A common mitochondrial polymorphism 10398A>G is associated metabolic syndrome in a Chinese population.

We conducted a two-step case-control study to investigate the association between mtDNA variants and metabolic syndrome (MS) in Chinese. We initially screened 79 mitochondrial single nucleotide polymorphisms (mtSNPs) in 141 cases and 506 controls, and five mtSNPs had a p<0.05.

Mitochondrial dysfunction in human breast cancer cells and their transmitochondrial cybrids.

Somatic mitochondrial DNA alterations have been found in all types of cancer. To better understand the role of mitochondria and their involvement in the pathogenic mechanisms of cancer development, the effects of cancer mitochondria were investigated in a defined nuclear background using a transmitochondrial cybrid system. Our results demonstrated that cancer mitochondria confer a significant reduction in cell growth when cells are metabolically stressed in a galactose medium.

Mitochondrial DNA variant interactions modify breast cancer risk.

Interactions between mitochondrial deoxyribonucleic acid (mtDNA) variants and the risk of developing breast cancer were investigated using DNA samples collected from non-Jewish European American breast cancer patients and ethnically age-matched female controls. Logistic regression was used to evaluate two-way interactions between 17 mtDNA variants. To control for multiple testing, empirical P values were calculated using permutation.

Mitochondrial genetic background modifies breast cancer risk.

Inefficient mitochondrial electron transport chain (ETC) function has been implicated in the vicious cycle of reactive oxygen species (ROS) production that may predispose an individual to late onset diseases, such as diabetes, hypertension, and cancer. Mitochondrial DNA (mtDNA) variations may affect the efficiency of ETC and ROS production, thus contributing to cancer risk. To test this hypothesis, we genotyped 69 mtDNA variations in 156 unrelated European-American females with familial breast cancer and 260 age-matched European-American female controls.

Molecular bases of hearing loss in multi-systemic mitochondrial cytopathy.

Purpose: Hearing loss is a common clinical feature in classic mitochondrial syndromes. The purpose of this study was to evaluate the diverse molecular etiologies and natural history of hearing loss in multi-systemic mitochondrial cytopathies and the possible correlation between degree of hearing loss and neurological phenotype.

Methods: In this retrospective study we evaluated the clinical features and molecular bases of hearing loss associated with multi-systemic mitochondrial cytopathy.

Novel mitochondrial DNA mutations associated with myopathy, cardiomyopathy, renal failure, and deafness.

Patients with mitochondrial disease usually manifest multisystemic dysfunction with a broad clinical spectrum. When the tests for common mitochondrial DNA (mtDNA) point mutations are negative and the mtDNA defects are still hypothesized, it is necessary to screen the entire mitochondrial genome for unknown mutations in order to confirm the diagnosis. We report an 8-year-old girl who had a long history of ragged-red fiber myopathy, short stature, and deafness, who ultimately developed renal failure and fatal cardiac dysfunction.

Exercise intolerance associated with a novel 8300T > C mutation in mitochondrial transfer RNAlys.

Mutations in the mitochondrial genome contribute to the pathophysiology of many neuromuscular diseases. Recently there has been an increased appreciation of the role of mitochondrial DNA (mtDNA) mutations in the etiology of exercise intolerance. Using TTGE (temporal temperature-gradient gel electrophoresis) and sequence analyses of the entire mitochondrial genome, we identified a novel heteroplasmic mutation (8300T > C) in the tRNAlys gene (MTTK) from a patient with unexplained exercise intolerance.

Real-time quantitative polymerase chain reaction analysis of mitochondrial DNA point mutation.

Mitochondrial respiratory chain disorders are a group of clinically and genetically heterogeneous diseases. Several mitochondrial (mt)DNA point mutations are responsible for common mitochondrial diseases. These pathogenic mtDNA point mutations are usually heteroplasmic.

Significance of somatic mutations and content alteration of mitochondrial DNA in esophageal cancer.

Background: The roles of mitochondria in energy metabolism, the generation of ROS, aging, and the initiation of apoptosis have implicated their importance in tumorigenesis. In this study we aim to establish the mutation spectrum and to understand the role of somatic mtDNA mutations in esophageal cancer.

Methods: The entire mitochondrial genome was screened for somatic mutations in 20 pairs (18 esophageal squamous cell carcinomas, one adenosquamous carcinoma and one adenocarcinoma) of tumor/surrounding normal tissue of esophageal cancers, using temporal temperature gradient gel electrophoresis (TTGE), followed by direct DNA sequencing to identify the mutations.

Molecular-clinical correlations in a family with variable tissue mitochondrial DNA T8993G mutant load.

Unlike many pathogenic mitochondrial DNA mutations, the T8993G mutation associated with Leigh syndrome (LS) and neurogenic muscle weakness, ataxia, retinitis pigmentosa (NARP) typically shows little variation in mutant load between different tissue types. We describe the molecular and clinical findings in a family with variable disease severity and tissue T8993G mutant loads. Real-time ARMS qPCR testing showed that two brothers with features of NARP and LS had high mutant loads (>90%) in all tissues tested, similar to previously reported cases.

Simultaneous detection and quantification of mitochondrial DNA deletion(s), depletion, and over-replication in patients with mitochondrial disease.

Heterogeneous clinical expression of mitochondrial DNA (mtDNA) disorders depends on both qualitative and quantitative changes in mtDNA. We developed a sensitive and effective method that simultaneously detects mtDNA deletion(s) and quantifies total mtDNA content. The percentage of deletions and mtDNA content of 19 patients with single or multiple deletions were analyzed by real-time quantitative polymerase chain reaction (real-time qPCR) using TaqMan probes specific for mtDNA (tRNA leu(UUR), ND4, ATPase8, and D-loop regions) and nuclear DNA (AIB1, beta-2-microglobulin, and beta-actin).

Hearing loss in mitochondrial disorders.

Hearing loss is a common clinical feature in mitochondria-syndrome disorders. The underlining molecular etiology of hearing loss has not been fully investigated. In this study, 83 patients with mitochondrial syndromic hearing loss were evaluated clinically and their blood and tissue samples were examined molecularly.

Extensive investigations of mitochondrial DNA genome in treated HIV-infected subjects: beyond mitochondrial DNA depletion.

Background: Therapy with nucleoside reverse transcriptase inhibitor (NRTI) agents has been associated with lipoatrophy and lactic acidosis, presumably through inhibition of DNA polymerase-gamma and resultant mitochondrial DNA (mtDNA) depletion. In past investigations, studies have looked at mtDNA depletion and a few specific mutations but not at the entire mtDNA genome to correlate with clinical toxicity.

Methods: This is the largest prospective longitudinal study to date that has performed a complete analysis of the entire mtDNA genome in addition to mtDNA depletion.

D5 dopamine receptor regulation of phospholipase D.

D(1)-like receptors have been reported to decrease oxidative stress in vascular smooth muscle cells by decreasing phospholipase D (PLD) activity. However, the PLD isoform regulated by D(1)-like receptors (D(1) or D(5)) and whether abnormal regulation of PLD by D(1)-like receptors plays a role in the pathogenesis of hypertension are unknown. The hypothesis that the D(5) receptor is the D(1)-like receptor that inhibits PLD activity and serves to regulate blood pressure was tested using D(5) receptor mutant mice (D(5)(-/-)).

Quantitative PCR analysis of mitochondrial DNA content in patients with mitochondrial disease.

Molecular diagnosis of mitochondrial DNA disorder is usually focused on point mutations and large deletions. In the absence of detectable mtDNA mutations, abnormal amounts of mtDNA, either depletion or elevation, can be indicative of mitochondrial dysfunction. The amount of mitochondrial DNA (mtDNA), however, varies among individuals of different ages and among different tissues within the same individual.

Enhanced detection of deleterious mutations by TTGE analysis of mother and child's DNA side by side.

Mitochondrial DNA (mtDNA) disorders represent a group of heterogeneous diseases that are caused by mutations in mtDNA. We examined 45 pairs of mother and the affected child, by screening the entire mitochondrial genome with temporal temperature gradient gel electrophoresis (TTGE), using 32 pairs of overlapping primers. TTGE is an effective method of mutation detection.

Detection and quantification of heteroplasmic mutant mitochondrial DNA by real-time amplification refractory mutation system quantitative PCR analysis: a single-step approach.

Background: The A3243G mitochondrial tRNA leu(UUR) point mutation causes mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, the most common mitochondrial DNA (mtDNA) disorder, and is also found in patients with maternally inherited diabetes and deafness syndrome (MIDD). To correlate disease manifestation with mutation loads, it is necessary to measure the percentage of the A3243G mtDNA mutation.

Methods: To reliably quantify low proportions of the mutant mtDNA, we developed a real-time amplification refractory mutation system quantitative PCR (ARMS-qPCR) assay.

[Restoring beta1 integrin activation function in K562 cells transfected with antisense VEGF121 cDNA].

To investigate the effect of vascular endothelial growth factor (VEGF) on beta1 integrin (VLA-4 and VLA-5) activation ability in K562 cells transfected with antisense VEGF121 cDNA, K562 cells were transfected with antisense (As), sense (S) and vector (V, pcDNA(3)). Flow cytometry was used to evaluate the expression rate of VLA-4 (CD49d/CD29) and VLA-5 (CD49e/CD29) and beta1 integrin activation ability in the transfected K562 cells. The results showed that the expression rates of VLA-4 and VLA-5 were more than 92% in the transfected K562 cells and there was no difference among the K562/V, K562/S and K562/As cells.

[Expression of Vascular Endothelial Growth Factor in the Bone Marrow Cells from Adult Chronic Myelogenous Leukemia].

Vascular endothelial growth factor (VEGF) is one of the main angiogenic cytokines and plays an important role in the development of human solid tumors. However, it is not clarified whether VEGF governs the progress of the chronic myelogenous leukemia (CML). This study is to estimate VEGF expression in the bone marrow cells from normal and adult CML patients and various leukemic cell lines.

[Low Concentrations of STI571 Enhances beta1 Integrin Mediated Inhibitory Effect on Proliferation of Myeloid Progenitors in Ph(+)Chronic Myeloid Leukemia].

To investigate whether ABL specific tyrosine kinase specific inhibitor STI571 can restore beta1 integrin mediated negative effect on Ph(+) chronic myeloid leukemia(CML), the inhibitory effect of beta 1 integrin activator (beta1 integrin activating antibody 8A2, cytokines such as GM-CSF, G-CSF and SCF) and/or FN on the granulocyte-macrophage colony forming unit (CFU-GM) from 16 patients with Ph(+)CML and 13 normal individuals were examined; the bone marrow mononuclear cells (BMMNC) before and after ABL kinase specific inhibitor STI571 pretreatment (0.1 micro mol/L for 30-60 minutes) were target cells in this study. The roles which VLA4 and VLA5 played in this process were evaluated through blocking assay.

Comprehensive scanning of the entire mitochondrial genome for mutations.

Background: Definitive molecular diagnosis of mitochondrial disorders has been greatly hindered by the tremendous clinical and genetic heterogeneity, the heteroplasmic condition of pathogenic mutations, and the presence of numerous homoplasmic mitochondrial DNA (mtDNA) variations with unknown significance. We used temporal temperature gradient gel electrophoresis (TTGE) to detect heteroplasmic mutations from homoplasmic variations in the whole mitochondrial genome.

Methods: We screened 179 unrelated patients by TTGE with use of 32 overlapping primer pairs.

A cystic fibrosis patient with two novel mutations in mitochondrial DNA: mild disease led to delayed diagnosis of both disorders.

A 21-year-old woman who has been suspected of mitochondrial cytopathy, but negative for common mitochondrial DNA (mtDNA) point mutations and deletions, was screened for unknown mutations in the entire mitochondrial genome by temporal temperature gradient gel electrophoresis (TTGE). Her asymptomatic mother's blood DNA was also analyzed and used as a reference. Two tRNA regions showing different TTGE patterns between the proband and her mother were sequenced.

Comprehensive scanning of somatic mitochondrial DNA mutations in breast cancer.

To investigate the role of mitochondrial DNA (mtDNA) in tumorigenesis, a temporal temperature gradient gel electrophoresis method was used to analyze the somatic mtDNA mutations in breast cancer. The entire mitochondrial genomes in 19 tumor samples and paired normal tissues from the same patients were amplified using 32 pairs of overlapping primers. DNA fragments showing different banding patterns between normal and tumor mtDNA were sequenced to identify the mutations.