ABSTRACT
This study was aimed to investigate the mechanism of all-trans retinoic acid (ATRA) up-regulating apelin expression in vascular smooth muscle cells (VSMCs). The effect of ATRA on apelin expression in the VSMCs was investigated by RT-PCR, real-time PCR and Western blot analysis. To further define whether retinoic acid receptor α (RARα) mediated the induction of apelin by ATRA, endogenous RARα was down regulated by transfection of siRNA against RARα (si-RARα) or RARα was over-expressed by infection of the adenovirus vector pAd-GFP-RARα in the VSMCs. The results showed that ATRA significantly induced apelin expression in a time- and dose-dependent manner in the VSMCs. Although RARα expression was increased in a time-dependent manner, the expressions of RARβ and RARγ were little changed by the ATRA treatment. When VSMCs were treated with a RARα antagonist Ro 41-5253 prior to the addition of ATRA, or si-RARα was used to down regulate endogenous RARα expression, the blockade of RARα signaling partially reduced the response of apelin to ATRA. Moreover, RARα over-expression, induced by infection of pAd-GFP-RARα, further increased the induction of apelin by ATRA. In conclusion, ATRA may up-regulate apelin expression in VSMCs, and the mechanism may be RARα dependent.
Subject(s)
Benzoates , Chromans , Gene Expression Regulation , Intercellular Signaling Peptides and Proteins , Metabolism , Muscle, Smooth, Vascular , Cell Biology , Myocytes, Smooth Muscle , Metabolism , Real-Time Polymerase Chain Reaction , Receptors, Retinoic Acid , Metabolism , Retinoic Acid Receptor alpha , Signal Transduction , Transfection , Tretinoin , Metabolism , Up-RegulationABSTRACT
Aim To investgate the mechnism through which ginkgolides affect learning and memory capabilities of the Alzheimers disease-like rats. Methods Okadaic acid(OA)was injected into the CA1 region of the rat hippocampus and the rats were gavaged with ginkgolides. The learning and memory abilities of the rats were assessed through Morris water maze behavioral test, and the expressions of nicotinic acetylcholine receptors and ChAT were observed by Western blotting and immunohistochemistry, respectively.Results Compared with the control rats, the capabilities of learning and memory were lowered significantly(P