Analysis of transcription factors in accessible open chromatin in the 18-trisomy syndrome based on single cell ATAC sequencing technique.

Trisomy 18 syndrome is one of the most common autosomal aneuploidy disorders. Little is known about the genetic regulation leading to the clinical phenotypes associated with the occurrence and development of trisomy 18 syndrome disorders (e.g., mental retardation, cardiac and renal abnormalities). To explore the regulatory factors that influence the phenotypes of the disease, this study used single-cell ATAC sequencing to analyze transcription factors in the accessibility chromatin regions of the single-nucleus cells of the cord blood from 18-trisomy syndrome and control subjects. A single-cell library constructed by capturing 11,611 cells identified seven major immune cell populations, and the results of cell number statistics suggested the presence of abnormalities in the immune system of 18-trisomy syndrome patients. Fourteen transcription factors (P<0.05, |FC|>1.2) were identified by analyzed accessibility chromatin regions. The relative expression levels of four of these transcription factors (TEAD1, TEAD2, TEAD4, Twist2) were confirmed using real-time quantitative fluorescence PCR. In conjunction with information from the literature, this study suggests that these four transcription factors may be associated with abnormalities in cardiac and skeletal development in patients with the 18-trisomy syndrome, thereby providing candidate molecules for mechanistic studies on the occurrence and development of the 18-trisomy syndrome phenotypes.

Chronic Trigeminal Nerve Stimulation Protects Against Seizures, Cognitive Impairments, Hippocampal Apoptosis, and Inflammatory Responses in Epileptic Rats.

Trigeminal nerve stimulation (TNS) has recently been demonstrated effective in the treatment of epilepsy and mood disorders. Here, we aim to determine the effects of TNS on epileptogenesis, cognitive function, and the associated hippocampal apoptosis and inflammatory responses. Rats were injected with pilocarpine to produce status epilepticus (SE) and the following chronic epilepsy. After SE induction, TNS treatment was conducted for 4 consecutive weeks. A pilocarpine re-injection was then used to induce a seizure in the epileptic rats. The hippocampal neuronal apoptosis induced by seizure was assessed by TUNEL staining and inflammatory responses by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). The spontaneous recurrent seizure (SRS) number was counted through video monitoring, and the cognitive function assessed through Morris Water Maze (MWM) test. TNS treatment attenuated the SRS attacks and improved the cognitive impairment in epileptic rats. A pilocarpine re-injection resulted in less hippocampal neuronal apoptosis and reduced level of interleukin-1 beta (IL-1ß), tumor necrosis factor-α (TNF-α), and microglial activation in epileptic rats with TNS treatment in comparison to the epileptic rats without TNS treatment. It is concluded that TNS treatment shortly after SE not only protected against the chronic spontaneous seizures but also improved cognitive impairments. These antiepileptic properties of TNS may be related to its attenuating effects on hippocampal apoptosis and pro-inflammatory responses.

Neuronal and astroglial TGFß-Smad3 signaling pathways differentially regulate dendrite growth and synaptogenesis.

To address the role of the transforming growth factor beta (TGFß)-Smad3 signaling pathway in dendrite growth and associated synaptogenesis, we used small inhibitory RNA to knockdown the Smad3 gene in either cultured neurons and or primary astrocytes. We found that TGFß1 treatment of primary neurons increased dendrite extensions and the number of synapsin-1-positive synapses. When Smad3 was knockdown in primary neurons, dendrite growth was inhibited and the number of synapsin-1-positive synapses reduced even with TGFß1 treatment. When astrocyte-conditioned medium (ACM), collected from TGFß1-treated astrocytes (TGFß1-stimulated ACM), was added to cultured neurons, dendritic growth was inhibited and the number of synapsin-1-positive puncta reduced. When TGFß1-stimulated ACM was collected from astrocytes with Smad3 knocked down, this conditioned media promoted the growth of dendrites and the number of synapsin-1-positive puncta in cultured neurons. We further found that TGFß1 signaling through Smad3 increased the expression of chondroitin sulfate proteoglycans, neurocan, and phosphacan in ACM. Application of chondroitinase ABC to the TGFß1-stimulated ACM reversed its inhibitory effects on the dendrite growth and the number of synapsin-1-positive puncta. On the other hand, we found that TGFß1 treatment caused a facilitation of Smad3 phosphorylation and translocation to the nucleus induced by status epilepticus (SE) in wild-type (Smad3(+/+)) mice, and this treatment also caused a promotion of γ-aminobutyric acid-ergic synaptogenesis impaired by SE in Smad3(+/+) as well as in Smad3(-/-) mice, but more dramatic promotion in Smad3(+/+) mice. Thus, we provide evidence for the first time that TGFß-Smad3 signaling pathways within neuron and astrocyte differentially regulate dendrite growth and synaptogenesis, and this pathway may be involved in the pathogenesis of some central nervous system diseases, such as epilepsy.