Arrestins are a small family of four proteins in most vertebrates that bind hundreds of different G protein-coupled receptors (GPCRs). Arrestin binding to a GPCR has at least three functions: precluding further receptor coupling to G proteins, facilitating receptor internalization, and initiating distinct arrestin-mediated signaling. The molecular mechanism of arrestin–GPCR interactions has been extensively studied and discussed from the “arrestin perspective”, focusing on the roles of arrestin elements in receptor binding. Here, we discuss this phenomenon from the “receptor perspective”, focusing on the receptor elements involved in arrestin binding and emphasizing existing gaps in our knowledge that need to be filled. It is vitally important to understand the role of receptor elements in arrestin activation and how the interaction of each of these elements with arrestin contributes to the latter’s transition to the high-affinity binding state. A more precise knowledge of the molecular mechanisms of arrestin activation is needed to enable the construction of arrestin mutants with desired functional characteristics.
Active targeted chemotherapy is expected to provide more specific delivery of cytotoxic drugs to the tumor cells and hence reducing the side effects on healthy tissues. Due to the over expression of biotin receptors on cancerous cells as a result of further requirement for rapid proliferations, biotin can be a good candidate as a targeting agent. In this study, biotin decorated PLGA nanoparticles (NPs) containing SN-38 were prepared and in vitro studies were evaluated for their improved anti-cancer properties. In conclusion, biotin targeted PLGA NPs containing SN-38 showed preferential anticancer properties against tumor cells with biotin receptor over expression.
Nowadays, polymeric nanoparticles have drawn more attention as drug carrier by investigators.In this study, we synthesized high selective imprinted nanoparticle polymer using olanzapine as template. The aim of this study was preparing efficient imprinted polymer nanoparticles from olanzapine as the template for the controlled release of olanzapine as a therapeutic drug for central nervous systems (CNS) disease at different pH values and the solid-phase extraction (SPE) as the sample clean-up technique combined with high-performance liquid chromatography (HPLC). The morphology of the nanoparticles was determined using scanning electron microscopy (SEM) images. Drug release, binding properties and dynamic light scattering (DLS) of the molecularly imprinted polymers (MIPs) were studied in this investigation. The adsorption isotherm was fitted with Langmuir and Freundlich models. The performance of the MIPs for the controlled release of olanzapine was assessed in two different media (SDS 1% and PBS). Results revealed that the MIPs have potential application in controlled drug release. Moreover, cytotoxicity of the MIP nanoparticles was measured on NIH/ 3 T3 cell line using MTT method.Furthermore, the MIPs were applied to extraction of olanzapine from human blood plasma samples. The limit of detection (LOD) and limit of quantification (LOQ) were evaluated and were 0.18 µg L -1 and 0.39 µg L -1 , respectively. These results collectively illustrate that MIP nanoparticles can be employed as an efficient technique for the extraction of the olanzapine from human plasma.
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