Decreased Wave V Amplitude in Auditory Brainstem Responses of Children with Cerebellar Lesions

【Background】 This study aims to elucidate the effect of isolated cerebellar lesions sparing the brainstem on the auditory brainstem responses in children. 【Methods】 We enrolled 10 children (aged 1?16 years) with cerebellar lesions on neuroimaging but lacking clinical brainstem involvement signs and with normal brainstem volumes on magnetic resonance imaging. 【Results】 The interpeak latency of waves I and V was normal in 9 patients and was marginally prolonged in 1 patient. While amplitudes of waves I and III were normal, we noted a decreased amplitude of wave V and/or an increased I/V amplitude ratio in 6 patients; these included 5 of 8 patients with cerebellar hypoplasia/atrophy and 1 patient with acute cerebellar ataxia. 【Conclusion】 Our results support the hypothesis of an inhibitory input from the cerebellar fastigial nucleus on the inferior colliculus, which might be disinhibited because of Purkinje cells dysfunction due to cerebellar cortex lesions, especially within the cerebellar vermis

Extracellular nanovesicles for packaging of CRISPR-Cas9 protein and sgRNA to induce therapeutic exon skipping

Prolonged expression of the CRISPR-Cas9 nuclease and gRNA from viral vectors may cause off-target mutagenesis and immunogenicity. Thus, a transient delivery system is needed for therapeutic genome editing applications. Here, we develop an extracellular nanovesicle-based ribonucleoprotein delivery system named NanoMEDIC by utilizing two distinct homing mechanisms. Chemical induced dimerization recruits Cas9 protein into extracellular nanovesicles, and then a viral RNA packaging signal and two self-cleaving riboswitches tether and release sgRNA into nanovesicles. We demonstrate efficient genome editing in various hard-to-transfect cell types, including human induced pluripotent stem (iPS) cells, neurons, and myoblasts. NanoMEDIC also achieves over 90% exon skipping efficiencies in skeletal muscle cells derived from Duchenne muscular dystrophy (DMD) patient iPS cells. Finally, single intramuscular injection of NanoMEDIC induces permanent genomic exon skipping in a luciferase reporter mouse and in mdx mice, indicating its utility for in vivo genome editing therapy of DMD and beyond