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Rationale: Stroke is a leading cause of adult disability worldwide, but no drug provides functional recovery during the repair phase. Accumulating evidence demonstrates that environmental enrichment (EE) promotes stroke recovery by enhancing network excitability. However, the complexities of utilizing EE in a clinical setting limit its translation. Methods: We used multifaceted approaches combining electrophysiology, chemogenetics, optogenetics, and floxed mice in a mouse photothrombotic stroke model to reveal the key target of EE-mediated stroke recovery. Results: EE reduced tonic gamma-aminobutyric acid (GABA) inhibition and facilitated phasic GABA inhibition in the peri-infarct cortex, thereby promoting network excitability and stroke recovery. These beneficial effects depended on GAT-1, a GABA transporter regulating both tonic and phasic GABA signaling, as EE positively regulated GAT-1 expression, trafficking, and function. Furthermore, GAT-1 was necessary for EE-induced network plasticity, including structural neuroplasticity, input synaptic strengthening in the peri-infarct cortex, output synaptic strengthening in the corticospinal tract, and sprouting of uninjured corticospinal axons across the midline into the territory of denervated spinal cord, and functional recovery from stroke. Moreover, restoration of GAT-1 function in the peri-infarct cortex by its overexpression showed similar beneficial effects on stroke recovery as EE exposure. Conclusion: GAT-1 is a key molecular substrate of the effects of EE on network excitability and consequent stroke recovery and can serve as a novel therapeutic target for stroke treatment during the repair phase.

Human pluripotent stem cells (hPSCs) play important role in studying the function of human glutamatergic neurons and related disease pathogenesis. However, the current hPSC-derived cortical system produced a significant number of inhibitory GABAergic neurons that reduced the purity of excitatory neurons. In this study, we established a robust hPSC-derived cortical neurogenesis system by applying the SHH inhibitor cyclopamine. Cyclopamine specified the dorsal cortical fate in a dose-dependent manner and enhanced the generation of cortical glutamatergic neurons, expressing PAX6, TBR1, TBR2, CTIP2, SATB2, and vesicular glutamate transporters (vGLUT). In contrast, the ventral patterning was inhibited and the GABAergic neurons were significantly reduced to 12% with the treatment of cyclopamine. In addition, we applied our current method to generate trisomy 21 iPSC-derived glutamatergic neurons that showed a robust reduction of vesicular glutamate transporters in the glutamatergic neurons with trisomy 21, revealing the developmental deficits in cortical glutamatergic neurons. Our method enriched the generation of cortical glutamatergic neurons which may facilitate the study of human neurological diseases and cell therapy.

Background Basal forebrain cholinergic neurons (BFCNs) play critical roles in learning, memory and cognition. Dysfunction or degeneration of BFCNs may connect to neuropathology, such as Alzheimer’s disease, Down’s syndrome and dementia. Generation of functional BFCNs may contribute to the studies of cell-based therapy and pathogenesis that is related to learning and memory deficits. New method Here we describe a detail method for robust generation of BFCNs from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). In this method, BFCN progenitors are patterned from hESC or hiPSC-derived primitive neuroepithelial cells, with the treatment of sonic hedgehog (SHH) or combination with its agonist Purmorphamine, and by co-culturing with human astrocytes. Results At day 20, ∼90% hPSC-derived progenitors expressed NKX2.1, which is a transcriptional marker for MGE. Moreover, around 40% of NKX2.1+ cells co-expressed OLIG2 and ∼15% of NKX2.1+ cells co-expressed ISLET1, which are ventral markers. At day 35, ∼40% neurons robustly express ChAT, most of which are co-labeled with NKX2.1, ISLET1 and FOXG1, indicating the basal forebrain-like identity. At day 45, these neurons express mature neuronal markers MAP2, Synapsin, and VAChT. Comparison with existing method(s) In this method, undefined conditions including genetic modification or cell-sorting are avoided. As a choice, feeder free conditions are used to avoid ingredients of animal origin. Moreover, Purmorphamine can be substituted for SHH to induce ventral progenitors effectively and economically. Conclusion We provide an efficient method to generate BFCNs from multiple hPSC lines, which offers the potential application for disease modeling and pharmacological studies.

Conventional Fourier-transform mixes the frequency components of the entire temporal terahertz waveform in one frequency domain; therefore, it cannot distinguish the terahertz frequency in the main pulse from the noise frequency in the pulse tail. Thus traditional Fourier-transform produces inconsistent spectra from different scanning lengths of terahertz pulse. And the interference spectrum appears when the THz echo pulse is recorded. The authors applied wavelet-transform and removed the inconsistent spectra and the interference spectra. Wavelet-transform technique exhibited the local frequency of THz in different time locations. This technique would find applications in THz time-resolved spectroscopy.