Cellular Targets Research Articles

Unveiling the promising anticancer activity of palladium(II)-aryl complexes bearing diphosphine ligands: a structure-activity relationship analysis.

In continuation of our previous works on the cytotoxic properties of organopalladium compounds, in this contribution we describe the first systematic study of the anticancer activity of Pd(II)-aryl complexes. To this end, we have prepared and thoroughly characterized a wide range of palladium derivatives bearing different diphosphine, aryl and halide ligands, developing, when necessary, specific synthetic protocols. Most of the synthesized compounds showed remarkable cytotoxicity towards ovarian and breast cancer cell lines, with IC50 values often comparable to or lower than that of cisplatin. The most promising complexes ([PdI(Ph)(dppe)] and [PdI(p-CH3-Ph)(dppe)]), characterized by a diphosphine ligand with a low bite angle, exhibited, in addition to excellent cytotoxicity towards cancer cells, low activity on normal cells (MRC5 human lung fibroblasts). Specific immunofluorescence tests (cytochrome c and H2AX assays), performed to clarify the possible mechanism of action of this class of organopalladium derivatives, seemed to indicate DNA as the primary cellular target, whereas caspase 3/7 assays proved that the complex [PdI(Ph)(dppe)] was able to promote intrinsic apoptotic cell death. A detailed molecular docking analysis confirmed the importance of a diphosphine ligand with a reduced bite angle to ensure a strong DNA-complex interaction. Finally, one of the most promising complexes was tested towards patient-derived organoids, showing promising ex vivo cytotoxicity.

Icariin prevents methylmercury-induced experimental neurotoxicity: Evidence from cerebrospinal fluid, blood plasma, brain samples, and in-silico investigations

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that causes significant neurodegeneration. Methylmercury (MeHg+) is a neurotoxin that induces axonal neurodegeneration and motor nerve degeneration by destroying oligodendrocytes, degenerating white matter, inducing apoptosis, excitotoxicity, and reducing myelin basic protein (MBP). This study examines the inhibition of SIRT-1 (silence information regulator 1), Nrf-2 (nuclear factor E2-related factor 2), HO-1 (heme oxygenase 1), and TDP-43 (TAR-DNA-binding protein 43) accumulation in the context of ALS, as well as the modulation of these proteins by icariin (15 and 30 mg/kg, orally), a glycoside flavonoid with neuroprotective properties. Neuroprotective icariin activates SIRT-1, Nrf-2, and HO-1, mitigating inflammation and neuronal injury in neurodegenerative disorders. In-vivo and in-silico testing of experimental ALS models confirmed icariin efficacy in modulating these cellular targets. The addition of sirtinol 10 mg/kg, an inhibitor of SIRT-1, helps determine the effectiveness of icariin. In this study, we also examined neurobehavioral, neurochemical, histopathological, and LFB (Luxol fast blue) markers in various biological samples, including Cerebrospinal fluid (CSF), blood plasma, and brain homogenates (Cerebral Cortex, Hippocampus, Striatum, mid-brain, and Cerebellum). These results demonstrate that the administration of icariin ameliorates experimental ALS and that the mechanism underlying these benefits is likely related to regulating the SIRT-1, Nrf-2, and HO-1 signaling pathways.

Transfection of Babesia duncani: A Genetic Toolbox of this Pathogen to Advance Babesia Biology.

Human babesiosis is a tick-borne disease caused by Babesia pathogens. The disease, which presents with malaria-like symptoms, can be life-threatening, especially in individuals with weakened immune systems and the elderly. The worldwide prevalence of human babesiosis has been gradually rising, prompting alarm among public health experts. In other pathogens, genetic techniques have proven to be valuable tools for conducting functional studies to understand the importance of specific genes in development and pathogenesis as well as to validate novel cellular targets for drug discovery. Genetic manipulation methods have been established for several non-human Babesia and Theileria species and, more recently, have begun to be developed for human Babesia parasites. We have previously reported the development of a method for genetic manipulation of the human pathogen Babesia duncani. This method is based on positive selection using the hDHFR gene as a selectable marker, whose expression is regulated by the ef-1aB promoter, along with homology regions that facilitate integration into the gene of interest through homologous recombination. Herein, we provide a detailed description of the steps needed to implement this strategy in B. duncani to study gene function. It is anticipated that the implementation of this method will significantly improve our understanding of babesiosis and facilitate the development of novel and more effective therapeutic strategies for the treatment of human babesiosis. Key features This protocol provides an effective means of transfection of B. duncani, enabling genetic manipulation and editing to gain further insights into its biology and pathogenesis. The protocol outlined here for the electroporation of B. duncani represents an advancement over previous methods used for B. bovis [1]. Improvements include higher volume of culture used during the electroporation step and an enhancement in the number of electroporation pulses. These modifications likely enhance the efficiency of gene editing in B. duncani, allowing for quicker and more effective selection of transgenic parasites.

An Optimized P. berghei Liver Stage-HepG2 Infection Model for Simultaneous Quantitative Bioimaging of Host and Parasite Nascent Proteomes.

The Plasmodium parasites that cause malaria undergo an obligate, asymptomatic developmental stage in the host liver before initiating the symptomatic blood-stage infection. The parasite liver stage is a key intervention point for antimalarial chemoprophylaxis: successful targeting of liver-stage parasites prevents disease development in individuals and can help to reduce parasite transmission in populations, as the gametocyte forms that transmit infection to mosquitos are exclusively found in the blood stage. Antimalarial drugs that can target multiple parasite stages are thus highly desirable, and one emerging cellular target for such multistage active compounds is the process of protein synthesis or translation. Quantitative study of liver stage translation, and thus mechanistic evaluation of translation inhibitors against liver stage parasites, is not amenable to the methods allowing quantification of asexual blood stage translation, such as radiolabeled amino acid incorporation or lysate-based translation of reporter transcripts. Here, we present a method using o-propargyl puromycin (OPP) labeling of host and parasite nascent proteomes in the P. berghei-HepG2 infection model, followed by automated confocal image acquisition and computational separation of P. berghei vs. H. sapiens nascent proteome signals to allow simultaneous readout of the effects of translation inhibitors on both host and parasite. This protocol details our HepG2 cell culture and infected monolayer handling optimized for microscopy, our OPP labeling workflow, and our approach to automated confocal imaging, image processing, and data analysis. Key features • Uses the o-propargyl puromycin labeling technique developed by Liu et al. to quantitatively analyze protein synthesis in Plasmodium berghei liver-stage parasites in actively translating hepatoma cells. • This quantitative approach should be adaptable for other puromycin-sensitive intracellular pathogens residing in actively translating host cells. • The P. berghei-infected HepG2 recovery and reseeding protocol presented here is of use in applications beyond nascent proteome labeling and quantification.

Correlative cryo-microscopy pipelines for in situ cellular studies.

Correlative cryo-microscopy pipelines combining light and electron microscopy and tomography in cryogenic conditions (cryoCLEM) on the same sample are powerful methods for investigating the structure of specific cellular targets identified by a fluorescent tag within their unperturbed cellular environment. CryoCLEM approaches circumvent one of the inherent limitations of cryo EM, and specifically cryo electron tomography (cryoET), of identifying the imaged structures in the crowded 3D environment of cells. Whereas several cryoCLEM approaches are based on thinning the sample by cryo FIB milling, here we present detailed protocols of two alternative cryoCLEM approaches for in situ studies of adherent cells at the single-cell level without the need for such cryo-thinning. The first approach is a complete cryogenic pipeline in which both fluorescence and electronic imaging are performed on frozen-hydrated samples, the second is a hybrid cryoCLEM approach in which fluorescence imaging is performed at room temperature, followed by rapid freezing and subsequent cryoEM imaging. We provide a detailed description of the two methods we have employed for imaging fluorescently labeled cellular structures with thickness below 350-500nm, such as cell protrusions and organelles located in the peripheral areas of the cells.

Ellagic acid-modified gold nanoparticles to combat multi-drug resistant bacterial infections in vitro and in vivo.

The overuse of antibiotics has led to the rapid development of multi-drug resistant bacteria, making antibiotics increasingly ineffective against bacterial infections. Consequently, there is an urgent need to develop alternative strategies to combat multi-drug-resistant bacterial infections. In this study, gold nanoparticles modified with ellagic acid (EA-AuNPs) were prepared using a simple and mild one-pot hydrothermal process. EA-AuNPs demonstrated high bactericidal efficacy and broad-spectrum antimicrobial activities against clinical isolates of the antibiotic-resistant ESKAPE pathogens. Furthermore, EA-AuNPs effectively disperse biofilms of multi-drug-resistant bacteria. Additionally, EA-AuNPs mitigated inflammatory responses at the bacterial infection sites. The combined bactericidal and anti-inflammatory treatment with EA-AuNPs resulted in faster curing of peritonitis caused by Staphylococcus aureus in mice compared to treatment with free EA or gentamicin. Moreover, transcriptome analysis revealed that EA-AuNPs exhibited a multi-targeting mechanism, making resistance development in pathogens more challenging than traditional antibiotics that recognize specific cellular targets. Overall, EA-AuNPs emerged as a promising antimicrobial agent against multi-drug-resistant bacterial infections.

Bone Remodeling and Modeling: Cellular Targets for Antiresorptive and Anabolic Treatments, Including Approaches Through the Parathyroid Hormone (PTH)/PTH-Related Protein Pathway.

Bone is continuously in a state of building and renewal, though the process of remodeling that takes place at many sites asynchronously throughout the skeleton, with bone formation and resorption equal at these sites (bone multicellular units). Remodeling takes place on bone surfaces, both on trabeculae and in the cortex, and serves the purposes of replacing old bone or that damaged by microfractures throughout the skeleton. The bone loss and consequent osteoporotic fractures that result from excess resorption over formation have mainly been prevented or treated by antiresorptive drugs that inhibit osteoclast formation and/or activity. Virtually all of the evidence leading to acceptance of antiresorptive drugs as treatment has depended upon their prevention of vertebral fractures. In recent decades, new prospects came of anabolic treatments that partly restore bone volume and microstructure restore bone that has been lost. The first of these was parathyroid hormone (PTH), shown by daily injection to increase markers of bone formation and prevent fractures. This field of interest enlarged with the discovery of PTH-related protein (PTHrP), so closely related in structure and action to PTH. The structural relationship between PTH and PTHrP is important in assessing their physiological and pharmacological roles, with the N-terminal domains of the 2 having virtually equal actions on target cells. Abaloparatide, a peptide analogue based on the structures of PTHrP and PTH, has been approved in some countries as a therapy for osteoporosis. Treatment through the PTH receptor activation pathway, and probably with any anabolic therapy, needs to be followed by antiresorptive treatment in order to maintain bone that has been restored. No matter how effective anabolic therapies for the skeleton become, it seems highly likely that there will be a continuing need for antiresorptive drugs.

Cellular Basis for Sequencing of Antiresorptive and Anabolic Therapies for Bone: Commentary on "Bone Remodeling and Modeling: Cellular Targets for Antiresorptive and Anabolic Treatments, Including Approaches Through the Parathyroid Hormone (PTH)/PTH-Related Protein Pathway".

Cellular Basis for Sequencing of Antiresorptive and Anabolic Therapies for Bone: Commentary on "Bone Remodeling and Modeling: Cellular Targets for Antiresorptive and Anabolic Treatments, Including Approaches Through the Parathyroid Hormone (PTH)/PTH-Related Protein Pathway".

Development of potent and selective ULK1/2 inhibitors based on 7-azaindole scaffold with favorable in vivo properties

The UNC-51-like kinase-1 (ULK1) is one of the central upstream regulators of the autophagy pathway, represents a key target for the development of molecular probes to abrogate autophagy and explore potential therapeutic avenues. Here we report the discovery, structure-activity and structure-property relationships of selective, potent, and cell-active ULK1/2 inhibitors based on a 7-azaindole scaffold. Using structure-based drug design, we have developed a series of analogs with excellent binding affinity and biochemical activity against ULK1/2 (IC50 < 25 nM). The validation of cellular target engagement for these compounds was achieved through the employment of the ULK1 NanoBRET intracellular kinase assay. Notably, we have successfully solved the crystal structure of the lead compound, MR-2088, bound to the active site of ULK1. Moreover, the combination treatment of MR-2088 with known KRAS→RAF→MEK→ERK pathway inhibitors, such as trametinib, showed promising synergistic effect in vitro using H2030 (KRASG12C) cell lines. Lastly, our findings underscore MR-2088’s potential to inhibit starvation/stimuli-induced autophagic flux, coupled with its suitability for in vivo studies based on its pharmacokinetic properties.

Anemoside B4, a new pyruvate carboxylase inhibitor, alleviates colitis by reprogramming macrophage function.

Colitis is a global disease usually accompanied by intestinal epithelial damage and intestinal inflammation, and an increasing number of studies have found natural products to be highly effective in treating colitis. Anemoside B4 (AB4), an abundant saponin isolated from Pulsatilla chinensis (Bunge), whichwas found to have strong anti-inflammatory activity. However, the exact molecular mechanisms and direct targets of AB4 in the treatment of colitis remain to be discovered. The anti-inflammatory activities of AB4 were verified in LPS-induced cell models and 2, 4, 6-trinitrobenzene sulfonic (TNBS) or dextran sulfate sodium (DSS)-induced colitis mice and rat models. The molecular target of AB4 was identified by affinity chromatography analysis using chemical probes derived from AB4. Experiments including proteomics, molecular docking, biotin pull-down, surface plasmon resonance (SPR), and cellular thermal shift assay (CETSA) were used to confirm the binding of AB4 to itsmolecular target. Overexpression of pyruvate carboxylase (PC) and PC agonist were used to study the effects of PC on the anti-inflammatory and metabolic regulation of AB4 in vitro and in vivo. AB4 not only significantly inhibited LPS-induced NF-κB activation and increased ROS levels in THP-1 cells, but also suppressed TNBS/DSS-induced colonic inflammation in mice and rats. The molecular target of AB4 was identified as PC, a key enzyme related to fatty acid, amino acid and tricarboxylic acid (TCA) cycle. We next demonstrated that AB4 specifically bound to the His879 site of PC and altered the protein's spatial conformation, thereby affecting the enzymatic activity of PC. LPS activated NF-κB pathway and increased PC activity, which caused metabolic reprogramming, while AB4 reversed this phenomenon by inhibiting the PC activity. In vivo studies showed that diisopropylamine dichloroacetate (DADA),a PC agonist, eliminated the therapeutic effects of AB4 by changing the metabolic rearrangement of intestinal tissues in colitis mice. We identified PC as a direct cellular target of AB4 in the modulation of inflammation, especially colitis. Moreover, PC/pyruvate metabolism/NF-κB is crucial for LPS-driven inflammation andoxidative stress. These findings shed more light on thepossibilities ofPC as a potential new target for treating colitis.

Global deletome profile of Saccharomyces cerevisiae exposed to lithium.

The increasing use of lithium (Li) in new technologies raises the question of its impact on living microorganisms. In the present study, we aimed to identify putative Li targets and resistance mechanisms in the yeast model Saccharomyces cerevisiae using a deletomic approach based on the screening of a collection of 4733 knockout mutants under Li exposure. This screening highlighted 60 mutants resistant to Li and 124 mutants sensitive to Li. Through functional enrichment analyses, transport systems were identified as playing a central role in cell resistance to toxic concentrations of Li. In contrast, the AKT/protein kinase B family, signal transduction or cell communication were identified as potential toxic targets of Li. The majority of the mutants with a Li-sensitive phenotype were also sensitive to other alkali and alkaline earth metals, whereas the Li-resistance phenotype was mostly resistant to Na but poorly resistant to other metals. A comparison with the results of deletomics studies carried out in the presence of other metals highlighted Li-specific phenotypes. Three genes (NAM7, NMD2, UPF3) of the nonsense-mediated decay pathway were specifically involved in resistance to Li. In contrast, mutants with the NCA2, SPT20, GCN5, YOR376W, YPK3, and DCW1 genes deleted were specifically resistant to Li. These genes encode various functions from putative mannosidase to constitution of the Spt-Ada-Gcn5 acetyltransferase complex. This work provides a better understanding of potential specific resistance mechanisms and cellular targets of Li in yeast.

Chalcone derivatives disrupt cell membrane integrity of Saccharomyces cerevisiae cells and alter their biochemical composition.

Fungal infections can be serious or life threatening in severe cases, and the need to discover and find novel antifungal agents persists. Chalcones are plant-derived aromatic compounds that have been appealing synthons for pharmaceutical industry as they have good anticancer, antibacterial, antifungal and anti-inflammatory properties. Although there are few structure-activity relationship studies on chalcones, studies that link the structural features of these compounds to their mode of action are scant. Thus, in this study, we aim to clarify the relationship between chalcone derivatives and their cellular target within the yeast cell Saccharomyces cerevisiae. We observed that some chalcone compounds lead to disruption of cell membrane and cause ion leakage out of the cell. Moreover, chalcones alter the biochemical composition of yeast cells detectable by FTIR spectroscopy and bind to the DNA as shown by our titration experiments based on UV-Vis absorbance spectroscopy. Thus, their interaction with the DNA may be the major impact of these compounds on yeast cells.

Single cell RNA-sequencing profiling to improve the translation between human IBD and in vivo models.

Inflammatory bowel disease (IBD) is an umbrella term for two conditions (Crohn's Disease and Ulcerative Colitis) that is characterized by chronic inflammation of the gastrointestinal tract. The use of pre-clinical animal models has been invaluable for the understanding of potential disease mechanisms. However, despite promising results of numerous therapeutics in mouse colitis models, many of these therapies did not show clinical benefits in patients with IBD. Single cell RNA-sequencing (scRNA-seq) has recently revolutionized our understanding of complex interactions between the immune system, stromal cells, and epithelial cells by mapping novel cell subpopulations and their remodeling during disease. This technology has not been widely applied to pre-clinical models of IBD. ScRNA-seq profiling of murine models may provide an opportunity to increase the translatability into the clinic, and to choose the most appropriate model to test hypotheses and novel therapeutics. In this review, we have summarized some of the key findings at the single cell transcriptomic level in IBD, how specific signatures have been functionally validated in vivo, and highlighted the similarities and differences between scRNA-seq findings in human IBD and experimental mouse models. In each section of this review, we highlight the importance of utilizing this technology to find the most suitable or translational models of IBD based on the cellular therapeutic target.

Accelerating multiplexed profiling of protein-ligand interactions: High-throughput plate-based reactive cysteine profiling with minimal input

Chemoproteomics has made significant progress in investigating small-molecule-protein interactions. However, the proteome-wide profiling of cysteine ligandability remains challenging to adapt for high-throughput applications, primarily due to a lack of platforms capable of achieving the desired depth using low input in 96- or 384-well plates. Here, we introduce a revamped, plate-based platform which enables routine interrogation of either ∼18,000 or ∼24,000 reactive cysteines based on starting amounts of 10 or 20μg, respectively. This represents a 5-10X reduction in input and 2-3X improved coverage. We applied the platform to screen 192 electrophiles in the native HEK293T proteome, mapping the ligandability of 38,450 reactive cysteines from 8,274 human proteins. We further applied the platform to characterize new cellular targets of established drugs, uncovering that ARS-1620, a KRASG12C inhibitor, binds to and inhibits an off-target adenosine kinase ADK. The platform represents a major step forward to high-throughput proteome-wide evaluation of reactive cysteines.

Discovery of a cannabinoid CB2 receptor fluorescent probe based on a pyridin-2-yl-benzyl-imidazolidine-2,4-dione scaffold

Cannabinoid receptor type 2 (CB2R) agonists have therapeutic potential for the treatment of (neuro)inflammatory diseases. Fluorescent probes enable the detection of CB2R in relevant cell types and serve as a chemical tool in cellular target engagement studies. Here, we report the structure-based design and synthesis of a new CB2R selective fluorescent probe. Based on the cryo-EM structure of LEI-102 in complex with the CB2R, we synthesized 5-fluoropyridin-2-yl-benzyl-imidazolidine-2,4-dione analogues in which we introduced a variety of linkers and fluorophores. Molecular pharmacological characterization showed that compound 22 containing a Cy5-fluorophore with an alkyl-spacer was the most potent probe with a pKi of 6.2 ± 0.6. It was selective over the cannabinoid CB1 receptor and behaved as an inverse agonist (EC50 5.3 ± 0.1, Emax -63% ± 6). Probe 22 may serve as a chemical tool in target and lead validation studies for the CB2R.

Exploring the molecular mechanism of Artemisia rupestris L. for the treatment of hepatocellular carcinoma via PI3K/AKT pathway

Ethnopharmacological relevanceHepatocellular carcinoma (HCC) is a common gastrointestinal malignancy in China. Most tumors develop from chronic inflammation. Artemisia rupestris L. (ARL) has been found to have a significant effect on viral influenza and hepatitis, but the mechanism of action of ARL against liver cancer is unclear. Aim of the studyThe study objective was to explore the mechanism of action of ARL for the treatment of hepatocellular carcinoma (HCC) by ethanol extract and in vitro experimental design. Materials and methodsInteractions between ARL and cellular target proteins against HCC were analyzed through network pharmacology and network topology with the utilization of the DAVID database. The rate of HepG2 cells' growth inhibition was assessed using the MTT assay in vitro cellular assay; hoechst33342 detects apoptosis of cells; the ability of HepG2 cells to migrate and invade was assessed using the transwell assay and the cell scratch experiment; and the levels of protein expression in HepG2 cells were assessed using the western blot assay. ResultsNetwork pharmacology prediction results demonstrated that 22 active ingredients were tested, 176 possible action targets were discovered, and the PI3K/Akt signaling pathway was found to be the most pertinent action pathway for the treatment of hepatocellular carcinoma. In vitro results showed that it can effectively restrict HepG2 cell proliferation, apoptosis, migration, and invasion as well as the regulation of protein expressions. ConclusionConclusively, Quercetin, Linarin, and Kaempferol were found most essential active ingredients from ARL that regulate the antitumor effects against HCC through the PI3K/Akt signaling pathway. The study provides a fundamental basis for further comprehensive evaluation of ARL to treat tumor diseases in general and its therapeutic potential against hepatocellular carcinoma in particular.

Integrated spectroscopic and MD simulation approach to decipher the effect of pH on the structure function of Staphylococcus aureus thymidine kinase

Staphylococcus aureus is a major human pathogen responsible for a variety of clinical infections, becoming increasingly resistant to antibiotics. To address this challenge, there is a need to identify new cellular targets and innovative approaches to expand treatment options. One such target is thymidine kinase (TK), a crucial enzyme in the pyrimidine salvage pathway, which plays a key role in the phosphorylation of thymidine, an essential component in DNA synthesis and repair. In this study, we have successfully cloned, expressed, and purified the TK protein. A comprehensive investigation into how different pH levels affect the structure and functional activity of TK, using a combination of spectroscopy, classical molecular dynamics simulations, and enzyme activity assays was conducted. Our study revealed that variation in pH disrupts secondary and tertiary structures of TK with noticeable aggregate formation at pH 5.0. Enzyme activity studies demonstrated that TK exhibited its maximum kinase activity within the physiological pH range. These findings strongly suggest a connection between structural changes and enzymatic activity, which was further supported by the agreement between the spectroscopic features we measured and the results of our MD simulations. Our study provides a deeper insight into the structural features of TK, which could potentially be harnessed for the development of therapeutic strategies aimed at combatting infectious diseases. Conformational dynamics plays an essential role in the design and development of effective inhibitors. Considering the effects of pH on the conformational dynamics of TK, our findings may be implicated in the development of potent and selective inhibitors. Communicated by Ramaswamy H. Sarma

Simvastatin Differentially Modulates Glial Functions in Cultured Cortical and Hypothalamic Astrocytes Derived from Interferon α/β Receptor Knockout mice.

Astrocytes have key regulatory roles in central nervous system (CNS), integrating metabolic, inflammatory and synaptic responses. In this regard, type I interferon (IFN) receptor signaling in astrocytes can regulate synaptic plasticity. Simvastatin is a cholesterol-lowering drug that has shown anti-inflammatory properties, but its effects on astrocytes, a main source of cholesterol for neurons, remain to be elucidated. Herein, we investigated the effects of simvastatin in inflammatory and functional parameters of primary cortical and hypothalamic astrocyte cultures obtained from IFNα/β receptor knockout (IFNα/βR-/-) mice. Overall, simvastatin decreased extracellular levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), which were related to a downregulation in gene expression in hypothalamic, but not in cortical astrocytes. Moreover, there was an increase in anti-inflammatory interleukin-10 (IL-10) in both structures. Effects of simvastatin in inflammatory signaling also involved a downregulation of cyclooxygenase 2 (COX-2) gene expression as well as an upregulation of nuclear factor κB subunit p65 (NFκB p65). The expression of cytoprotective genes sirtuin 1 (SIRT1) and nuclear factor erythroid derived 2 like 2 (Nrf2) was also increased by simvastatin. In addition, simvastatin increased glutamine synthetase (GS) activity and glutathione (GSH) levels only in cortical astrocytes. Our findings provide evidence that astrocytes from different regions are important cellular targets of simvastatin in the CNS, even in the absence of IFNα/βR, which was showed by the modulation of cytokine production and release, as well as the expression of cytoprotective genes and functional parameters.

Acute stress modulates hippocampal to entorhinal cortex communication.

Feed-forward inhibition is vital in the transfer and processing of synaptic information within the hippocampal-entorhinal loop by controlling the strength and direction of excitation flow between different neuronal populations and individual neurons. While the cellular targets in the hippocampus that receive excitatory inputs from the entorhinal cortex have been well studied, and the role of feedforward inhibitory neurons has been attributed to neurogliafom cells, the cortical interneurons providing feed-forward control over receiving layer V in the entorhinal cortex remain unknown. We used sharp-wave ripple oscillations as a natural excitatory stimulus of the entorhinal cortex, driven by the hippocampus, to study the function of synaptic interactions between neurons in the deep layers of the entorhinal cortex. We discovered that CB1R-expressing interneurons in the deep layers of the entorhinal cortex constitute the major relay station that translates hippocampal excitation into efficient inhibition of cortical pyramidal cells. The impact of inhibition provided by these interneurons is under strong endocannabinoid control and can be drastically reduced either by enhanced activity of postsynaptic targets or by stress-induced elevation of cannabinoids.

O-GlcNAcylation: cellular physiology and therapeutic target for human diseases.

O-linked-β-N-acetylglucosamine (O-GlcNAcylation) is a distinctive posttranslational protein modification involving the coordinated action of O-GlcNAc transferase and O-GlcNAcase, primarily targeting serine or threonine residues in various proteins. This modification impacts protein functionality, influencing stability, protein-protein interactions, and localization. Its interaction with other modifications such as phosphorylation and ubiquitination is becoming increasingly evident. Dysregulation of O-GlcNAcylation is associated with numerous human diseases, including diabetes, nervous system degeneration, and cancers. This review extensively explores the regulatory mechanisms of O-GlcNAcylation, its effects on cellular physiology, and its role in the pathogenesis of diseases. It examines the implications of aberrant O-GlcNAcylation in diabetes and tumorigenesis, highlighting novel insights into its potential role in cardiovascular diseases. The review also discusses the interplay of O-GlcNAcylation with other protein modifications and its impact on cell growth and metabolism. By synthesizing current research, this review elucidates the multifaceted roles of O-GlcNAcylation, providing a comprehensive reference for future studies. It underscores the potential of targeting the O-GlcNAcylation cycle in developing novel therapeutic strategies for various pathologies.