Identification of small-molecule inducers of pancreatic β-cell expansion

Abstract

To identify small molecules that can induce β-cell replication, a large chemical library was screened for proliferation of growth-arrested, reversibly immortalized mouse β cells by using an automated high-throughput screening platform. A number of structurally diverse, active compounds were identified, including phorbol esters, which likely act through protein kinase C, and a group of thiophene-pyrimidines that stimulate β-cell proliferation by activating the Wnt signaling pathway. A group of dihydropyridine (DHP) derivatives was also shown to reversibly induce β-cell replication in vitro by activating L-type calcium channels (LTCCs). Our data suggest that the LTCC agonist 2a affects the expression of genes involved in cell cycle progression and cellular proliferation. Furthermore, treatment of β cells with both LTCC agonist 2a and the Glp-1 receptor agonist Exendin-4 showed an additive effect on β-cell replication. The identification of small molecules that induce β-cell proliferation suggests that it may be possible to reversibly expand other quiescent cells to overcome deficits associated with degenerative and/or autoimmune diseases.

Small molecule-based disruption of the Axin/β-catenin protein complex regulates mesenchymal stem cell differentiation

“…Because GSK-3β is involved in multiple signaling pathways other than Wnt/β-catenin signaling, GSK-3β inhibitors are less than ideal drugs, as they could have unexpected effects on the cell and/or model organisms. In addition, although pyrimidine analogs have been identified as agonist of the Wnt/β-catenin pathway, their molecular targets and mechanisms of action are still unknown [31]. In our study, SKL2001 did not affect GSK-3β activity in regard to β-catenin phosphorylation at Ser33/37/Thr41 residues in vitro, suggesting that a novel mechanism, not dependent on the inhibition of GSK-3β activity, may mediate the inhibition of β-catenin phosphorylation by SKL2001 in cells.…”

How to make a functional β-cell

“…Additional molecular regulators of β-cell replication in rodents have been identified through high-throughput screening of reversibly immortalized β-cell lines or primary rodent islets. These regulators include phorbol esters, thiophene-pyrimidines, dihydropyridine derivatives and adenosine kinase inhibitors (Annes et al, 2012;Wang et al, 2009). Glucose or Glp1r agonists have an additive effect on the replication induced by most of these recently identified factors (Annes et al, 2012;Wang et al, 2009); however, it remains to be seen whether these small molecules will have an inductive effect on human islets.…”

“…One such device has been successfully used for the protected transplantation of human islets and hESC-derived pancreatic progenitors into mice (Lee et al, 2009;Xie et al, 2013). An alternative strategy to avoid allogeneic immune rejection might be to develop protocols for the differentiation or reprogramming of patient-specific iPSCs into β-cells, particularly iPSCs that have been generated by non-viral methods.…”

“…These regulators include phorbol esters, thiophene-pyrimidines, dihydropyridine derivatives and adenosine kinase inhibitors (Annes et al, 2012;Wang et al, 2009). Glucose or Glp1r agonists have an additive effect on the replication induced by most of these recently identified factors (Annes et al, 2012;Wang et al, 2009); however, it remains to be seen whether these small molecules will have an inductive effect on human islets. More recently, Schultz and colleagues identified a novel small molecule, WS6, that increased both rat and human β-cell replication in vitro by sixfold in dispersed islets and by more than tenfold in intact islets (Shen et al, 2013).…”

The New Generation of Beta-Cells: Replication, Stem Cell Differentiation, and the Role of Small Molecules

“…Therefore, screening for factors that increase β-cell replication in vivo may have direct therapeutic benefits to diabetic patients. Recently, a high-throughput screening of a chemical library for inducers of β-cell proliferation has been done by Wang et al [41]. The group used growth-arrested, reversibly immortalized mouse β-cells, and found a number of diverse molecules that promoted beta-cell replication.…”