Platelet-rich plasma inhibits the apoptosis of highly adipogenic homogeneous preadipocytes in an in vitro culture system

Auto-transplantation of adipose tissue is commonly used for the treatment of tissue defects in plastic surgery. The survival of the transplanted adipose tissue is not always constant, and one of reasons is the accelerated apoptosis of the implanted preadipocytes. We have recently established highly homogeneous preadipocytes, named ccdPAs. The aim of the current study was to evaluate the regulation of the potency of platelet-rich plasma (PRP) on the apoptosis of ccdPAs in vitro. PRP stimulated the proliferation of the preadipocytes in a dose-dependent manner, and the stimulatory activity of 2% PRP was significantly higher than that of 2% FBS or 2% platelet-poor plasma (PPP). The presence of 2% PRP significantly inhibited serum starvation- or TNF-alpha/cycloheximide-induced apoptosis in comparison to 2% FBS or 2% PPP. DAPK1 and Bcl-2-interacting mediator of cell death (BIM) mRNAs were reduced in the preadipocytes cultured with 2% PRP in comparison to those cultured in 2% FBS. The gene expression levels were significantly higher in cells cultured without serum in comparison to cells cultured with 2% FBS, and the levels in the cells with 2% PRP were reduced to 5-10% of those in the cells without serum. These results indicated that ccdPAs exhibit anti-apoptotic activities, in addition to increased proliferation, when cultured in 2% PRP in comparison to the same concentration of FBS, and that this was accompanied with reduced levels of DAPK1 and BIM mRNA expression in in vitro culture. PRP may improve the outcome of transplantation of adipose tissue by enhancing the anti-apoptotic activities of the implanted preadipocytes.

Effects of water-soluble antioxidants and MAPKK/MEK inhibitor on curcumin-induced apoptosis in HL-60 human leukemic cells.

Curcumin is the main biologically active phytochemical compound in turmeric. It has been shown to have anticarcinogenic activity. The aims of the study were to identify the mechanism of apoptosis of HL-60 human promyelocytic leukemic cells induced by curcumin and to determine the effects of water-soluble antioxidants, ascorbic acid, Trolox (a water-soluble form of vitamin E), glutathione (GSH) and N-acetylcysteine (NAC) on this process. HL-60 cells were incubated with curcumin for 24 h and apoptotic cells were quantitated by flow cytometry following staining with annexin V-FITC and propidium iodide. Curcumin-treated HL-60 cells produced reactive oxygen species as detected by the dichlorofluorescein fluorescent assay. Apoptosis occurred via the mitochondria pathway as curcumin reduced mitochondrial membrane potential in a dose-dependent manner. In the presence of 10 microM curcumin, vitamin C (56 nM-5.6 microM) inhibited apoptosis of HL-60 cells; GSH at low concentration (1 microM) reduced apoptosis but had no effect at higher concentrations (10, 100 microM); and Trolox and NAC at 10 and 100 microM, respectively, enhanced apoptosis, but this effect was abolished at higher concentration (1 mM) of NAC. MAPKK/MEK inhibitor PD98059, enhanced curcumin-induced HL-60 apoptotic cell death.

PD98059 inhibits expression of pERK1 protein and collagen alpha1(I) mRNA in rat pancreatic stellate cells activated by platelet-derived growth factor.

OBJECTIVE: Pancreatic stellate cells (PSC) are considered as the principal effector cells in pancreatic fibrosis. We studied the role of platelet-derived growth factor (PDGF) in the activation of PSC. METHODS: Cultured rat PSC were co-incubated with PDGF-BB (25 ng/mL) and different doses (0-40 ng/mL) of PD98059, a specific inhibitor of extracellular signal-regulated kinase (ERK). Expressions of p ERK1 protein and of collagen a1(I) mRNA were measured. RESULTS: Expression of p ERK1 protein was up-regulated by PDGF-BB, and was down-regulated in a dose-dependent manner by PD98059. Expression of collagen a1(I) mRNA also showed an increase with PDGF-BB and non-dose-dependent inhibition by PD98059. CONCLUSION: Our findings suggest that PSC activation is mediated by PDGF signal pathway, and ERK1 protein plays an important role in this activation.

Memory of inhibitory avoidance in the rat is regulated by glutamate metabotropic receptors and by calcium/calmodulin kinase II in the hippocampus

We studied the effect on memory of the bilateral intrahippocampal posttraining infusion of the glutamate metabotropic receptor (mGLUR) agonist, 1S,2R-aminocyclopentane dicarboxylate (ACPD), of the mGLUR antagonist, [RS]-alpha-methyl-4-carboxyphenyl glycine (MCPG), and of the inhibitor of calcium/calmodulin protein kinase II (CaM II), 1-[N,O-Bis (5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenyl piperazine (KN62). Male Wistar rats were implanted with cannulae in the CA1 region of the dorsal hippocampus. After recovery from surgery they were trained in a step-down inhibitory avoidance task and tested for retention 24 h later. Immediately or 180 min after training they received an intrahippocampal infusion of saline (0.5 mul), KN62 (100 mumoles), ACPD (20 nmoles), MCPG (13 nmoles) or of ACPD plus MCPG in 0.5 mul of saline. When given immediately after training, KN62 and MCPG were amnestic and ACPD caused memory facilitation and antagonized the effect od MCPG. When given 180 min after training, the drugs had no effect on memory. The results indicate that the early phase of memory is regulated by mGLURs in the hippocampus and requires CaM II activity. The data support the suggestion that memory involves long-term potentiation in the hippocampus.