Analysis of sequence homology between human and mouse mitochondrial DNA

Mitochondrial Transfer Ameliorates Cognitive Deficits, Neuronal Loss, and Gliosis in Alzheimer's Disease Mice

Pathogenesis of neurodegenerative diseases involves dysfunction of mitochondria, one of the most important cell organelles in the brain, with its most prominent roles in producing energy and regulating cellular metabolism. Here we investigated the effect of transferring active intact mitochondria as a potential therapy for Alzheimer's disease (AD), in order to correct as many mitochondrial functions as possible, rather than a mono-drug related therapy. For this purpose, AD-mice (amyloid-β intracerebroventricularly injected) were treated intravenously (IV) with fresh human isolated mitochondria. One to two weeks later, a significantly better cognitive performance was noticed in the mitochondria treated AD-mice relative to vehicle treated AD-mice, approaching the performance of non-AD mice. We also detected a significant decrease in neuronal loss and reduced gliosis in the hippocampus of treated mice relative to untreated AD-mice. An amelioration of the mitochondrial dysfunction in brain was noticed by the increase of citrate-synthase and cytochrome c oxidase activities relative to untreated AD-mice, reaching activity levels of non-AD-mice. Increased mitochondrial activity was also detected in the liver of mitochondria treated mice. No treatment-related toxicity was noted. Thus, IV mitochondrial transfer may possibly offer a novel therapeutic approach for AD.

Microenvironment involved in FPR1 expression by human glioblastomas

Formyl peptide receptor 1 (FPR1) activity in U87 glioblastoma (GBM) cells contributes to tumor cell motility. The present study aimed to evaluate the FPR1 expression in human GBM, the possibility to elicit agonist induced FPR1 activation of GBM cells and inhibit this activation with chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS). Immunohistochemistry was used to assess FPR1 expression in GBM patient samples, which was present in all 178 samples. Also FPR1 mRNA levels measured with quantitative PCR, could be detected in all 25 GBM patient samples tested. Activation of FPR1 in U87 cells, as measured by human mitochondrial-derived agonists, increased calcium mobilization, AKT and ERK1/2 phosphorylation, and ligand-induced migration. Inhibition of all responses could be achieved with CHIPS. Eight early passage human Groningen Glioma (GG) cell lines, isolated from primary GBM tissue were screened for the presence of FPR1. FPR1 mRNA and protein expression as well as receptor activation could not be detected in any of these early passage GG cell lines. However FPR1 was present in ex vivo tumors formed by the same GG cell lines after being implanted in mouse brains. FPR1 is highly expressed in human GBM specimens, it can be activated by human mitochondrial-derived agonists in U87 and inhibited with CHIPS. FPR1 cannot be detected in early passage GG cell lines in vitro, however when engrafted in the mouse brain these cells show FPR1 expression. These results suggest a role of the brain microenvironment in FPR1 expression in GBM.

Effects of cytoplasmic inheritance on production traits of dairy cattle

Pedigrees of 4461 cows were traced to the original female in a maternal line. Cytoplasmic origin was defined as the first female in the maternal lineage. There were 102 cytoplasmic lines. Most cows were at least 10 generations removed from the origin. After adjustment for sire, herd, calving year, calving month, and age, cytoplasmic effects accounted for 2.0, 1.8, 1.8, and 3.5% of total variation of milk yield, milk fat yield, 3.7% fat-corrected milk yield, and milk fat percentage in first lactation. Cytoplasmic effects were also in models that included adjustments for sires, maternal grand-sires, and dam's production. Correlations among independent subsets agreed with expectations. Cytoplasmic origin was a significant source of variation of production traits of dairy cattle.

Propagation of two species of mitochondrial DNA in chinese hamster-mouse somatic cell hybrids

Mouse-hamster hybrid cells were analyzed for the species of mitochondrial DNA (mtDNA) retained using Southern blotting and hybridization with highly labeled mitochondrial DNA probes. Initial analyses were performed as soon as there were 10(7) cells, which took between five and eight weeks from the time the fusion was performed (approximately 23 cell doublings). The majority of clones tested had detectable levels of both mouse and hamster mtDNA at first testing.

Altered ribosomal RNA genes in mitochondria from mammalian cells with chloramphenicol resistance

Chloramphenicol resistance in mammalian cells is cytoplasmically inherited. In yeast, a similar phenotype is caused by mutations in the mitochondrial DNA (mtDNA), and sequencing of carefully constructed strains has identified nucleotide monosubstitutions in the 3' region of the large (21S) rRNA gene which correlate with the antibiotic resistance. We have sequenced the corresponding section of mammalian mtDNA from chloramphenicol-resistant cell lines for comparison with the wild-type sequence. Differences between the sequences occur at positions similar to those altered in the yeast mutants, in a highly conserved region of the large (16S) rRNA gene.

Maternal inheritance of human mitochondrial DNA

Human mitochondrial DNA was obtained from peripheral blood platelets donated by the members of several independent families. The samples were screened for nucleotide sequence polymorphisms between individuals within these families. In each family in which we were able to detect a distinctly different restriction endonuclease cleavage pattern between the parents, the progeny exhibited the maternal cleavage pattern. Informative polymorphisms were detected for Hae II (PuGCGCPy) in a three-generation family composed of 33 members, for HincII (GTPyPuAC) in a two-generation family composed of four members, and for Hae III(GGCC) in a two-generation family composed of four members. The Hae II polymorphism was analyzed through all three generations in both the maternal and paternal lines. The results of this study demonstrate that human mitochondrial DNA is maternally inherited. The techniques described for using peripheral blood platelets as a source of human mitochondrial DNA represent a convenient way to obtain data on mitochondrial DNA variation in both individuals and populations.