Expression Profile of Neural, Trophic, and Immunomodulatory Genes in Multiple Sclerosis Donor-Derived Mesenchymal Stem Cell-Neural Progenitors

Multiple sclerosis (MS) is an autoimmune-mediated demyelinating disease of the CNS. Patients with progressive MS experience a steady worsening of neurologic function attributed to chronic demyelination and axonal loss. A novel regenerative therapy utilizing autologous mesenchymal stem cell-derived neural progenitors (MSC-NP) is currently under clinical investigation in patients with progressive MS. MSC-NPs promote neural repair though the paracrine release of trophic and immuno-modulatory factors. Recent results from a phase I trial demonstrated reversal of established disability after repeated intrathecal MSC-NP injections. A phase II randomized double-blind placebo-controlled trial is underway to confirm the efficacy of this approach. As this autologous cell therapy moves into clinical use, there is a need to better define and characterize MSC-NPs in order to better understand the mechanisms underlying therapeutic potency. The objective of this study was to define the transcriptional profile of MSC-NPs from secondary progressive MS (SPMS), primary progressive MS (PPMS), and non-MS donors in order to better understand their functional characteristics and therapeutic potential in multiple sclerosis. MSCs were derived from sternal bone marrow of MS patients (SPMS, n=4; PPMS, n=4) as part of an IRB-approved study protocol (Western IRB). MSCs from non-MS donors (n=2) were isolated from commercially available bone marrow aspirates. MSCs were expanded for up to 4 passages in growth medium containing 5% human platelet lysate, then transferred to neural progenitor medium containing EGF/bFGF to generate MSC-NPs. Population doubling time (PDT) of MSCs was determined by cell counting. RNA isolated from MSC and MSC-NP cells was analyzed for gene expression differences by RNA sequencing and validated by quantitative PCR. Donor characteristics had no impact cell growth rate or the yield of MSC-NPs generated. Transcriptional profiling of MSC/MSC-NP pairs confirmed the upregulation of neural genes such as Nestin, and the downregulation of mesodermal genes such as Thy-1 and Acta2, thus affirming MSC-NP identity. In addition, gene candidates that mediate trophic/immunoregulatory mechanisms of action of MSC-NPs were identified, including HGF and TGF-ß. Characterization of the transcriptional profile of MSC-NPs has revealed potential pathways that mediate therapeutic mechanisms of this novel cell therapy in MS. These studies form the basis of marker-based potency assays that may be used to better predict the therapeutic efficacy of individual batches of autologous MSC-NPs administered to patients during clinical trials.