Transcriptome Regulation by Oncogenic ALK Pathway in Mammalian Cortical Development Revealed by Single-Cell RNA Sequencing.

Precise regulation of embryonic neurodevelopment is crucial for proper structural organization and functioning of the adult brain. The key molecular machinery orchestrating this process remains unclear. Anaplastic lymphoma kinase (ALK) is an oncogenic receptor-type protein tyrosine kinase that is specifically and transiently expressed in developing nervous system. However, its role in the mammalian brain development is unknown. We found that transient embryonic ALK inactivation caused long-lasting abnormalities in the adult mouse brain, including impaired neuronal connectivity and cognition, along with delayed neuronal migration and decreased neuronal proliferation during neurodevelopment. scRNA-seq on human cerebral organoids revealed a delayed transition of cell-type composition. Molecular characterization identified a group of differentially expressed genes (DEGs) that were temporally regulated by ALK at distinct developmental stages. In addition to oncogenes, many DEGs found by scRNA-seq are associated with neurological or neuropsychiatric disorders. Our study demonstrates a pivotal role of oncogenic ALK pathway in neurodevelopment and characterized cell-type-specific transcriptome regulated by ALK for better understanding mammalian cortical development.

Folic Acid Rescues Valproic Acid-Induced Morphogenesis Inhibition in Neural Rosettes Derived From Human Pluripotent Stem Cells.

The ability of human pluripotent stem cells (hPSCs) to specialize in neuroepithelial tissue makes them ideal candidates for use in the disease models of neural tube defects. In this study, we cultured hPSCs in suspension with modified neural induction method, and immunostaining was applied to detect important markers associated with cell fate and morphogenesis to verify the establishment of the neural tube model in vitro. We carried out the drug experiments to further investigate the toxicity of valproic acid (VPA) exposure and the potential protective effect of folic acid (FA). The results demonstrated that neural rosette undergoes cell fate speciation and lumen formation accompanied by a spatiotemporal shift in the expression patterns of cadherin, indicating the model was successfully established. The results showed that VPA caused morphogenesis inhibition of lumen formation by altering cytoskeletal function and cell polarization, which could be rescued by FA supplement.

Abnormal mitochondria in Down syndrome iPSC-derived GABAergic interneurons and organoids.

Down syndrome (DS) is caused by trisomy 21, and it is characterized by developmental brain disorders and neurological dysfunction. Clinical studies and basic research have revealed that defects in mitochondrial function contribute to the pathogenesis of DS. However, the underlying mechanisms of mitochondrial dysfunction in DS remain unclear. In this study, we first generated GABAergic interneurons and medial ganglionic eminence (MGE) organoids from DS patients and control induced pluripotent stem cells. The mitochondria were abnormally clustered in the perinuclear region of GABA neurons and cell in MGE organoids from DS patients, which exhibited impaired mitochondrial function as assessed by seahorse oxidative phosphorylation assay. Inhibition of the DSCAM-PAK1 pathway by gene editing or treatment with a small molecule corrected mitochondrial perinuclear aggregation in cells from DS patients. Therefore, our study provides insight into the potential mechanism of mitochondrial dysfunction in DS.

Modeling Down Syndrome with Patient iPSCs Reveals Cellular and Migration Deficits of GABAergic Neurons.

The brain of Down syndrome (DS) patients exhibits fewer interneurons in the cerebral cortex, but its underlying mechanism remains unknown. By morphometric analysis of cortical interneurons generated from DS and euploid induced pluripotent stem cells (iPSCs), we found that DS GABA neurons are smaller and with fewer neuronal processes. The proportion of calretinin over calbindin GABA neurons is reduced, and the neuronal migration capacity is decreased. Such phenotypes were replicated following transplantation of the DS GABAergic progenitors into the mouse medial septum. Gene expression profiling revealed altered cell migratory pathways, and correction of the PAK1 pathway mitigated the cell migration deficit in vitro. These results suggest that impaired migration of DS GABAergic neurons may contribute to the reduced number of interneurons in the cerebral cortex and hippocampus in DS patients.

Induction of human somatostatin and parvalbumin neurons by expressing a single transcription factor LIM homeobox 6.

Human GABAergic interneurons (GIN) are implicated in normal brain function and in numerous mental disorders. However, the generation of functional human GIN subtypes from human pluripotent stem cells (hPSCs) has not been established. By expressing LHX6, a transcriptional factor that is critical for GIN development, we induced hPSCs to form GINs, including somatostatin (SST, 29%) and parvalbumin (PV, 21%) neurons. Our RNAseq results also confirmed the alteration of GIN identity with the overexpression of LHX6. Five months after transplantation into the mouse brain, the human GABA precursors generated increased population of SST and PV neurons by overexpressing LHX6. Importantly, the grafted human GINs exhibited functional electrophysiological properties and even fast-spiking-like action potentials. Thus, expression of the single transcription factor LHX6 under our GIN differentiation condition is sufficient to robustly induce human PV and SST subtypes.

Pharmacist interventions for prophylactic antibiotic use in urological inpatients undergoing clean or clean-contaminated operations in a Chinese hospital.

OBJECTIVES: To evaluate the impact and cost-benefit value of pharmacist interventions for prophylactic antibiotic use in surgical patients undergoing clean or clean-contaminated operations. METHODS: A pre-to-post intervention study was performed in the Department of Urological Surgery of a tertiary hospital. Patients admitted from January through June 2011, undergoing clean or clean-contaminated surgery, served as the pre-intervention group; patients admitted from January through June 2012 formed the post-intervention group. Pharmacist interventions were performed for the surgeries in the post-intervention group. The criteria for the rational use of antibiotic prophylaxis were established by the hospital administration. The pharmacist interventions included real-time monitoring of medical records and controlling of the prescriptions of prophylactic antibiotics against the criteria. The pre- and post-intervention groups were then compared to evaluate the outcomes of the pharmacist interventions. A cost-benefit analysis was performed to determine the economic effects of implementing the pharmacist intervention on preoperative antibiotic prophylaxis. RESULTS: After the pharmacist intervention, a significant decrease was found in the rate of no indications for prophylactic antibiotic use (p = 0.004), the rate of broad-spectrum antibiotic use (p<0.001), the rate of drug replacement (p<0.001) and the rate of prolonged duration of prophylaxis (p<0.001). Significant reductions were observed in the mean antibiotic cost (p<0.001), the mean duration of antibiotic prophylaxis (p<0.001) and the mean number of antibiotics used (p<0.001). A significant increase was observed in the rate of correct choice of antibiotics (p<0.001). The ratio of the net mean cost savings for antibiotics to the mean cost of pharmacist time was approximately 18.79:1. CONCLUSION: Real-time interventions provided by a clinical pharmacist promoted rational use of prophylactic antibiotics, with a significant reduction in antibiotic costs, thus leading to favorable economic outcomes.