In Escherichia coli, cyclic AMP receptor protein (CRP) is known to regulate the transcription of about 100 genes. The signal to activate CRP is the binding of cyclic AMP. It has been suggested that binding of cAMP to CRP leads to a long-distance signal transduction from the N-terminal cAMP-binding domain to the C-terminal domain of the protein, which is responsible for interaction with specific sequences of DNA. The signal transduction plays a crucial role in the activation of the protein. The most sophisticated spectroscopic techniques, other techniques frequently used in structural biochemistry, and site-directed mutagenesis have been used to investigate the details of cAMP-mediated allosteric control over CRP conformation and activity as a transcription factor. The aim of this review is to summarize recent works and developments pertaining to cAMP-dependent CRP signal transduction in E. coli.

An investigation of the interactions between bio-polymeric nanoparticles (NPs) and the RAW 264.7 mouse murine macrophage cell line has been presented. The cell viability, immunological response, and endocytosis efficiency of NPs were studied. Biopolymeric NPs were synthesized from a nanoemulsion using the phase inversion composition (PIC) technique. The two types of biopolymeric NPs that were obtained consisted of a biocompatible polymer, polycaprolactone (PCL), either with or without its copolymer with poly(ethylene glycol) (PCL-b-PEG). Both types of synthesized PCL NPs passed the first in vitro quality assessments as potential drug nanocarriers. Non-pegylated PCL NPs were internalized more effectively and the clathrin-mediated pathway was involved in that process. The investigated NPs did not affect the viability of the cells and did not elicit an immune response in the RAW 264.7 cells (neither a significant increase in the expression of genes encoding pro-inflammatory cytokines nor NO (nitric oxide) production were observed). It may be concluded that the synthesized NPs are promising candidates as nanocarriers of therapeutic compounds.

J. Neurochem. (2010) 113, 848–859. The present study uses a proteomic approach to examine possible alterations of protein expression in the hippocampus of rats that are subjected to chronic mild stress (CMS). These rats serve as an animal model that was developed to mimic anhedonia, which is one of the core symptoms of depression. As antidepressant treatment is effective after a few weeks of administration, we also aimed to identify changes that were linked to chronic (once daily for 4 weeks) and ‘pulse’ (once a week) administration of imipramine. Fifteen differential proteins were identified with 2D electrophoresis followed by mass spectrometry. Although both methods of imipramine administration restored normal sucrose consumption in rats that were subjected to CMS, the molecular mechanisms of these two therapies were different. CMS‐induced changes in the levels of dynactin 2, Ash 2, non‐neuronal SNAP25 and alpha‐enolase were reversed by chronic imipramine, but ‘pulse’ treatment was not that effective.

Background: Obtaining human neurons and astrocytes for in vitro studies presents a significant challenge owing to the complexity of replicating their development and functionality outside the human brain. The Ntera-2 cell line is a valuable source of human neurons and astrocytes in neuroscience research. However, differentiating Ntera-2 cells into neurons and astrocytes with all-trans retinoic acid is complicated by the lack of reliable markers to monitor differentiation stages effectively. This study aimed to characterize neuron-enriched and pure astrocyte cultures at two maturation stages and to compare these with the original Ntera-2 cells. Ntera-2 cells and NT2 cells are used interchangeably in this publication. Methods: Using an advanced proteomic approach, we assessed the protein composition and abundance of neuron and astrocyte co-cultures and discovered that the astrocytic protein profile in co-culture with neurons was more representative compared with that in pure astrocyte cultures. Additionally, electrophysiological studies were conducted to investigate the best astrocyte content for neuronal functionality. Results: Mass spectrometry-based analysis provided insights into over 9000 proteins, covering well-known protein markers, proteins unique to specific cell types, and differentially expressed proteins. Notably, differences in transcription factors, regulatory proteins, intermediate filaments, and proteins unique to early and mature astrocytes highlighted the distinct maturation, activation, and functional profiles of the various cells. These findings offer a straightforward tool for characterization and monitoring the differentiation process. Three weeks of maturation in pure culture yielded immature astrocytes; however, extending the maturation period to 6 weeks significantly altered the composition of the cellular proteome, indicating increased astrocyte maturity. Studies revealed a broader repertoire of astrocytic proteins in co-culture with neurons. Meanwhile, electrophysiological analyses demonstrated that a high content of astrocytes is essential for neuronal functional maturity. Conclusions: Astrocyte–neuron co-cultures offer a more accurate model of neural tissue than pure cultures, highlighting the complexity of cell maturation and providing insights for improving in vitro modeling of human neural development. Graphical