MOLLERS, C and DROBNIK, W and RESINK, T and SCHMITZ, G (1995) HIGH-DENSITY-LIPOPROTEIN AND LOW-DENSITY LIPOPROTEIN-MEDIATED SIGNAL-TRANSDUCTION IN CULTURED HUMAN SKIN FIBROBLASTS. CELLULAR SIGNALLING, 7 (7). pp. 695-707. ISSN 0898-6568,
Full text not available from this repository.Abstract
The signalling mechanisms whereby high-density lipoproteins (HDL) and low-density lipoproteins (LDL) affect a number of cellular functions in fibroblasts are unclear. This study has analyzed the influence of HDL(3) and LDL on the phosphatidylinositol specific phospholipase C pathway in human skin fibroblasts. Exposure of myo-[2-H-3]-inositol prelabelled fibroblasts to HDL(3) or LDL elicited major increases in IP1 and minor increases in IP2 and IP3 within 30 s. In fura-2 loaded suspended fibroblasts, HDL(3) and LDL increased intracellular Ca2+ concentrations ([Ca2+](i)) with comparable rapid, transient kinetics. The dose-profiles for HDL(3)- and LDL-induced increases in [Ca2+](i) were also comparable, with half-maximally and maximally effective concentrations being approximate to 15 mu g/mL and approximate to 50 mu g/mL, respectively. HDL(3)- and LDL-induced increases in [Ca2+](i) were diminished by approximate to 60% (vs. control fibroblasts) in thapsigargin-pretreated fibroblasts, indicating that release of Ca2+ from intracellular pools is the major contributor toward lipoprotein-induced increases in [Ca2+](i). Pertussis toxin-pretreatment of cells completely abolished lipoprotein induced Ca2+-transient, indicating the involvement of a guanine nucleotide-binding protein in the signalling process. In [3H]-palmitic acid-prelabelled fibroblasts, both HDL(3) and LDL were observed to stimulate production of DAG. Activation of protein kinase C (PKC) was analysed by determining the cytosol-to-membrane translocation of both enzymatic activity and immunoreactivity of specific PKC isoforms (alpha, delta, epsilon, and zeta). Stimulation with HDL(3) and LDL evoked a rapid (within 2.5 min) translocation of PKC activity, with PKC alpha and PKC epsilon being the isoforms translocated. It is concluded that HDL(3) and LDL acutely stimulate a phosphoinositide-specific phospholipase C pathway in human skin fibroblasts. However, the specific cell membrane events mediating this signal transduction remain to be further elucidated.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SMOOTH-MUSCLE CELLS; PROTEIN-KINASE-C; PLACENTAL-LACTOGEN RELEASE; HUMAN TROPHOBLAST CELLS; INTRACELLULAR CALCIUM; INOSITOL PHOSPHATES; ENDOTHELIAL-CELLS; HUMAN-LYMPHOCYTES; PLASMA-MEMBRANE; BINDING-PROTEIN; HIGH-DENSITY LIPOPROTEINS (HDL); LOW-DENSITY LIPOPROTEINS; SIGNAL TRANSDUCTION; FIBROBLASTS |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52332 |
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