Publications by authors named "Rene G Feichtinger"

59 Publications

Targeted Metabolomics Identifies Plasma Biomarkers in Mice with Metabolically Heterogeneous Melanoma Xenografts.

Cancers (Basel) 2021 Jan 23;13(3). Epub 2021 Jan 23.

Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.

Melanomas are genetically and metabolically heterogeneous, which influences therapeutic efficacy and contributes to the development of treatment resistance in patients with metastatic disease. Metabolite phenotyping helps to better understand complex metabolic diseases, such as melanoma, and facilitates the development of novel therapies. Our aim was to characterize the tumor and plasma metabolomes of mice bearing genetically different melanoma xenografts. We engrafted the human melanoma cell lines A375 (BRAF mutant), WM47 (BRAF mutant), WM3000 (NRAS mutant), and WM3311 (BRAF, NRAS, NF1 triple-wildtype) and performed a broad-spectrum targeted metabolomics analysis of tumor and plasma samples obtained from melanoma-bearing mice as well as plasma samples from healthy control mice. Differences in ceramide and phosphatidylcholine species were observed between melanoma subtypes irrespective of the genetic driver mutation. Furthermore, beta-alanine metabolism differed between melanoma subtypes and was significantly enriched in plasma from melanoma-bearing mice compared to healthy mice. Moreover, we identified beta-alanine, -cresol sulfate, sarcosine, tiglylcarnitine, two dihexosylceramides, and one phosphatidylcholine as potential melanoma biomarkers in plasma. The present data reflect the metabolic heterogeneity of melanomas but also suggest a diagnostic biomarker signature for melanoma screening.
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http://dx.doi.org/10.3390/cancers13030434DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865782PMC
January 2021

A new ketogenic formulation improves functional outcome and reduces tissue loss following traumatic brain injury in adult mice.

Theranostics 2021 1;11(1):346-360. Epub 2021 Jan 1.

Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel, London, E1 2AT, UK.

Traumatic brain injury (TBI) leads to neurological impairment, with no satisfactory treatments available. Classical ketogenic diets (KD), which reduce reliance on carbohydrates and provide ketones as fuel, have neuroprotective potential, but their high fat content reduces compliance, and experimental evidence suggests they protect juvenile brain against TBI, but not adult brain, which would strongly limit their applicability in TBI. We designed a new-KD with a fat to carbohydrate plus protein ratio of 2:1, containing medium chain triglycerides (MCT), docosahexaenoic acid (DHA), low glycaemic index carbohydrates, fibres and the ketogenic amino acid leucine, and evaluated its neuroprotective potential in adult TBI. Adult male C57BL6 mice were injured by controlled cortical impact (CCI) and assessed for 70 days, during which they received a control diet or the new-KD. The new-KD, that markedly increased plasma Beta-hydroxybutyrate (β-HB), significantly attenuated sensorimotor deficits and corrected spatial memory deficit. The lesion size, perilesional inflammation and oxidation were markedly reduced. Oligodendrocyte loss appeared to be significantly reduced. TBI activated the mTOR pathway and the new-KD enhanced this increase and increased histone acetylation and methylation. The behavioural improvement and tissue protection provide proof of principle that this new formulation has therapeutic potential in adult TBI.
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http://dx.doi.org/10.7150/thno.48995DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7681084PMC
January 2021

The switch in the diagnosis of mitochondrial diseases from the classical 'function first' to the NGS-based 'genetics first' diagnostic era.

J Mother Child 2020 Oct 2;24(2):47-52. Epub 2020 Oct 2.

Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria.

The knowledge of causes and pathophysiology of mitochondrial diseases has increased exponentially in the last four decades. Recently, due to the decreased costs of new sequencing technologies (exome and whole genome sequencing), these technologies were applied more and more in clinical routine. The traditional diagnostic approach ('biopsy first') of evaluating the patient and his body fluids and the analysis of enzymes of the oxidative phosphorylation system in skeletal muscle with subsequent Sanger sequencing of single candidate genes ('from function to gene') were replaced by next generation sequencing techniques with a diagnostic yield of >40%. In this 'genetics first' approach, the detection of new candidate genes necessitates often functional evaluations ('from gene to function') leading to reverse phenotyping of affected individuals. The new genetic era has offered a clear new challenge for the responsibility of the diagnostic centres: the interplay of clinicians, geneticists and functional biochemists is a prerequisite for a validated diagnosis. It becomes evident that expanded diagnostics builds an interface to research. Only competence centres with high numbers of patients, clinical and diagnostic experience and exchange of knowledge with other comparable units can fulfil all those requirements.
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http://dx.doi.org/10.34763/jmotherandchild.20202402si.2005.000008DOI Listing
October 2020

Targeting Mitochondria in Melanoma.

Biomolecules 2020 09 30;10(10). Epub 2020 Sep 30.

Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria.

Drastically elevated glycolytic activity is a prominent metabolic feature of cancer cells. Until recently it was thought that tumor cells shift their entire energy production from oxidative phosphorylation (OXPHOS) to glycolysis. However, new evidence indicates that many cancer cells still have functional OXPHOS, despite their increased reliance on glycolysis. Growing pre-clinical and clinical evidence suggests that targeting mitochondrial metabolism has anti-cancer effects. Here, we analyzed mitochondrial respiration and the amount and activity of OXPHOS complexes in four melanoma cell lines and normal human dermal fibroblasts (HDFs) by Seahorse real-time cell metabolic analysis, immunoblotting, and spectrophotometry. We also tested three clinically approved antibiotics, one anti-parasitic drug (pyrvinium pamoate), and a novel anti-cancer agent (ONC212) for effects on mitochondrial respiration and proliferation of melanoma cells and HDFs. We found that three of the four melanoma cell lines have elevated glycolysis as well as OXPHOS, but contain dysfunctional mitochondria. The antibiotics produced different effects on the melanoma cells and HDFs. The anti-parasitic drug strongly inhibited respiration and proliferation of both the melanoma cells and HDFs. ONC212 reduced respiration in melanoma cells and HDFs, and inhibited the proliferation of melanoma cells. Our findings highlight ONC212 as a promising drug for targeting mitochondrial respiration in cancer.
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http://dx.doi.org/10.3390/biom10101395DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7599575PMC
September 2020

Age-Related Deterioration of Mitochondrial Function in the Intestine.

Oxid Med Cell Longev 2020 18;2020:4898217. Epub 2020 Aug 18.

Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.

Aging is an important and inevitable biological process in human life, associated with the onset of chronic disease and death. The mechanisms behind aging remain unclear. However, changes in mitochondrial function and structure, including reduced activity of the mitochondrial respiratory chain and increased production of reactive oxygen species-thus oxidative damage-are believed to play a major role. Mitochondria are the main source of cellular energy, producing adenosine triphosphate (ATP) via oxidative phosphorylation. Accumulation of damaged cellular components reduces a body's capacity to preserve tissue homeostasis and affects biological aging and all age-related chronic conditions. This includes the onset and progression of classic degenerative diseases such as cardiovascular disease, kidney failure, neurodegenerative diseases, and cancer. Clinical manifestations of intestinal disorders, such as mucosal barrier dysfunction, intestinal dysmotility, and chronic obstipation, are highly prevalent in the elderly population and have been shown to be associated with an age-dependent decline of mitochondrial function. This review summarizes our current understanding of the role of mitochondrial dysfunction in intestinal aging.
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http://dx.doi.org/10.1155/2020/4898217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453234PMC
August 2020

Bi-allelic HPDL Variants Cause a Neurodegenerative Disease Ranging from Neonatal Encephalopathy to Adolescent-Onset Spastic Paraplegia.

Am J Hum Genet 2020 08 23;107(2):364-373. Epub 2020 Jul 23.

Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany; Centre for Rare Diseases, University of Tuebingen, 72076 Tübingen, Germany. Electronic address:

We report bi-allelic pathogenic HPDL variants as a cause of a progressive, pediatric-onset spastic movement disorder with variable clinical presentation. The single-exon gene HPDL encodes a protein of unknown function with sequence similarity to 4-hydroxyphenylpyruvate dioxygenase. Exome sequencing studies in 13 families revealed bi-allelic HPDL variants in each of the 17 individuals affected with this clinically heterogeneous autosomal-recessive neurological disorder. HPDL levels were significantly reduced in fibroblast cell lines derived from more severely affected individuals, indicating the identified HPDL variants resulted in the loss of HPDL protein. Clinical presentation ranged from severe, neonatal-onset neurodevelopmental delay with neuroimaging findings resembling mitochondrial encephalopathy to milder manifestation of adolescent-onset, isolated hereditary spastic paraplegia. All affected individuals developed spasticity predominantly of the lower limbs over the course of the disease. We demonstrated through bioinformatic and cellular studies that HPDL has a mitochondrial localization signal and consequently localizes to mitochondria suggesting a putative role in mitochondrial metabolism. Taken together, these genetic, bioinformatic, and functional studies demonstrate HPDL is a mitochondrial protein, the loss of which causes a clinically variable form of pediatric-onset spastic movement disorder.
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http://dx.doi.org/10.1016/j.ajhg.2020.06.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413886PMC
August 2020

Metabolic reprogramming related to whole-chromosome instability in models for Hürthle cell carcinoma.

Sci Rep 2020 06 12;10(1):9578. Epub 2020 Jun 12.

Department of Pathology, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands.

Hürthle cell carcinoma (HCC) is a recurrent subtype of non-medullary thyroid cancer. HCC is characterized by profound whole-chromosome instability (w-CIN), resulting in a near-homozygous genome (NHG), a phenomenon recently attributed to reactive oxygen species (ROS) generated during mitosis by malfunctioning mitochondria. We studied shared metabolic traits during standard and glucose-depleted cell culture in thyroid cancer cell lines (TCCLs), with or without a NHG, using quantitative analysis of extra and intracellular metabolites and ROS production following inhibition of complex III with antimycin A. We found that the XTC.UC1 and FTC-236 cell lines (both NHG) are functionally impaired in complex I and produce significantly more superoxide radicals than SW579 and BHP 2-7 (non-NHG) after challenge with antimycin A. FTC-236 showed the lowest levels of glutathione and SOD2. XTC.UC1 and FTC-236 both exhibited reduced glycolytic activity and utilization of alternative sources to meet energy demands. Both cell lines also shared low levels of α-ketoglutarate and high levels of creatine, phosphocreatine, uridine diphosphate-N-acetylglucosamine, pyruvate and acetylcarnitine. Furthermore, the metabolism of XTC.UC1 was skewed towards the de novo synthesis of aspartate, an effect that persisted even in glucose-free media, pointing to reductive carboxylation. Our data suggests that metabolic reprogramming and a subtle balance between ROS generation and scavenging/conversion of intermediates may be involved in ROS-induced w-CIN in HCC and possibly also in rare cases of follicular thyroid cancer showing a NHG.
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http://dx.doi.org/10.1038/s41598-020-66599-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293353PMC
June 2020

Changes in the expression of oxidative phosphorylation complexes in the aging intestinal mucosa.

Exp Gerontol 2020 07 13;135:110924. Epub 2020 Mar 13.

Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.

Objective: Mitochondria produce cellular energy via oxidative phosphorylation (OXPHOS), mediated by respiratory chain complexes I to IV and ATP synthase (complex V). Mitochondrial respiratory complexes have been shown to decline with age in several tissues. As the intestinal epithelium is a tissue with a high energy demand, the aim of the present study was to establish whether the expression profile of OXPHOS subunits in the intestinal mucosa changes during the aging process.

Design: Biopsies of intestinal mucosa with no evidence of endoscopic or histomorphologic abnormalities, taken from 55 patients (mean age 42 years, age range 4-82 years; 62% female), were divided into four age groups (4-19, 20-39, 40-59, ≥60 years). Sections from different intestinal segments (terminal ileum, ascending colon, and sigmoid colon/rectum) were stained immunohistochemically (IHC) for subunits of OXPHOS complexes I-V and the voltage-dependent anion-selective channel 1 protein (VDAC1, porin), a marker of mitochondrial mass. Scores for IHC staining were determined by multiplication of the staining intensity and the percentage of positive cells. In addition, the numbers of intestinal crypts staining positive, partly positive, and negative were assessed.

Results: The average protein expression levels of OXPHOS subunits increased continuously from childhood onward, peaked in persons aged 20 to 59 years, and declined thereafter. This was seen for complexes II to V in the terminal ileum, complexes I to V in the ascending colon, and complexes I to IV in the sigmoid colon/rectum. Across all age groups, no effect of age on expression of the porin subunit VDAC1 was detected. The number of complex I- and IV-negative crypts in different intestinal segments increased with age.

Conclusion: The protein expression levels of OXPHOS complexes increases from childhood onward and declines in elderly individuals, while the numbers of crypts with partial or complete loss of expression of complexes I and IV increase continuously with age. These data suggest that the continued reductions in the levels of mitochondrial OXPHOS complexes in crypts might be compensated in adulthood, but that, ultimately, reduced expression levels occur in persons aged 60 years and older. These findings raise two important questions: first, can the process of aging could be delayed through (pharmacological) intervention of mitochondrial pathways, and second, pathophysiologically, are these findings associated with disorders of the intestinal mucosa, e.g. inflammation?
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http://dx.doi.org/10.1016/j.exger.2020.110924DOI Listing
July 2020

Bi-Allelic UQCRFS1 Variants Are Associated with Mitochondrial Complex III Deficiency, Cardiomyopathy, and Alopecia Totalis.

Am J Hum Genet 2020 01 26;106(1):102-111. Epub 2019 Dec 26.

Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: Department of Neuropediatrics, 13353 Berlin, Germany. Electronic address:

Isolated complex III (CIII) deficiencies are among the least frequently diagnosed mitochondrial disorders. Clinical symptoms range from isolated myopathy to severe multi-systemic disorders with early death and disability. To date, we know of pathogenic variants in genes encoding five out of 10 subunits and five out of 13 assembly factors of CIII. Here we describe rare bi-allelic variants in the gene of a catalytic subunit of CIII, UQCRFS1, which encodes the Rieske iron-sulfur protein, in two unrelated individuals. Affected children presented with low CIII activity in fibroblasts, lactic acidosis, fetal bradycardia, hypertrophic cardiomyopathy, and alopecia totalis. Studies in proband-derived fibroblasts showed a deleterious effect of the variants on UQCRFS1 protein abundance, mitochondrial import, CIII assembly, and cellular respiration. Complementation studies via lentiviral transduction and overexpression of wild-type UQCRFS1 restored mitochondrial function and rescued the cellular phenotype, confirming UQCRFS1 variants as causative for CIII deficiency. We demonstrate that mutations in UQCRFS1 can cause mitochondrial disease, and our results thereby expand the clinical and mutational spectrum of CIII deficiencies.
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http://dx.doi.org/10.1016/j.ajhg.2019.12.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042493PMC
January 2020

Targeting L-Lactate Metabolism to Overcome Resistance to Immune Therapy of Melanoma and Other Tumor Entities.

J Oncol 2019 3;2019:2084195. Epub 2019 Nov 3.

Department of Dermatology and Allergology, University Hospital Salzburg, Paracelsus Medical University, Salzburg 5020, Austria.

Although immunotherapy plays a significant role in tumor therapy, its efficacy is impaired by an immunosuppressive tumor microenvironment. A molecule that contributes to the protumor microenvironment is the metabolic product lactate. Lactate is produced in large amounts by cancer cells in response to either hypoxia or pseudohypoxia, and its presence in excess alters the normal functioning of immune cells. A key enzyme involved in lactate metabolism is lactate dehydrogenase (LDH). Elevated baseline LDH serum levels are associated with poor outcomes of current anticancer (immune) therapies, especially in patients with melanoma. Therefore, targeting LDH and other molecules involved in lactate metabolism might improve the efficacy of immune therapies. This review summarizes current knowledge about lactate metabolism and its role in the tumor microenvironment. Based on that information, we develop a rationale for deploying drugs that target lactate metabolism in combination with immune checkpoint inhibitors to overcome lactate-mediated immune escape of tumor cells.
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http://dx.doi.org/10.1155/2019/2084195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875281PMC
November 2019

Ketogenic diet in the treatment of cancer - Where do we stand?

Mol Metab 2020 03 27;33:102-121. Epub 2019 Jul 27.

Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Müllner Hauptstraße 48, 5020, Salzburg, Austria. Electronic address:

Background: Cancer is one of the greatest public health challenges worldwide, and we still lack complementary approaches to significantly enhance the efficacy of standard anticancer therapies. The ketogenic diet, a high-fat, low-carbohydrate diet with adequate amounts of protein, appears to sensitize most cancers to standard treatment by exploiting the reprogramed metabolism of cancer cells, making the diet a promising candidate as an adjuvant cancer therapy.

Scope Of Review: To critically evaluate available preclinical and clinical evidence regarding the ketogenic diet in the context of cancer therapy. Furthermore, we highlight important mechanisms that could explain the potential antitumor effects of the ketogenic diet.

Major Conclusions: The ketogenic diet probably creates an unfavorable metabolic environment for cancer cells and thus can be regarded as a promising adjuvant as a patient-specific multifactorial therapy. The majority of preclinical and several clinical studies argue for the use of the ketogenic diet in combination with standard therapies based on its potential to enhance the antitumor effects of classic chemo- and radiotherapy, its overall good safety and tolerability and increase in quality of life. However, to further elucidate the mechanisms of the ketogenic diet as a therapy and evaluate its application in clinical practice, more molecular studies as well as uniformly controlled clinical trials are needed.
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http://dx.doi.org/10.1016/j.molmet.2019.06.026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7056920PMC
March 2020

Untargeted Metabolomics Reveals Molecular Effects of Ketogenic Diet on Healthy and Tumor Xenograft Mouse Models.

Int J Mol Sci 2019 Aug 8;20(16). Epub 2019 Aug 8.

Bioanalytical Research Laboratories, Department of Biosciences and Cancer Cluster Salzburg, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.

The application of ketogenic diet (KD) (high fat/low carbohydrate/adequate protein) as an auxiliary cancer therapy is a field of growing attention. KD provides sufficient energy supply for healthy cells, while possibly impairing energy production in highly glycolytic tumor cells. Moreover, KD regulates insulin and tumor related growth factors (like insulin growth factor-1, IGF-1). In order to provide molecular evidence for the proposed additional inhibition of tumor growth when combining chemotherapy with KD, we applied untargeted quantitative metabolome analysis on a spontaneous breast cancer xenograft mouse model, using MDA-MB-468 cells. Healthy mice and mice bearing breast cancer xenografts and receiving cyclophosphamide chemotherapy were compared after treatment with control diet and KD. Metabolomic profiling was performed on plasma samples, applying high-performance liquid chromatography coupled to tandem mass spectrometry. Statistical analysis revealed metabolic fingerprints comprising numerous significantly regulated features in the group of mice bearing breast cancer. This fingerprint disappeared after treatment with KD, resulting in recovery to the metabolic status observed in healthy mice receiving control diet. Moreover, amino acid metabolism as well as fatty acid transport were found to be affected by both the tumor and the applied KD. Our results provide clear evidence of a significant molecular effect of adjuvant KD in the context of tumor growth inhibition and suggest additional mechanisms of tumor suppression beyond the proposed constrain in energy supply of tumor cells.
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http://dx.doi.org/10.3390/ijms20163873DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719192PMC
August 2019

Utility of Whole Blood Thiamine Pyrophosphate Evaluation in -Related Diseases.

J Clin Med 2019 07 8;8(7). Epub 2019 Jul 8.

MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK.

mutations are a rare, but potentially treatable, cause of thiamine deficiency. Diagnosis is challenging given the phenotypic overlap that exists with other metabolic and neurological disorders. We report a case of -related disease presenting with Leigh-like syndrome and review the diagnostic utility of thiamine pyrophosphate (TPP) blood measurement. The proband, a 35-year-old male, presented at four months of age with recurrent episodes of post-infectious encephalopathy. He subsequently developed epilepsy, learning difficulties, sensorineural hearing loss, spasticity, and dysphagia. There was a positive family history for Leigh syndrome in an older brother. Plasma lactate was elevated (3.51 mmol/L) and brain MRI showed bilateral basal ganglia hyperintensities, indicative of Leigh syndrome. Histochemical and spectrophotometric analysis of mitochondrial respiratory chain complexes I, II+III, and IV was normal. Genetic analysis of muscle mitochondrial DNA was negative. Whole exome sequencing of the proband confirmed compound heterozygous variants in : c. 426G>C (p. Leu142Phe) and c. 258+1G>A (p.?). Blood TPP levels were reduced, providing functional evidence for the deleterious effects of the variants. We highlight the clinical and bioinformatics challenges to diagnosing rare genetic disorders and the continued utility of biochemical analyses, despite major advances in DNA sequencing technology, when investigating novel, potentially disease-causing, genetic variants. Blood TPP measurement represents a fast and cost-effective diagnostic tool in -related diseases.
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http://dx.doi.org/10.3390/jcm8070991DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679130PMC
July 2019

From old to new - Repurposing drugs to target mitochondrial energy metabolism in cancer.

Semin Cell Dev Biol 2020 02 4;98:211-223. Epub 2019 Jun 4.

Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria.

Although we have entered the era of personalized medicine and tailored therapies, drugs that target a large variety of cancers regardless of individual patient differences would be a major advance nonetheless. This review article summarizes current concepts and therapeutic opportunities in the area of targeting aerobic mitochondrial energy metabolism in cancer. Old drugs previously used for diseases other than cancer, such as antibiotics and antidiabetics, have the potential to inhibit the growth of various tumor entities. Many drugs are reported to influence mitochondrial metabolism. However, here we consider only those drugs which predominantly inhibit oxidative phosphorylation.
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http://dx.doi.org/10.1016/j.semcdb.2019.05.025DOI Listing
February 2020

Biallelic variants in the transcription factor PAX7 are a new genetic cause of myopathy.

Genet Med 2019 11 16;21(11):2521-2531. Epub 2019 May 16.

CHU Sainte-Justine Research Center, University of Montreal, Montreal, QC, Canada.

Purpose: Skeletal muscle growth and regeneration rely on muscle stem cells, called satellite cells. Specific transcription factors, particularly PAX7, are key regulators of the function of these cells. Knockout of this factor in mice leads to poor postnatal survival; however, the consequences of a lack of PAX7 in humans have not been established.

Methods: Here, we study five individuals with myopathy of variable severity from four unrelated consanguineous couples. Exome sequencing identified pathogenic variants in the PAX7 gene. Clinical examination, laboratory tests, and muscle biopsies were performed to characterize the disease.

Results: The disease was characterized by hypotonia, ptosis, muscular atrophy, scoliosis, and mildly dysmorphic facial features. The disease spectrum ranged from mild to severe and appears to be progressive. Muscle biopsies showed the presence of atrophic fibers and fibroadipose tissue replacement, with the absence of myofiber necrosis. A lack of PAX7 expression was associated with satellite cell pool exhaustion; however, the presence of residual myoblasts together with regenerating myofibers suggest that a population of PAX7-independent myogenic cells partially contributes to muscle regeneration.

Conclusion: These findings show that biallelic variants in the master transcription factor PAX7 cause a new type of myopathy that specifically affects satellite cell survival.
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http://dx.doi.org/10.1038/s41436-019-0532-zDOI Listing
November 2019

Mitochondrial complex deficiency by novel compound heterozygous variants and correlation with developmental delay, undescended testicle, and left ventricular noncompaction in a Japanese patient: A case report.

Clin Case Rep 2019 Mar 7;7(3):553-557. Epub 2019 Feb 7.

Department of Metabolism Center for Medical Genetics Chiba Children's Hospital Midori-ku Chiba Japan.

We identified novel compound heterozygous variants in a Japanese patient who had hyperlactacidemia, metabolic acidosis, hyperalaninemia, developmental delay, undescended testicle, and left ventricular noncompaction. The urinary organic acids profile revealed elevated levels of 3-MGA, and BN-PAGE/Western blotting analysis and ETC. activity confirmed complex V deficiency.
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http://dx.doi.org/10.1002/ccr3.2050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6406168PMC
March 2019

Severe Deoxyguanosine Kinase Deficiency in Austria: A 6-Patient Series.

J Pediatr Gastroenterol Nutr 2019 01;68(1):e1-e6

Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna.

Mutations in the nuclear gene DGUOK, encoding deoxyguanosine kinase, cause an infantile hepatocerebral type of mitochondrial depletion syndrome (MDS). We report 6 MDS patients harboring bi-allelic DGUOK mutations, of which 3 are novel, including a large intragenic Austrian founder deletion. One patient was diagnosed with hepatocellular carcinoma aged 6 months, supporting a link between mitochondrial DNA depletion and tumorigenesis; liver transplantation proved beneficial with regard to both tumor treatment and psychomotor development.
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http://dx.doi.org/10.1097/MPG.0000000000002149DOI Listing
January 2019

Reduced Levels of ATP Synthase Subunit ATP5F1A Correlate with Earlier-Onset Prostate Cancer.

Oxid Med Cell Longev 2018 14;2018:1347174. Epub 2018 Nov 14.

Division of Experimental Urology, Department of Urology, Medical University of Innsbruck, 6020 Innsbruck, Austria.

Switching of cellular energy production from oxidative phosphorylation (OXPHOS) to aerobic glycolysis occurs in many types of tumors. However, the significance of energy metabolism for the development of prostate carcinoma is poorly understood. We investigated the expression of OXPHOS complexes in 94 human prostate carcinomas and paired benign tissue using immunohistochemistry. Overall mitochondrial mass was upregulated in carcinomas compared to benign prostate tissue in all Gleason grades. A significant direct correlation between the expression of OXPHOS complexes I, II, and V and the Gleason score was observed. However, 17% of prostate carcinomas and 18% of benign prostate tissues showed isolated or combined deficiency of OXPHOS complexes (one deficiency in 12% of the tumors, combined deficiencies in 5%). Complex I was absent in 9% of the samples, with only parts of the tumor affected. ATP5F1A, a complex V protein, was the most frequently affected subunit, in 10% of tumors and 11% of benign prostate tissues (but not both tissues in any single patient). A possible role of complex V in prostate cancer development is suggested by the significant positive correlation of ATP5F1A levels with earlier-onset prostate cancer (age at diagnosis and at prostatectomy) and free PSA percentage. The relatively high percentage (17%) of prostate carcinomas with regional foci of partial OXPHOS complex deficiencies could have important therapeutic implications.
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http://dx.doi.org/10.1155/2018/1347174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6261400PMC
January 2019

Bi-allelic ADPRHL2 Mutations Cause Neurodegeneration with Developmental Delay, Ataxia, and Axonal Neuropathy.

Am J Hum Genet 2018 11 25;103(5):817-825. Epub 2018 Oct 25.

Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany; Centre for Rare Diseases, University of Tuebingen, 72076 Tübingen, Germany. Electronic address:

ADP-ribosylation is a reversible posttranslational modification used to regulate protein function. ADP-ribosyltransferases transfer ADP-ribose from NAD to the target protein, and ADP-ribosylhydrolases, such as ADPRHL2, reverse the reaction. We used exome sequencing to identify five different bi-allelic pathogenic ADPRHL2 variants in 12 individuals from 8 families affected by a neurodegenerative disorder manifesting in childhood or adolescence with key clinical features including developmental delay or regression, seizures, ataxia, and axonal (sensori-)motor neuropathy. ADPRHL2 was virtually absent in available affected individuals' fibroblasts, and cell viability was reduced upon hydrogen peroxide exposure, although it was rescued by expression of wild-type ADPRHL2 mRNA as well as treatment with a PARP1 inhibitor. Our findings suggest impaired protein ribosylation as another pathway that, if disturbed, causes neurodegenerative diseases.
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http://dx.doi.org/10.1016/j.ajhg.2018.10.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6218634PMC
November 2018

Bi-allelic Mutations in NDUFA6 Establish Its Role in Early-Onset Isolated Mitochondrial Complex I Deficiency.

Am J Hum Genet 2018 10 20;103(4):592-601. Epub 2018 Sep 20.

Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK. Electronic address:

Isolated complex I deficiency is a common biochemical phenotype observed in pediatric mitochondrial disease and often arises as a consequence of pathogenic variants affecting one of the ∼65 genes encoding the complex I structural subunits or assembly factors. Such genetic heterogeneity means that application of next-generation sequencing technologies to undiagnosed cohorts has been a catalyst for genetic diagnosis and gene-disease associations. We describe the clinical and molecular genetic investigations of four unrelated children who presented with neuroradiological findings and/or elevated lactate levels, highly suggestive of an underlying mitochondrial diagnosis. Next-generation sequencing identified bi-allelic variants in NDUFA6, encoding a 15 kDa LYR-motif-containing complex I subunit that forms part of the Q-module. Functional investigations using subjects' fibroblast cell lines demonstrated complex I assembly defects, which were characterized in detail by mass-spectrometry-based complexome profiling. This confirmed a marked reduction in incorporated NDUFA6 and a concomitant reduction in other Q-module subunits, including NDUFAB1, NDUFA7, and NDUFA12. Lentiviral transduction of subjects' fibroblasts showed normalization of complex I. These data also support supercomplex formation, whereby the ∼830 kDa complex I intermediate (consisting of the P- and Q-modules) is in complex with assembled complex III and IV holoenzymes despite lacking the N-module. Interestingly, RNA-sequencing data provided evidence that the consensus RefSeq accession number does not correspond to the predominant transcript in clinically relevant tissues, prompting revision of the NDUFA6 RefSeq transcript and highlighting not only the importance of thorough variant interpretation but also the assessment of appropriate transcripts for analysis.
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http://dx.doi.org/10.1016/j.ajhg.2018.08.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174280PMC
October 2018

PRUNE1 Deficiency: Expanding the Clinical and Genetic Spectrum.

Neuropediatrics 2018 10 25;49(5):330-338. Epub 2018 Jun 25.

Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria.

Background: Primary microcephaly and profound global developmental delay have been considered the core clinical phenotype in patients with bi-allelic mutations.

Methods: Linkage analysis and whole-exome sequencing (WES) in a multiplex family and extraction of further cases from a WES repository containing 571 children with severe developmental disabilities and neurologic symptoms.

Results: We identified bi-allelic mutations in twelve children from six unrelated families. All patients who survived beyond the first 6 months of life had early-onset global developmental delay, bilateral spastic paresis, dysphagia and difficult-to-treat seizures, while congenital or later-evolving microcephaly was not a consistent finding. Brain MRI showed variable anomalies with progressive cerebral and cerebellar atrophies and T2-hyperintense brain stem lesions. Peripheral neuropathy was documented in five cases. Disease course was progressive in all patients and eight children died in the first or early second decade of life. In addition to the previously reported missense mutation p.(Asp106Asn), we observed a novel homozygous missense variant p.(Leu172Pro) and a homozygous contiguous gene deletion encompassing most of the gene and part of the neighboring gene.

Conclusions: deficiency causes severe early-onset disease affecting the central and peripheral nervous systems. Microcephaly is probably not a universal feature.
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http://dx.doi.org/10.1055/s-0038-1661396DOI Listing
October 2018

Biallelic Mutations in ATP5F1D, which Encodes a Subunit of ATP Synthase, Cause a Metabolic Disorder.

Am J Hum Genet 2018 03 22;102(3):494-504. Epub 2018 Feb 22.

Center for Undiagnosed Diseases, Stanford University, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. Electronic address:

ATP synthase, H transporting, mitochondrial F1 complex, δ subunit (ATP5F1D; formerly ATP5D) is a subunit of mitochondrial ATP synthase and plays an important role in coupling proton translocation and ATP production. Here, we describe two individuals, each with homozygous missense variants in ATP5F1D, who presented with episodic lethargy, metabolic acidosis, 3-methylglutaconic aciduria, and hyperammonemia. Subject 1, homozygous for c.245C>T (p.Pro82Leu), presented with recurrent metabolic decompensation starting in the neonatal period, and subject 2, homozygous for c.317T>G (p.Val106Gly), presented with acute encephalopathy in childhood. Cultured skin fibroblasts from these individuals exhibited impaired assembly of FF ATP synthase and subsequent reduced complex V activity. Cells from subject 1 also exhibited a significant decrease in mitochondrial cristae. Knockdown of Drosophila ATPsynδ, the ATP5F1D homolog, in developing eyes and brains caused a near complete loss of the fly head, a phenotype that was fully rescued by wild-type human ATP5F1D. In contrast, expression of the ATP5F1D c.245C>T and c.317T>G variants rescued the head-size phenotype but recapitulated the eye and antennae defects seen in other genetic models of mitochondrial oxidative phosphorylation deficiency. Our data establish c.245C>T (p.Pro82Leu) and c.317T>G (p.Val106Gly) in ATP5F1D as pathogenic variants leading to a Mendelian mitochondrial disease featuring episodic metabolic decompensation.
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http://dx.doi.org/10.1016/j.ajhg.2018.01.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6117612PMC
March 2018

NDUFB8 Mutations Cause Mitochondrial Complex I Deficiency in Individuals with Leigh-like Encephalomyopathy.

Am J Hum Genet 2018 03 8;102(3):460-467. Epub 2018 Feb 8.

Department of Pediatrics, Salzburger Landeskliniken and Paracelsus Medical University Salzburg, 5020 Salzburg, Austria. Electronic address:

Respiratory chain complex I deficiency is the most frequently identified biochemical defect in childhood mitochondrial diseases. Clinical symptoms range from fatal infantile lactic acidosis to Leigh syndrome and other encephalomyopathies or cardiomyopathies. To date, disease-causing variants in genes coding for 27 complex I subunits, including 7 mitochondrial DNA genes, and in 11 genes encoding complex I assembly factors have been reported. Here, we describe rare biallelic variants in NDUFB8 encoding a complex I accessory subunit revealed by whole-exome sequencing in two individuals from two families. Both presented with a progressive course of disease with encephalo(cardio)myopathic features including muscular hypotonia, cardiac hypertrophy, respiratory failure, failure to thrive, and developmental delay. Blood lactate was elevated. Neuroimaging disclosed progressive changes in the basal ganglia and either brain stem or internal capsule. Biochemical analyses showed an isolated decrease in complex I enzymatic activity in muscle and fibroblasts. Complementation studies by expression of wild-type NDUFB8 in cells from affected individuals restored mitochondrial function, confirming NDUFB8 variants as the cause of complex I deficiency. Hereby we establish NDUFB8 as a relevant gene in childhood-onset mitochondrial disease.
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http://dx.doi.org/10.1016/j.ajhg.2018.01.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5985356PMC
March 2018

Melanoma tumors exhibit a variable but distinct metabolic signature.

Exp Dermatol 2018 02 10;27(2):204-207. Epub 2018 Jan 10.

Laboratory for Pathology Weger, Emberger, Salzburg, Austria.

The Warburg theory of cancer postulates that an important driver of tumorigenesis is insufficient respiration due to mitochondrial defects, and concomitant enhancement of lactate production due to increased aerobic glycolysis. We analysed 48 melanoma samples by immunohistochemistry and found that 38% of melanomas are characterized by areas of isolated or combined deficiencies of complexes of the oxidative phosphorylation (OXPHOS) system, whereby the incidence of OXPHOS-deficient areas is associated with an increased Breslow index; 62% of melanomas showed high expression of all OXPHOS complexes. Expression of carbonic anhydrase IX was low, indicating that melanomas generally are well-oxygenated. Expression of HIF-1α and MCT4 was high, which might be a consequence of increased lactate dehydrogenase A levels in melanomas. Our data indicate that there are two types of melanomas: one that features a classic Warburg effect, whereas the other one, despite being glycolytic, maintains a high level of OXPHOS complexes.
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http://dx.doi.org/10.1111/exd.13465DOI Listing
February 2018

Biallelic C1QBP Mutations Cause Severe Neonatal-, Childhood-, or Later-Onset Cardiomyopathy Associated with Combined Respiratory-Chain Deficiencies.

Am J Hum Genet 2017 Oct 21;101(4):525-538. Epub 2017 Sep 21.

Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany. Electronic address:

Complement component 1 Q subcomponent-binding protein (C1QBP; also known as p32) is a multi-compartmental protein whose precise function remains unknown. It is an evolutionary conserved multifunctional protein localized primarily in the mitochondrial matrix and has roles in inflammation and infection processes, mitochondrial ribosome biogenesis, and regulation of apoptosis and nuclear transcription. It has an N-terminal mitochondrial targeting peptide that is proteolytically processed after import into the mitochondrial matrix, where it forms a homotrimeric complex organized in a doughnut-shaped structure. Although C1QBP has been reported to exert pleiotropic effects on many cellular processes, we report here four individuals from unrelated families where biallelic mutations in C1QBP cause a defect in mitochondrial energy metabolism. Infants presented with cardiomyopathy accompanied by multisystemic involvement (liver, kidney, and brain), and children and adults presented with myopathy and progressive external ophthalmoplegia. Multiple mitochondrial respiratory-chain defects, associated with the accumulation of multiple deletions of mitochondrial DNA in the later-onset myopathic cases, were identified in all affected individuals. Steady-state C1QBP levels were decreased in all individuals' samples, leading to combined respiratory-chain enzyme deficiency of complexes I, III, and IV. C1qbp mouse embryonic fibroblasts (MEFs) resembled the human disease phenotype by showing multiple defects in oxidative phosphorylation (OXPHOS). Complementation with wild-type, but not mutagenized, C1qbp restored OXPHOS protein levels and mitochondrial enzyme activities in C1qbp MEFs. C1QBP deficiency represents an important mitochondrial disorder associated with a clinical spectrum ranging from infantile lactic acidosis to childhood (cardio)myopathy and late-onset progressive external ophthalmoplegia.
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http://dx.doi.org/10.1016/j.ajhg.2017.08.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5630164PMC
October 2017

Biallelic variants in WARS2 encoding mitochondrial tryptophanyl-tRNA synthase in six individuals with mitochondrial encephalopathy.

Hum Mutat 2017 12 6;38(12):1786-1795. Epub 2017 Oct 6.

Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.

Mitochondrial protein synthesis involves an intricate interplay between mitochondrial DNA encoded RNAs and nuclear DNA encoded proteins, such as ribosomal proteins and aminoacyl-tRNA synthases. Eukaryotic cells contain 17 mitochondria-specific aminoacyl-tRNA synthases. WARS2 encodes mitochondrial tryptophanyl-tRNA synthase (mtTrpRS), a homodimeric class Ic enzyme (mitochondrial tryptophan-tRNA ligase; EC 6.1.1.2). Here, we report six individuals from five families presenting with either severe neonatal onset lactic acidosis, encephalomyopathy and early death or a later onset, more attenuated course of disease with predominating intellectual disability. Respiratory chain enzymes were usually normal in muscle and fibroblasts, while a severe combined respiratory chain deficiency was found in the liver of a severely affected individual. Exome sequencing revealed rare biallelic variants in WARS2 in all affected individuals. An increase of uncharged mitochondrial tRNA and a decrease of mtTrpRS protein content were found in fibroblasts of affected individuals. We hereby define the clinical, neuroradiological, and metabolic phenotype of WARS2 defects. This confidently implicates that mutations in WARS2 cause mitochondrial disease with a broad spectrum of clinical presentation.
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http://dx.doi.org/10.1002/humu.23340DOI Listing
December 2017

Combined Respiratory Chain Deficiency and Mutations in Neonatal Encephalomyopathy: Defective Supercomplex Assembly in Complex III Deficiencies.

Oxid Med Cell Longev 2017 19;2017:7202589. Epub 2017 Jul 19.

Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria.

Vertebrate respiratory chain complex III consists of eleven subunits. Mutations in five subunits either mitochondrial (MT-CYB) or nuclear (CYC1, UQCRC2, UQCRB, and UQCRQ) encoded have been reported. Defects in five further factors for assembly (TTC19, UQCC2, and UQCC3) or iron-sulphur cluster loading (BCS1L and LYRM7) cause complex III deficiency. Here, we report a second patient with UQCC2 deficiency. This girl was born prematurely; pregnancy was complicated by intrauterine growth retardation and oligohydramnios. She presented with respiratory distress syndrome, developed epileptic seizures progressing to status epilepticus, and died at day 33. She had profound lactic acidosis and elevated urinary pyruvate. Exome sequencing revealed two homozygous missense variants in , leading to a severe reduction of UQCC2 protein. Deficiency of complexes I and III was found enzymatically and on the protein level. A review of the literature on genetically distinct complex III defects revealed that, except TTC19 deficiency, the biochemical pattern was very often a combined respiratory chain deficiency. Besides complex III, typically, complex I was decreased, in some cases complex IV. In accordance with previous observations, the presence of assembled complex III is required for the stability or assembly of complexes I and IV, which might be related to respirasome/supercomplex formation.
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http://dx.doi.org/10.1155/2017/7202589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540226PMC
May 2018

Biallelic Mutations in LIPT2 Cause a Mitochondrial Lipoylation Defect Associated with Severe Neonatal Encephalopathy.

Am J Hum Genet 2017 Aug 27;101(2):283-290. Epub 2017 Jul 27.

Reference Center of Inherited Metabolic Diseases, University Paris Descartes, Hospital Necker Enfants Malades, APHP, 75015 Paris, France; UMR1163, University Paris Descartes, Sorbonne Paris Cité, Institut IMAGINE, 24 Boulevard du Montparnasse, 75015 Paris, France. Electronic address:

Lipoate serves as a cofactor for the glycine cleavage system (GCS) and four 2-oxoacid dehydrogenases functioning in energy metabolism (α-oxoglutarate dehydrogenase [α-KGDHc] and pyruvate dehydrogenase [PDHc]), or amino acid metabolism (branched-chain oxoacid dehydrogenase, 2-oxoadipate dehydrogenase). Mitochondrial lipoate synthesis involves three enzymatic steps catalyzed sequentially by lipoyl(octanoyl) transferase 2 (LIPT2), lipoic acid synthetase (LIAS), and lipoyltransferase 1 (LIPT1). Mutations in LIAS have been associated with nonketotic hyperglycinemia-like early-onset convulsions and encephalopathy combined with a defect in mitochondrial energy metabolism. LIPT1 deficiency spares GCS deficiency and has been associated with a biochemical signature of combined 2-oxoacid dehydrogenase deficiency leading to early death or Leigh-like encephalopathy. We report on the identification of biallelic LIPT2 mutations in three affected individuals from two families with severe neonatal encephalopathy. Brain MRI showed major cortical atrophy with white matter abnormalities and cysts. Plasma glycine was mildly increased. Affected individuals' fibroblasts showed reduced oxygen consumption rates, PDHc, α-KGDHc activities, leucine catabolic flux, and decreased protein lipoylation. A normalization of lipoylation was observed after expression of wild-type LIPT2, arguing for LIPT2 requirement in intramitochondrial lipoate synthesis. Lipoic acid supplementation did not improve clinical condition nor activities of PDHc, α-KGDHc, or leucine metabolism in fibroblasts and was ineffective in yeast deleted for the orthologous LIP2.
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http://dx.doi.org/10.1016/j.ajhg.2017.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544388PMC
August 2017

Oxidative Phosphorylation System in Gastric Carcinomas and Gastritis.

Oxid Med Cell Longev 2017 28;2017:1320241. Epub 2017 Jun 28.

Laura-Bassi Centre of Expertise, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, 5020 Salzburg, Austria.

Switching of cellular energy production from oxidative phosphorylation (OXPHOS) by mitochondria to aerobic glycolysis occurs in many types of tumors. However, the significance of this switching for the development of gastric carcinoma and what connection it may have to infection of the gut, a primary cause of gastric cancer, are poorly understood. Therefore, we investigated the expression of OXPHOS complexes in two types of human gastric carcinomas ("intestinal" and "diffuse"), bacterial gastritis with and without metaplasia, and chemically induced gastritis by using immunohistochemistry. Furthermore, we analyzed the effect of HP infection on several key mitochondrial proteins. Complex I expression was significantly reduced in intestinal type (but not diffuse) gastric carcinomas compared to adjacent control tissue, and the reduction was independent of HP infection. Significantly, higher complex I and complex II expression was present in large tumors. Furthermore, higher complex II and complex III protein levels were also obvious in grade 3 versus grade 2. No differences of OXPHOS complexes and markers of mitochondrial biogenesis were found between bacterially caused and chemically induced gastritis. Thus, intestinal gastric carcinomas, but not precancerous stages, are frequently characterized by loss of complex I, and this pathophysiology occurs independently of HP infection.
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http://dx.doi.org/10.1155/2017/1320241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506471PMC
April 2018

LYRM7 - associated complex III deficiency: A clinical, molecular genetic, MR tomographic, and biochemical study.

Mitochondrion 2017 11 8;37:55-61. Epub 2017 Jul 8.

Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

LYRM7 is involved in the last steps of mitochondrial complex III assembly where it acts as a chaperone for the Rieske iron‑sulfur (Fe-S) protein in the mitochondrial matrix. Using exome sequencing, we identified homozygosity for a splice site destroying 4 base pair deletion in LYRM7 in a child with recurrent lactic acidotic crises and distinct early-onset leukencephalopathy. Sanger sequencing showed variant segregation in similarly affected family members. Functional analyses revealed a reduced amount of the Rieske Fe-S protein, which was restored after re-expression of LYRM7. Our data provide further evidence for the importance of LYRM7 for mitochondrial function and emphasize the importance of whole exome sequencing in the diagnosis of rare mitochondrial diseases.
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http://dx.doi.org/10.1016/j.mito.2017.07.001DOI Listing
November 2017