Different combinations of GABA, BMP7, and Activin A induced the in vitro differentiation of rat pancreatic ductal stem cells into insulin-secreting islet-like cell clusters.

AIMS: We investigated the in vitro differentiation of adult rat PDESCs into ß-like cells through supplementation of different combinations of GABA, BMP7, and Activin A in basic culture media. MATERIALS AND METHODS: The PDESCs were cultured using different inducement combinations for 28 days and microscopy, dithizone (DTZ) staining, immunohistochemical staining, real-time PCR, and glucose-stimulated insulin secretion (GSIS) assay were used to delineate the differentiation inducement potential of these combinations. KEY FINDINGS: The results show that after 28 days, the PDESCs were differentiated into ICCs containing insulin-secreting ß-like cells in different groups treated with A + B, A + G, B + G, and A + B + G but not in the control group. Upon DTZ staining the cells in ICCs were stained crimson red, demonstrating the presence of ß-like cells in ICCs and the immunohistochemistry showed the expression of Pdx1 and insulin in ICCs. Further, on 28 d the expression of Pdx1 and insulin mRNA was high in inducement groups as compared to the control group and ß-like cells in ICCs also secreted insulin and C-peptide upon glucose stimulation. Thus, the supplementation of GABA, BMP7, and Activin A in different combinations in basic culture media can induce the in vitro differentiation of PDESCs into ICCs containing ß-like cells. SIGNIFICANCE: The in vitro development of ß-like cells is a herald for cell therapy of diabetic patients and our results are a step closer towards finding the cure for diabetes.

Differentiation of rat pancreatic duct stem cells into insulin-secreting islet-like cell clusters through BMP7 inducement.

To cure the epidemic of diabetes, in vitro produced ß-like cells are lauded for cell therapy of diabetic patients. In this regard, we investigated the effects of different concentrations of bone morphogenetic protein 7 (BMP7) on the differentiation of rat pancreatic ductal epithelial-like stem cells (PDESCs) into ß-like cells. For inducement of the differentiation, PDESCs were cultured in the basal media (H-DMEM + 10 % FBS + 1% penicillin-streptomycin) supplemented with 5 ng/mL, 10 ng/mL, 15 ng/mL, and 20 ng/mL of BMP7 for 28 days. To corroborate the identity of induced cells, they were examined through cell morphology, dithizone (DTZ) staining, immunofluorescence staining, real-time polymerase chain reaction (qPCR), and glucose-stimulated insulin secretion assay (GSIS). The enrichment of induced cells was high among 5 ng/mL, 10 ng/mL, 15 ng/mL, and 20 ng/mL of BMP7 supplemented groups as compared to the control group. Further, the induced cells were positive, while, the control group cells were negative to DTZ staining and the differentiated cells also have shown the upregulated expression of ß cell-specific marker genes (Ins1 and Pdx1). The GSIS assay of inducement groups for insulin and C-peptide secretion has shown significantly higher values as compared to the control group (P < 0.01). Hence, the addition of BMP7 to basal medium has effectually induced differentiation of adult rat PDESCs into islet like-cell clusters containing insulin-secreting ß-like cells.

Gimmicks of gamma-aminobutyric acid (GABA) in pancreatic ß-cell regeneration through transdifferentiation of pancreatic α- to ß-cells.

In vivo regeneration of lost or dysfunctional islet ß cells can fulfill the promise of improved therapy for diabetic patients. To achieve this, many mitogenic factors have been attempted, including gamma-aminobutyric acid (GABA). GABA remarkably affects pancreatic islet cells' (α cells and ß cells) function through paracrine and/or autocrine binding to its membrane receptors on these cells. GABA has also been studied for promoting the transformation of α cells to ß cells. Nonetheless, the gimmickry of GABA-induced α-cell transformation to ß cells has two different perspectives. On the one hand, GABA was found to induce α-cell transformation to ß cells in vivo and insulin-secreting ß-like cells in vitro. On the other hand, GABA treatment showed that it has no α- to ß-cell transformation response. Here, we will summarize the physiological effects of GABA on pancreatic islet ß cells with an emphasis on its regenerative effects for transdifferentiation of islet α cells to ß cells. We will also critically discuss the controversial results about GABA-mediated transdifferentiation of α cells to ß cells.