PDGF signalling controls age-dependent proliferation in pancreatic β-cells

May combine two claims.

Neither β-cell BrdU incorporation nor mass are increased in βEzh2KO-RαTg mice compared to controls.

“However, neither β-cell BrdU incorporation nor mass were increased in βEzh2KO-RαTg mice compared to controls (Fig. 4c, d and Supplementary Fig. 7).”

May combine two claims.

Islet PDGFRAD842V mRNA levels in both βEzh2KO-RαTg and βEzh2HET-RαTg mice are elevated and indistinguishable.

“Islet PDGFRAD842V mRNA levels in both βEzh2KO-RαTg and βEzh2HET-RαTg mice were elevated and indistinguishable (Fig. 4a).”

May combine two claims.

Total pancreatic mass and islet architecture in βPDGFRαTg mice and controls are indistinguishable.

“In contrast, total pancreatic mass and islet architecture in βPDGFRαTg mice and controls were indistinguishable (Supplementary Figs 5c and 6b).”

May combine two claims.

βPDGFRαTg islets have elevated levels of Ccnd1 mRNA encoding cyclin D1, and increased β-cells with nuclear cyclin D1 and phosphorylated Rb protein.

“PDGF/ERK signalling activates cell cycle regulators to stimulate proliferation24,25, and βPDGFRαTg islets had elevated levels of Ccnd1 mRNA encoding cyclin D1, and increased β-cells with nuclear cyclin D1 and phosphorylated Rb protein (Fig. 5c–e and Supplementary Fig. 9a).”

• cites [24] Uhrbom, L., Nerio, E. & Holland, E. C. Dissecting tumor maintenance requirements using bioluminescence imaging of cell proliferation in a mouse glioma model. Nature Med. 10, 1257–1260 (2004) sourceNot checked yet

  Not checked in the free run.

• cites [25] Furstoss, O., Manes, G. & Roche, S. Cyclin E and cyclin A are likely targets of Src for PDGF-induced DNA synthesis in fibroblasts. FEBS Lett. 526, 82–86 (2002) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Islet ChIP studies in RbTriKO mice reveal increased E2f1 association and reduced E2f4 association with Ezh2 cis-regulatory elements.

“Islet ChIP studies revealed increased E2f1 association, and reduced E2f4 association with Ezh2 cis-regulatory elements (Supplementary Fig. 12d, e).”

May combine two claims.

Ezh2 induction in juvenile wild-type islets exposed to PDGF-AA is blocked by U0126, but not by LY294002 or U-73122.

“Ezh2 induction in juvenile wild-type islets exposed to PDGF-AA was blocked by U0126, which inhibits Erk1/2 activation23, but not by LY294002 or U-73122, inhibitors of PI3K or PLC-γ signalling (Supplementary Fig. 8a).”

• cites [23] Duncia, J. V. et al. MEK inhibitors: the chemistry and biological activity of U0126, its analogs, and cyclization products. Bioorg. Med. Chem. Lett. 8, 2839–2844 (1998) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

βPdgfrαKO mice permit conditional Pdgfra inactivation in islet β-cells and loss of detectable Pdgfra mRNA and protein expression.

“To assess whether premature Pdgfr loss might compromise Ezh2-dependent neonatal β-cell proliferation, we generated RIP-Cre; Pdgfraf/f mice (abbreviated to βPdgfrαKO) that permit conditional Pdgfra inactivation in islet β-cells and loss of detectable Pdgfra mRNA and protein expression (Fig. 1d and Supplementary Fig. 3a).”

May combine two claims.

β-cell BrdU incorporation and mass are increased in βEzh2HET-RαTg mice compared to controls.

“As expected, β-cell BrdU incorporation and mass were increased in βEzh2HET-RαTg mice (Fig. 4c, d and Supplementary Fig. 7) compared to controls (either Ezh2f/f, R26-PDGFRαD842V or Ezh2f/+, R26-PDGFRαD842V genotype).”

May combine two claims.

β-cell mass in control mice gradually recovers after STZ treatment, accompanied by increased β-cell Ezh2 expression and proliferation.

“Consistent with this view, β-cell mass in control mice gradually recovered after STZ treatment, accompanied by increased β-cell Ezh2 expression and proliferation; in contrast, βPdgfαKO β-cells failed to increase Ezh2 or proliferation to restore β-cell mass (Fig. 2c–e).”

May combine two claims.

Increased phosphorylation of Erk1/2, but not phosphorylation of Akt or PLC-γ, is detected in βPDGFRαTg islets compared to control islets.

“We also detected increased phosphorylation of Erk1/2, but not phosphorylation of Akt or PLC-γ, in βPDGFRαTg islets compared to control islets (Fig. 5a, b).”

May combine two claims.

βPDGFRαTg mice express human PDGFRA mRNA and PDGFR-a(D842V) protein in islet β-cells.

“In contrast to littermate controls, mice with the RIP-Cre; R26-PDGFRAD842V genotype (abbreviated to βPDGFRαTg) expressed human PDGFRA mRNA and PDGFR-a(D842V) protein in islet β-cells (Fig. 3a and Supplementary Fig. 5a).”

May combine two claims.

ChIP studies reveal that association of E2f1 with Ezh2 decreases, whereas association of E2f4 with Ezh2 elements increases in islets with age.

“ChIP studies also revealed that association of E2f1 with Ezh2 decreased, whereas association of E2f4 with Ezh2 elements increased in islets with age (Supplementary Fig. 11c, d).”

May combine two claims.

β-cell Ezh2 expression in βPDGFRαTg mice is maintained at elevated levels, a difference that persists for 8-14 months.

“By 3 months, β-cell Ezh2 expression had declined in control mice, but β-cell Ezh2 expression in βPDGFRαTg mice was maintained at elevated levels, a difference that persisted for 8–14 months (Fig. 3e, f).”

May combine two claims.

Increased β-cell BrdU incorporation in islets exposed to PDGF-AA is blocked by U0126, but not by LY294002.

“Similarly, increased β-cell BrdU incorporation in islets exposed to PDGF-AA was blocked by U0126, but not by LY294002 (Supplementary Fig. 8b), indicating that Erk mediates β-cell Pdgf signalling responses.”

May combine two claims.

ChIP studies show increased E2f1 association and reduced E2f4 association with Ezh2 elements in βPDGFRαTg islets.

“We identified two conserved candidate E2f-binding elements near the Ezh2 promoter (Supplementary Fig. 10), and chromatin immunoprecipitation (ChIP) studies showed increased E2f1 association and reduced E2f4 association with these Ezh2 elements in βPDGFRαTg islets (Fig. 5f, g).”

May combine two claims.

Exposure of 3-week-old islets to PDGF-AA increases Ezh2 mRNA and protein levels, but not Ezh1 expression.

“Exposure of 3-week-old islets to PDGF-AA increased phospho-Pdgfr-α levels and Ezh2 mRNA and protein levels, but not Ezh1 expression (Supplementary Fig. 4a–c).”

May combine two claims.

Increased islet Ezh2 mRNA levels and β-cell Ezh2 protein are not observed in βEzh2KO-RαTg or βEzh2KO littermates, confirming Cre-mediated deletion of Ezh2.

“By contrast, increased islet Ezh2 mRNA levels and β-cell Ezh2 protein were not observed in βEzh2KO-RαTg or βEzh2KO littermates (Fig. 4b and Supplementary Fig. 7), confirming Cre-mediated deletion of Ezh2 in these mice.”

May combine two claims.

β-cell Ezh2 protein and islet Ezh2 mRNA levels are reduced in βPdgfrαKO islets compared to controls.

“Compared to controls, β-cell Ezh2 protein and islet Ezh2 mRNA levels were reduced whereas p16INK4a mRNA levels were increased in βPdgfrαKO islets (Fig. 1e and Supplementary Fig. 3a, b); in contrast, Pdgfrb and Ezh1 mRNA levels were unchanged in βPdgfrαKO islets (Supplementary Fig. 3c, d).”

May combine two claims.

During re-feeding after overnight fast, βPDGFRαTg mice have a 25% reduction of blood glucose, associated with a modest elevation of plasma insulin levels, and both changes are sustained for up to 14 months.

“During re-feeding after overnight fast, βPDGFRαTg mice had a 25% reduction of blood glucose (Fig. 3g), associated with a modest elevation of plasma insulin levels (Supplementary Fig. 6i), and both changes were sustained for up to 14 months.”

May combine two claims.

Expression of R26-PDGFRαD842V does not affect β-cell expansion and glucose control in neonatal or juvenile βPDGFRαTg mice.

“Expression of R26-PDGFRαD842V did not affect endogenous islet Pdgfra mRNA levels (Fig. 3a) or β-cell expansion and glucose control in neonatal or juvenile βPDGFRαTg mice (Fig. 3b, c and Supplementary Figs 5b and 6a–d).”

May combine two claims.

β-cell mass is increased in βPDGFRαTg mice at 3 months and remains increased at 14 months compared to age-matched controls.

“β-cell mass was increased in βPDGFRαTg mice at 3 months, and remained increased at 14 months compared to age-matched controls (Fig. 3b).”

May combine two claims.

Modest postprandial blood glucose reduction and increased blood insulin levels are detected in βEzh2HET-RαTg mice, but not in βEzh2KO-RαTg mice.

“Consistent with these findings, we detected modest postprandial blood glucose reduction and increased blood insulin levels in βEzh2HET-RαTg mice, but not in βEzh2KO-RαTg mice (Fig. 4e, f).”

May combine two claims.

Control mice become moderately diabetic immediately after STZ challenge, but achieve restored glucose control 3-4 weeks thereafter, coinciding with increases of β-cell mass.

“In contrast, control mice became moderately diabetic immediately after STZ challenge, but achieved restored glucose control 3–4 weeks thereafter (Fig. 2f), coinciding with increases of β-cell mass (Fig. 2e).”

May combine two claims.

Loss of β-cell Pdgf signalling in βPdgfαKO mice diminishes islet levels of Ccnd1 mRNA, and reduces numbers of phospho-Erk1/2+ and phospho-Rb+ β-cells.

“In contrast, loss of β-cell Pdgf signalling in βPdgfαKO mice diminished islet levels of Ccnd1 mRNA, and reduced numbers of phospho-Erk1/2+ and phospho-Rb+ β-cells (Supplementary Fig. 9b, c).”

May combine two claims.

Pdgfrb and Ezh1 mRNA levels are unchanged in βPdgfrαKO islets.

“Compared to controls, β-cell Ezh2 protein and islet Ezh2 mRNA levels were reduced whereas p16INK4a mRNA levels were increased in βPdgfrαKO islets (Fig. 1e and Supplementary Fig. 3a, b); in contrast, Pdgfrb and Ezh1 mRNA levels were unchanged in βPdgfrαKO islets (Supplementary Fig. 3c, d).”

May combine two claims.

Basal EZH2 mRNA levels are lower in adult human islets and not induced by PDGF-AA.

“In contrast, basal EZH2 mRNA levels were lower in adult islets and not induced by PDGF-AA (Fig. 6c).”

May combine two claims.

mRNA levels of EZH2, but not EZH1, are increased in juvenile human islets exposed to PDGF-AA, an effect blocked by Sunitinib or U0126.

“mRNA levels of EZH2, but not EZH1, were increased in juvenile human islets exposed to PDGF-AA, an effect blocked by Sunitinib or U0126 (Fig. 6c and Supplementary Fig. 13a).”

May combine two claims.

PDGFR-a is only detected in non-β-cells of islets from adult human donors, with little to no detectable phospho-ERK1/2, phospho-RB or EZH2 in β-cells.

“In contrast, PDGFR-a was only detected in non-β-cells of islets from adult human donors, with little to no detectable phospho-ERK1/2, phospho-RB or EZH2 in β-cells (Fig. 6a, b), suggesting that PDGF signalling attenuation is a conserved feature of ageing islet β-cells.”

May combine two claims.

RbTriKO mice become hypoglycaemic and develop other islet and metabolic phenotypes reminiscent of insulinoma pathogenesis.

“RbTriKO mice became hypoglycaemic and developed other islet and metabolic phenotypes reminiscent of insulinoma pathogenesis.”

May combine two claims.

ChIP studies demonstrate PDGF-AA-stimulated association of E2F1 with the human EZH2 locus, an effect blocked by Sunitinib.

“Similar to juvenile mouse islets with activated Pdgf signalling, ChIP studies demonstrated PDGF-AA-stimulated association of E2F1 with the human EZH2 locus, an effect blocked by Sunitinib (Fig. 6d).”

May combine two claims.

Juvenile human islets exposed to PDGF-AA have a sixfold increase of β-cell BrdU incorporation, an effect eliminated by Sunitinib or U0126.

“Compared to vehicle-exposed controls, juvenile islets exposed to PDGF-AA had a sixfold increase of β-cell BrdU incorporation, an effect eliminated by simultaneous exposure to Sunitinib or U0126 (Fig. 6e, f).”

May combine two claims.

PDGFR-α protein and phospho-ERK1/2 levels are readily detected in islets from young human donors.

“Like in juvenile mice, PDGFR-α protein and phospho-ERK1/2 levels were readily detected in islets from young human donors (Fig. 6a, b).”

May combine two claims.

Proliferating BrdU+ cells in juvenile human islets stimulated by PDGF-AA are predominantly β-cells, verified by immuno-localization.

“Proliferating BrdU+ cells in juvenile islets stimulated by PDGF-AA were predominantly β-cells, verified by immuno-localization of BrdU+ nuclei within insulin+ cells and PDX1+ nuclei with confocal microscopy (Fig. 6f and Supplementary Fig. 13b, c).”

May combine two claims.

Pathological loss of all Rb family proteins in RbTriKO islets leads to a fourfold increase in Ezh2 mRNA and a 15-fold increase in β-cell proliferation.

“However, pathological loss of all Rb family proteins in RbTriKO islets led to a fourfold increase in Ezh2 mRNA, and a 15-fold increase in β-cell proliferation.”

Classified as probably not a substantial claim. May combine two claims.

Ezh2 is a histone methyltransferase crucial for trimethylation of histone H3 on Lys 27 (H3K27me3), a modification mediating transcriptional repression.

“Ezh2 is a histone methyltransferase crucial for trimethylation of histone H3 on Lys 27 (H3K27me3), a modification mediating transcriptional repression14,15.”

• cites [14] Cao, R. et al. Role of histone H3 lysine 27 methylation in Polycomb-group silencing. Science 298, 1039–1043 (2002) sourceNot checked yet

  Not checked in the free run.

• cites [15] van der Vlag, J. & Otte, A. P. Transcriptional repression mediated by the human polycomb-group protein EED involves histone deacetylation. Nature Genet. 23, 474–478 (1999) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Induction of human islet β-cell proliferation remains an unattained goal, with studies reporting inconsistent mitogenic responses.

“Likewise, induction of human islet β-cell proliferation remains an unattained goal, with studies reporting inconsistent mitogenic responses5,6.”

• cites [5] Beattie, G. M. et al. A novel approach to increase human islet cell mass while preserving β-cell function. Diabetes 51, 3435–3439 (2002) sourceNot checked yet

  Not checked in the free run.

• cites [6] Parnaud, G. et al. Proliferation of sorted human and rat β-cells. Diabetologia 51, 91–100 (2008) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Ezh2 represses Cdkn2a and promotes β-cell proliferation in juvenile mouse islets.

“We showed that the polycomb group protein Ezh2 represses Cdkn2a and promotes β-cell proliferation in juvenile mouse islets13.”

• cites [13] Chen, H. et al. Polycomb protein Ezh2 regulates pancreatic β-cell Ink4a/Arf expression and regeneration in diabetes mellitus. Genes Dev. 23, 975–985 (2009) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In mice or other experimental animals, β-cell expansion from modulating intracellular factors or activating intrinsic pathways with extrinsic mitogenic factors has been transient or limited, and often complicated by uncontrolled β-cell growth, loss of defining β-cell features and impaired metabolic control.

“In mice or other experimental animals, β-cell expansion from such efforts has been transient or limited, and often complicated by uncontrolled β-cell growth, loss of defining β-cell features and impaired metabolic control3,4.”

• cites [3] Vasavada, R. C. et al. Targeted expression of placental lactogen in the β-cells of transgenic mice results in β-cell proliferation, islet mass augmentation, and hypoglycemia. J. Biol. Chem. 275, 15399–15406 (2000) sourceNot checked yet

  Not checked in the free run.

• cites [4] Garcia-Ocana, A. et al. Hepatocyte growth factor overexpression in the islet of transgenic mice increases β-cell proliferation, enhances islet mass, and induces mild hypoglycemia. J. Biol. Chem. 275, 1226–1232 (2000) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Pancreatic β-cell proliferation decreases rapidly in juvenile mice and humans, then declines more slowly in adults.

“Pancreatic β-cell proliferation decreases rapidly in juvenile mice and humans, then declines more slowly in adults9,10.”

• cites [9] Teta, M. et al. Very slow turnover of β-cells in aged adult mice. Diabetes 54, 2557–2567 (2005) sourceNot checked yet

  Not checked in the free run.

• cites [10] Meier, J. J. et al. β-Cell replication is the primary mechanism subserving the postnatal expansion of β-cell mass in humans. Diabetes 57, 1584–1594 (2008) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Premature loss of Pdgfra impairs β-cell proliferation and expansion and glucose control in young mice.

“Thus, premature loss of Pdgfra impairs β-cell proliferation and expansion and glucose control in young mice.”

May combine two claims.

Modulation of β-cell Pdgf signalling attenuates age-dependent proliferative failure and Ezh2 loss, permitting in vivo expansion of β-cells with regulated function.

“Modulation of β-cell Pdgf signalling attenuates age-dependent proliferative failure and Ezh2 loss, permitting in vivo expansion of β-cells with regulated function.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Pdgfr signalling promotes proliferation, survival and migration in diverse cell types.

“Pdgfr signalling promotes proliferation, survival and migration in diverse cell types16.”

• cites [16] Schlessinger, J. Cell signaling by receptor tyrosine kinases. Cell 103, 211–225 (2000) sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Pdgf-induced actin polymerization in fibroblasts requires Ezh2.

“Pdgf-induced actin polymerization in fibroblasts requires Ezh2 (ref. 19), suggesting that Pdgf signalling might regulate Ezh2 expression and age-dependent β-cell proliferation in islets.”

• cites [19] Su, I. et al. Polycomb group protein Ezh2 controls actin polymerization and cell signaling. Cell 121, 425–436 (2005) sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Age-dependent attenuation of β-cell Pdgfr-α alters Erk and Rb/E2f signalling, resulting in reduced Ezh2 expression.

“Thus, age-dependent attenuation of β-cell Pdgfr-α altered Erk and Rb/E2f signalling, resulting in reduced Ezh2 expression.”

May combine two claims.

PDGF-AA exposure is sufficient to stimulate β-cell replication in juvenile islets, but loss of competence for Pdgf prevents this response in adult islets.

“Thus, PDGF-AA exposure was sufficient to stimulate β-cell replication in juvenile islets, but loss of competence for Pdgf prevented this response to PDGF-AA in adult islets.”

May combine two claims.

PDGFRaTg mice maintain normal glucose-regulated insulin release and glycaemic control, suggesting that β-cell function remained regulated in these mice.

“Thus, PDGFRaTg mice maintained normal glucose-regulated insulin release and glycaemic control, suggesting that β-cell function remained regulated in these mice.”

May combine two claims.

Cardinal features of this pathway are conserved in human islets, permitting conditional induction of human β-cell replication.

“Cardinal features of this pathway are conserved in human islets, permitting conditional induction of human β-cell replication.”

Classified as probably not a substantial claim. May combine two claims.

The molecular basis for proliferative responses to PDGF decline and the roles of Pdgf signalling in islet β-cell growth and development were not established.

“However, the molecular basis for these observations and the roles of Pdgf signalling in islet β-cell growth and development were not established17,18,32.”

• cites [17] Swenne, I. et al. Effects of platelet-derived growth factor and somatomedin-C/insulin-like growth factor I on the deoxyribonucleic acid replication of fetal rat islets of Langerhans in tissue culture. Endocrinology 122, 214–218 (1988) sourceNot checked yet

  Not checked in the free run.

• cites [18] Welsh, M. et al. Coexpression of the platelet-derived growth factor (PDGF) B chain and the PDGF beta receptor in isolated pancreatic islet cells stimulates DNA synthesis. Proc. Natl Acad. Sci. USA 87, 5807–5811 (1990) sourceNot checked yet

  Not checked in the free run.

• cites [32] LeBras, S., Czernichow, P. & Scharfmann, R. A search for tyrosine kinase receptors expressed in the rat embryonic pancreas. Diabetologia 41, 1474–1481 (1998) sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Proliferative responses to PDGF decline in some ageing cells.

“Proliferative responses to PDGF decline in some ageing cells30, and progenitor cell self-renewal is impaired by Pdgf signalling disruption31.”

• cites [30] Scherping, S. C., Jr et al. Effect of growth factors on the proliferation of ligament fibroblasts from skeletally mature rabbits. Connect. Tissue Res. 36, 1–8 (1997) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Stanford University School of Medicine's institutional review board approved the research use of human tissue.

“Institutional review board approval for research use of tissue was obtained from Stanford University School of Medicine.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Erk regulation of Ezh2 occurs in cancer cells.

“Our work also suggests that Mapk/Erk regulation links Pdgfr activation to Ezh2 induction and β-cell proliferation, consistent with studies demonstrating Erk regulation of Ezh2 in cancer cells33, and Erk activation that accompanies mouse β-cell expansion in pregnancy34.”

• cites [33] Fujii, S. et al. MEK–ERK pathway regulates EZH2 overexpression in association with aggressive breast cancer subtypes. Oncogene 10.1038/onc.2011.118 (18 April 2011) sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

FACS-sorted MIP-GFP-positive β-cells were harvested at greater than 95% purity.

“MIP-GFP+ β-cells with >95% purity were harvested and immediately lysed for RNA purification and real-time RT–PCR analysis.”

May combine two claims.

β-cell Pdgfr signalling is required for Ezh2 induction, to sustain both physiological and regenerative β-cell proliferation.

“We found that β-cell Pdgfr signalling was required for Ezh2 induction, to sustain both physiological and regenerative β-cell proliferation.”

May combine two claims.

Rb proteins constrain Ezh2 expression and adult islet cell growth.

“Thus, Rb proteins constrain Ezh2 expression and adult islet cell growth.”

Classified as probably not a substantial claim. May combine two claims.

β-cell mass and proliferation were morphometrically quantified by independent researchers blinded to sample identity.

“β-cell mass and proliferation were morphometrically quantified13 by independent researchers blinded to sample identity.”

• cites [13] Chen, H. et al. Polycomb protein Ezh2 regulates pancreatic β-cell Ink4a/Arf expression and regeneration in diabetes mellitus. Genes Dev. 23, 975–985 (2009) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

PDGF ligands are measurable in serum, and regulation of such circulating signalling agonists may provide an additional level of growth control in competent islet β-cells.

“PDGF ligands are measurable in serum, and regulation of such circulating signalling agonists may provide an additional level of growth control in competent islet β-cells.”

Classified as probably not a substantial claim.

Human pancreas or islet tissue from organ donors was procured with appropriate consent.

“Human pancreases or islets from organ donors were procured by arrangement with the National Disease Resource Interchange and the University of Alabama, Birmingham with appropriate consent.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Mechanisms underlying pancreatic β-cell expansion in physiological settings may differ between species.

“Although the mechanisms underlying pancreatic β-cell expansion in physiological settings may differ between species36,37, age-dependent restriction of β-cell proliferation is a conserved feature in mice and humans9,10.”

• cites [36] Butler, A. E. et al. Adaptive changes in pancreatic β-cell fractional area and β-cell turnover in human pregnancy. Diabetologia 53, 2167–2176 (2010) sourceNot checked yet

  Not checked in the free run.

• cites [37] Rieck, S. & Kaestner, K. H. Expansion of β-cell mass in response to pregnancy. Trends Endocrinol. Metab. 21, 151–158 (2010) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Erk activation accompanies mouse β-cell expansion in pregnancy.

“Our work also suggests that Mapk/Erk regulation links Pdgfr activation to Ezh2 induction and β-cell proliferation, consistent with studies demonstrating Erk regulation of Ezh2 in cancer cells33, and Erk activation that accompanies mouse β-cell expansion in pregnancy34.”

• cites [34] Gupta, R. K. et al. Expansion of adult β-cell mass in response to increased metabolic demand is dependent on HNF-4α. Genes Dev. 21, 756–769 (2007) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Prior studies correlated increased PDGFR and EZH2 expression in human endocrine neoplasias.

“Prior studies correlated increased PDGFR and EZH2 expression in human endocrine neoplasias38, and disrupted PDGF signalling in β-cells of humans with type 2 diabetes39.”

• cites [38] Ebert, M. et al. Induction of platelet-derived growth factor A and B chains and over-expression of their receptors in human pancreatic cancer. Int. J. Cancer 62, 529–535 (1995) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The study's animal experiments and methods received approval from Stanford University's Institutional Animal Care and Use Committee.

“All animal experiments and methods were approved by the Institutional Animal Care and Use Committee of Stanford University.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Repeated experiments on multiple pancreas sections from each donor pancreas yielded similar results.

“Experiments were repeated onmultiple pancreas sections for every donor pancreas and similar results were obtained.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Progenitor cell self-renewal is impaired by Pdgf signalling disruption.

“Proliferative responses to PDGF decline in some ageing cells30, and progenitor cell self-renewal is impaired by Pdgf signalling disruption31.”

• cites [31] Pallante, B. A. et al. Bone marrow Oct3/4+ cells differentiate into cardiac myocytes via age-dependent paracrine mechanisms. Circ. Res. 100, e1–e11 (2007) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The mice used in the study were age- and gender-matched littermates and included both sexes.

“Mice used in this study were age- and gender-matched littermates including both sexes.”

May combine two claims.

PDGF signalling regulates EZH2, CDKN2A and β-cell proliferation in human islets.

“Thus, our demonstration that PDGF signalling regulates EZH2,CDKN2A and β-cell proliferation in human islets combines several observations into a new molecular model for physiological and pathological β-cell growth.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Morphometric image analysis was performed by observers who were blinded to genotype.

“Images were analysed with an ImagePro program by observers blinded to genotype, and pancreatic β-cell mass and percentage of BrdU+ β-cells were calculated as described previously13.”

May combine two claims.

In vivo activation of β-cell PDGFR-α signalling increases Ezh2 expression and mitigates age-dependent decline of β-cell proliferation.

“In vivo activation of β-cell PDGFR-α signalling increased Ezh2 expression and mitigated age-dependent decline of β-cell proliferation.”