Effects of Exendine-4 on The Differentiation of Insulin Producing Cells from Rat Adipose-Derived Mesenchymal Stem Cells

Efficiency of Stem Cell (SC) Differentiation into Insulin-Producing Cells for Treating Diabetes: a Systematic Review

Over the recent years, the use of stem cells has provided a new opportunity to treat various disorders including diabetes. Stem cells are unspecialized cells with a capacity for self-renewal and differentiation into more specialized cell types. Many factors contribute to the differentiation of SCs and thus play an important role in regulating the fate of stem cells. Accordingly, a wide range of protocols has been used to differentiate SCs to insulin-producing cells but the effectiveness of SC differentiation varies. The aim of this systematic review was to evaluate the results obtained from different studies on SC differentiation for higher efficacy to treat diabetes. This search was done in PubMed, Web of Science (WOS), and Scopus using keywords “insulin-producing cell (IPC),” “pancreatic B cell,” “insulin-secreting cell,” “stem cell,” “progenitor cells,” “mother cell,” and “colony-forming unit.” Among more than 3646 papers, 32 studies were considered eligible for more evaluations. The obtained results indicated that most of the studies were performed on the mesenchymal stem cells (MSCs) derived from different tissues as compared with other types of SCs. Different evaluations of in vitro studies as well as animal models supported their role in the recovery of diabetes. In the present review, we summarize and discuss recent advances in increasing the efficiency of SC differentiation using different materials, but despite the promising results of this systematic review, further studies are needed to assess the efficiency and safety of transplantation of these cells in diabetes recovery.

Insulin-Producing Cell Transplantation Platform for Veterinary Practice

Diabetes mellitus (DM) remains a global concern in both human and veterinary medicine. Type I DM requires prolonged and consistent exogenous insulin administration to address hyperglycemia, which can increase the risk of diabetes complications such as retinopathy, nephropathy, neuropathy, and heart disorders. Cell-based therapies have been successful in human medicine using the Edmonton protocol. These therapies help maintain the production of endogenous insulin and stabilize blood glucose levels and may possibly be adapted to veterinary clinical practice. The limited number of cadaveric pancreas donors and the long-term use of immunosuppressive agents are the main obstacles for this protocol. Over the past decade, the development of potential therapies for DM has mainly focused on the generation of effective insulin-producing cells (IPCs) from various sources of stem cells that can be transplanted into the body. Another successful application of stem cells in type I DM therapies is transplanting generated IPCs. Encapsulation can be an alternative strategy to protect IPCs from rejection by the body due to their immunoisolation properties. This review summarizes current concepts of IPCs and encapsulation technology for veterinary clinical application and proposes a potential stem-cell-based platform for veterinary diabetic regenerative therapy.

Short-Term Protocols to Obtain Insulin-Producing Cells from Rat Adipose Tissue: Signaling Pathways and In Vivo Effect

Studies using mesenchymal stromal cells (MSCs) as a source of insulin-secreting cells (IPCs) are a promising path in the pursuit for diabetes therapy. Here, we investigate three short-term differentiation protocols in order to generate IPCs from autologous adipose-derived stromal cells (ADSCs) with an expressive insulin-secreting profile in vitro and in vivo, as well as the signaling pathways involved in the chosen differentiation protocols. We extracted and cultured ADSCs and differentiated them into IPCs, using three different protocols with different inductors. Afterwards, the secretory profile was analyzed and IPCs differentiated in exendin-4/activin A medium, which presented the best secretory profile, was implanted in the kidney subcapsular region of diabetic rats. All protocols induced the differentiation, but media supplemented with exendin-4/activin A or resveratrol induced the expression and secretion of insulin more efficiently, and only the exendin-4/activin-A-supplemented medium generated an insulin secretion profile more like β-cells, in response to glucose. The PI3K/Akt pathway seems to play a negative role in IPC differentiation; however, the differentiation of ADSCs with exendin-4/activin A positively modulated the p38/MAPK pathway. Resveratrol medium activated the Jak/STAT3 pathway and generated IPCs apparently less sensitive to insulin and insulin-like receptors. Finally, the implant of IPCs with the best secretory behavior caused a decrease in hyperglycemia after one-week implantation in diabetic rats. Our data provide further information regarding the generation of IPCs from ADSCs and strengthen evidence to support the use of MSCs in regenerative medicine, specially the use of exendin-4/activin A to produce rapid and effectively IPCs with significant in vivo effects.

Exendin-4 enhances the differentiation of Wharton's jelly mesenchymal stem cells into insulin-producing cells through activation of various β-cell markers

Background

Diabetes mellitus is a devastating metabolic disease. Generation of insulin-producing cells (IPCs) from stem cells, especially from Wharton’s jelly mesenchymal stem cells (WJ-MSCs), has sparked much interest recently. Exendin-4 has several beneficial effects on MSCs and β cells. However, its effects on generation of IPCs from WJ-MSCs specifically have not been studied adequately. The purpose of this study was therefore to investigate how exendin-4 could affect the differentiation outcome of WJ-MSCs into IPCs, and to investigate the role played by exendin-4 in this differentiation process.

Methods

WJ-MSCs were isolated, characterized and then induced to differentiate into IPCs using two differentiation protocols: protocol A, without exendin-4; and protocol B, with exendin-4. Differentiated IPCs were assessed by the expression of various β-cell-related markers using quantitative RT-PCR, and functionally by measuring glucose-stimulated insulin secretion.

Results

The differentiation protocol B incorporating exendin-4 significantly boosted the expression levels of β-cell-related genes Pdx-1, Nkx2.2, Isl-1 and MafA. Moreover, IPCs generated by protocol B showed much better response to variable glucose concentrations as compared with those derived from protocol A, which totally lacked such response. Furthermore, exendin-4 alone induced early differentiation markers such as Pdx-1 and Nkx2.2 but not Isl-1, besides inducing late markers such as MafA. In addition, exendin-4 showed a synergistic effect with nicotinamide and β-mercaptoethanol in the induction of these markers.

Conclusions

Exendin-4 profoundly improves the differentiation outcome of WJ-MSCs into IPCs, possibly through the ability to induce the expression of β-cell markers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0374-4) contains supplementary material, which is available to authorized users.