A role of CPEB1 in the modulation of proliferation and neuronal maturation of rat primary neural progenitor cells

Depletion of CPEB1 protects against oxidized LDL-induced endothelial apoptosis and inflammation though SIRT1/LOX-1 signalling pathway

Atherosclerosis (AS) is a chronic inflammatory disease that results from Oxidized low-density lipoprotein (Ox-LDL) induced endothelial dysfunction. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) is closely related to the development of epithelial cells, but the role of CPEB1 in AS remains unknown. The RNA and protein levels of CPEB1 expression are increased by Ox-LDL exposure, which is abrogated by c-Jun amino-terminal kinase (JNK) inhibitor SP600125. CPEB1 small interfering RNA (siRNA) suppressed the oxidative stress, inflammation, and apoptosis. Furthermore, CPEB1 siRNA enhanced the sirtuin 1 (SIRT1) transcription levels in Ox-LDL-treated HUVECs. Co-Immunoprecipitation (Co-IP) assay showed that CPEB1 siRNA declined the ubiquitination of SIRT1, and SIRT1 siRNA enhanced the Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), which were decreased by CPEB1 siRNA. In addition, LOX-1 and SIRT1 attenuated the protection of SIRT1 siRNA on Ox-LDL-induced oxidative stress. Therefore, our study revealed that CPEB1 depletion might play an anti-inflammatory and antiapoptotic role in Ox-LDL-induced apoptosis and inflammation though SIRT1/LOX-1 signalling pathway.

Role of P2 receptors in normal brain development and in neurodevelopmental psychiatric disorders

The purinergic signaling system, including P2 receptors, plays an important role in various central nervous system (CNS) disorders. Over the last few decades, a substantial amount of accumulated data suggest that most P2 receptor subtypes (P2X1, 2, 3, 4, 6, and 7, and P2Y₁, ₂, ₆, ₁₂, and ₁₃) regulate neuronal/neuroglial developmental processes, such as proliferation, differentiation, migration of neuronal precursors, and neurite outgrowth. However, only a few of these subtypes (P2X2, P2X3, P2X4, P2X7, P2Y₁, and P2Y₂) have been investigated in the context of neurodevelopmental psychiatric disorders. The activation of these potential target receptors and their underlying mechanisms mainly influence the process of neuroinflammation. In particular, P2 receptor-mediated inflammatory cytokine release has been indicated to contribute to the complex mechanisms of a variety of CNS disorders. The released inflammatory cytokines could be utilized as biomarkers for neurodevelopmental and psychiatric disorders to improve the early diagnosis intervention, and prognosis. The population changes in gut microbiota after birth are closely linked to neurodevelopmental/neuropsychiatric disorders in later life; thus, the dynamic expression and function of P2 receptors on gut epithelial cells during disease processes indicate a novel avenue for the evaluation of disease progression and for the discovery of related therapeutic compounds.

Aurora kinase A is not involved in CPEB1 phosphorylation and cyclin B1 mRNA polyadenylation during meiotic maturation of porcine oocytes

Regulation of mRNA translation by cytoplasmic polyadenylation is known to be important for oocyte maturation and further development. This process is generally controlled by phosphorylation of cytoplasmic polyadenylation element binding protein 1 (CPEB1). The aim of this study is to determine the role of Aurora kinase A in CPEB1 phosphorylation and the consequent CPEB1-dependent polyadenylation of maternal mRNAs during mammalian oocyte meiosis. For this purpose, we specifically inhibited Aurora kinase A with MLN8237 during meiotic maturation of porcine oocytes. Using poly(A)-test PCR method, we monitored the effect of Aurora kinase A inhibition on poly(A)-tail extension of long and short cyclin B1 encoding mRNAs as markers of CPEB1-dependent cytoplasmic polyadenylation. Our results show that inhibition of Aurora kinase A activity impairs neither cyclin B1 mRNA polyadenylation nor its translation and that Aurora kinase A is unlikely to be involved in CPEB1 activating phosphorylation.