Mieko Ogura

Development of Glomerulus-, Tubule-, and Collecting Duct-Specific mRNA Assay in Human Urinary Exosomes and Microvesicles

Urinary exosomes and microvesicles (EMV) are promising biomarkers for renal diseases. Although the density of EMV is very low in urine, large quantity of urine can be easily obtained. In order to analyze urinary EMV mRNA, a unique filter device to adsorb urinary EMV from 10 mL urine was developed, which is far more convenient than the standard ultracentrifugation protocol. The filter part of the device is detachable and aligned to a 96-well microplate format, therefore multiple samples can be processed simultaneously in a high throughput manner following the isolation step. For EMV mRNA quantification, the EMV on the filter is lysed directly by adding lysis buffer and transferred to an oligo(dT)-immobilized microplate for mRNA isolation followed by cDNA synthesis and real-time PCR. Under the optimized assay condition, our method provided comparable or even superior results to the standard ultracentrifugation method in terms of mRNA assay sensitivity, linearity, intra-assay reproducibility, and ease of use. The assay system was applied to quantification of kidney-specific mRNAs such as NPHN and PDCN (glomerular filtration), SLC12A1 (tubular absorption), UMOD and ALB (tubular secretion), and AQP2 (collecting duct water absorption). 12-hour urine samples were collected from four healthy subjects for two weeks, and day-to-day and individual-to-individual variations were investigated. Kidney-specific genes as well as control genes (GAPDH, ACTB, etc.) were successfully detected and confirmed their stable expressions through the two-week study period. In conclusion, this method is readily available to clinical studies of kidney diseases.

Ex Vivo Induction of mRNA in Human Whole Blood as a New Platform of Drug and Dietary Supplement Development

PurposeWe introduced a new concept of ex vivo gene expression analysis (Mitsuhashi, Clin Chem 53:148–149, 2007), where drug action was simulated under physiological conditions. This model system was applied to study various fields of drug development.Materials and MethodsHeparinized human whole blood was incubated with drugs for less than 4h. The changes of specific mRNA were then quantified using the method we developed (Mitsuhashi, Tomozawa, Endo, and Shinagawa, Clin Chem 52:634–642, 2006).ResultsThe mRNA quantitation method was used as a model system to study the following areas: (1) identification of respondents and non-respondents, (2) ex vivo compound screening, (3) determination of individually optimized doses, (4) drug-to-drug comparison, (5) assessment of leukocyte toxicity, (6) discovery of molecular targets, (7) assessment of the action of dietary supplements, and (8) characterization of respondents and non-respondents for various dietary supplements.ConclusionSince ex vivo assays are safe, a large number of healthy donors and disease patients can be recruited to identify individual-to-individual variations, which is not available from current preclinical study models. Although each system should be validated using a large number of samples, the ex vivo analysis will be a new tool for the development of drugs and dietary supplements in future.

Ex vivo TCR-induced leukocyte gene expression of inflammatory mediators is increased in type 1 diabetic patients but not in overweight children.

Abnormal systemic concentrations of proinflammatory cytokines/chemokines have been implicated in the development of long‐term cardiovascular complications in type 1 diabetes (T1DM) and obesity. Whether leukocyte white blood cell (WBC) gene expression of these proinflammatory mediators contributes to their increased systemic levels, however, remains unclear, especially in the pediatric patient populations. This study examines mRNA changes of 9 cytokines and chemokines in WBCs following ex vivo immunostimulation from 9 T1DM (13.4 ± 0.5 year, 4F/5 M), 23 overweight (OW, 12.3 ± 0.5 year, 10F/13M, BMI% 97.1 ± 0.5 and > 90.0), and 21 healthy (CL, 13.8 ± 0.7 year, 9F/12 M, BMI% 59.6 ± 4.6 and < 85.0) children.

Immunological and polyfunctional T cell profiling following therapy with DPX-Survivac as a predictive tool of vaccine efficacy

Predicting the likelihood of a clinical outcome using biomarkers during the course of a cancer immunotherapy can be a powerful tool for time-sensitive decision making on personalized treatment options. In a clinical trial with the survivin-targeting vaccine DPX-Survivac, we showed using established methods (ELISpot/tetramer/flow cytometry) that a high-dose of DPX-Survivac vaccine in combination with low dose metronomic oral cyclophosphamide (mCPA) induced much stronger immune responses in ovarian cancer patients (cohort C, n=6) compared to vaccine alone (cohort A, n=6) or low dose vaccine with mCPA (cohort B, n=6). Immune responses were detected ex vivo in patients’ PBMCs particularly in cohort C, a reflection of the magnitude of the immune responses generated by the vaccine. We further analyzed the kinetics of various T cell phenotypes of the CD4 and CD8 lineages, including effector/ central memory T cells and late differentiated CD8 T cells. We established a model for the sequential appearance of polyfunctional T cells of the various phenotypes and for the persistence of these cell types following repeated immunizations with DPX-Survivac. In addition, we explored a unique PCR-based ‘real-time’ method developed by Hitachi Chemical Research Center for analyzing mRNA expression signatures that could be associated with vaccine induced immune responses. For this, small quantities of fresh blood from immunized patients were directly incubated with vaccine antigens and analyzed by qPCR at pre- and one month post-immunization time points. Among 9 immune response-related biomarkers tested, mRNA for molecules such as IFN-g, GM-CSF, TNF-a and CXCL10 were detected de novo in the blood of four out of four subjects tested among six patients from cohort C at one month following the third vaccination. These results are in keeping with the establishment of stronger immune responses and the kinetics of vaccine-induced memory/ effector T cells observed at this time point in patients receiving the combination of DPX-Survivac and cyclophosphamide. Taken together, these findings provide a framework for identifying a potential immune response signature soon after initiation of the vaccine therapy. We will determine whether this immune response signature is predictive of clinical activity in a planned randomized phase 2 trial.