Search results for "Cell biology"
showing 10 items of 8732 documents
Mtlinteracts with members of Egfr signaling and cell adhesion genes in the Drosophila eye
2011
Mtl is a member of the Rho family of small GTPases in Drosophila. It was shown that Mtl is involved in planar cell polarity (PCP) establishment, together with other members of the same family like Cdc42, Rac1, Rac2 and RhoA. However, while Rac1, Rac2 and RhoA function downstream of Dsh in Fz/PCP signaling and upstream of a JNK cassette, Mtl and Cdc42 do not. To determine the functional context of Mtl during PCP establishment in the Drosophila eye, we performed a loss-of-function screen to search for dominant modifiers of a sev>Mtl rough eye phenotype. In addition, genetic interaction assays with candidate genes were also carried out. Our results show that Mtl interacts genetically with memb…
Activation of astroglial phospholipase D activity by phorbol ester involves ARF and Rho proteins.
2000
Primary cultures of rat cortical astrocytes express phospholipase D (PLD) isoforms 1 and 2 as determined by RT-PCR and Western blot. Basal PLD activity was strongly (10-fold) increased by 4beta-phorbol-12beta,13alpha-dibutyrate (PDB) (EC(50): 56 nM), an effect which was inhibited by Ro 31-8220 (0.1-1 microM), an inhibitor of protein kinase C (PKC), and by brefeldin A (10-100 microg/ml), an inhibitor of ADP-ribosylating factor (ARF) activation. Pretreatment of the cultures with Clostridium difficile toxin B-10463 (0.1-1 ng/ml), which inactivates small G proteins of the Rho family, led to a breakdown of the astroglial cytoskeleton; concomitantly, PLD activation by PDB was reduced by up to 50%…
Rho GTPases: Promising Cellular Targets for Novel Anticancer Drugs
2006
Ras-homologous (Rho) GTPases play a pivotal role in the regulation of numerous cellular functions associated with malignant transformation and metastasis. Rho GTPases are localized at membranes and become activated upon stimulation of cell surface receptors. In their GTP-bound (=active) state, Rho proteins bind to effector proteins, thereby triggering specific cellular responses. Members of the Rho family of small GTPases are key regulators of actin reorganization, cell motility, cell-cell and cell-extracellular matrix (ECM) adhesion as well as of cell cycle progression, gene expression and apoptosis. Each of these functions is of importance for the development and progression of cancer. Fu…
Inhibition of Protein Isoprenylation Impairs Rho-Regulated Early Cellular Response to Genotoxic Stress
2000
Activation of c-Jun N-terminal kinases (JNKs) and nuclear factor-kappaB (NF-kappaB) are early cellular responses to genotoxic stress involved in the regulation of gene expression. Pretreatment of cells with the hydroxymethyl glutaryl-CoA reductase inhibitor lovastatin blocked stimulation of JNK1 activity by UV irradiation and by treatment with the alkylating compound methyl methanesulfonate but did not affect activation of extracellular signal-regulated kinase 2 by UV light. Lovastatin also attenuated UV-induced degradation of the NF-kappaB inhibitor IkappaBalpha. The effects of lovastatin on UV-triggered stimulation of JNK1 as well as on IkappaBalpha degradation were reverted by cotreatmen…
Chronic ethanol exposure alters the levels, assembly, and cellular organization of the actin cytoskeleton and microtubules in hippocampal neurons in …
2010
The organization and dynamics of microtubules (MTs) and the actin cytoskeleton are critical for the correct development and functions of neurons, including intracellular traffic and signaling. In vitro ethanol exposure impairs endocytosis, exocytosis, and nucleocytoplasmic traffic in astrocytes and alters endocytosis in cultured neurons. In astrocytes, these effects relate to changes in the organization and/or function of MTs and the actin cytoskeleton. To evaluate this possibility in hippocampal cultured neurons, we analyzed if chronic ethanol exposure affects the levels, assembly, and cellular organization of both cytoskeleton elements and the possible underlying mechanisms of these effec…
Lovastatin inhibits Rho-regulated expression of E-selectin by TNFalpha and attenuates tumor cell adhesion.
2003
E-selectin mediated cell-cell adhesion plays an important role in inflammatory processes and extravasation of tumor cells. Tumor necrosis factor-alpha (TNF-alpha) induces E-selectin gene and protein expression in primary human endothelial cells (HUVEC) and in an endothelial cell line (EA.hy-926). As shown by ELISA and FACS analyses, HMG-CoA reductase inhibitors (e.g., lovastatin) impair the TNF-alpha stimulated increase in E-selectin protein expression. Similar results were obtained for E-selectin mRNA expression and promoter activity, indicating that the effect of lovastatin is based on inhibition of gene expression. The effective inhibitory concentration of lovastatin was in a physiologic…
Inhibition of Rho modulates cytokine-induced prostaglandin E2 formation in renal mesangial cells.
2003
Stimulation of rat mesangial cells for 24 h with interleukin-1β(IL-1β) plus forskolin (Fk) leads to a marked increase in prostaglandin E 2 (PGE 2 ) synthesis. This effect is further enhanced by the small G-protein Rho inhibitor toxin A. A similar increase in PGE 2 formation is obtained with Y27632, a Rho-dependent kinase inhibitor, and with lovastatin, a hydroxymethylglutaryl-coenzyme A inhibitor which depletes cells from geranylgeranyl moieties and thus blocks Rho activation. In parallel to the increased PGE 2 synthesis, a potentiation of IL-1β-induced secretory group IIA phospholipases A 2 (sPLA 2 -IIA) protein expression also occurs by Rho inhibition. However, only toxin A triggers an in…
Bcl-xL as a Modulator of Senescence and Aging
2021
Many features of aging result from the incapacity of cells to adapt to stress conditions. When cells are overwhelmed by stress, they can undergo senescence to avoid unrestricted growth of damaged cells. Recent findings have proven that cellular senescence is more than that. A specific grade of senescence promotes embryo development, tissue remodeling and wound healing. However, constant stresses and a weakening immune system can lead to senescence chronicity with aging. The accumulation of senescent cells is directly related to tissue dysfunction and age-related pathologies. Centenarians, the most aged individuals, should accumulate senescent cells and suffer from their deleterious effects,…
Comparison of essential oil components and in vitro anticancer activity in wild and cultivated Salvia verbenaca.
2015
The objectives of our research were to study the chemical composition and the in vitro anticancer effect of the essential oil of Salvia verbenaca growing in natural sites in comparison with those of cultivated (Sc) plants. The oil from wild (Sw) S. verbenaca presented hexadecanoic acid (23.1%) as the main constituent, while the oil from Sc plants contained high quantities of hexahydrofarnesyl acetone (9.7%), scarce in the natural oil (0.7%). The growth-inhibitory and proapoptotic effects of the essential oils from Sw and Sc S. verbenaca were evaluated in the human melanoma cell line M14, testing cell vitality, cell membrane integrity, genomic DNA fragmentation and caspase-3 activity. Both t…
Skin Immunomodulation during Regeneration: Emerging New Targets
2021
Adipose-Derived Stem Cells (ADSC) are present within the hypodermis and are also expected to play a pivotal role in wound healing, immunomodulation, and rejuvenation activities. They orchestrate, through their exosome, the mechanisms associated to cell differentiation, proliferation, and cell migration by upregulating genes implicated in different functions including skin barrier, immunomodulation, cell proliferation, and epidermal regeneration. ADSCs directly interact with their microenvironment and specifically the immune cells, including macrophages and T and B cells, resulting in differential inflammatory and anti-inflammatory mechanisms impacting, in return, ADSCs microenvironment and …