Intravenously delivered multilineage-differentiating stress enduring cells dampen excessive glutamate metabolism and microglial activation in experimental perinatal hypoxic ischemic encephalopathy

Abstract

Perinatal hypoxic ischemic encephalopathy (HIE) results in serious neurological dysfunction and mortality. Clinical trials of multilineage-differentiating stress enduring cells (Muse cells) have commenced in stroke using intravenous delivery of donor-derived Muse cells. Here, we investigated the therapeutic effects of human Muse cells in an HIE model. Seven-day-old rats underwent ligation of the left carotid artery then were exposed to 8% oxygen for 60 min, and 72 hours later intravenously transplanted with 1 × 104 of human-Muse and -non-Muse cells, collected from bone marrow-mesenchymal stem cells as stage-specific embryonic antigen-3 (SSEA-3)+ and −, respectively, or saline (vehicle) without immunosuppression. Human-specific probe revealed Muse cells distributed mainly to the injured brain at 2 and 4 weeks, and expressed neuronal and glial markers until 6 months. In contrast, non-Muse cells lodged in the lung at 2 weeks, but undetectable by 4 weeks. Magnetic resonance spectroscopy and positron emission tomography demonstrated that Muse cells dampened excitotoxic brain glutamatergic metabolites and suppressed microglial activation. Muse cell-treated group exhibited significant improvements in motor and cognitive functions at 4 weeks and 5 months. Intravenously transplanted Muse cells afforded functional benefits in experimental HIE possibly via regulation of glutamate metabolism and reduction of microglial activation.

Non-Tumorigenic Pluripotent Reparative Muse Cells Provide a New Therapeutic Approach for Neurologic Diseases

“…Muse cell-derived neuronal cells incorporate into the pyramidal tract, including the pyramidal decussation, as demonstrated by anterograde and retrograde tracing, and into the sensory tract, as demonstrated by somatosensory-evoked potentials and the formation of synapses with host neuronal cells at 3 months, leading to statistically meaningful functional recovery [ 34 , 38 ]. Spontaneous differentiation of Muse cells into neuronal and glial cells after homing to the damaged central nervous system is also reported in other models, perinatal hypoxic ischemic encephalopathy, brain hemorrhage, ALS, and STEC-related encephalopathy [ 36 , 37 , 39 , 40 ]. In an acute myocardial infarction model, Muse cells homed to the post-infarct tissue and within 2 weeks spontaneously differentiated into cells positive for cardiomyocyte markers, such as troponin-I, sarcomeric α-actinin, and connexin 43, exhibiting calcium influx and efflux synchronous with heart activity recorded by an electrocardiogram [ 6 ].…”

“…In a rabbit acute myocardial infarction model, ~14.5% of intravenously injected Muse cells engrafted into the post-infarct heart at 3 days, whereas only a few or no MSCs integrated into the heart in the same model [ 6 ] ( Figure 6 ). In mouse models of epidermolysis bullosa [ 33 ], lacunar stroke l [ 34 ], doxorubicin-induced nephropathy [ 35 ], ALS [ 36 ], and Shiga toxin-producing Escherichia coli (STEC)-associated encephalopathy [ 37 ], as well as in rat models of middle cerebral artery occlusion ischemia and perinatal hypoxic ischemic encephalopathy [ 38 , 39 ], Muse cells exhibited superiority over MSCs/non-Muse MSCs in selective homing to the sites of damage. Not only in these animal models, but also the data collected from patients with stroke and acute myocardial infarction demonstrated that an increase in the serum S1P level precedes the increase in the number of circulating endogenous Muse cells after the cell injury onset [ 3 , 7 ].…”

“…Muse cells possess unique immunomodulatory properties: allogenic Muse cells can survive and are incorporated into rabbit acute myocardial infarction host tissue for an extended period (>6 months), even without immunosuppressant treatment [ 6 ]. In both normal (Wistar) rats and immunocompromised (SCID) mice, intravenously injected human Muse cells survive as neuronal and glial cells in the ischemic brain tissue for 6 months, while MSCs or cells other than Muse cells in MSCs (i.e., SSEA-3(-) non-Muse MSCs that correspond to ~98% of total MSCs) became undetectable in all the tissues in the body within 2 weeks [ 34 , 39 ]. Interestingly, these species-mismatch experiments were conducted without immunosuppressant treatment.…”

“…In addition, in a swine hepatectomy model, animals that received allogenic Muse cells exhibited less necrosis, compared with animals that received allogenic MSCs [ 16 ]. In damaged brain tissue, Muse cells ameliorated the effects of excitotoxic brain glutamatergic metabolites and suppressed microglial activation, as shown by magnetic resonance spectroscopy and positron tomography, respectively [ 39 ]. Thus, Muse cells have greater tissue protective effects than MSCs.…”

“…In a rabbit acute myocardial infarction model, for example, the infarct size reduction was ~2.5-fold greater in the Muse group than in the MSC/non-Muse MSC group both at 2 weeks and 2 months [ 6 ]. Functional recovery in rat/mouse stroke and hypoxic ischemic encephalopathy models also exhibited statistically meaningful superiority of the Muse group over the MSC/non-Muse MSC group ( p < 0.001 and p < 0.01) in the modified neurologic severity, rotarod, and other neurologic function scores at 3 months or even beyond 3 months after administration [ 38 , 39 ]. Statistically significant anti-apoptotic, anti-inflammatory, and anti-fibrosis effects were observed in the Muse cell group, compared with the MSC/non-Muse MSC group in models of mouse chronic kidney disease, mouse hepatitis, and rat lung ischemic-reperfusion [ 27 , 35 , 47 ].…”