Mieko Kogi

Role of the p70 S6 kinase cascade in neutrophilic differentiation and proliferation of HL-60 cells—a study of transferrin receptor-positive and -negative cells obtained from dimethyl sulfoxide- or retinoic acid-treated HL-60 cells

Previously, we suggested that p70 S6 kinase (p70 S6K) plays an important role in the regulation of neutrophilic differentiation of HL-60 cells; this conclusion was based on our analysis of transferrin receptor (Trf-R) positive (Trf-R(+)) and negative (Trf-R(-)) cells that appeared after treatment with dimethyl sulfoxide (Me(2)SO). In this study, we analyzed the upstream of p70 S6K in relation to the differentiation and proliferation of both cell types. The granulocyte colony-stimulating factor (G-CSF)-induced enhancement of phosphatidylinositol 3-kinase (PI3K) activity in Trf-R(+) cells was markedly higher than that in Trf-R(-) cells. Wortmannin, a specific inhibitor of PI3K, partially inhibited G-CSF-induced p70 S6K activity and G-CSF-dependent proliferation, whereas rapamycin, an inhibitor of p70 S6K, completely inhibited these activities. The wortmannin-dependent enhancement of neutrophilic differentiation was similar to that induced by rapamycin. From these results, we conclude that the PI3K/p70 S6K cascade may play an important role in negative regulation of neutrophilic differentiation in HL-60 cells. For the G-CSF-dependent proliferation, however, p70 S6K appears to be a highly important pathway through not only a PI3K-dependent but also possibly an independent cascade.

Increased salivary chromogranin A associated with sympathetic nervous activity during psychological stress

Infiltrating T lymphocytes following traumatic injury of the central nervous system (CNS) are considered to be detrimental, but detailed kinetics and specific subsets of T lymphocytes in the injured CNS are still unclear. Moreover, efficacy of T cell-implantation after the CNS trauma remains to be elusive. Here we show that Th1 cells ameliorate functional recovery after spinal cord injury (SCI). In vitro, Th1 cells enhance neurite outgrowth of cerebral cortical neurons by a mechanism independent of direct interferon(IFN)-action. After SCI, IFN+ interleukin-17 (IL-17)+ double positive-CD4+ helper T and T cells infiltrate into the spinal cord. Implantation of cultured Th1 cells ex vivo into mice after SCI unexpectedly diminishes IFN+ IL-17+ double positive-CD4+ helper T and T cells and activates interleukin-10 (IL-10)producing microglia/macrophages and results in improvement of functional recovery. However, implantation of cultured Th17 cells did not improve recovery of motor function after SCI or were prone to exacerbate functional recovery. Reported detrimental effects of T lymphocytes may be due to IL-17-producing T lymphocytes. We observed enhanced sprouting of corticospinal tract and regeneration of serotonergic fiber by Th1-implantation. Thus, immunomodulation with Th1 cells is promising intervention in the treatment of CNS injury.

Study of laser induced stress waves emerged by laser-target interaction

Laser induced emergent stress wave (LIESW) generated by interaction between laser and target. LIESW can be emerged by the following complicated mechanisms: Optical breakdown, ablation and plasma formations, and stress wave with recoil momentum. We propose a method of gene transfection using LIESW. This method has several advantages such as a nonchemical, nonviral, and noninvasive and so on. In this report, we report a summary of our research.

Microarray analysis of responsible genes in increased growth rate in the subline of HL60 (HL60RG) cells.

HL60RG, a subline of human promyelocytic leukemia HL60 cells, has a increased growth rate than their parental cells. To gain information of the mechanisms involved in the increased growth rate of HL60RG, we performed a multiplex fluorescence in situ hybridization (M-FISH), standard cytogenetics analysis (G-banding) and genome scan using 10K SNP mapping array on both cell types. Characteristic genomic alterations in HL60RG cells were identified including uniparental disomy (UPD) of chromosome 1, and hemizygous deletion in 10p and 11p. However, no such defects were observed in HL60 cells. Changes in gene expression in HL60RG cells were determined using expression arrays (Affymetrix GeneChip, HU133A). Candidate genes associated with the rapid growth of HL60RG cells were identified. Two tumor necrosis factor receptors, TNFRSF1B (type II tumor necrosis factor-α receptor) and TNFRSF8 (also known as a tumor marker CD30), which are adjacently located on chromosome 1 showed opposing changes in gene expression in HL60RG cells-over-expression of TNFRSF8 and repression of TNFRSF1B. Differences in the DNA methylation status in the transcriptional regulatory regions of both genes between HL60 and HL60RG was detected by a methylation-specific PCR assay. In conclusion, alterations in chromosome and gene expression in HL60RG may be associated with increased growth rate.