Transcriptomic profiling across human serotonin neuron differentiation via the FEV reporter system.

BACKGROUND: The detailed transcriptomic profiles during human serotonin neuron (SN) differentiation remain elusive. The establishment of a reporter system based on SN terminal selector holds promise to produce highly-purified cells with an early serotonergic fate and help elucidate the molecular events during human SN development process. METHODS: A fifth Ewing variant (FEV)-EGFP reporter system was established by CRISPR/Cas9 technology to indicate SN since postmitotic stage. FACS was performed to purify SN from the heterogeneous cell populations. RNA-sequencing analysis was performed for cells at four key stages of differentiation (pluripotent stem cells, serotonergic neural progenitors, purified postmitotic SN and purifed mature SN) to explore the transcriptomic dynamics during SN differentiation. RESULTS: We found that human serotonergic fate specification may commence as early as day 21 of differentiation from human pluripotent stem cells. Furthermore, the transcriptional factors ZIC1, HOXA2 and MSX2 were identified as the hub genes responsible for orchestrating serotonergic fate determination. CONCLUSIONS: For the first time, we exposed the developmental transcriptomic profiles of human SN via FEV reporter system, which will further our understanding for the development process of human SN.

Corticosterone Impairs Hippocampal Neurogenesis and Behaviors through p21-Mediated ROS Accumulation.

Stress is known to induce a reduction in adult hippocampal neurogenesis (AHN) and anxiety-like behaviors. Glucocorticoids (GCs) are secreted in response to stress, and the hippocampus possesses the greatest levels of GC receptors, highlighting the potential of GCs in mediating stress-induced hippocampal alterations and behavior deficits. Herein, RNA-sequencing (RNA-seq) analysis of the hippocampus following corticosterone (CORT) exposure revealed the central regulatory role of the p21 (Cdkna1a) gene, which exhibited interactions with oxidative stress-related differentially expressed genes (DEGs), suggesting a potential link between p21 and oxidative stress-related pathways. Remarkably, p21-overexpression in the hippocampal dentate gyrus partially recapitulated CORT-induced phenotypes, including reactive oxygen species (ROS) accumulation, diminished AHN, dendritic atrophy, and the onset of anxiety-like behaviors. Significantly, inhibiting ROS exhibited a partial rescue of anxiety-like behaviors and hippocampal alterations induced by p21-overexpression, as well as those induced by CORT, underscoring the therapeutic potential of targeting ROS or p21 in the hippocampus as a promising avenue for mitigating anxiety disorders provoked by chronic stress.

Uncovering the role of FOXA2 in the Development of Human Serotonin Neurons.

Directed differentiation of serotonin neurons (SNs) from human pluripotent stem cells (hPSCs) provides a valuable tool for uncovering the mechanism of human SN development and the associated neuropsychiatric disorders. Previous studies report that FOXA2 is expressed by serotonergic progenitors (SNPs) and functioned as a serotonergic fate determinant in mouse. However, in the routine differentiation experiments, it is accidentally found that less SNs and more non-neuronal cells are obtained from SNP stage with higher percentage of FOXA2-positive cells. This phenomenon prompted them to question the role of FOXA2 as an intrinsic fate determinant for human SN differentiation. Herein, by direct differentiation of engineered hPSCs into SNs, it is found that the SNs are not derived from FOXA2-lineage cells; FOXA2-knockout hPSCs can still differentiate into mature and functional SNs with typical serotonergic identity; FOXA2 overexpression suppresses the SN differentiation, indicating that FOXA2 is not intrinsically required for human SN differentiation. Furthermore, repressing FOXA2 expression by retinoic acid (RA) and dynamically modulating Sonic Hedgehog (SHH) signaling pathway promotes human SN differentiation. This study uncovers the role of FOXA2 in human SN development and improves the differentiation efficiency of hPSCs into SNs by repressing FOXA2 expression.

Maternal exposure to PM2.5 induces cognitive impairment in offspring via cerebellar neuroinflammation and oxidative stress.

Available evidence suggest that exposure to PM2.5 during pregnancy is associated with reduced cognitive function in offspring. This study aimed to investigate the effects of maternal exposure to PM2.5 on offspring cognitive function and to elucidate the underlying mechanisms. In this work, pregnant C57BL/6 female mice were exposed to concentrated ambient PM2.5 or filtered air from day 0.5 (=vaginal plug) to day 15.5 in the Shanghai Meteorological and Environmental Animal Exposure System, and offspring cerebellar tissues were collected on embryonic day 15.5, as well as postnatal days 0, 10 and 42. The mean PM2.5 concentrations exposed to the pregnant mice were 73.06 ± 4.90 µg/m3 and 11.15 ± 2.71 µg/m3 in the concentrated ambient PM2.5 and filtered air chambers, respectively. Maternal concentrated PM2.5 exposure was negatively correlated with offspring spatial memory significantly as assessed by the Morris water maze. Compared with the filtered air group, PM2.5-exposed offspring mice had reduced cerebellar microglia. Both RNA and protein levels of IL-8 and TNF-α were elevated in the concentrated ambient PM2.5 group. PM2.5 exposure increased the level of 8-OHG in miRNA of microglia and Purkinje cells in 6-week-old offspring. The level of prostaglandin F2α (8-iso-PGF2Aα) in the cerebellum was increased at different growing stages of offspring after gestational exposure of PM2.5. These results suggested that maternal air pollution exposure might cause inflammatory damage and oxidative stress to the cerebellum, contributing to reduced cognitive performance in mice offspring.

Generation of a TPH2-EGFP reporter cell line for purification and monitoring of human serotonin neurons in vitro and in vivo.

Generation of serotonin neurons (SNs) from human pluripotent stem cells (hPSCs) provides a promising platform to explore the mechanisms of serotonin-associated neuropsychiatric disorders. However, neural differentiation always yields heterogeneous cell populations, making it difficult to identify and purify SNs in vitro or track them in vivo following transplantation. Herein, we generated a TPH2-EGFP reporter hPSC line with insertion of EGFP into the endogenous tryptophan hydroxylase 2 (TPH2) locus using CRISPR-Cas9-mediated gene editing technology. This TPH2-reporter, which faithfully indicated TPH2 expression during differentiation, enabled us to obtain purified SNs for subsequent transcriptional analysis and study of pharmacological responses to antidepressants. In addition, the reporter system showed strong EGFP expression to indicate SNs, which enabled us to explore in vitro and ex vivo electrophysiological properties of SNs. In conclusion, this TPH2-EGFP reporter cell line might be of great significance for studies on human SN-related development and differentiation, drug screening, disease modeling, and cell replacement therapies.

miR-152/TNS1 axis inhibits non-small cell lung cancer progression through Akt/mTOR/RhoA pathway.

AIM: The purpose of the present study was to explore the function and mechanism of tensin 1 (TNS1) in non-small cell lung cancer (NSCLC) progression. METHODS: The expression of TNS1 in NSCLC cells and tissues was assessed by RT-PCR and Western blot. Besides, Kaplan-Meier survival analysis was recruited to explore the association between TNS1 and NSCLC. Cell growth was analyzed by MTT and flow cytometry assay, while cell metastasis was determined by wound healing and transwell assays. The targeting relationship between TNS1 and miR-152 was assessed by luciferase activity assays. And Western blot was employed to determine the expression of related proteins of Akt/mTOR/RhoA pathway. RESULTS: TNS1 level was boosted in NSCLC cells and tissues, related to the prognosis of NSCLC patients. Furthermore, it was proved that TNS1 promoted the growth and metastasis of NSCLC cells via Akt/mTOR/RhoA pathway. And miR-152 targeted TNS1 to affect the progression of NSCLC. CONCLUSION: miR-152/TNS1 axis inhibits the progression of NSCLC by Akt/mTOR/RhoA pathway.

Multiscale noise suppression and feature frequency extraction in SSVEP based on underdamped second-order stochastic resonance.

OBJECTIVE: As one of the commonly used control signals of brain-computer interface (BCI), steady-state visual evoked potential (SSVEP) exhibits advantages of stability, periodicity and minimal training requirements. However, SSVEP retains the non-linear, non-stationary and low signal-to-noise ratio (SNR) characteristics of EEG. The traditional SSVEP extraction methods regard noise as harmful information and highlight the useful signal by suppressing the noise. In the collected EEG, noise and SSVEP are usually coupled together, the useful signal is inevitably attenuated while the noise is suppressed. Also, an additional band-pass filter is needed to eliminate the multi-scale noise, which causes the edge effect. APPROACH: To address this issue, a novel method based on underdamped second-order stochastic resonance (USSR) is proposed in this paper for SSVEP extraction. MAIN RESULTS: A synergistic effect produced by noise, useful signal and the nonlinear system can force the energy of noise to be transferred into SSVEP, and hence amplifying the useful signal while suppressing multi-scale noise. The recognition performances of detection are compared with the widely-used canonical coefficient analysis (CCA) and multivariate synchronization index (MSI). SIGNIFICANCE: The comparison results indicate that USSR exhibits increased accuracy and faster processing speed, which effectively improves the information transmission rate (ITR) of SSVEP-based BCI.