression of serpinb1 increased the regeneration of β cells following β cell ablation in zebrafish embryos. In several models of acute and chronic insulin resistance, serpinb1 knockout mice exhibited reduced β cell proliferation compared with wild-type controls. However, β cell proliferation was not abolished in serpinb1 knockouts, indicating that additional factors can induce compensatory proliferation of β cells. Phosphoproteomic analyses demonstrated that treatment of cultured mouse β cells with human serpinB1 stimulated signaling through several pathways that promote cell proliferation and survival. Commentary by Tarasov and Rorsman considers how these findings might be put to clinical use.A. El Ouaamari, E. Dirice, N. Gedeon, J. Hu, J.-Y. Zhou, J. Shirakawa, L. Hou, J. Goodman, C. Karampelias, G. Qiang, J. Boucher, R. Martinez, M. A. Gritsenko, D. F. De Jesus, S. Kahraman, S. Bhatt, R. D. Smith, H.-D. Beer, P. Jungtrakoon, Y. Gong, A. B. Goldfine, C. W. Liew, A. Doria, O. Andersson, W.-J. Qian, E. Remold-O’Donnell, R. N. Kulkarni, SerpinB1 promotes pancreatic β cell proliferation. CellMetab. 23, 194–205 (2016). [PubMed] A. I. Tarasov, P. Rorsman, Dramatis personae in β-cell mass regulation: Enter SerpinB1. CellMetab. 23, 8–10 (2016). [Online Journal]

2019 ◽  
Vol 317 (5) ◽  
pp. E794-E804 ◽  
Author(s):  
Guneet Makkar ◽  
Vipul Shrivastava ◽  
Brittyne Hlavay ◽  
Marle Pretorius ◽  
Barry D. Kyle ◽  
...  

Pancreatic islets adapt to the increase in insulin demand during pregnancy by upregulating β-cell number, insulin synthesis, and secretion. These changes require prolactin receptor (PrlR) signaling, as mice with PrlR deletion are glucose intolerant with a lower β-cell mass. Prolactin also prevents β-cell apoptosis. Many genes participate in these adaptive changes in the islet, and Lrrc55 is one of the most upregulated genes with unknown function in islets. Because Lrrc55 expression increases in parallel to the increase in β-cell number and insulin production during pregnancy, we hypothesize that Lrrc55 might regulate β-cell proliferation/apoptosis (thus β-cell number) and insulin synthesis. Here, we found that Lrrc55 expression was upregulated by >60-fold during pregnancy in a PrlR-dependent manner, and this increase was restricted only to the islets. Overexpression of Lrrc55 in β-cells had minimal effect on β-cell proliferation and glucose-stimulated insulin secretion but protected β-cells from glucolipotoxicity-induced reduction in insulin gene expression. Moreover, Lrrc55 protects β-cells from glucolipotoxicity-induced apoptosis, with upregulation of prosurvival signals and downregulation of proapoptotic signals of the endoplasmic reticulum (ER) stress pathway. Furthermore, Lrrc55 attenuated calcium depletion induced by glucolipotoxicity, which may contribute to its antiapoptotic effect. Hence our findings suggest that Lrrc55 is a novel prosurvival factor that is upregulated specifically in islets during pregnancy, and it prevents conversion of adaptive unfolded protein response to unresolved ER stress and apoptosis in β-cells. Lrrc55 could be a potential therapeutic target in diabetes by reducing ER stress and promoting β-cell survival.


2017 ◽  
Vol 313 (3) ◽  
pp. E367-E380 ◽  
Author(s):  
Kazuki Tajima ◽  
Jun Shirakawa ◽  
Tomoko Okuyama ◽  
Mayu Kyohara ◽  
Shunsuke Yamazaki ◽  
...  

Metformin has been widely used for the treatment of type 2 diabetes. However, the effect of metformin on pancreatic β-cells remains controversial. In this study, we investigated the impacts of treatment with metformin on pancreatic β-cells in a mouse model fed a high-fat diet (HFD), which triggers adaptive β-cell replication. An 8-wk treatment with metformin improved insulin resistance and suppressed the compensatory β-cell hyperplasia induced by HFD-feeding. In contrast, the increment in β-cell mass arising from 60 wk of HFD feeding was similar in mice treated with and those treated without metformin. Interestingly, metformin suppressed β-cell proliferation induced by 1 wk of HFD feeding without any changes in insulin resistance. Metformin directly suppressed glucose-induced β-cell proliferation in islets and INS-1 cells in accordance with a reduction in mammalian target of rapamycin phosphorylation. Taken together, metformin suppressed HFD-induced β-cell proliferation independent of the improvement of insulin resistance, partly via direct actions.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Angel Nadal ◽  
Talia Boronat-Belda ◽  
Ivan Quesada ◽  
Esther Fuentes ◽  
Jan-Ake Gustafsson ◽  
...  

Abstract Bisphenol-A (BPA) is one of the highest volume chemicals produced worldwide. It is used as the base compound in the manufacture of polycarbonate plastics, epoxies and resins. Humans are consistently exposed to BPA and consistently it has been detected in the majority of individuals examined. Experimental research in animals, as well as human epidemiological studies, converge to conclude that BPA is a risk factor for the development of type 2 diabetes. In previous studies we have demonstrated that the exposure to BPA during embryonic development promote an increment of pancreatic β-cell mass. This was correlated with increased β-cell division and altered global gene expression in pancreatic β-cells. The aim of this work was to determinate whether ERβ was involved in the in the β-cell mass and proliferation increment observed in male mice offspring. ERβ+/- pregnant mice were treated with vehicle or BPA (10 μg/kg/day) from day 9 to 16 of gestation. Offspring pancreatic β-cell mass was measured at postnatal day 0 (P0) and 30 (P30). For ex vivo experiments Wild-type (WT) and ERβ-/- neonates as well as adult male and female mice were used. For in vitro, single islets cells were cultured for 48 h in the presence of 10 μmol/L BrdU, and vehicle, BPA (1, 10, 100 nM) or the specific ERβ agonist WAY200070 (1, 10, 100 nM). β-cell proliferation rate was quantified as the percentage of BrdU-positive pancreatic β-cells. In vivo exposure to BPA during pregnancy promoted an increment of pancreatic β-cell mass and proliferation in WT mice at P30 which was absent in ERβ -/- mice. In order to explore if these changes were related to a direct action of BPA on pancreatic β-cell division we performed a series of ex vivo experiments. Augmented β-cell proliferation rate was observed in BPA-exposed β-cells isolated from both adult male and female WT animals in comparison to controls. The increment was significant at all BPA doses tested. The effect was imitated by the selective ERβ agonist, WAY200070, and was abolished in cells from ERβ-/- mice. We also explored the effects of BPA in pancreatic β-cells from neonates and found an increment in BPA-exposed cells compared to controls, although the difference was only significant at the dose of 1 nM. A similar effect was observed in neonate cells treated with WAY200070 (10 nM). The effects on β-cell replication were abolished in cells from ERβ-/- neonate mice treated either with BPA or WAY200070. Our findings suggest that BPA modulate pancreatic β-cell growth and mass in an ERβ-dependent manner. This could have important implications for metabolic programming of T2DM. Ministerio de Economía y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) grants BPU2017-86579-R (AN) and BFU2016-77125-R (IQ); Generalitat Valenciana PROMETEO II/2015/016 (AN). CIBERDEM is an initiative of the Instituto de Salud Carlos III.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenda Strutt ◽  
Sandra Szlapinski ◽  
Thineesha Gnaneswaran ◽  
Sarah Donegan ◽  
Jessica Hill ◽  
...  

AbstractThe apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9–12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dror Sever ◽  
Anat Hershko-Moshe ◽  
Rohit Srivastava ◽  
Roy Eldor ◽  
Daniel Hibsher ◽  
...  

AbstractNF-κB is a well-characterized transcription factor, widely known for its roles in inflammation and immune responses, as well as in control of cell division and apoptosis. However, its function in β-cells is still being debated, as it appears to depend on the timing and kinetics of its activation. To elucidate the temporal role of NF-κB in vivo, we have generated two transgenic mouse models, the ToIβ and NOD/ToIβ mice, in which NF-κB activation is specifically and conditionally inhibited in β-cells. In this study, we present a novel function of the canonical NF-κB pathway during murine islet β-cell development. Interestingly, inhibiting the NF-κB pathway in β-cells during embryogenesis, but not after birth, in both ToIβ and NOD/ToIβ mice, increased β-cell turnover, ultimately resulting in a reduced β-cell mass. On the NOD background, this was associated with a marked increase in insulitis and diabetes incidence. While a robust nuclear immunoreactivity of the NF-κB p65-subunit was found in neonatal β-cells, significant activation was not detected in β-cells of either adult NOD/ToIβ mice or in the pancreata of recently diagnosed adult T1D patients. Moreover, in NOD/ToIβ mice, inhibiting NF-κB post-weaning had no effect on the development of diabetes or β-cell dysfunction. In conclusion, our data point to NF-κB as an important component of the physiological regulatory circuit that controls the balance of β-cell proliferation and apoptosis in the early developmental stages of insulin-producing cells, thus modulating β-cell mass and the development of diabetes in the mouse model of T1D.


2013 ◽  
Vol 305 (1) ◽  
pp. E149-E159 ◽  
Author(s):  
Rachel E. Stamateris ◽  
Rohit B. Sharma ◽  
Douglas A. Hollern ◽  
Laura C. Alonso

Type 2 diabetes (T2D) is caused by relative insulin deficiency, due in part to reduced β-cell mass ( 11 , 62 ). Therapies aimed at expanding β-cell mass may be useful to treat T2D ( 14 ). Although feeding rodents a high-fat diet (HFD) for an extended period (3–6 mo) increases β-cell mass by inducing β-cell proliferation ( 16 , 20 , 53 , 54 ), evidence suggests that adult human β-cells may not meaningfully proliferate in response to obesity. The timing and identity of the earliest initiators of the rodent compensatory growth response, possible therapeutic targets to drive proliferation in refractory human β-cells, are not known. To develop a model to identify early drivers of β-cell proliferation, we studied mice during the first week of HFD exposure, determining the onset of proliferation in the context of diet-related physiological changes. Within the first week of HFD, mice consumed more kilocalories, gained weight and fat mass, and developed hyperglycemia, hyperinsulinemia, and glucose intolerance due to impaired insulin secretion. The β-cell proliferative response also began within the first week of HFD feeding. Intriguingly, β-cell proliferation increased before insulin resistance was detected. Cyclin D2 protein expression was increased in islets by day 7, suggesting it may be an early effector driving compensatory β-cell proliferation in mice. This study defines the time frame and physiology to identify novel upstream regulatory signals driving mouse β-cell mass expansion, in order to explore their efficacy, or reasons for inefficacy, in initiating human β-cell proliferation.


Endocrinology ◽  
2019 ◽  
Vol 160 (8) ◽  
pp. 1885-1894 ◽  
Author(s):  
Shannon E Townsend ◽  
Maureen Gannon

Abstract This review describes formation of the islet basement membrane and the function of extracellular matrix (ECM) components in β-cell proliferation and survival. Implications for islet transplantation are discussed. The insulin-producing β-cell is key for maintaining glucose homeostasis. The islet microenvironment greatly influences β-cell survival and proliferation. Within the islet, β-cells contact the ECM, which is deposited primarily by intraislet endothelial cells, and this interaction has been shown to modulate proliferation and survival. ECM-localized growth factors, such as vascular endothelial growth factor and cellular communication network 2, signal through specific receptors and integrins on the β-cell surface. Further understanding of how the ECM functions to influence β-cell proliferation and survival will provide targets for enhancing functional β-cell mass for the treatment of diabetes.


Endocrinology ◽  
2013 ◽  
Vol 154 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Kazuki Orime ◽  
Jun Shirakawa ◽  
Yu Togashi ◽  
Kazuki Tajima ◽  
Hideaki Inoue ◽  
...  

Decreased β-cell mass is a hallmark of type 2 diabetes, and therapeutic approaches to increase the pancreatic β-cell mass have been expected. In recent years, gastrointestinal incretin peptides have been shown to exert a cell-proliferative effect in pancreatic β-cells. Trefoil factor 2 (TFF2), which is predominantly expressed in the surface epithelium of the stomach, plays a role in antiapoptosis, migration, and proliferation. The TFF family is expressed in pancreatic β-cells, whereas the role of TFF2 in pancreatic β-cells has been obscure. In this study, we investigated the mechanism by which TFF2 enhances pancreatic β-cell proliferation. The effects of TFF2 on cell proliferation were evaluated in INS-1 cells, MIN6 cells, and mouse islets using an adenovirus vector containing TFF2 or a recombinant TFF2 peptide. The forced expression of TFF2 led to an increase in bromodeoxyuridine (BrdU) incorporation in both INS-1 cells and islets, without any alteration in insulin secretion. TFF2 significantly increased the mRNA expression of cyclin A2, D1, D2, D3, and E1 in islets. TFF2 peptide increased ERK1/2 phosphorylation and BrdU incorporation in MIN6 cells. A MAPK kinase inhibitor (U0126) abrogated the TFF2 peptide-mediated proliferation of MIN6 cells. A CX-chemokine receptor-4 antagonist also prevented the TFF2 peptide-mediated increase in ERK1/2 phosphorylation and BrdU incorporation in MIN6 cells. These results indicated that TFF2 is involved in β-cell proliferation at least partially via CX-chemokine receptor-4-mediated ERK1/2 phosphorylation, suggesting TFF2 may be a novel target for inducing β-cell proliferation.


2006 ◽  
Vol 26 (7) ◽  
pp. 2772-2781 ◽  
Author(s):  
Bangyan L. Stiles ◽  
Christine Kuralwalla-Martinez ◽  
Wei Guo ◽  
Caroline Gregorian ◽  
Ying Wang ◽  
...  

ABSTRACT Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid phosphatase. PTEN inhibits the action of phosphatidylinositol-3-kinase and reduces the levels of phosphatidylinositol triphosphate, a crucial second messenger for cell proliferation and survival, as well as insulin signaling. In this study, we deleted Pten specifically in the insulin producing β cells during murine pancreatic development. Pten deletion leads to increased cell proliferation and decreased cell death, without significant alteration of β-cell differentiation. Consequently, the mutant pancreas generates more and larger islets, with a significant increase in total β-cell mass. PTEN loss also protects animals from developing streptozotocin-induced diabetes. Our data demonstrate that PTEN loss in β cells is not tumorigenic but beneficial. This suggests that modulating the PTEN-controlled signaling pathway is a potential approach for β-cell protection and regeneration therapies.


2009 ◽  
Vol 297 (2) ◽  
pp. E323-E330 ◽  
Author(s):  
Erica Manesso ◽  
Gianna M. Toffolo ◽  
Yoshifumi Saisho ◽  
Alexandra E. Butler ◽  
Aleksey V. Matveyenko ◽  
...  

Type 2 diabetes is characterized by hyperglycemia, a deficit in β-cells, increased β-cell apoptosis, and islet amyloid derived from islet amyloid polypeptide (IAPP). These characteristics are recapitulated in the human IAPP transgenic (HIP) rat. We developed a mathematical model to quantify β-cell turnover and applied it to nondiabetic wild type (WT) vs. HIP rats from age 2 days to 10 mo to establish 1) whether β-cell formation is derived exclusively from β-cell replication, or whether other sources of β-cells (OSB) are present, and 2) to what extent, if any, there is attempted β-cell regeneration in the HIP rat and if this is through β-cell replication or OSB. We conclude that formation and maintenance of adult β-cells depends largely (∼80%) on formation of β-cells independent from β-cell duplication. Moreover, this source adaptively increases in the HIP rat, implying attempted β-cell regeneration that substantially slows loss of β-cell mass.


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