Mechanisms of peripheral neurotoxicity associated with four chemotherapy drugs using human induced pluripotent stem cell-derived peripheral neurons.

The awareness of the long-term toxicities of cancer survivors after chemotherapy treatment has been gradually strengthened as the population of cancer survivors grows. Generally, chemotherapy-induced peripheral neurotoxicity (CIPN) is studied by animal models which are not only expensive and time-consuming, but also species-specific differences. The generation of human induced pluripotent stem cells (hiPSCs) and differentiation of peripheral neurons have provided an in vitro model to elucidate the risk of CIPN. Here, we developed a drug-induced peripheral neurotoxicity model using hiPSC-derived peripheral neurons (hiPSC-PNs) to study the mechanisms of different chemotherapeutic agents on neuronal viability using LDH assay, a cell apoptosis assay determined by caspase 3/7 activation, neurite outgrowth, ion channel expression and neurotransmitter release following treatment of cisplatin, bortezomib, ixabepilone, or pomalidomide. Our data showed that the multiple endpoints of the hiPSC-PNs model had different sensitivity to various chemotherapeutic agents. Furthermore, the chemotherapeutics separated cell viability from the decrease in neurite lengthand changed levels of ion channels and neurotransmitters to a certain extent. Thus, we study the mechanisms of peripheral neurotoxicity induced by chemotherapeutic agents through changes in these indicators.

Derivation of clinically applicable schwann cells from bone marrow stromal cells for neural repair and regeneration.

Schwann cells are critically important for tissue repair, axonal regrowth and remyelination following injury to peripheral nerves. The absence of Schwann cells or an equivalent cell type in the central nervous system (CNS) may limit the regeneration capacity of the CNS. Mesenchymal stem cells (MSCs) have therefore been investigated for their potential to be induced to develop a Schwann cell phenotype. The methods for derivation of Schwann cell-like cells from MSCs and the benefits and limitations of each of these methods are presented in this review. Issues related to instability of the derived Schwann cell phenotype, apoptosis of derived cells in transplants, and the inability to predict with confidence how the cells will behave after transplantation are discussed. Finally, we suggest the need for further elucidation of the biology of Schwann cell differentiation and the signals for their derivation from MSC, in order to resolve these obstacles and to enable transplantation of MSC-derived Schwann cells as a therapeutic strategy in CNS injury.

Bone marrow-derived Schwann cells achieve fate commitment--a prerequisite for remyelination therapy.

Schwann cell transplantation improves post-traumatic nerve regeneration in both PNS and CNS but sufficient numbers of immunocompatible cells are required for clinical application. Currently, Schwann cell-like cells derived from the bone marrow lack fate commitment and revert to a fibroblast-like phenotype upon withdrawal of differentiation-inducing factors. In recapitulation of embryonic events leading to Schwann cell maturation, we hypothesize that the Schwann cell-like cells acquire the switch to fate commitment through contact-dependent cues from incipient neurons of the developing dorsal root ganglia. To address this, Schwann cell-like cells derived from adult rat bone marrow were cocultured with neurons purified from embryonic dorsal root ganglia. A cell-intrinsic switch to the Schwann cell fate was achieved consistently and the cell progeny maintained expression of the markers S100 beta, p75(NTR) , GFAP, P0 and Sox 10 even without exogenous differentiation-inducing factors or neurons. In vitro formation of MBP-positive segments under myelinating conditions by the cell progeny was comparable to that by sciatic nerve-derived Schwann cells. Controls in which Schwann cell-like cells were barred from direct contact with neurons in coculture reverted to SMA/CD90-expressing myofibroblasts. We demonstrate therefore for the first time fate commitment among bone marrow-derived Schwann cells. The therapeutic potential of these cells may be tested in future transplantation studies. (206 words).