Different Effects of p52SHC1 and p52SHC3 on the Cell Cycle of Neurons and Neural Stem Cells

Hypoxic conditioned promotes the proliferation of human olfactory mucosa mesenchymal stem cells and relevant lncRNA and mRNA analysis

AIMS

LncRNAs are involved in many biological processes, and hypoxia contributed to the alterations of lncRNAs. Hypoxic preconditioned olfactory mucosa mesenchymal stem cells (OM-MSCs) exerted stronger anti-apoptotic ability in models of disease, but the molecules that controlled different biological characteristics of human OM-MSCs between hypoxic and normoxic conditions were unclear. The present study was aimed to explore the molecules that controlled different biological characteristics of human OM-MSCs between hypoxic and normoxic conditions.

MAIN METHODS

LncRNAs and mRNAs expression profiles of human OM-MSCs between hypoxic (3%) and normoxic conditions were analyzed by Next-Generation Sequencing (NGS) analysis, bioinformatics analysis on these data were further performed. Moreover, loss-of function assay was conducted to investigate the impact of hypoxic condition on the proliferation and apoptosis of OM-MSCs.

KEY FINDINGS

Through the comparative analysis and bioinformatics analysis, a total of 1741 lncRNAs and 1603 mRNAs were significant differentially expressed in the hypoxia group compared with normoxia group. Enrichment analysis revealed that differentially expressed genes of human OM-MSCs mainly participated in cell cycle regulation, secretin of cytokines and so on. Meanwhile, hypoxic condition significantly promoted proliferation and inhibited apoptosis of human OM-MSCs, following loss-of-function assays confirmed that lncRNA DARS-AS1 were involved in this regulatory process by hypoxic condition. Further prediction of targeted genes and the construction of lncRNA-miRNA-mRNA interaction network enriched the significance regarding the mechanism of DARS-AS1.

SIGNIFICANCE

Altogether, these findings provided a new perspective for understanding the molecules expression patterns in hypoxia that contributed to corresponding phenotype alterations of OM-MSCs.

Neonatal ketamine exposure-induced hippocampal neuroapoptosis in the developing brain impairs adult spatial learning ability

Ketamine exposure can lead to selective neuroapoptosis in the developing brain. p66ShcA, the cellular adapter protein expressed selectively in immature neurons, is a known pro-apoptotic molecule that triggers neuroapoptosis when activated. Sprague-Dawley rats at postnatal day 7 were subcutaneously injected in the neck with ketamine 20 mg/kg, six times at 2-hour intervals. At 0, 1, 3, and 6 hours after final injection, western blot assay was used to detect the expression of cleaved caspase-3, p66ShcA, and phosphorylated p66ShcA. We found that the expression of activated p66ShcA and caspase-3 increased after ketamine exposure and peaked at 3 hours. The same procedure was performed on a different group of rats. At the age of 4 weeks, spatial learning and memory abilities were tested with the Morris water maze. Latency to find the hidden platform for these rats was longer than it was for control rats, although the residence time in the target quadrant was similar. These findings indicate that ketamine exposure resulted in p66ShcA being activated in the course of an apoptotic cascade during the neonatal period. This may have contributed to the deficit in spatial learning and memory that persisted into adulthood. The experimental protocol was approved by the Institutional Animal Care and Use Committee at the University of Texas at Arlington, USA (approval No. A13.008) on January 22, 2013.