Recent Advances in Disease Modeling and Drug Discovery for Diabetes Mellitus Using Induced Pluripotent Stem Cells

Abstract

Diabetes mellitus (DM) is a widespread metabolic disease with a progressive incidence of morbidity and mortality worldwide. Despite extensive research, treatment options for diabetic patients remains limited. Although significant challenges remain, induced pluripotent stem cells (iPSCs) have the capacity to differentiate into any cell type, including insulin-secreting pancreatic β cells, highlighting its potential as a treatment option for DM. Several iPSC lines have recently been derived from both diabetic and healthy donors. Using different reprogramming techniques, iPSCs were differentiated into insulin-secreting pancreatic βcells. Furthermore, diabetes patient-derived iPSCs (DiPSCs) are increasingly being used as a platform to perform cell-based drug screening in order to develop DiPSC-based cell therapies against DM. Toxicity and teratogenicity assays based on iPSC-derived cells can also provide additional information on safety before advancing drugs to clinical trials. In this review, we summarize recent advances in the development of techniques for differentiation of iPSCs or DiPSCs into insulin-secreting pancreatic β cells, their applications in drug screening, and their role in complementing and replacing animal testing in clinical use. Advances in iPSC technologies will provide new knowledge needed to develop patient-specific iPSC-based diabetic therapies.

Keywords: cell-based drug screening; diabetes mellitus; iPSC-based diabetic therapy; induced pluripotent stem cells; insulin-secreting β cells.

Figure 1

Schematic presentation of generation of iPSCs (induced pluripotent stem cells) from healthy and diabetic patients and their application in the patient-specific iPSC-based diabetic therapy. Footprint-free iPSCs can be generated from healthy individual- or diabetic patient-derived somatic cells using reprogramming DNA-, RNA-, protein-, miRNA-, or small molecule-mediated reprogramming system. DiPSCs (iPSCs derived from diabetic patients) can be further differentiated into insulin-secreting pancreatic β cells for cell-based diabetic drug screening or for transplantation into diabetic patients for cell therapy. DiPSCs can also be repaired by gene correction and then be differentiated into functional insulin-secreting pancreatic β cells, which can be transplanted into a specific diabetic patient. For disease modeling, DiPSCs can be differentiated into insulin-secreting pancreatic β cells for drug screening or pathogenesis studies to develop the compounds or therapies to treat specific type of diabetes.

Figure 2

Schematic diagram depicting the various pancreatic β cell differentiation protocols for healthy iPSCs (A) and/or DiPSCs (B). The iPSCs and DiPSC can be differentiated into insulin-secreting functional β cells through the stages, embryoid body (EB), definitive endoderm (DE), pancreatic gut tube (PGT), pancreatic progenitor (PP), posterior fore gut (PFG), multi-lineage progenitor (MP), spontaneous differentiation (SD), progenitor expansion (PE), pancreatic differentiation (PD), NKX6-1⁺/C-peptide⁺ EN cells, stem cell-derived β (SC-β) cells, and/or pancreatic β-cells using specific transcription factors and small molecules. The following transcription factors, small molecules, and specific differentiation markers were used for the pancreatic β cell differentiation; EGF (epidermal growth factor), bFGF (basic fibroblast growth factor), NA butyrate (sodium butyrate), CHIR99021 (aGSK3β inhibitor), KGF (keratinocyte growth factor), RA (retinoic acid), SANT1 (a sonic hedgehog pathway antagonist), CMRL-supplement, PdBu (phorbol 12,13-dibutyrate; a PKC activator), LDN (LDN193189; a BMP pathway inhibitor), T3 (triiodothyronine; a thyroid hormone), Alk5i (ALK5 receptor inhibitor), FGF10 (fibroblast growth factor 10), CYC (cyclopamine; a Hh signaling pathway inhibitor), ILV (indolactam V; a PKC activator), SST (somatostatin; somatotropin (growth hormone) release–inhibiting hormone), GCG (glucagon), INS (insulin), HGF (hepatocyte growth factor), DAPT (a γ-secretase (NOTCH signaling pathway) inhibitor), GLP-1 (glucagon-like peptide 1), LP1 (synaptic membrane fractions), Nico (nicotinamide), FOXA2 (forkhead box protein A2), PAX4 (paired homeobox transcription factor 4), PAX 6 (paired homeobox transcription factor 6), NGN3 (neurogenin 3), HNF (hepatocyte nuclear factor), PDX1 (pancreatic and duodenal homeobox 1); NKX6.1 (NK6 homeobox transcription factor related, locus 1), SOX17 (SRY-box 17), and NKX2.2 (NK2 homeobox transcription factor related, locus 2).