Human adult tissue derived MSCs

Human adult-tissue-derived MSCs have shown therapeutic utility in experimental autoimmune encephalitis (EAE) models of MS (Bai et al., 2009; Gordon et al., 2008, 2010; Peron et al., 2012; Zhang et al., 2005) and in clinical trials for MS patients (Connick et al., 2012; Karussis et al., 2010; Mohyeddin Bonab et al., 2007; Yamout et al., 2010); however, the large variability in the efficacy of MSCs hinders their development as a standard MS therapy. Extensive in vitro expansion of MSCs may diminish the efficacy of these paricalcitol (Kyriakou et al., 2008), and MSCs derived from younger cell sources (e.g., embryonic, fetal, and umbilical cells) have higher in vitro proliferation potential and can more readily differentiate (Barlow et al., 2008; Giuliani et al., 2011). Thus, deriving MSCs from a young and renewable (i.e., pluripotent) cell source, such as human embryonic stem cells (hESCs), could (1) alleviate the quantity and quality issues involved in the use of adult-tissue-derived MSCs, (2) obviate the need for constant donor recruitment, and (3) reduce the risk of pathogenicity from the use of multiple donors. Different groups have derived MSCs from hESCs (hES-MSCs) with a morphology and immunophenotype similar to those of BM-MSCs. Previously described derivation methods involve coculturing with mouse OP9 cells and sorting, scraping, or handpicking of cells (Barberi et al., 2005; Brown et al., 2009; Gruenloh et al., 2011; Hwang et al., 2008; Olivier et al., 2006; Vodyanik et al., 2010), which limits the efficiency and purity of the hES-MSCs, as well as the ability to scale up their production. hES-MSCs have been used in some disease models, such as inflammatory bowel disease, lupus, and uveitis (Kimbrel et al., 2014; Sánchez et al., 2011); however, no one has shown whether hES-MSCs can be used to treat an EAE model of MS or compared the immunosuppressive functions of hES-MSCs and BM-MSCs. Here, using an improved hemangioblast-enriching method (Lu et al., 2007), we generated hES-MSCs from the MA09 ESC line (Kimbrel et al., 2014) and multiple other hESC lines. We demonstrate that these hES-MSC lines can effectively treat an EAE model of MS and outperform multiple lines of BM-MSCs in therapeutic activities.
Results
Discussion In examining the effects of hES-MSCs on EAE induction, we observed that preonset treatment of MOG35-55/CFA-immunized mice was more effective in attenuating disease scores than postonset treatment. This is not surprising, since preonset treatment begins before the development of severe demyelination, axonal damage, or inflammatory cell infiltration. Costaining for MBP and NF in day 32 lumbar spine sections of treated animals showed that hES-MSC treatment protected against demyelination without affecting the number of surviving axons. These results do not rule out the possibility that hES-MSCs may also contribute to remyelination of axons that have already lost their myelin. This remains to be elucidated by further investigations examining whether and how hES-MSCs may contribute to neural regeneration. Future studies in the postonset model will also be needed to address whether larger doses and/or repeated injections of cells could enhance the therapeutic effects. Of note, irradiated hES-MSCs were also effective in reducing the EAE disease score and had the same lifespan in vivo as their nonirradiated counterparts. Thus, irradiation of cells may provide an important clinical benefit by reducing concerns about the tumorigenic potential of MSCs. The muted in vivo efficacy of BM-MSCs that we observed is consistent with previous reports that showed only mild (Gordon et al., 2008; Zhang et al., 2005) or negligible (Payne et al., 2013) effects in the EAE mouse model. Interestingly, BM-MSC#6, the BM-MSC line that caused a modest reduction in EAE disease scores in the preonset model at passage 2 (Figure 3C), failed to show any therapeutic effects when used at passage 4 during the anti-iL-6 antibody experiment (Figure 5F). On the other hand, hES-MSCs consistently resulted in large reductions in the disease score of MOG35-55/CFA-immunized mice when used from passage 2 to 5. This indicates that the therapeutic capacity of BM-MSCs may be more vulnerable to extended in vitro culture than that of hES-MSCs.