Dusp4 Contributes to Anesthesia Neurotoxicity via Mediated Neural Differentiation in Primates.

BACKGROUND: Children who are exposed to anesthesia multiple times may undergo cognitive impairment during development. The underlying mechanism has been revealed as anesthesia-induced cognitive deficiency in young rodents and monkeys. However, the molecular mechanism of sevoflurane-induced neural development toxicity is unclear. METHODS: By combining RNA sequencing analysis of macaques' prefrontal cortex and human neural differentiation, this study investigates the mechanism of sevoflurane-induced neurotoxicity in primates. RESULTS: The level of dual specificity protein phosphatase 4 (Dusp4) was significantly downregulated in non-human primates after sevoflurane treatment. We further uncovered the dynamical expression of Dusp4 during the human neural differentiation of human embryonic stem cells and found that knockdown of Dusp4 could significantly inhibit human neural differentiation. CONCLUSION: This study indicated that Dusp4 is critically involved in the sevoflurane-induced inhibition of neural differentiation in non-human primate and the regulation of human neural differentiation. It also suggested that Dusp4 is a potential therapeutic target for preventing the sevoflurane-induced neurotoxicity in primates.

Conversion of Astrocytes and Fibroblasts into Functional Noradrenergic Neurons.

Dysfunction of noradrenergic (NA) neurons is associated with a number of neuronal disorders. Diverse neuronal subtypes can be generated by direct reprogramming. However, it is still unknown how to convert non-neuronal cells into NA neurons. Here, we show that seven transcription factors (TFs) (Ascl1, Phox2b, AP-2α, Gata3, Hand2, Nurr1, and Phox2a) are able to convert astrocytes and fibroblasts into induced NA (iNA) neurons. These iNA neurons express the genes required for the biosynthesis, release, and re-uptake of noradrenaline. Moreover, iNA neurons fire action potentials, receive synaptic inputs, and control the beating rate of co-cultured ventricular myocytes. Furthermore, iNA neurons survive and integrate into neural circuits after transplantation. Last, human fibroblasts can be converted into functional iNA neurons as well. Together, iNA neurons are generated by direct reprogramming, and they could be potentially useful for disease modeling and cell-based therapies.

[Expression of YY 1 protein in human insulinoma and its clinical implication].

OBJECTIVE: To investigate the expression of Yin Yang 1 (YY1) protein in human insulinoma and explore its clinical significance. METHODS: Nineteen pancreatic neuroendocrine tumor tissue were collected from patients treated in Nanfang Hospital between 2000 and 2014. The protein expression of YY1 in benign and malignant insulinoma tissues were detected by immunohistochemistry. RESULTS: Positive expression for YY1 protein was detected in both benign and malignant tumor tissues, but the malignant tissues had a significantly greater intensity of YY1 expression than the benign tissues (P=0.042). The intensity of YY1 expression was positively correlated with the nature of the tumor, and the insulinomas with high expressions of YY1 had significantly greater malignant potentials (P=0.037). CONCLUSION: The high expression of YY1 protein is associated with the development of insulinima. YY1 may serve as a new tumor marker for detecting the malignant transformation of insulinoma.

Smad6 inhibits the transcriptional activity of Tbx6 by mediating its degradation.

Members of the bone morphogenetic protein (BMP) and T-box gene families play several critical roles in the early embryonic development and tissue homeostasis. Although BMP proteins are the upstream regulators of T-box genes, few studies have investigated the molecular mechanisms between these two protein families. Here, we report that Tbx6 interacts directly with Smad6, an inhibitory Smad that antagonizes the BMP signal. This interaction is mediated through the Mad homology 2 (MH2) domain of Smad6 and residues 90-180 of Tbx6. We demonstrate that Smad6 facilitates the degradation of Tbx6 protein through recruitment of Smurf1, a ubiquitin E3 ligase. Consequently, Smad6 reduces Tbx6-mediated Myf-5 gene activation. Furthermore, specific knockdown of endogenous Smad6 and Smurf1 by small interfering RNA increases the protein levels of Tbx6 and enhance the expression of Tbx6 target genes. Collectively, these findings reveal that Smad6 serves as a critical mediator of BMP signal via a functional interaction with Tbx6, thus regulating the activation of Tbx6 downstream genes during cell differentiation.

[Persistently exist of ES-like cell population in long-term cultured embryoid bodies].

Undifferentiated embryonic stem (ES) cells can be maintained in vitro if cultured in the presence of the cytokine leukaemia inhibitory factor (LIF). ES cells can also differentiate in vitro. A particularly efficient method for inducing ES cell differentiation is to culture ES cells as aggregates in the absence of LIF. Under these conditions they form structures known as embryoid bodies (EBs). However the current protocols for EB formation are still diverse. In order to facilitate further study, we carefully controlled the culture conditions for EB formation, and here we report an efficient protocol by which uniformly differentiated EBs were obtained, monitored by measuring the differentiation of beating cardiomyocytes. Furthermore, by using this protocol we observed in long-term cultured plating EBs (> 60 days) there still exist cell colony with pluripotency. This observation raised a potential possibility that ES cells may keep pluripotent in a niche provided by differentiated cells.