Search results for "Signal Transduction"
showing 10 items of 2020 documents
The complex modulation of lysosomal degradation pathways by cannabinoid receptors 1 and 2
2015
The two main receptors of the endocannabinoid system, cannabinoid receptors 1 (CB1R) and 2 (CB2R), were described in the early 1990s. Since then, different physiological functions have been revealed that are linked to the activity of these two G-protein-coupled receptors. CB1R and CB2R activities influence signal cascades, which are known to play a role in the regulation of the cellular "self-digestion" process called autophagy. A variety of these signaling pathways are integrated by the mammalian target of rapamycin complex 1 (mTORC1) that acts as an inhibitor of autophagy. Others, like AMP-activated protein kinase dependent signaling pathway, are able to bypass mTORC1 to modulate the auto…
Apoptosis induced in HepG2 cells by the synthetic cannabinoid WIN: involvement of the transcription factor PPARgamma.
2008
It has recently been shown that cannabinoids induce growth inhibition and apoptosis in different tumour cell lines. In the current study, the effects of WIN 55,212-2 (WIN), a synthetic and potent cannabinoid receptor agonist, are investigated in hepatoma HepG2 cells and a possible signal transduction pathway is proposed. In these cells, WIN induces a clear apoptotic effect which was accompanied by up-regulation of the death-signalling factors Bax, Bcl-X(S), t-Bid and down-regulation of the survival factors survivin, phospho-AKT, Hsp72 and Bcl-2. Moreover, WIN-induced apoptosis is associated with JNK/p38 MAPK pathway activation and mitochondrial depolarisation demonstrated by a cytofluorimet…
Subsynaptic Distribution, Lipid Raft Targeting and G Protein-Dependent Signalling of the Type 1 Cannabinoid Receptor in Synaptosomes from the Mouse H…
2021
Numerous studies have investigated the roles of the type 1 cannabinoid receptor (CB1) in glutamatergic and GABAergic neurons. Here, we used the cell-type-specific CB1 rescue model in mice to gain insight into the organizational principles of plasma membrane targeting and Gαi/o protein signalling of the CB1 receptor at excitatory and inhibitory terminals of the frontal cortex and hippocampus. By applying biochemical fractionation techniques and Western blot analyses to synaptosomal membranes, we explored the subsynaptic distribution (pre-, post-, and extra-synaptic) and CB1 receptor compartmentalization into lipid and non-lipid raft plasma membrane microdomains and the signalling properties.…
Neuron-type specific cannabinoid-mediated G protein signalling in mouse hippocampus
2013
Type 1 cannabinoid receptor (CB1) is expressed in different neuronal populations in the mammalian brain. In particular, CB1 on GABAergic or glutamatergic neurons exerts different functions and display different pharmacological properties in vivo. This suggests the existence of neuron-type specific signalling pathways activated by different subpopulations of CB1. In this study, we analysed CB1 expression, binding and signalling in the hippocampus of conditional mutant mice, bearing CB1 deletion in GABAergic (GABA-CB1-KO mice) or cortical glutamatergic neurons (Glu-CB1-KO mice). Compared to their wild-type littermates, Glu-CB1-KO displayed a small decrease of CB1 mRNA amount, immunoreactivity…
WIN 55,212-2, agonist of cannabinoid receptors, prevents amyloid β1-42 effects on astrocytes in primary culture
2015
Alzheimer's disease (AD), a neurodegenerative illness involving synaptic dysfunction with extracellular accumulation of Aβ1-42 toxic peptide, glial activation, inflammatory response and oxidative stress, can lead to neuronal death. Endogenous cannabinoid system is implicated in physiological and physiopathological events in central nervous system (CNS), and changes in this system are related to many human diseases, including AD. However, studies on the effects of cannabinoids on astrocytes functions are scarce. In primary cultured astrocytes we studied cellular viability using MTT assay. Inflammatory and oxidative stress mediators were determined by ELISA and Western-blot techniques both in…
Aspidin PB, a phloroglucinol derivative, induces apoptosis in human hepatocarcinoma HepG2 cells by modulating PI3K/Akt/GSK3β pathway.
2012
Aspidin PB, a phloroglucinol derivative isolated from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In the present study, we analyzed the apoptotic mechanisms of aspidin PB on human hepatoma cell line, HepG2. Initially, aspidin PB was shown to inhibit the growth of HepG2 cells in a time and dose-dependent manner. After treatment with aspidin PB for 72 h, 48 h and 24 h using MTT assay, the IC(50) values were 10.59 μM, 20.86 μM and 46.59 μM, respectively. Aspidin PB was capable to induce apoptosis, as measured by mitochondrial membrane potential (ΔΨm), acridine orange (AO) staining and propidium iodide (PI)/annexin V-FITC double staining. T…
Immunoadhesins of interleukin-6 and the IL-6/soluble IL-6R fusion protein hyper-IL-6.
1999
Signal transduction in response to interleukin-6 (IL-6) results from homodimerization of gp130. This dimerization occurs after binding of IL-6 to its surface receptor (IL-6R) and can also be triggered by the complex of soluble IL-6R and IL-6. We fused IL-6 to the constant region of a human IgG1 heavy chain (Fc). IL-6Fc was expressed in COS-7 cells and purified via Protein A Sepharose. Using three different assays we found that the biological activity of this dimeric IL-6 protein is comparable with monomeric IL-6. Recently, we described the designer cytokine Hyper-IL-6 (H-IL-6) in which soluble IL-6R and IL-6 are connected via a flexible peptide linker. This molecule turned out to be 100-100…
Immune Control in Hepatocellular Carcinoma Development and Progression: Role of Stromal Cells
2014
Immune control of hepatocellular carcinoma (HCC) is executed by effector immune cells, which efficiently eliminate malignant transformed cells. However, progression of HCC clearly documents failure of tumor immune control, which led to the concept of immune subversion by the tumor environment. Particularly tumor-associated stromal cells cooperate within an inflammatory network, which is responsible for immune privilege. The stromal cell composition matures during tumor growth and is derived from surrounding noncancerous tissue or from circulating cells recruited to the tumor site. Therefore, immunosuppressive stromal cells represent heterogeneous cell lineages, including myeloid cells, lymp…
Molecular diagnosis and therapy of hepatocellular carcinoma (HCC): an emerging field for advanced technologies.
2011
Despite great progress in diagnosis and management of hepatocellular carcinoma (HCC), the exact biology of the tumor remains poorly understood overall limiting the patients' outcome. Detailed analysis and characterization of the molecular mechanisms and subsequently individual prediction of corresponding prognostic traits would revolutionize both diagnosis and treatment of HCC and is the key goal of modern personalized medicine. Over the recent years systematic approaches for the analysis of whole tumor genomes and transcriptomes as well as epigenomes became affordable tools in translational research. This includes simultaneous analyses of thousands of molecular targets using microarray-bas…
Cardioprotection by gene therapy
2015
Ischemic heart disease remains the leading cause of death worldwide. Ischemic pre-, post-, and remote conditionings trigger endogenous cardioprotection that renders the heart resistant to ischemic-reperfusion injury (IRI). Mimicking endogenous cardioprotection by modulating genes involved in cardioprotective signal transduction provides an opportunity to reproduce endogenous cardioprotection with better possibilities of translation into the clinical setting. Genes and signaling pathways by which conditioning maneuvers exert their effects on the heart are partially understood. This is due to the targeted approach that allowed identifying one or a few genes associated with IRI and cardioprote…