No abstract

The mitochondria are the most important cytoplasmic organelles in determining cell survival and death. Mitochondrial dysfunction leads to a wide range of disorders, including neurodegenerative diseases. The central events in the mitochondrial‑dependent cell death pathway are the activation of the mitochodrial permeability transition pore (mPTP) and the disruption of mitochondrial membrane potential, which cause the release of apoptogenic molecules and finally lead to cell death. This is thought to be at least partly responsible for the loss of dopaminergic neurons in Parkinson's disease (PD); thus, the attenuation of mitochondrial dysfunction may contribute to alleviating the severity and progression of this disease. Guanosine is a pleiotropic molecule affecting multiple cellular processes, including cellular growth, differentiation and survival. Its protective effects on the central nervous system and and on several cell types by inhibiting apoptosis have been shown in a number of pathological conditions. This study aimed to analyze the ability of guanosine to protect neuronal PC12 cells from the toxicity induced by 1-methyl-4-phenylpyridinium (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which mediates selective damage to dopaminergic neurons and causes irreversible Parkinson-like symptoms in humans and primates. Our results demonstrated that the apoptosis of PC12 cells induced by MPP+ was significantly prevented by pre-treatment for 3 h with guanosine. In addition, guanosine attenuated the MPP+-induced collapse of mitochondrial transmembrane potential and prevented the sebsequent activation of caspase-3, thereby protecting dopaminergic neurons against mitochondrial stress-induced damage.

No abstract

Mammalian early embryonic development is controlled by a unique program of gene expression, and involves epigenetic reprogramming of histone modifications and DNA methylation. SET and MYND domain-containing protein 3 (SMYD3) is a histone H3 lysine 4 methyltransferase that plays important roles in transcription regulation. The expression of SMYD3 has been studied in some cancer cell lines. However, its expression in oocytes and embryos has not previously been reported. Here, we detected the SMYD3 mRNA and found that it was expressed throughout bovine oocyte in vitro maturation and early embryonic development. Microinjection of SMYD3 siRNA at germinal vesicle stage decreased the transcription level of NANOG, and blocked the development of in vitro fertilization embryos at 4-8 cell stage. Conversely, Microinjection of SMYD3 siRNA at pronuclear stage did not affect early embryonic development. Our findings suggest that SMYD3 regulates the expression of NANOG, and plays an essential role in bovine early embryonic development.

In this research, bone marrow mesenchymal stem cells (BMSCs) were isolated from mouse, and induced differentiation into myocardial cells in vitro after overexpression of miR-1a. The results showed that the BMSCs could induce differentiation into myocardial cells under the special condition medium, but when the miR-1a was over-expressed in BMSCs, the differentiation efficiency and induction time of myocardial cells from BMSCs could be promoted. This reason was demonstrated that Delta-like 1 (Dll-1) was a transcriptional repressor of myocardium gene expression during myocardium differentiation, miR-1a reduced Dll-1 levels, leading to the accumulation of myocardium gene mRNA and a dramatic increase in myocardium gene protein.