Direct Differentiation of Bone Marrow Mononucleated Cells Into Insulin-Producing Cells Using 4 Specific Soluble Factors

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.

Comments:

This study outlines a promising method for differentiating bone marrow-derived stem cells into mature insulin-producing cells (IPCs). The researchers utilized a unique combination of four differentiation-inducing factors (DIFs) – putrescine, glucosamine, nicotinamide, and BP-1-102 – to induce the differentiation of these cells into functional IPCs. The differentiated cells expressed key genes related to pancreatic beta cell development and function, such as PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin. They also produced insulin/C-peptide and PDX1, confirming their identity as IPCs.

Importantly, these induced IPCs exhibited glucose-responsive insulin secretion, similar to normal pancreatic beta cells. When transplanted under the kidney capsules of mice with streptozotocin-induced diabetes, the IPCs effectively alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. This successful transplantation suggests the potential application of these induced cells in cell-based therapy for diabetes mellitus.

This research provides a relatively simple and effective protocol for differentiating bone marrow-derived stem cells into mature insulin-producing cells, offering a novel approach for diabetes treatment through cell-based therapy.