iMPAQT reveals that adequate mitohormesis from TFAM overexpression leads to life extension in mice.

Mitochondrial transcription factor A, TFAM, is essential for mitochondrial function. We examined the effects of overexpressing the TFAM gene in mice. Two types of transgenic mice were created: TFAM heterozygous (TFAM Tg) and homozygous (TFAM Tg/Tg) mice. TFAM Tg/Tg mice were smaller and leaner notably with longer lifespans. In skeletal muscle, TFAM overexpression changed gene and protein expression in mitochondrial respiratory chain complexes, with down-regulation in complexes 1, 3, and 4 and up-regulation in complexes 2 and 5. The iMPAQT analysis combined with metabolomics was able to clearly separate the metabolomic features of the three types of mice, with increased degradation of fatty acids and branched-chain amino acids and decreased glycolysis in homozygotes. Consistent with these observations, comprehensive gene expression analysis revealed signs of mitochondrial stress, with elevation of genes associated with the integrated and mitochondrial stress responses, including Atf4, Fgf21, and Gdf15. These found that mitohormesis develops and metabolic shifts in skeletal muscle occur as an adaptive strategy.

Extracellular vesicles expressing CEACAM proteins in the urine of bladder cancer patients.

Early detection and long-term monitoring are important for urothelial carcinoma of the bladder (UCB). Urine cytology and existing markers have insufficient diagnostic performance. Here, we examined medium-sized extracellular vesicles (EVs) in urine to identify specific markers for UCB and evaluated their usefulness as diagnostic material. To identify specific markers in urinary EVs derived from UCB, we undertook shotgun proteomics using urine from four UCB patients and four healthy subjects. Next, 29 healthy specimens, 18 noncancer specimens, and 33 UCB specimens, all from men, were analyzed for urinary EVs by flow cytometry to evaluate the diagnostic performance of UCB-specific EVs. Nanoparticle-tracking analysis indicated that the size of EVs extracted from urine was mostly <400 nm. By shotgun proteomics, we detected several proteins characteristic of UCB and found that carcinoembryonic antigen-related adhesion molecule (CEACAM) proteins were increased in patients. Flow cytometric analysis revealed that the degree of expression of CEACAM1, CEACAM5, and CEACAM6 proteins on the surface of EVs varied among patients. Extracellular vesicles expressing CEACAM proteins also expressed mucin 1, suggesting that they were derived from tumorigenic uroepithelial cells. The number of EVs expressing CEACAM1, 5, and 6 proteins was significantly increased in UCB (mean ± SD, 8.6 ± 13%) compared to non-UCB (0.69 ± 0.46) and healthy (0.46 ± 0.34) by flow cytometry. The results of receiver operating characteristic (ROC) analysis showed a good score of area under the ROC curve of 0.907. We identified EVs that specifically express CEACAM proteins in urine and have potential for diagnostic applications. These EVs are potential targets in a new liquid biopsy test for UCB patients.

Multiblock metabolomics: An approach to elucidate whole-body metabolism with multiblock principal component analysis.

Principal component analysis (PCA) is a useful tool for omics analysis to identify underlying factors and visualize relationships between biomarkers. However, this approach is limited in addressing life complexity and further improvement is required. This study aimed to develop a new approach that combines mass spectrometry-based metabolomics with multiblock PCA to elucidate the whole-body global metabolic network, thereby generating comparable metabolite maps to clarify the metabolic relationships among several organs. To evaluate the newly developed method, Zucker diabetic fatty (ZDF) rats (n = 6) were used as type 2 diabetic models and Sprague Dawley (SD) rats (n = 6) as controls. Metabolites in the heart, kidney, and liver were analyzed by capillary electrophoresis and liquid chromatography mass spectrometry, respectively, and the detected metabolites were analyzed by multiblock PCA. More than 300 metabolites were detected in the heart, kidney, and liver. When the metabolites obtained from the three organs were analyzed with multiblock PCA, the score and loading maps obtained were highly synchronized and their metabolism patterns were visually comparable. A significant finding in this study was the different expression patterns in lipid metabolism among the three organs; notably triacylglycerols with polyunsaturated fatty acids or less unsaturated fatty acids showed specific accumulation patterns depending on the organs.

Mitochondrial translation inhibition triggers ATF4 activation, leading to integrated stress response but not to mitochondrial unfolded protein response.

Mitochondrial-nuclear communication, known as retrograde signaling, is important for regulating nuclear gene expression in response to mitochondrial dysfunction. Previously, we have found that p32/C1qbp-deficient mice, which have a mitochondrial translation defect, show endoplasmic reticulum (ER) stress response and integrated stress response (ISR) gene expression in the heart and brain. However, the mechanism by which mitochondrial translation inhibition elicits these responses is not clear. Among the transcription factors that respond to mitochondrial stress, activating transcription factor 4 (ATF4) is a key transcription factor in the ISR. Herein, chloramphenicol (CAP), which inhibits mitochondrial DNA (mtDNA)-encoded protein expression, induced eukaryotic initiation factor 2 α subunit (eIF2α) phosphorylation and ATF4 induction, leading to ISR gene expression. However, the expression of the mitochondrial unfolded protein response (mtUPR) genes, which has been shown in Caenorhabditis elegans, was not induced. Short hairpin RNA-based knockdown of ATF4 markedly inhibited the CAP-induced ISR gene expression. We also observed by ChIP analysis that induced ATF4 bound to the promoter region of several ISR genes, suggesting that mitochondrial translation inhibition induces ISR gene expression through ATF4 activation. In the present study, we showed that mitochondrial translation inhibition induced the ISR through ATF4 activation rather than the mtUPR.

Mitochondrial p32/C1qbp Is a Critical Regulator of Dendritic Cell Metabolism and Maturation.

Dendritic cell (DC) maturation induced by Toll-like receptor agonists requires activation of downstream signal transduction and metabolic changes. The endogenous metabolite citrate has recently emerged as a modulator of DC activation. However, the metabolic requirements that support citrate production remain poorly defined. Here, we demonstrate that p32/C1qbp, which functions as a multifunctional chaperone protein in mitochondria, supports mitochondrial metabolism and DC maturation. Metabolic analysis revealed that the citrate increase induced by lipopolysaccharide (LPS) is impaired in p32-deficient DCs. We also found that p32 interacts with dihydrolipoamide S-acetyltransferase (E2 component of pyruvate dehydrogenase [PDH] complex) and positively regulates PDH activity in DCs. Therefore, we suggest that DC maturation is regulated by citrate production via p32-dependent PDH activity. p32-null mice administered a PDH inhibitor show decreased DC maturation and ovalbumin-specific IgG production in vivo, suggesting that p32 may serve as a therapeutic target for DC-related autoimmune diseases.

p32 is Required for Appropriate Interleukin-6 Production Upon LPS Stimulation and Protects Mice from Endotoxin Shock.

Sepsis is a major cause of morbidity and mortality in seriously ill patients and mitochondrial dysfunction is associated with poor outcomes in septic patients. Although interleukin-6 (IL-6) is a good prognostic marker for sepsis, the relationship between mitochondrial dysfunction and IL-6 remains poorly understood. We identified p32/C1QBP/HABP1 as a regulator of IL-6 production in response to lipopolysaccharide (LPS). LPS induced IL-6 overproduction in p32 deficient mouse embryonic fibroblasts (MEFs) through NF-κB independent but activating transcription factor (ATF) 4 dependent pathways. Short hairpin RNA-based knockdown of ATF4 in p32 deficient MEFs markedly inhibited LPS-induced IL-6 production. Furthermore, MEFs treated with chloramphenicol, an inhibitor of mitochondrial translation, produced excessive IL-6 via ATF4 pathways. Using a LPS-induced endotoxin shock model, mice with p32 ablation in myeloid cells showed increased lethality and overproduction of IL-6. Thus, this study provides a molecular link how mitochondrial dysfunction leads to IL-6 overproduction and poor prognosis of sepsis.

Performance evaluation of the new rapid fertility assays in whole blood and plasma on PATHFAST.

BACKGROUND: The purpose of this study was to evaluate the validity of the PATHFAST fertility marker assays for the rapid measurement of female hormones including: LH, FSH, Estradiol (E2), Progesterone (P4), Prolactin (PRL), and HCG. As for the PATHFAST fertility marker assays, female hormones can be measured by whole blood, plasma, and serum. METHODS: The correlation of the heparin whole blood and the plasma samples in the PATHFAST was examined. The method comparison study of PATHFAST fertility marker assays was performed with the Elecsys 2010, AIA-360, IMMULITE 2000, miniVIDAS, and ARCHITECT i2000. Determination of the reference range values of the PATHFAST fertility marker assays was performed with serum samples which were obtained during the follicular phase, mid-cycle, luteal phase, and postmenopausal phase. RESULTS: The results of plasma samples of female hormones measured by the PATHFAST correlated highly with those of whole blood samples (r > 0.9). The results of LH, FSH, E2, P4, PRL, and HCG as measured by the PATHFAST correlated well with other commercial fertility assays (r > 0.9). Reference values of PATHFAST fertility marker assays were equivalent to those of other commercial methods. CONCLUSIONS: The PATHFAST system is an accurate diagnostic tool for the rapid assay of female hormones. The PATHFAST fertility marker assays can be useful in a physician's office laboratory (POL) as well as various clinical sites during infertility treatment.

Activation of c-Met (hepatocyte growth factor receptor) in human gastric cancer tissue.

c-Met is a high-affinity receptor for hepatocyte growth factor (HGF) and plays a crucial role in embryonic development, as well as in the process of tissue repair. Overexpression and amplification of c-Met are often observed in various cancer tissues, especially in gastric carcinoma. It has, however, been unclear whether the overexpression leads to activation of the c-Met receptor. To address this point, we prepared an antibody (anti-phospho-Met) which specifically recognizes c-Met that is phosphorylated at Y1235, a major phosphorylation site of c-Met. Normal as well as cancerous gastric tissue was positive for anti-total-Met staining, whereas only cancerous tissue was strongly positive for anti-phospho-Met staining; cells near the basal layer were moderately positive, and the proliferative zone in normal tissue was only weakly positive. Among cancerous tissues from seven patients examined in the present study, those from six patients were strongly positive for phospho-Met staining. These results indicate that c-Met is actually activated in gastric carcinoma tissue, and may trigger proliferation/anti-apoptotic signals.