OBJECTIVE: To explore the genetic basis for a Chinese pedigree with suspected mitochondrial functional defects through combined next-generation sequencing (NGS), copy number variation sequencing (CNV-seq), and mitochondrial DNA (mtDNA) sequencing. METHODS: Clinical data of the proband and his family members were collected. The patient and his parents were subjected to family-trio whole-exome sequencing (WES), CNV-seq and mtDNA variant detection. Candidate variant was verified by Sanger sequencing. RESULTS: Trio-WES revealed that the proband has carried compound heterozygous variants of the NDUFS1 gene, including a paternally derived c.64C>T (p.R22X) nonsense variant and a maternally derived c.845A>G (p.N282S) missense variant. Both variants may cause loss of protein function. No variant that may cause the phenotype was identified by CNV-seq and mtDNA variant analysis. CONCLUSION Children with suspected mitochondrial disorders may have no specific syndromes or laboratory findings. A comprehensive strategy including mtDNA testing may facilitate the diagnosis and early clinical interventions.
Child ; China ; DNA Copy Number Variations ; Electron Transport ; Humans ; Mutation ; NADH Dehydrogenase/genetics* ; Pedigree

In the present study, a Spirometra species of Tanzania origin obtained from an African leopard (Panthera pardus) and spotted hyena (Crocuta crocuta) was identified based on molecular analysis of cytochrome c oxidase I (cox1) and NADH dehydrogenase subunit I (nad1) as well as by morphological observations of an adult tapeworm. One strobila and several segments of a Spirometra species were obtained from the intestine of an African male leopard (Panthera pardus) and spotted hyena (Crocuta crocuta) in the Maswa Game Reserve of Tanzania. The morphological characteristics of S. theileri observed comprised 3 uterine loops on one side and 4 on the other side of the mid-line, a uterine pore situated posterior to the vagina and alternating irregularly either to the right or left of the latter, and vesicular seminis that were much smaller than other Spirometra species. Sequence differences in the cox1 and nad1 genes between S. theileri (Tanzania origin) and S. erinaceieuropaei were 10.1% (cox1) and 12.0% (nad1), while those of S. decipiens and S. ranarum were 9.6%, 9.8% (cox1) and 13.0%, 12.6% (nad1), respectively. The morphological features of the Tanzania-origin Spirometra specimens coincided with those of S. theileri, and the molecular data was also consistent with that of S. theileri, thereby demonstrating the distribution of S. theileri in Tanzania. This places the leopard (Panthera pardus) and spotted hyena (Crocuta crocuta) as new definitive hosts of this spirometrid tapeworm.
Adult ; Animals ; Cestoda ; Electron Transport Complex IV ; Humans ; Hyaenidae ; Intestines ; Male ; NADH Dehydrogenase ; Panthera ; Spirometra ; Tanzania ; Vagina

OBJECTIVEThis study aimed to investigate the genetic background of mitochondrial genes in young patients with Coronary heart disease (CHD) to provide a foundation for the early prevention of young patients with CHD.

METHODS115 cases of young (⋜ 45 years) CHD Chinese Han patients (case group), 100 cases of older (> 45 years) Chinese Han CHD patients (experimental group) hospitalized and 100 cases of healthy people through physical examination (control group) at the General Hospital of PLA between January 2014 and December 2015 were selected. General information, clinical assessment, pedigree analysis, and mitochondrial full sequence scanning were performed. The pedigrees of one patient harbouring the C5263T mutation were recruited. Mitochondrial functional analysis including cellular reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were performed on pedigrees with the C5263T mutation (mutation group) and without the mutation (non-mutation group).

RESULTSThe differences in biochemical tests (P > 0.05) between the case group and experimental group were not significant. The C5263T single-nucleotide mutation of the mitochondrial ND2 gene was observed in 2 young CHD patients in the case group. The premature CHD of these 2 patients followed a pattern of maternal inheritance. The mutation group (I1, II2) had higher ROS levels (4750.82 ± 1045.55 vs. 3888.58 ± 487.60, P = 0.022) and lower MMP levels (P = 0.045) than the non-mutation group (II1, III1, III2).

CONCLUSIONWe speculated that the mitochondrial C5263T mutation might be associated with the occurrence CHD in Chinese Han young people.

Adult ; Aged ; Aged, 80 and over ; Base Sequence ; China ; epidemiology ; Coronary Disease ; epidemiology ; genetics ; Female ; Genes, Mitochondrial ; Humans ; Male ; Middle Aged ; Mitochondrial Proteins ; genetics ; metabolism ; Mutation ; NADH Dehydrogenase ; genetics ; metabolism

BACKGROUND/OBJECTIVES: A high-fat diet (HFD) induces obesity, which is a major risk factor for cardiovascular disease and cancer, while a calorie-restricted diet can extend life span by reducing the risk of these diseases. It is known that health effects of diet are partially conveyed through epigenetic mechanism including DNA methylation. In this study, we investigated the genome-wide hepatic DNA methylation to identify the epigenetic effects of HFD-induced obesity. MATERIALS AND METHODS: Seven-week-old male C57BL/6 mice were fed control diet (CD), calorie-restricted control diet (CRCD), or HFD for 16 weeks (after one week of acclimation to the control diet). Food intake, body weight, and liver weight were measured. Hepatic triacylglycerol and cholesterol levels were determined using enzymatic colorimetric methods. Changes in genome-wide DNA methylation were determined by a DNA methylation microarray method combined with methylated DNA immunoprecipitation. The level of transcription of individual genes was measured by real-time PCR. RESULTS: The DNA methylation statuses of genes in biological networks related to lipid metabolism and hepatic steatosis were influenced by HFD-induced obesity. In HFD group, a proinflammatory Casp1 (Caspase 1) gene had hypomethylated CpG sites at the 1.5-kb upstream region of its transcription start site (TSS), and its mRNA level was higher compared with that in CD group. Additionally, an energy metabolism-associated gene Ndufb9 (NADH dehydrogenase 1 beta subcomplex 9) in HFD group had hypermethylated CpG sites at the 2.6-kb downstream region of its TSS, and its mRNA level was lower compared with that in CRCD group. CONCLUSIONS: HFD alters DNA methylation profiles in genes associated with liver lipid metabolism and hepatic steatosis. The methylation statuses of Casp1 and Ndufb9 were particularly influenced by the HFD. The expression of these genes in HFD differed significantly compared with CD and CRCD, respectively, suggesting that the expressions of Casp1 and Ndufb9 in liver were regulated by their methylation statuses.
Acclimatization ; Animals ; Body Weight ; Cardiovascular Diseases ; Caspase 1 ; Cholesterol ; Diet ; Diet, High-Fat ; DNA Methylation* ; DNA* ; Eating ; Epigenomics ; Humans ; Immunoprecipitation ; Lipid Metabolism ; Liver ; Male ; Methods ; Methylation ; Mice ; Mice, Obese* ; NADH Dehydrogenase ; Obesity ; Oxidoreductases ; Real-Time Polymerase Chain Reaction ; Risk Factors ; RNA, Messenger ; Transcription Initiation Site ; Triglycerides

Recent studies indicate that mitochondria are an important source of reactive oxygen species (ROS) in the spinal dorsal horn. In our previous study, application of malate, a mitochondrial electron transport complex I substrate, induced a membrane depolarization, which was inhibited by pretreatment with ROS scavengers. In the present study, we used patch clamp recording in the substantia geletinosa (SG) neurons of spinal slices, to investigate the cellular mechanism of mitochondrial ROS on neuronal excitability. DNQX (an AMPA receptor antagonist) and AP5 (an NMDA receptor antagonist) decreased the malate-induced depolarization. In an external calcium free solution and addition of tetrodotoxin (TTX) for blockade of synaptic transmission, the malateinduced depolarization remained unchanged. In the presence of DNQX, AP5 and AP3 (a group I metabotropic glutamate receptor (mGluR) antagonist), glutamate depolarized the membrane potential, which was suppressed by PBN. However, oligomycin (a mitochondrial ATP synthase inhibitor) or PPADS (a P2 receptor inhibitor) did not affect the substrates-induced depolarization. These results suggest that mitochondrial substrate-induced ROS in SG neuron directly acts on the postsynaptic neuron, therefore increasing the ion influx via glutamate receptors.
Animals ; Calcium ; Electron Transport Complex I ; Glutamic Acid ; Membrane Potentials ; Membranes ; Mitochondria ; Mitochondrial Proton-Translocating ATPases ; N-Methylaspartate ; Neurons* ; Oligomycins ; Rats* ; Reactive Oxygen Species ; Receptors, AMPA ; Receptors, Glutamate ; Receptors, Metabotropic Glutamate ; Spinal Cord Dorsal Horn ; Substantia Gelatinosa* ; Synaptic Transmission ; Tetrodotoxin

The genus Spirometra belongs to the family Diphyllobothriidae and order Pseudophyllidea, and includes intestinal parasites of cats and dogs. In this study, a plerocercoid labeled as Spirometra mansonoides from the USA was examined for species identification and phylogenetic analysis using 2 complete mitochondrial genes, cytochrome c oxidase I (cox1) and NADH dehydrogenase subunit 3 (nad3). The cox1 sequences (1,566 bp) of the plerocercoid specimen (USA) showed 99.2% similarity to the reference sequences of the plerocercoid of Korean Spirometra decipiens (GenBank no. KJ599679), and 99.1% similarity in regard to nad3 (346 bp). Phylogenetic tree topologies generated using 4 analytical methods were identical and showed high confidence levels with bootstrap values of 1.00, 100%, 100%, and 100% for Bayesian inference (BI), maximum-likelihood (ML), neighbor-joining (NJ), and maximum parsimony (MP) methods, respectively. Representatives of Diphyllobothrium and Spirometra species formed a monophyletic group, and the sister-genera status between these species was well supported. Trapezoic proglottids in the posterior 1/5 region of an adult worm obtained from an experimentally infected cat were morphologically examined. The outer uterine loop of the uterus coiling characteristically consisted of 2 complete turns. The results clearly indicated that the examined Spirometra specimen from the USA matched to S. decipiens very well, and indicated possible presence of the life cycle of this species in this region.
Adult ; Animals ; Cats ; Diphyllobothrium ; Dogs ; Electron Transport Complex IV ; Genes, Mitochondrial ; Humans ; Life Cycle Stages ; NADH Dehydrogenase ; Parasites ; Sparganum ; Spirometra* ; Trees ; United States* ; Uterus

OBJECTIVETo investigate the role of MT-ND1 m.3635G>A mutation in the pathogenesis of Leber's hereditary optic neuropathy (LHON).

METHODSBiochemical characteristics including the activity of complex Ⅰ, ATP production and oxygen consumption rate among lymphoblastoid cell lines derived from 3 carriers, 3 affected matrilineal relatives of the families and 3 controls were compared.

RESULTSComparison of mitochondrial functions in lymphoblastoid cell lines of the carriers, patients and controls showed a 51.0% decrease in the activity of complex Ⅰ in patients compared with controls (P<0.05). The m.3635G>A mutation has resulted in decreased efficiency of ATP synthesis (P<0.05). Comparison of oxygen consumption rate showed that the basal OCR (P<0.05), ATP-linked OCR (P<0.05) and the maximum OCR (P<0.05) have all reduced to some extent compared with the controls.

CONCLUSIONThese results showed that m.3635G>A, as a LHON-associated mutation, can lead to mitochondrial dysfunction.

Adenosine Triphosphate ; genetics ; Asian Continental Ancestry Group ; genetics ; Female ; Humans ; Male ; Mitochondria ; genetics ; Mutation ; genetics ; NADH Dehydrogenase ; genetics ; Optic Atrophy, Hereditary, Leber ; genetics ; Pedigree

PURPOSE: In this study, we investigated the effects of chronic alcohol and excessive iron intake on mitochondrial DNA (mtDNA) damage and the progression of alcoholic liver injury in rats. METHODS: Twenty-four Sprague-Dawley male rats were divided into four groups (Control, EtOH, Fe, and EtOH + Fe), and fed either control or ethanol (36% of total calories) liquid diet with or without 0.6% carbonyl iron for eight weeks. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malondialdehyde concentrations were measured by colorimetric assays. Liver histopathology was examined by Hematoxylin-eosin staining of the fixed liver tissues. The integrity of the hepatic mtDNA and nuclear DNA was measured by long-range PCR. The gene expression levels of cytochrome c oxidase subunit 1 (Cox1) and NADH dehydrogenase subunit 4 (Nd4) were examined by real-time PCR. RESULTS: Serum ALT and AST activities were significantly higher in the EtOH+Fe group, as compared to the Control group. Similarly, among four groups, liver histology showed the most severe lipid accumulation, inflammation, and necrosis in the EtOH + Fe group. PCR amplification of near-full-length (15.9 kb) mtDNA showed more than 50% loss of full-length product in the liver of the EtOH + Fe group, whereas amounts of PCR products of a nuclear DNA were unaffected. In addition, the changes in the mtDNA integrity showed correlation with reductions in the mRNA levels of mitochondrial gene Cox1 and Nd4. CONCLUSION: Our data suggested that the liver injury associated with excessive iron and alcohol intake involved mtDNA damage and corresponding mitochondrial dysfunction.
Alanine Transaminase ; Alcoholics ; Animals ; Aspartate Aminotransferases ; Diet ; DNA ; DNA, Mitochondrial* ; Electron Transport Complex IV ; Ethanol ; Gene Expression ; Genes, Mitochondrial ; Humans ; Inflammation ; Iron* ; Liver* ; Male ; Malondialdehyde ; NADH Dehydrogenase ; Necrosis ; Polymerase Chain Reaction ; Rats* ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; RNA, Messenger

OBJECTIVETo report on the clinical, genetic and molecular characteristics of three ethnic Han Chinese families affected with Leber's hereditary optic neuropathy (LHON).

METHODSThe three families were all diagnosed with LHON. Ophthalmologic examinations were conducted on the probands . The ND1, ND4 and ND6 genes of the mitochondrial DNA (mtDNA) were amplified with PCR respectively for the screening of three primary mutations G3460A, G11778A and T14484C. The entire mtDNA of the probands were also amplified by PCR.

RESULTSAnalysis of mtDNA in the three pedigrees has failed to find the presence of the three LHON associated mutations but presence of a homoplastic ND1 T3866C mutation in all probands and their matrilineal relatives . The probands had different levels of visual impairment. The penetrance in the three families has been calculated as 12.5%, 11.1% and 33.3%, respectively. The T3866C mutation has resulted in replacement of isoleucine at position 187 with theronine. The isoleucine at position 187 is located at one of the transmembrane domains of ND1 polypeptide.

CONCLUSIONAbove results have suggested that the ND1 T3866C mutation might have been involved in the pathogenesis of LHON in the three Chinese families studied.

Adolescent ; Asian Continental Ancestry Group ; ethnology ; genetics ; Base Sequence ; Child ; Female ; Humans ; Male ; Mitochondria ; genetics ; Molecular Sequence Data ; NADH Dehydrogenase ; genetics ; Optic Atrophy, Hereditary, Leber ; ethnology ; genetics ; Pedigree ; Point Mutation

OBJECTIVETo study the effects of indium exposure on the relative content of mitochondrial ND1 gene in lymphocytes.

METHODSVenous blood was obtained from 14 healthy workers and anticoagulated with heparin. Blood lymphocytes were separated and divided into three tube cultures. For two tubes in the exposed group, indium chloride was added to final concentrations of 0.2 mmol/L and 0.8 mmol/L, respectively. For one tube in the control group, an equal volume of normal saline solution was added. After incubation for 72 h, the relative content of mitochondrial gene in each group was determined using quantitative real-time PCR.

RESULTSLymphocytes exposed to 0.8 mmol/L indium chloride had a significantly higher relative content of mitochondrial gene than those exposed to 0.2 mmol/L indium chloride and those in the control group (P < 0.05, P < 0.05).

CONCLUSIONLymphocytes exposed to a high concentration of indium and its compounds have an elevated relative content of mitochondrial ND1 gene, indicating increased oxidative DNA damage induced by exposure to a high concentration of indium and its compounds.

DNA Damage ; drug effects ; DNA, Mitochondrial ; genetics ; Humans ; Indium ; toxicity ; Lymphocytes ; drug effects ; NADH Dehydrogenase ; genetics ; Occupational Exposure