Hypoxia-ischemia brain damage (HIBD) is a neurological disorder occring in neonates, which is exacerbated by neuronal apoptosis. Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) have been proposed as a promising strategy for treating or preventing ischemia-related diseases. However, their mechanisms in HIBD remain unclear. Thus, we aimed to address the role of EV-derived microRNA (miR)-410 in HIBD. Neonatal HIBD mouse model was constructed using HI insult, from which neurons were isolated, followed by exposure to oxygen glucose deprivation (OGD). EVs were isolated from human umbilical cord (hUC)-derived MSCs. In silico analyses, dual-luciferase reporter gene and chromatin immunoprecipitation assays were adopted to determine relationships among miR-410, histone deacetylase 1 (HDAC1), early growth response protein 2 (EGR2), and B cell lymphoma/leukemia 2 (Bcl2). The functional roles of EV-derived miR-410 were determined using loss- and gain-of functions experiments, and by evaluating neuronal viability, cell-cycle distribution and neuronal apoptosis in vitro as well as modified neurological severity score (mNSS), edema formation, and cerebral infarction volume in vivo. hUC-MSCs-derived EVs protected against HIBD in vivo and inhibited the OGD-induced neuronal apoptosis in vitro. miR-410 was successfully delivered to neurons by hUC-MSCs-EVs and negatively targeted HDAC1, which inversely mediated the expression of EGR2/Bcl2. Upregulation of EV-derived miR-410 promoted the viability but inhibited apoptosis of neurons, which was reversed by HDAC1 overexpression. EV-derived miR-410 elevation reduced mNSS, edema formation, and cerebral infarction volume by increasing EGR2/Bcl2 expression through downregulating HDAC1 expression in vivo. In summary, EV-derived miR-410 impeded neuronal apoptosis by elevating the expression of EGR2/Bcl2 via HDAC1 downregulation, thereby providing a potential strategy for treating or preventing HIBD.

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Stem cells from human exfoliated deciduous teeth (SHEDs) are highly proliferative, clonogenic, and multipotent stem cells with a neural crest cell origin. This property could be a desirable option for potential therapeutic applications. In this study, we focus on the effects of Rho kinase inhibitors Y‐27632 and Noggin on the proliferation of SHEDs and their differentiation into neuron‐like cells. SHEDs were extracted from 10 samples of deciduous teeth obtained from healthy children aged from 5 to 10. The passaged SHEDs were transfected with Noggin, Y‐27632, or their combination. By means of MTT and colony formation assays, the effects of Y‐27632 and Noggin on cell viability and colony formation were detected. Cellular morphology and neurosphere formation were observed under a microscope. Y‐27632 transfection in SHEDs showed enhanced cell viability, colony formation, and neurosphere formation indicating that Y‐27632 could promote cell proliferation of SHEDs. Furthermore, we observed that the SHEDs treated with Noggin in combination with Y‐27632 displayed typical neuron‐like cell morphology and reticular processes. Noggin or Y‐27632 alone or in combination induced obviously increased NSE, Nestin, and GFAP levels, which were highest in SHEDs treated with the combination of Noggin and Y‐27632. These findings suggest that Y‐27632 promotes the proliferation of SHEDs, and Y‐27632 and Noggin in combination have a synergistic effect on promoting differentiation of SHEDs into neuron‐like cells.

BACKGROUND Leigh syndrome (LS) is one of the most common mitochondrial diseases in infants and children. LS often manifests as early-onset with delayed phenotypic development. However, late-onset LS with normal development and white matter lesions in the brain is rarely reported, thereby highlighting the phenotypic variability of LS expression. CASE SUMMARY We report a 12-year-old boy who presented with an unusual late-onset and fulminant form of LS that is maternally inherited without developmental delay. The patient was admitted to the hospital with symptoms of ptosis and somnolence, and died within 2 mo. Analysis of peripheral blood leukocytes showed a homoplasmic m.9176T>C mutation in the patient. Magnetic resonance imaging also revealed lesions in bilateral white matter as well as symmetrical lesions in the basal ganglia and brain stem. The patient was diagnosed with LS. The patient was treated with vitamin C, vitamin D, and adenosine-triphosphate. The patient died within 2 mo of hospital admission. CONCLUSION LS can present in both infants and older children with different phenotypes.

A number of causative mutations in mitochondrial and nuclear DNA have been identified for Leigh syndrome, a neurodegenerative encephalopathy, including m. 8993 T>G, m.8993 T>C, and m.3243A>G mutations in the MTATP6, MTATP6, and MT-TL1 genes, respectively, which have been reported in Leigh syndrome patients in China. The m.13513 G>A mutation has been described only a few times in the literature and not previously reported in China. Here we report the case of a 15-month-old boy who presented with ptosis and developmental delay and was diagnosed with Leigh syndrome and well as Wolff-Parkinson-White (WPW) syndrome. The m.13513 G>A mutation was found in DNA from blood. He was intubated due to respiratory failure and died at 23 months of age. The m.13513 G>A mutation in the ND5 gene of mitochondrial DNA is associated with Leigh syndrome and WPW syndrome; however, this is the first report of this mutation in a patient in China, highlighting the geographical and racial variability of Leigh syndrome.