Transplantation of Unique Subpopulation of Fibroblasts, Muse Cells, Ameliorates Experimental Stroke Possibly via Robust Neuronal Differentiation.
OBJECTIVE
Muse cells reside as pre-existing pluripotent-like stem cells within the fibroblasts, are nontumorigenic, exhibit differentiation capacity into triploblastic-lineage cells, and replenish lost cells when transplanted in injury models. Cell fate and function of human skin fibroblast-derived Muse cells were evaluated in a rat stroke model.


METHODS
Muse cells (30,000), collected by pluripotent surface marker stage-specific embryonic antigen-3, were injected stereotaxically into three deposits within the rat ischemic cortex at 2 days after transient middle cerebral artery occlusion, and the cells' biological effects were examined for more than 84 days.


RESULTS
Muse cells spontaneously and promptly committed to neural/neuronal-lineage cells when cocultured with stroke brain slices. Muse-transplanted stroke rats exhibited significant improvements in neurological and motor functions compared to control groups at chronic days 70 and 84, without a reduction in the infarct size. Muse cells survived in the host brain for up to 84 days and differentiated into NeuN (∼ 65%), MAP-2 (∼ 32%), calbindin (∼ 28%), and GST-π (∼ 25%)-positive cells in the cortex, but glial fibrillary acidic protein-positive cells were rare. Tumor formation was not observed. Muse cells integrated into the sensory-motor cortex, extended their neurites into cervical spinal cord, and displayed normalized hind limb somatosensory evoked potentials.


INTERPRETATION
Muse cells are unique from other stem cells in that they differentiate with high ratio into neuronal cells after integration with host brain microenvironment, possibly reconstructing the neuronal circuit to mitigate stroke symptoms. Human fibroblast-derived Muse cells pose as a novel source of transplantable stem cells, circumventing the need for gene manipulations, especially when contemplating autologous cell therapy for stroke.
['Uchida|Hiroki|H|', 'Morita|Takahiro|T|', 'Niizuma|Kuniyasu|K|', 'Kushida|Yoshihiro|Y|', 'Kuroda|Yasumasa|Y|', 'Wakao|Shohei|S|', 'Sakata|Hiroyuki|H|', 'Matsuzaka|Yoshiya|Y|', 'Mushiake|Hajime|H|', 'Tominaga|Teiji|T|', 'Borlongan|Cesario V|CV|', 'Dezawa|Mari|M|']
D000328:Adult D000818:Animals D001522:Behavior, Animal D001921:Brain D002454:Cell Differentiation D019070:Cell Lineage D002470:Cell Survival D060833:Cellular Microenvironment D055724:Electrophysiological Phenomena D005347:Fibroblasts D006801:Humans D016513:Mice, SCID D009044:Motor Cortex D009474:Neurons D051381:Rats D020521:Stroke
Transplantation Neuronal differentiation Cellular therapy Mesenchymal stem cells Pluripotent stem cells