coenzyme-q10 and ubiquinone-7

Apart from the well-known matrix effects that can occur in ESI LC-MS, biological matrices may have other effects influencing the quantitative reliability of bioanalytical methods. In this paper, six case studies are presented that show the effect that aging, that is the change in properties and composition of biological matrices over time, can have on the performance of bioanalytical methods. It is shown that selectivity can be affected due to the formation or disappearance of endogenous compounds. Stability can be influenced because of the decrease (or increase) of enzyme activities and recovery can be impacted if the extractability from binding sites in the matrix is enhanced or decreased. A general discussion on the importance of these matrix effects is provided as well as a perspective on how to properly address them in the method-development and validation stages of regulated bioanalysis.

Topics: Animals; Cholesterol; Chromatography, High Pressure Liquid; Cyclosporine; Cytarabine; Humans; Hydroxycholesterols; Isotope Labeling; Mice; Oxidation-Reduction; Serum; Spectrometry, Mass, Electrospray Ionization; Temperature; Time Factors; Ubiquinone

Identification of single-gene causes of steroid-resistant nephrotic syndrome (SRNS) has furthered the understanding of the pathogenesis of this disease. Here, using a combination of homozygosity mapping and whole human exome resequencing, we identified mutations in the aarF domain containing kinase 4 (ADCK4) gene in 15 individuals with SRNS from 8 unrelated families. ADCK4 was highly similar to ADCK3, which has been shown to participate in coenzyme Q10 (CoQ10) biosynthesis. Mutations in ADCK4 resulted in reduced CoQ10 levels and reduced mitochondrial respiratory enzyme activity in cells isolated from individuals with SRNS and transformed lymphoblasts. Knockdown of adck4 in zebrafish and Drosophila recapitulated nephrotic syndrome-associated phenotypes. Furthermore, ADCK4 was expressed in glomerular podocytes and partially localized to podocyte mitochondria and foot processes in rat kidneys and cultured human podocytes. In human podocytes, ADCK4 interacted with members of the CoQ10 biosynthesis pathway, including COQ6, which has been linked with SRNS and COQ7. Knockdown of ADCK4 in podocytes resulted in decreased migration, which was reversed by CoQ10 addition. Interestingly, a patient with SRNS with a homozygous ADCK4 frameshift mutation had partial remission following CoQ10 treatment. These data indicate that individuals with SRNS with mutations in ADCK4 or other genes that participate in CoQ10 biosynthesis may be treatable with CoQ10.

Topics: Adolescent; Adrenal Cortex Hormones; Amino Acid Sequence; Animals; Cells, Cultured; Child; Consanguinity; Conserved Sequence; Disease Models, Animal; DNA Mutational Analysis; Drosophila Proteins; Drug Resistance; Exome; Fibroblasts; Gene Knockdown Techniques; Humans; Mitochondria; Molecular Sequence Data; Mutation; Nephrotic Syndrome; Podocytes; Protein Kinases; Rats; Sequence Alignment; Sequence Homology, Amino Acid; Ubiquinone; Young Adult; Zebrafish; Zebrafish Proteins

We studied ubiquinone (Q), Q homologue ratio, and steady-state levels of mCOQ transcripts in tissues from mice fed ad libitum or under calorie restriction. Maximum ubiquinone levels on a protein basis were found in kidney and heart, followed by liver, brain, and skeletal muscle. Liver and skeletal muscle showed the highest Q(9)/Q(10) ratios with significant interindividual variability. Heart, kidney, and particularly brain exhibited lower Q(9)/Q(10) ratios and interindividual variability. In skeletal muscle and heart, the most abundant mCOQ transcript was mCOQ7, followed by mCOQ8, mCOQ2, mPDSS2, mPDSS1, and mCOQ3. In nonmuscular tissues (liver, kidney, and brain) the most abundant mCOQ transcript was mCOQ2, followed by mCOQ7, mCOQ8, mPDSS1, mPDSS2, and mCOQ3. Calorie restriction increased both ubiquinone homologues and mPDSS2 mRNA in skeletal muscle, but mCOQ7 was decreased. In contrast, Q(9) and most mCOQ transcripts were decreased in heart. Calorie restriction also modified the Q(9)/Q(10) ratio, which was increased in kidney and decreased in heart without alterations in mPDSS1 or mPDSS2 transcripts. We demonstrate for the first time that unique patterns of mCOQ transcripts exist in muscular and nonmuscular tissues and that Q and COQ genes are targets of calorie restriction in a tissue-specific way.

Topics: Animals; Brain; Caloric Restriction; Free Radicals; Kidney; Liver; Mice; Muscle, Skeletal; Myocardium; Organ Specificity; RNA, Messenger; Ubiquinone

The thermotropic properties of coenzymes Q10, Q9, Q8, and Q7 have been examined by differential scanning calorimetry and wide-angle X-ray diffraction. Typical scanning calorimetry cooling curves of coenzyme Q from the liquid state exhibit a single exothermic phase transition into a crystalline state at a temperature that decreases as the length of the polyisoprenoid side-chain substituent decreases. Upon subsequent heating, the molecules undergo a series of thermal events which precede the main crystalline-to-liquid endothermic phase transition. The temperature of these transitions increases with increasing chain length. The crystallization phase transition temperature depends markedly on the rate at which the sample is cooled and increases with decreasing scan rate; the temperature of the melting endotherm is not markedly affected by the scan rate. Detailed calorimetric studies of coenzyme Q10 indicate that two crystalline states are formed, one at relatively high cooling rates to low temperatures and the other when preparations are cooled slowly from the liquid state to relatively high temperatures. Heating the crystalline phase formed by rapid cooling causes its transformation into the phase observed by cooling slowly. X-ray diffraction analysis confirmed the existence of these two crystal phases in coenzymes Q9 and Q10 and the transformation from the rapidly crystallized form to the more ordered form associated with slower cooling rates. At body temperature (310 K) under equilibrium conditions coenzyme Q10 exists in an ordered crystalline phase; the implications of the thermotropic behavior of coenzyme Q10 on mitochondrial function in vitro and in vivo are discussed.

Topics: Calorimetry, Differential Scanning; Coenzymes; Crystallization; Crystallography, X-Ray; Mitochondria; Thermodynamics; Ubiquinone

Topics: Animals; Anti-Infective Agents; Coenzymes; Female; Immunity, Cellular; Listeriosis; Mice; Spleen; Ubiquinone