• BMB Reports
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• v.48 no.11
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• pp.597-598
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• 2015

Mitochondrial respiratory defect is a key bioenergetics feature of hepatocellular carcinoma (HCC) cells. However, their involvement and roles in HCC development and progression remain unclear. Recently, we identified 10 common mitochondrial defect (CMD) signature genes that may be induced by retrograde signaling-mediated transcriptional reprogramming in response to HCC mitochondrial defects. HCC patients with enriched expression of these genes had poor prognostic outcomes, such as shorter periods of overall survival and recurrence-free survival. Nuclear protein 1 (NUPR1), a key transcription regulator, was up-regulated by Ca⁺⁺-mediated retrograde signaling. NUPR1-centric network analysis and a biochemical promoter-binding assay demonstrated that granulin (GRN) is a key downstream effector of NUPR1 for the regulation of HCC cell invasiveness; association analysis of the NUPR1-GRN pathway supported this conclusion. Mitochondrial respiratory defects and retrograde signaling thus play pivotal roles in HCC progression, highlighting the potential of the NUPR1-GRN axis as a novel diagnostic marker and therapeutic target for HCC.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.1
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• pp.25-28
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• 2015

Mitochondrial disorders are rare metabolic diseases. They often present during neonatal period but with nonspecific clinical features such as feeding difficulties, failure to thrive, and seizures. Mitochondrial defects have also known to be associated with neurological disorders, as well as cancers. We report the first case of neonatal mitochondrial respiratory chain defect with sarcoma botryoides confirmed by pathologic diagnosis, suggesting another possible link between mitochondrial dysfunction and cancer.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.3
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• pp.95-98
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• 2018

A striking feature of mitochondrial disorders is the vast heterogeneity in their clinical symptoms that ranges from a single organ to severe multisystem involvement. Though a variety of ocular symptoms such as ptosis, pigmentary retinal degeneration, external ophthalmoplegia, and optic nerve atrophy can occur in association with mitochondrial cytopathies, progressive bilateral cataracts are rare among their ocular findings. A 5-year-old girl with no previous medical history came to our hospital presenting symptoms of seizure. She started showing progressive developmental regression, increased seizure frequency, hypotonia, general weakness, dysphagia and decreased vision. Lactic acidosis was noted in metabolic screening test and we confirmed mitochondrial respiratory chain complex I defect in spectrophotometric enzyme assay using the muscle tissue. Progressive bilateral cataracts then developed and were fully evident at the age of 7. She underwent cataract extraction with posterior chamber lens implantation. We are reporting a case of mitochondrial respiratory chain defect with multiorgan involvements including bilateral progressive cataract, an uncommon ocular manifestation. Ophthalmologic evaluation is highly recommended not to overlook the possible ocular manifestations in mitochondrial disorders.

• Development and Reproduction
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• v.21 no.4
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• pp.417-424
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• 2017

Alzheimer's disease (AD) is neurodegenerative disease, characterized by the progressive decline of memory, cognitive functions, and changes in personality. The major pathological features in postmortem brains are neurofibrillary tangles and amyloid beta ($A{\beta}$) deposits. The majority of AD cases are sporadic and age-related. Although AD pathogenesis has not been established, aging and declining mitochondrial function has been associated. Mitochondrial dysfunction has been observed in AD patients' brains and AD mice models, and the mice with a genetic defect in mitochondrial complex I showed enhanced $A{\beta}$ level in vivo. To elucidate the role of mitochondrial complex I in AD, we used SH-SY5Y cells transfected with DNA constructs expressing human amyloid precursor protein (APP) or human Swedish APP mutant (APP-swe). The expression of APP-swe increased the level of $A{\beta}$ protein in comparison with control. When complex I was inhibited by rotenone, the increase of ROS level was remarkably higher in the cells overexpressing APP-swe compared to control. The number of dead cell was significantly increased in APP-swe-expressing cells by complex I inhibition. We suggest that complex I dysfunction accelerate amyloid toxicity and mitochondrial complex I dysfunction in aging may contribute to the pathogenesis of sporadic AD.

• Clinical and Experimental Pediatrics
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• v.53 no.12
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• pp.994-999
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• 2010

Purpose: Mitochondrial dysfunction can present with various symptoms depending on the organ it has affected. This research tried to analyze the ophthalmologic symptoms and ophthalmologic examination (OE) results in patients with mitochondrial disease (MD). Methods: Seventy-four patients diagnosed with mitochondrial respiratory chain complex defect with biochemical enzyme assay were included in the study. They were divided into 2 groups based on the OE results by funduscopy and were analyzed on the basis of their clinical features, biochemical test results, morphological analysis, and neuroimaging findings. Results: Thirty-seven (50%) of the 74 MD patients developed ophthalmologic symptoms. Abnormal findings were observed in 36 (48.6%) patients during an OE, and 16 (21.6%) of them had no ocular symptoms. Significantly higher rates of prematurity, clinical history of epilepsy or frequent apnea events, abnormal light microscopic findings in muscle pathology, diffuse cerebral atrophy in magnetic resonance imaging, and brainstem hyperintensity and lactate peaks in magnetic resonance spectroscopy were noted in the group with abnormal OE results. Conclusion: Although the ophthalmologic symptoms are not very remarkable in MD patients, an OE is required. When the risk factors mentioned above are observed, a more active approach should be taken in the OE because a higher frequency of ocular involvement can be expected.

• Clinical and Experimental Pediatrics
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• v.55 no.2
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• pp.58-62
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• 2012

Carnitine (${\beta}$-hydroxy-${\gamma}$-trimethylaminobutyric acid) is involved in the transport of long-chain fatty acids into the mitochondrial matrix and the removal of potentially toxic acylcarnitine esters. Transient carnitine transport defect is a rare condition in newborns reported in 1/90,000 live births. In this paper, we describe a case of transient carnitine transport defect found in a premature baby who had prolonged cholestatic jaundice and poor weight gain, and who responded dramatically to oral carnitine supplementation.

• Journal of Korean Neurosurgical Society
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• v.29 no.2
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• pp.188-195
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• 2000

Objective : Essential tremor(ET) is the most common movement disorder, however, there has been little agreement in the neurologic literature regarding diagnostic criteria for ET. Familial ET is an autosomal dominant disorder presenting as an isolated postural tremor. The main feature of ET is postural tremor of the arms with later involvement of the head, voice, or legs. In previous studies, it was reported that ET susceptibility was inherited in an autosomal dominant inheritance. As previous results, it would suggest that ET might be associated with defect of mitochondrial or nuclear DNA. Recent studies are focusing on molecular genetic detection of movement disorders, such as essential tremor and restless legs syndrome. Moreover, authors have analysed mitochondrial DNA(mtDNA) from the blood cell of positive control(PC) and ET patients via long and accurate polymerase chain reaction(LA PCR). Materials & Methods : Blood samples were collected from PC and 9 ET patients. Total DNA was extracted twice with phenol followed by chloroform : isoamylalcohol. For the analysis of mtDNA, LA PCR was performed by mitochondrial specific primers. Results : With this technique, deletions of large quantities were detected within several regions of mtDNA in ET patients except for D-loop and CO I regions. Conclusion : The authors believe that ET is a genentic disorder with deficiency of mitochondrial DNA multicomplexes and mitochondiral dysfunction could be one of major causative factors of ET. Mitochondrial dysfunction may play an important role in the pathogenesis and possibility of disease progression among familial group with ET patients.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.14 no.2
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• pp.191-194
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• 2014

Mitochondrial myopathy results from a primary dysfunction of the respiratory chain and is frequently accompanied with endocrine manifestations. Among the endocrine manifestations of mitochondrial disease, diabetes mellitus is relatively common. Diabetes mellitus in the mitochondrial myopathy is usually insulin dependent due to the defect in insulin secretion resulted from mitochondrial dysfunction. But it is seldom manifested as diabetes ketoacidosis and doesn't usually have an auto-antibody. We report a patient with mitochondrial myopathy who was diagnosed as having diabetes mellitus by presenting as diabetes ketoacidosis and had both of the auto-glutamic acid decarboxylase (GAD) antibody and anti-insulin auto-antibody.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.72-77
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• 2015

Purpose: Deficits of the respiratory chain are reported to be the major cause of Leigh syndrome is said to be the underlying causes. The need for biochemical diagnosis to draw more accurate diagnosis or prognosis to support treatments is rapidly increasing. This study tried to analyze the aspects of clinical characteristics and biochemical diagnosis of mitochondrial respiratory chain complex (MRC) defect in Leigh syndrome, using methods of biochemical enzyme assay. Methods: We included total number of 47 patients who satisfied the clinical criteria of Leigh syndrome and confirmed by biochemical diagnosis. All those patients went through muscle biopsy to perform biochemical enzyme assay to analyze MRC enzyme in order to find the underlying cause of Leigh syndrome. Results: MRC I defect was seen in 23 (48.9%) cases taking the first place and MRC IV defect in 15 (31.9%) following it. There were 9 (19.2%) cases of combined MRC defect. Combined cases of type I and IV were detected in 7 (14.9%) patients while type I and V in 2 (4.3%). The onset age of symptom was less than 1 year old in 28 (59.6%). The most common early symptom, observed in 23 (48.9%), was delayed development, but there were other various neurological symptoms observed as well. In regard with the disease progression, 35 (74.5%) patients showed slowly progressive course, the one that progressed continuously but slowly over 2 years of period. As for Maximum motor development, 22 (46.8%) were bed-ridden state, most of them suffering serious delayed development. Patients showed various symptoms with different organs involved, though neuromuscular involvement was most prominent. Delayed development was seen in all cases. Multifocal lesion in brain MRI study was seen in 36 (76.6 %) cases, taking a greater percentage than 11 (23.4%) cases with single lesion. In MR spectroscopy study, the characteristic lactate peak of mitochondrial disease was identified in 20 (42.6%) patients. Conclusions: Further analysis of clinical and biochemical diagnosis on more extended group of patients with Leigh syndrome will enable us to improve diagnostic precision and to understand the natural course of mitochondrial disease.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.84-91
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• 2006

A Saccharomyces cerevisiae pgs1 nulI mutant, which is deficient with phosphatidyl glycerol (PG) and cardiolipin (CL) biosynthesis, grows well on most fermentable carbon sources, but fails to grow on non-fermentable carbon sources such as glycerol, ethanol, and lactate. This mutant also cannot grow on galactose medium as the sole carbon source. We found that the incorporation of $[^{14}C]-galactose$, which is the first step of the galactose metabolic pathway (Leloir pathway), into the pgs 1 null mutant cell was extremely repressed. Exogenously expressed PGS1 (YCpPGS1) under indigenous promoter could completely restore the pgs1 growth defect on non-fermentable carbon sources, and dramatically recovered $[^{14}C]-galactose$ incorporation into the pgs1 mutant cell. However, PGS1 expression under the GALl promoter $(YEpP_{GAL1}-PGS1myc)$ could not complement pgs1 mutation, and the GAL2-lacZ fusion gene $(YEpP_{GAL2}-lacZ)$ also did not exhibit its $\beta-galactosidase$ activity in the pgs1 mutant. In wild-type yeast, antimycin $A(1\;{\mu}g/ml)$, which inhibits mitochondrial complex III, severely repressed not only the expression of the GAL2-lacZ fusion gene, but also uptake of $[^{14}C]-galactose$. However, exogenously expressed PGS1 partially relieved these inhibitory effects of antimycin A in both the pgs1 mutant and wild-type yeast, although it could not basically restore the growth defect on galactose by antimycin A. These results suggest that the PGSI gene product has an important role in utilization of galactose by Gal genes, and that intact mitochondrial function with PGS1 should be required for galactose incorporation into the Leloir pathway. The PGS1 gene might provide a clue to resolve the historic issue about the incapability of galactose with deteriorated mitochondrial function.