They have good disease induction in their control groups, their targeted mRNA therapy shows pretty remarkable efficacy, and they show they can diversify a little bit with respect to the target.
These models are a little too "furry test tube" for me for this application. They work by injecting an antigen, either a short version of the myelin oligodendrocyte glycoprotein (MOG) peptide or the myelin proteolipid protein (PLP). The mouse makes antibodies against that antigen, and those antibodies also attack those antigens in their natural environments, leading to demyelination in the CNS. Well their mRNA for the MOG model makes more MOG peptide, giving the antibodies another target so they don't cause demyelination. In the human condition, there are multiple antibodies against multiple targets, so I'm not sure this is as relevant as they're suggesting, unless I'm missing something. I do want to add that this paper has a ton of work in it, and it looks pretty high quality as far as I can tell.
None of this is to say there's no value here, I'm just not sure what target they would make an mRNA for to treat human MS based on this paper or how they'd identify and test that target to get FDA approval to move into trials.