New method to differentiate human peripheral blood monocytes into insulin producing cells: Human hematosphere culture

Ex vivo expansion of regulatory T cell and T helper 2 cells using a hematosphere culture

Regulatory T cells (T-reg) are important components of immune system required to understand the mechanistic details of cancer immunity and autoimmune diseases. However, reliable and efficient methods of regulatory T cell expansion have not been established yet. Here, we show that a human peripheral blood mononuclear cell (PBMNC) derived blood-born hematosphere (BBHS) culture without cytokine treatment increased T-reg and T helper 2 cell (Th2) populations in the cell suspension. We found that the isolated cells suspended around the hematospheres expressed T helper cell markers. Importantly, the Foxp3+/CD25+ T-reg and IL-4+/CD25+ Th2 cell populations in the cell suspension were greatly expanded during hematosphere culture. Through ELISA analysis of the supernatant, we showed that secretion of Th2-related cytokines such as IL-5, IL-10, and IL-13 also increased. Taken together, hematosphere culture is a good method for ex vivo expansion of T-reg and Th2, which can provide therapeutic benefits for the treatment of immune disorders.

Differentiation Potential of Nestin (+) and Nestin (-) Cells Derived from Human Bone Marrow Mesenchymal Stem Cells into Functional Insulin Producing Cells

The feasibility of isolating and manipulating mesenchymal stem cells (MSCs) from human patients provides hope for curing numerous diseases and disorders. Recent phenotypic analysis has shown heterogeneity of MSCs. Nestin progenitor cell is a subpopulation within MSCs which plays a role in pancreas regeneration during embryogenesis. This study aimed to separate nestin ⁽⁺⁾ cells from human bone marrow MSCs, and differentiate these cells into functional insulin producing cells (IPCs) compared with nestin ^(-) cells. Manual magnetic separation was performed to obtain nestin ⁽⁺⁾ cells from MSCs. Approximately 91±3.3% of nestin ⁽⁺⁾ cells were positive for anti-nestin antibody. Pluripotent genes were overexpressed in nestin ⁽⁺⁾ cells compared with nestin ^(-) cells as revealed by quantitative real time-PCR (qRT-PCR). Following in vitro differentiation, flow cytometric analysis showed that 2.7±0.5% of differentiated nestin ⁽⁺⁾ cells were positive for anti-insulin antibody in comparison with 0.08±0.02% of nestin ^(-) cells. QRT-PCR showed higher expression of insulin and other endocrine genes in comparison with nestin ^(-) cells. While immunofluorescence technique showed the presence of insulin and C-peptide granules in nestin ⁽⁺⁾ cells. Therefore, our results introduced nestin ⁽⁺⁾ cells as a pluripotent subpopulation within human MSCs which is capable to differentiate and produce functional IPCs.

Induction of Nestin Early Expression as a Hallmark for Mesenchymal Stem Cells Expression of PDX-1 as a Pre-disposing Factor for Their Conversion into Insulin Producing Cells

Diabetes constitutes a worldwide epidemic that affects all ethnic groups. Cell therapy is one of the best alternatives of treatment, by providing an effective way to regenerate insulin-producing cells lost during the course of the disease, but many issues remain to be solved. Several groups have been working in the development of a protocol capable of differentiating Mesenchymal Stem Cells (MSCs) into physiologically sound Insulin Producing Cells (IPCs). In order to obtain a simple, fast and direct method, we propose in this manuscript the induction of MSCs to express NESTIN in a short time period (2 h), proceeded by incubation in a low glucose induced medium (24 h) and lastly by incubation in a high glucose medium. Samples from cell cultures incubated in high glucose medium from 12 to 168 h were obtained to detect the expression of INSULIN-1, INSULIN -2, PDX-1 and GLUT-2 genes. Induced cells were exposed to a glucose challenge, in order to assess the production of insulin. This method allowed us to obtain cells expressing PDX-1, which resembles a progenitor insulin-producing cell.

Generation of monocyte-derived insulin-producing cells from non-human primates according to an optimized protocol for the generation of PCMO-derived insulin-producing cells

OBJECTIVE

The vision of potential autologous cell therapy for the cure of diabetes encourages ongoing research. According to a previously published protocol for the generation of insulin-producing cells from human monocytes, we analyzed whether the addition of growth factors could increase insulin production. This protocol was then transferred to a non-human primate model by using either blood- or spleen-derived monocytes.

METHODS

Human monocytes were treated to dedifferentiate into programmable cells of monocytic origin (PCMO). In addition to the published protocol, PCMOs were then treated with either activin A, betacellulin, exendin 3 or 4. Cells were characterized by protein expression of insulin, Pdx-1, C-peptide and Glut-2. After identifying the optimal protocol, monocytes from baboon blood were isolated and the procedure was repeated. Spleen monocytes following splenectomy of a live baboon were differentiated and analyzed in the same manner and calculated in number and volume.

RESULTS

Insulin content of human cells was highest when cells were treated with activin A and their insulin content was 13,000 µU/1 million cells. Insulin-producing cells form primate monocytes could successfully be generated despite using human growth factors and serum. Expression of insulin, Pdx-1, C-peptide and Glut-2 was comparable to that of human neo-islets. Total insulin content of activin A-treated baboon monocytes was 16,000 µU/1 million cells.

CONCLUSION

We were able to show that insulin-producing cells can be generated from baboon monocytes with human growth factors. The amount generated from one spleen could be enough to cure a baboon from experimentally induced diabetes in an autologous cell transplant setting.

Characterization of myelomonocytoid progenitor cells with mesenchymal differentiation potential obtained by outgrowth from pancreas explants

Progenitor cells can be obtained by outgrowth from tissue explants during primary ex vivo tissue culture. We have isolated and characterized cells outgrown from neonatal mouse pancreatic explants. A relatively uniform population of cells showing a distinctive morphology emerged over time in culture. This population expressed monocyte/macrophage and hematopoietic markers (CD11b(+) and CD45(+)), and some stromal-related markers (CD44(+) and CD29(+)), but not mesenchymal stem cell (MSC)-defining markers (CD90(-) and CD105(-)) nor endothelial (CD31(-)) or stem cell-associated markers (CD133(-) and stem cell antigen-1; Sca-1(-)). Cells could be maintained in culture as a plastic-adherent monolayer in culture medium (MesenCult MSC) for more than 1 year. Cells spontaneously formed sphere clusters "pancreatospheres" which, however, were nonclonal. When cultured in appropriate media, cells differentiated into multiple mesenchymal lineages (fat, cartilage, and bone). Positive dithizone staining suggested that a subset of cells differentiated into insulin-producing cells. However, further studies are needed to characterize the endocrine potential of these cells. These findings indicate that a myelomonocytoid population from pancreatic explant outgrowths has mesenchymal differentiation potential. These results are in line with recent data onmonocyte-derivedmesenchymal progenitors (MOMPs).