Significance: Hemophilia A, a genetic bleeding disorder, is often caused by chromosomal inversions that involve a portion of the blood coagulation factor VIII ( F8 ) gene that encodes one of the key enzymes in blood clotting. In this study, we developed enzymes known as transcription activator-like effector nucleases (TALENs) that cleave chromosomal DNA in a targeted manner to invert the 140-kbp chromosomal segment that spans the portion of the F8 gene in human induced pluripotent stem cells (iPSCs) to create a hemophilia A model cell line. In addition, we reverted the inverted segment back to its normal orientation using the same enzymes. This strategy provides an iPSC-based novel therapeutic option for the treatment of hemophilia A.

Periventricular leucomalacia has long been investigated as a leading cause of motor and cognitive dysfunction in patients with spastic diplegic cerebral palsy. However, patients with periventricular leucomalacia on conventional magnetic resonance imaging do not always have motor dysfunction and preterm children without neurological abnormalities may have periventricular leucomalacia. In addition, it is uncertain whether descending motor tract or overlying cortical injury is related to motor impairment. To investigate the relationship between motor pathway injury and motor impairment, we conducted voxelwise correlation analysis using tract-based spatial statistics of white matter diffusion anisotropy and voxel-based-morphometry of grey matter injury in patients with periventricular leucomalacia and spastic diplegia (n = 43, mean 12.86 ± 4.79 years, median 12 years). We also evaluated motor cortical and thalamocortical connectivity at resting state in 11 patients using functional magnetic resonance imaging. The functional connectivity results of patients with spastic diplegic cerebral palsy were compared with those of age-matched normal controls. Since γ-aminobutyric acid_A receptors play an important role in the remodelling process, we measured neuronal γ-aminobutyric acid_A receptor binding potential with dynamic positron emission tomography scans (n = 27) and compared the binding potential map of the patient group with controls (n = 20). In the current study, white matter volume reduction did not show significant correlation with motor dysfunction. Although fractional anisotropy within most of the major white matter tracts were significantly lower than that of age-matched healthy controls (P < 0.05, family wise error corrected), fractional anisotropy mainly within the bilateral corticospinal tracts and posterior body and isthmus of the corpus callosum showed more significant correlation with motor dysfunction (P < 0.03) than thalamocortical pathways (P < 0.05, family-wise error corrected). Cortical volume of the pre- and post-central gyri and the paracentral lobule tended to be negatively correlated with motor function. The motor cortical connectivity was diminished mainly within the bilateral somatosensory cortex, paracentral lobule, cingulate motor area and visual cortex in the patient group. Thalamovisual connectivity was not diminished despite severe optic radiation injury. γ-aminobutyric acid_A receptor binding potential was focally increased within the lower extremity homunculus, cingulate cortex, visual cortex and cerebellum in the patient group (P < 0.05, false discovery rate corrected). In conclusion, descending motor tract injury along with overlying cortical volume reduction and reduced functional connectivity appears to be a leading pathophysiological mechanism of motor dysfunction in patients with periventricular leucomalacia. Increased regional γ-aminobutyric acid_A receptor binding potential appears to result from a compensatory plasticity response after prenatal brain injury.

Ependymal overexpression of brain-derived neurotrophic factor (BDNF) stimulates neuronal addition to the adult striatum, from subependymal progenitor cells. Noggin, by suppressing subependymal gliogenesis and increasing progenitor availability, potentiates this process. We asked whether BDNF/Noggin overexpression might be used to recruit new striatal neurons in R6/2 huntingtin transgenic mice. R6/2 mice injected with adenoviral BDNF and adenoviral Noggin (AdBDNF/AdNoggin) recruited BrdU⁺βIII-tubulin⁺ neurons, which developed as DARPP-32⁺ and GABAergic medium spiny neurons that expressed either enkephalin or substance P and extended fibers to the globus pallidus. Only AdBDNF/AdNoggin-treated R6/2 mice harbored migrating doublecortin-defined neuroblasts in their striata, and the new neurons expressed p27 as a marker of mitotic quiescence after parenchymal integration. AdBDNF/AdNoggin-treated R6/2 mice sustained their rotarod performance and open-field activity and survived longer than did AdNull-treated and untreated controls. Neither motor performance nor survival improved in R6/2 mice treated only with AdBDNF, and intraventricular infusion of the mitotic inhibitor Ara-C completely blocked the performance and survival effects of AdBDNF/AdNoggin, suggesting that the benefits of AdBDNF/AdNoggin derived from neuronal addition. Thus, BDNF and Noggin induced striatal neuronal regeneration, delayed motor impairment, and extended survival in R6/2 mice, suggesting a new therapeutic strategy in Huntington disease.