Delphinidin-3-glucoside suppresses lipid accumulation in HepG2 cells.

Delphinidin is an anthocyanidin commonly found in various fruits and vegetables. Delphinidin has been known to possess many functions, such as an antioxidant, and anti-inflammatory, anti-cancer and anti-muscular atrophy agent. In this study, we attempted to evaluate the effects of delphinidin on lipid accumulation in hepatocytes. The results showed that palmitic acid (PA)-induced cellular senescence in HepG2 cells and reduced the expression of SMARCD1, which is known to regulate senescence-associated lipid accumulation in hepatocytes. However, delphinidin-3-glucoside (D3 g) suppressed PA-induced senescence and reversed the expression of SMARCD1 to the level of untreated HepG2 cells. Consequently, D3 g inhibited PA-induced lipid accumulation through the restoration of the expression of SMARCD1 and fatty acid oxidation genes. Taken together, our results suggest that D3 g suppresses the lipid accumulation induced by hepatocyte senescence.

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water.

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles.

Impaired ATP6V0A2 expression contributes to Golgi dispersion and glycosylation changes in senescent cells.

Many genes and signaling pathways have been found to be involved in cellular senescence program. In the present study, we have identified 16 senescence-associated genes by differential proteomic analysis of the normal human diploid fibroblast cell line, TIG-1, and focused on ATP6V0A2. The aim of this study is to clarify the role of ATP6V0A2, the causal gene for ARCL2, a syndrome of abnormal glycosylation and impaired Golgi trafficking, in cellular senescence program. Here we showed that ATP6V0A2 is critical for cellular senescence; impaired expression of ATP6V0A2 disperses the Golgi structure and triggers senescence, suggesting that ATP6V0A2 mediates these processes. FITC-lectin staining and glycoblotting revealed significantly different glycosylation structures in presenescent (young) and senescent (old) TIG-1 cells; reducing ATP6V0A2 expression in young TIG-1 cells yielded structures similar to those in old TIG-1 cells. Our results suggest that senescence-associated impaired expression of ATP6V0A2 triggers changes in Golgi structure and glycosylation in old TIG-1 cells, which demonstrates a role of ATP6V0A2 in cellular senescence program.

Molecular mechanisms for the p38-induced cellular senescence in normal human fibroblast.

We previously reported that TAK1, one of the mitogen-activated protein kinase kinase kinases (MAP3Ks), represses the transcription of the human telomerase reverse transcriptase (hTERT) gene in human cancer cells and induces cellular senescence in normal diploid human cells. On the basis of these results, we presumed a link between hTERT repression and the induction of cellular senescence. In this study, we identified the MAPK p38 as a downstream mediator of TAK1, which represses hTERT transcription. Further, we observed that hTERT expression was repressed in senescent normal human fibroblast, and was attenuated on treatment with SB203580, a p38-specific inhibitor, which suggests that p38 represses hTERT expression during cellular senescence. Next, we demonstrated that repression of hTERT, irrespective of the activation status of p38, is important for the induction of cellular senescence, by using hTERT-overexpressing cells and hTERT-knockdown cells. Our results suggested that p38 is activated during the serial passagings of normal human fibroblast, which results in the repression of hTERT transcription and induction of cellular senescence.

Suppression of immunoglobulin production in human peripheral blood mononuclear cells by monocytes via secretion of heavy-chain ferritin.

In vitro antigen stimulation of peripheral blood mononuclear cells (PBMCs) does not induce immunoglobulin (Ig) production. However, pretreatment of PBMCs with l-leucyl-l-leucine methyl ester (LLME) prior to in vitro stimulation removes the suppression of Ig production. In the present study, we attempted to identify the target cells of LLME and determine the mechanisms by which Ig production in PBMCs is suppressed. We found that CD14(+) monocytes are involved in the suppression of Ig production in PBMCs. Furthermore, we confirmed that heavy-chain ferritin derived from CD14(+) monocytes suppresses Ig production in PBMCs, possibly through iron sequestration.

In vitro immunization of Epstein-Barr virus-immortalized B cells augments antigen-specific antibody production.

The current method for in vitro immunization (IVI) uses several antigens including toxins, food allergens, pathogenic bacteria, and self-antigen-derived peptides that induce an antigen-specific immune response in peripheral blood mononuclear cells (PBMCs). This protocol, however, requires donor blood collection and preparation of PBMCs before every IVI. In the present study, we aimed to design a more efficient system utilizing B cells immortalized with Epstein-Barr virus (EBV-B) as host cells for IVI to make antigen-specific antibodies. Results showed that previously antigen-sensitized, EBV-B cells exposed to the antigen along with IL-6, CpG oligonucleotides, and CD40 ligand signal produced antigen-specific antibodies. These results provide evidence for a novel and easy method to expand memory-type B cells and produce antigen-specific antibodies.