Constraint-Induced Movement Therapy Promotes Myelin Remodeling and Motor Function by Mediating Sox2/Fyn Signals in Rats With Hemiplegic Cerebral Palsy.

OBJECTIVE: Hypoxic-ischemic brain injury in infants often leads to hemiplegic motor dysfunction. The mechanism of their motor dysfunction has been attributed to deficiencies of the transcription factor sex-determining region (SRY) box 2 (Sox2) or the non-receptor-type tyrosine kinase Fyn (involved in neuronal signal transduction), which causes a defect in myelin formation. Constraint-induced movement therapy (CIMT) following cerebral hypoxia-ischemia may stimulate myelin growth by regulating Sox2/Fyn, Ras homolog protein family A (RhoA), and rho-associated kinase 2 (ROCK2) expression levels. This study investigated how Sox2/Fyn regulates myelin remodeling following CIMT to improve motor function in rats with hemiplegic cerebral palsy (HCP). METHODS: To investigate the mechanism of Sox2 involvement in myelin growth and neural function in rats with HCP, Lentivirus (Lenti)-Sox2 adeno-associated virus and negative control-Lenti-Sox2 (LS) adeno-associated virus were injected into the lateral ventricle. The rats were divided into a control group and an HCP group with different interventions (CIMT, LS, or negative control-LS [NS] treatment), yielding the HCP, HCP plus CIMT (HCP + CIMT), HCP + LS, HCP + LS + CIMT, HCP + NS, and HCP + NS + CIMT groups. Front-limb suspension and RotaRod tests, Golgi-Cox staining, transmission electron microscopy, immunofluorescence staining, western blotting, and quantitative polymerase chain reaction experiments were used to analyze the motor function, dendrite/axon area, myelin ultrastructure, and levels of expression of oligodendrocytes and Sox2/Fyn/RhoA/ROCK2 in the motor cortex. RESULTS: The rats in the HCP + LS + CIMT group had better values for motor function, dendrite/axon area, myelin ultrastructure, oligodendrocytes, and Sox2/Fyn/RhoA/ROCK2 expression in the motor cortex than rats in the HCP and HCP + NS groups. The improvement of motor function and myelin remodeling, the expression of oligodendrocytes, and the expression of Sox2/Fyn/RhoA/ROCK2 in the HCP + LS group were similar to those in the HCP + CIMT group. CONCLUSION: CIMT might overcome RhoA/ROCK2 signaling by upregulating the transcription of Sox2 to Fyn in the brain to induce the maturation and differentiation of oligodendrocytes, thereby promoting myelin remodeling and improving motor function in rats with HCP. IMPACT: The pathway mediated by Sox2/Fyn could be a promising therapeutic target for HCP.

A positive feedback circuit driven by m6A-modified circular RNA facilitates colorectal cancer liver metastasis.

BACKGROUND: Liver metastasis is the leading cause of death in patients with colorectal cancer (CRC). Emerge evidence suggests that circular RNA (circRNA) is a pivotal player in cancer progression. However, its role in CRC liver metastasis remains largely unknown. METHODS: Circ-YAP expression was detected by qRT-PCR and in situ hybridization. The function of circ-YAP was tested by wound healing, transwell and CCK-8 assays. RNA immunoprecipitation, pull-down, luciferase reporter, chromatin immunoprecipitation assays were used to investigate the mechanism underlying circ-YAP promoting CRC liver metastasis. CRC liver metastasis animal model was established to assess the effect of circ-YAP in vivo. RESULTS: Circ-YAP was notably upregulated in CRC with liver metastasis, which was associated with dismal prognosis. Circ-YAP promoted CRC cell migration and invasion in vitro, and facilitated liver metastasis in patient-derived xenografts (PDX) models in vivo. Mechanistically, circ-YAP encoded a novel truncated protein containing 220 amino acids, termed as YAP-220aa, which competitively bound to LATS1, resulting in YAP dephosphorylation and nuclear translocation, thereby activating a cohort of metastasis-promoting genes. Importantly, N6-methyladenosine (m6A) modification orchestrated efficient initiation of circ-YAP translation, requiring m6A reader YTHDF3 and eIF4G2 translation initiation complex. Intriguingly, circ-YAP was transcriptionally enhanced by YAP/TEAD complex, thus forming a positive regulatory feed-forward loop. CONCLUSIONS: Our findings reveal a previously uncharacterized oncoprotein encoded by circ-YAP, implying a promising biomarker and therapeutic target for CRC patients with liver metastasis.

Potential optimized route for mesenchymal stem cell transplantation in a rat model of cerebral palsy.

Cerebral palsy (CP) is a movement and posture disorder that affects over 50 million people worldwide. Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation has emerged as an attractive therapeutic strategy for CP. The administration route appears to be crucial for hUC-MSC to provide adequate neuroprotection. Wistar rats were given hypoxia-ischemia to make the CP model on postnatal day 5. On postnatal day 21, DiR-labeled hUC-MSC were transplanted into the CP rats by intravenous, intrathecal, and lateral ventricle for cell tracking. Uninfused CP rats served as the negative control. The motor behavioral and pathological alteration was analyzed 11, 25, and 39 days after transplantation to assess motor function, immune inflammation, neurotrophy, and endogenous repair. In vivo imaging tracking techniques revealed that intravenous infusion resulted in fewer transplanted cells in the target brain than intrathecal and lateral ventricle infusion (p＜0.05). Three different routes of hUC-MSC infusion improved the motor function of CP rats (p＜0.05). At 11 days post-infusion, intrathecal infusion outperformed intravenous with a significant neurotrophic and oligodendrocyte maturation effect (p＜0.05). Intrathecal infusion equaled lateral ventricle infusion after 25 days. At 39 days post-infusion, lateral ventricle infusion exceeded intravenous and intrathecal infusion with a significant immunosuppressive effect (p＜0.05). Considering the improved effect and less trauma shown early in the intrathecal infusion, repeated intrathecal administration may ultimately lead to the greatest benefit.