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McLelland GL, Goiran T, Yi W, Dorval G, Chen CX, Lauinger ND, Krahn AI, Valimehr S, Rakovic A, Rouiller I, Durcan TM, Trempe JF, Fon EA. Mfn2 ubiquitination by PINK1/parkin gates the p97-dependent release of ER from mitochondria to drive mitophagy. eLife 2018; 7:32866. [PMID: 29676259 PMCID: PMC5927771 DOI: 10.7554/elife.32866] [Citation(s) in RCA: 243] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/19/2018] [Indexed: 12/23/2022] Open
Abstract
Despite their importance as signaling hubs, the function of mitochondria-ER contact sites in mitochondrial quality control pathways remains unexplored. Here we describe a mechanism by which Mfn2, a mitochondria-ER tether, gates the autophagic turnover of mitochondria by PINK1 and parkin. Mitochondria-ER appositions are destroyed during mitophagy, and reducing mitochondria-ER contacts increases the rate of mitochondrial degradation. Mechanistically, parkin/PINK1 catalyze a rapid burst of Mfn2 phosphoubiquitination to trigger p97-dependent disassembly of Mfn2 complexes from the outer mitochondrial membrane, dissociating mitochondria from the ER. We additionally demonstrate that a major portion of the facilitatory effect of p97 on mitophagy is epistatic to Mfn2 and promotes the availability of other parkin substrates such as VDAC1. Finally, we reconstitute the action of these factors on Mfn2 and VDAC1 ubiquitination in a cell-free assay. We show that mitochondria-ER tethering suppresses mitophagy and describe a parkin-/PINK1-dependent mechanism that regulates the destruction of mitochondria-ER contact sites.
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Prasuhn J, Mårtensson CU, Krajka V, Klein C, Rakovic A. Genome-Edited, TH-expressing Neuroblastoma Cells as a Disease Model for Dopamine-Related Disorders: A Proof-of-Concept Study on DJ-1-deficient Parkinsonism. Front Cell Neurosci 2018; 11:426. [PMID: 29379417 PMCID: PMC5770810 DOI: 10.3389/fncel.2017.00426] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 12/19/2017] [Indexed: 11/13/2022] Open
Abstract
Impairment of the dopaminergic (DA) system is a common cause of several movement disorders including Parkinson's disease (PD), however, little is known about the underlying disease mechanisms. The recent development of stem-cell-based protocols for the generation of DA neurons partially solved this issue, however, this technology is costly and time-consuming. Commonly used cell lines, i.e., neuroblastoma (SHSY5Y) and PC12 cells are still widely used to investigate PD and significantly contributed to our understanding of mechanisms involved in development of the disease. However, they either do not express DA at all or require additional, only partially efficient differentiations in order to produce DA. Here we generated and characterized transgenic SH-SY5Y cells, ectopically expressing tyrosine hydroxylase (SHTH+), that can be used as a homogenous, DA-producing model to study alterations in DA metabolism and oxidative stress. We demonstrated that SHTH+ produce high levels of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) making this model suitable to investigate not only alterations in DA synthesis but also its turnover. We also provide evidence for the presence of other enzymes involved in DA synthesis and its turnover in these cells. Finally, we showed that these cells can easily be genetically modified using CRISPR/Cas9 technology in order to study genetically defined forms of movement disorders using DJ1-linked PD as a model.
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Zanon A, Kalvakuri S, Rakovic A, Foco L, Guida M, Schwienbacher C, Serafin A, Rudolph F, Trilck M, Grünewald A, Stanslowsky N, Wegner F, Giorgio V, Lavdas AA, Bodmer R, Pramstaller PP, Klein C, Hicks AA, Pichler I, Seibler P. SLP-2 interacts with Parkin in mitochondria and prevents mitochondrial dysfunction in Parkin-deficient human iPSC-derived neurons and Drosophila. Hum Mol Genet 2017; 26:2412-2425. [PMID: 28379402 DOI: 10.1093/hmg/ddx132] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/16/2017] [Indexed: 12/26/2022] Open
Abstract
Mutations in the Parkin gene (PARK2) have been linked to a recessive form of Parkinson's disease (PD) characterized by the loss of dopaminergic neurons in the substantia nigra. Deficiencies of mitochondrial respiratory chain complex I activity have been observed in the substantia nigra of PD patients, and loss of Parkin results in the reduction of complex I activity shown in various cell and animal models. Using co-immunoprecipitation and proximity ligation assays on endogenous proteins, we demonstrate that Parkin interacts with mitochondrial Stomatin-like protein 2 (SLP-2), which also binds the mitochondrial lipid cardiolipin and functions in the assembly of respiratory chain proteins. SH-SY5Y cells with a stable knockdown of Parkin or SLP-2, as well as induced pluripotent stem cell-derived neurons from Parkin mutation carriers, showed decreased complex I activity and altered mitochondrial network morphology. Importantly, induced expression of SLP-2 corrected for these mitochondrial alterations caused by reduced Parkin function in these cells. In-vivo Drosophila studies showed a genetic interaction of Parkin and SLP-2, and further, tissue-specific or global overexpression of SLP-2 transgenes rescued parkin mutant phenotypes, in particular loss of dopaminergic neurons, mitochondrial network structure, reduced ATP production, and flight and motor dysfunction. The physical and genetic interaction between Parkin and SLP-2 and the compensatory potential of SLP-2 suggest a functional epistatic relationship to Parkin and a protective role of SLP-2 in neurons. This finding places further emphasis on the significance of Parkin for the maintenance of mitochondrial function in neurons and provides a novel target for therapeutic strategies.
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Hebert E, Borngräber F, Schmidt A, Rakovic A, Brænne I, Weissbach A, Hampf J, Vollstedt EJ, Größer L, Schaake S, Müller M, Manzoor H, Jabusch HC, Alvarez-Fischer D, Kasten M, Kostic VS, Gasser T, Zeuner KE, Kim HJ, Jeon B, Bauer P, Altenmüller E, Klein C, Lohmann K. Functional Characterization of Rare RAB12 Variants and Their Role in Musician's and Other Dystonias. Genes (Basel) 2017; 8:genes8100276. [PMID: 29057844 PMCID: PMC5664126 DOI: 10.3390/genes8100276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 01/07/2023] Open
Abstract
Mutations in RAB (member of the Ras superfamily) genes are increasingly recognized as cause of a variety of disorders including neurological conditions. While musician’s dystonia (MD) and writer’s dystonia (WD) are task-specific movement disorders, other dystonias persistently affect postures as in cervical dystonia. Little is known about the underlying etiology. Next-generation sequencing revealed a rare missense variant (c.586A>G; p.Ile196Val) in RAB12 in two of three MD/WD families. Next, we tested 916 additional dystonia patients; 512 Parkinson’s disease patients; and 461 healthy controls for RAB12 variants and identified 10 additional carriers of rare missense changes among dystonia patients (1.1%) but only one carrier in non-dystonic individuals (0.1%; p = 0.005). The detected variants among index patients comprised p.Ile196Val (n = 6); p.Ala174Thr (n = 3); p.Gly13Asp; p.Ala148Thr; and p.Arg181Gln in patients with MD; cervical dystonia; or WD. Two relatives of MD patients with WD also carried p.Ile196Val. The two variants identified in MD patients (p.Ile196Val; p.Gly13Asp) were characterized on endogenous levels in patient-derived fibroblasts and in two RAB12-overexpressing cell models. The ability to hydrolyze guanosine triphosphate (GTP), so called GTPase activity, was increased in mutants compared to wildtype. Furthermore, subcellular distribution of RAB12 in mutants was altered in fibroblasts. Soluble Transferrin receptor 1 levels were reduced in the blood of all three tested p.Ile196Val carriers. In conclusion, we demonstrate an enrichment of missense changes among dystonia patients. Functional characterization revealed altered enzyme activity and lysosomal distribution in mutants suggesting a contribution of RAB12 variants to MD and other dystonias.
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Lohmann K, Redin C, Tönnies H, Bressman SB, Subero JIM, Wiegers K, Hinrichs F, Hellenbroich Y, Rakovic A, Raymond D, Ozelius LJ, Schwinger E, Siebert R, Talkowski ME, Saunders-Pullman R, Klein C. Complex and Dynamic Chromosomal Rearrangements in a Family With Seemingly Non-Mendelian Inheritance of Dopa-Responsive Dystonia. JAMA Neurol 2017; 74:806-812. [PMID: 28558098 DOI: 10.1001/jamaneurol.2017.0666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Importance Chromosomal rearrangements are increasingly recognized to underlie neurologic disorders and are often accompanied by additional clinical signs beyond the gene-specific phenotypic spectrum. Objective To elucidate the causal genetic variant in a large US family with co-occurrence of dopa-responsive dystonia as well as skeletal and eye abnormalities (ie, ptosis, myopia, and retina detachment). Design, Setting, and Participants We examined 10 members of a family, including 5 patients with dopa-responsive dystonia and skeletal and/or eye abnormalities, from a US tertiary referral center for neurological diseases using multiple conventional molecular methods, including fluorescence in situ hybridization and array comparative genomic hybridization as well as large-insert whole-genome sequencing to survey multiple classes of genomic variations. Of note, there was a seemingly implausible transmission pattern in this family due to a mutation-negative obligate mutation carrier. Main Outcomes and Measures Genetic diagnosis in affected family members and insight into the formation of large deletions. Results Four members were diagnosed with definite and 1 with probable dopa-responsive dystonia. All 5 affected individuals carried a large heterozygous deletion encompassing all 6 exons of GCH1. Additionally, all mutation carriers had congenital ptosis requiring surgery, 4 had myopia, 2 had retinal detachment, and 2 showed skeletal abnormalities of the hands, ie, polydactyly or syndactyly or missing a hand digit. Two individuals were reported to be free of any disease. Analyses revealed complex chromosomal rearrangements on chromosome 14q21-22 in unaffected individuals that triggered the expansion to a larger deletion segregating with affection status. The expansion occurred recurrently, explaining the seemingly non-mendelian inheritance pattern. These rearrangements included a deletion of GCH1, which likely contributes to the dopa-responsive dystonia, as well as a deletion of BMP4 as a potential cause of digital and eye abnormalities. Conclusions and Relevance Our findings alert neurologists to the importance of clinical red flags, ie, unexpected co-occurrence of clinical features that may point to the presence of chromosomal rearrangements as the primary disease cause. The clinical management and diagnostics of such patients requires an interdisciplinary approach in modern clinical-diagnostic care.
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Vulinovic F, Schaake S, Domingo A, Kumar KR, Defazio G, Mir P, Simonyan K, Ozelius LJ, Brüggemann N, Chung SJ, Rakovic A, Lohmann K, Klein C. Screening study of TUBB4A in isolated dystonia. Parkinsonism Relat Disord 2017; 41:118-120. [PMID: 28655586 DOI: 10.1016/j.parkreldis.2017.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/01/2017] [Accepted: 06/09/2017] [Indexed: 01/25/2023]
Abstract
Mutations in TUBB4A have been identified to cause a wide phenotypic spectrum ranging from hereditary generalized dystonia with whispering dysphonia (DYT4) to the leukodystrophy hypomyelination syndrome with atrophy of the basal ganglia and cerebellum (H-ABC). To test for the contribution of TUBB4A mutations in different ethnicities (Spanish, Italian, Korean, Japanese), we screened 492 isolated dystonia cases for mutations in this gene and for the first time determined TUBB4A copy number variations in 336 dystonia patients. A potentially pathogenic rare 3bp-in-frame deletion was found in a patient with cervical dystonia but no copy number variations were detected in this study, suggesting that TUBB4A mutations exceedingly rarely contribute to the etiology of isolated dystonia.
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Vos M, Geens A, Böhm C, Deaulmerie L, Swerts J, Rossi M, Craessaerts K, Leites EP, Seibler P, Rakovic A, Lohnau T, De Strooper B, Fendt SM, Morais VA, Klein C, Verstreken P. Cardiolipin promotes electron transport between ubiquinone and complex I to rescue PINK1 deficiency. J Cell Biol 2017; 216:695-708. [PMID: 28137779 PMCID: PMC5346965 DOI: 10.1083/jcb.201511044] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 11/25/2016] [Accepted: 01/05/2017] [Indexed: 02/08/2023] Open
Abstract
Parkinson’s disease–causing mutations in PINK1 yield mitochondrial defects including inefficient electron transport between complex I and ubiquinone. Vos et al. show that genetic and pharmacological inhibition of fatty acid synthase bypass these complex I defects in fly, mouse, and human Parkinson’s disease models. PINK1 is mutated in Parkinson’s disease (PD), and mutations cause mitochondrial defects that include inefficient electron transport between complex I and ubiquinone. Neurodegeneration is also connected to changes in lipid homeostasis, but how these are related to PINK1-induced mitochondrial dysfunction is unknown. Based on an unbiased genetic screen, we found that partial genetic and pharmacological inhibition of fatty acid synthase (FASN) suppresses toxicity induced by PINK1 deficiency in flies, mouse cells, patient-derived fibroblasts, and induced pluripotent stem cell–derived dopaminergic neurons. Lower FASN activity in PINK1 mutants decreases palmitate levels and increases the levels of cardiolipin (CL), a mitochondrial inner membrane–specific lipid. Direct supplementation of CL to isolated mitochondria not only rescues the PINK1-induced complex I defects but also rescues the inefficient electron transfer between complex I and ubiquinone in specific mutants. Our data indicate that genetic or pharmacologic inhibition of FASN to increase CL levels bypasses the enzymatic defects at complex I in a PD model.
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Wortmann SB, Ziętkiewicz S, Kousi M, Szklarczyk R, Haack TB, Gersting SW, Muntau AC, Rakovic A, Renkema GH, Rodenburg RJ, Strom TM, Meitinger T, Rubio-Gozalbo ME, Chrusciel E, Distelmaier F, Golzio C, Jansen JH, van Karnebeek C, Lillquist Y, Lücke T, Õunap K, Zordania R, Yaplito-Lee J, van Bokhoven H, Spelbrink JN, Vaz FM, Pras-Raves M, Ploski R, Pronicka E, Klein C, Willemsen MAAP, de Brouwer APM, Prokisch H, Katsanis N, Wevers RA. CLPB mutations cause 3-methylglutaconic aciduria, progressive brain atrophy, intellectual disability, congenital neutropenia, cataracts, movement disorder. Am J Hum Genet 2015; 96:245-57. [PMID: 25597510 DOI: 10.1016/j.ajhg.2014.12.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 12/10/2014] [Indexed: 01/04/2023] Open
Abstract
We studied a group of individuals with elevated urinary excretion of 3-methylglutaconic acid, neutropenia that can develop into leukemia, a neurological phenotype ranging from nonprogressive intellectual disability to a prenatal encephalopathy with progressive brain atrophy, movement disorder, cataracts, and early death. Exome sequencing of two unrelated individuals and subsequent Sanger sequencing of 16 individuals with an overlapping phenotype identified a total of 14 rare, predicted deleterious alleles in CLPB in 14 individuals from 9 unrelated families. CLPB encodes caseinolytic peptidase B homolog ClpB, a member of the AAA+ protein family. To evaluate the relevance of CLPB in the pathogenesis of this syndrome, we developed a zebrafish model and an in vitro assay to measure ATPase activity. Suppression of clpb in zebrafish embryos induced a central nervous system phenotype that was consistent with cerebellar and cerebral atrophy that could be rescued by wild-type, but not mutant, human CLPB mRNA. Consistent with these data, the loss-of-function effect of one of the identified variants (c.1222A>G [p.Arg408Gly]) was supported further by in vitro evidence with the mutant peptides abolishing ATPase function. Additionally, we show that CLPB interacts biochemically with ATP2A2, known to be involved in apoptotic processes in severe congenital neutropenia (SCN) 3 (Kostmann disease [caused by HAX1 mutations]). Taken together, mutations in CLPB define a syndrome with intellectual disability, congenital neutropenia, progressive brain atrophy, movement disorder, cataracts, and 3-methylglutaconic aciduria.
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Kumar KR, Weyers S, Wilcox RA, Park JS, Rakovic A, Klein C, Mackay-Sim A, Sue CM. 3. J Clin Neurosci 2014. [DOI: 10.1016/j.jocn.2014.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Erogullari A, Hollstein R, Seibler P, Braunholz D, Koschmidder E, Depping R, Eckhold J, Lohnau T, Gillessen-Kaesbach G, Grünewald A, Rakovic A, Lohmann K, Kaiser FJ. THAP1, the gene mutated in DYT6 dystonia, autoregulates its own expression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1196-204. [PMID: 25088175 DOI: 10.1016/j.bbagrm.2014.07.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 02/07/2023]
Abstract
THAP1 encodes a transcription factor but its regulation is largely elusive. TOR1A was shown to be repressed by THAP1 in vitro. Notably, mutations in both of these genes lead to dystonia (DYT6 or DYT1). Surprisingly, expressional changes of TOR1A in THAP1 mutation carriers have not been detected indicating additional levels of regulation. Here, we investigated whether THAP1 is able to autoregulate its own expression. Using in-silico prediction, luciferase reporter gene assays, and (quantitative) chromatin immunoprecipitation (ChIP), we defined the THAP1 minimal promoter to a 480bp-fragment and demonstrated specific binding of THAP1 to this region which resulted in repression of the THAP1 promoter. This autoregulation was disturbed by different DYT6-causing mutations. Two mutants (Ser6Phe, Arg13His) were shown to be less stable than wildtype THAP1 adding to the effect of reduced binding to the THAP1 promoter. Overexpressed THAP1 is preferably degraded through the proteasome. Notably, endogenous THAP1 expression was significantly reduced in cells overexpressing wildtype THAP1 as demonstrated by quantitative PCR. In contrast, higher THAP1 levels were detected in induced pluripotent stem cell (iPS)-derived neurons from THAP1 mutation carriers. Thus, we identified a feedback-loop in the regulation of THAP1 expression and demonstrated that mutant THAP1 leads to higher THAP1 expression levels. This compensatory autoregulation may contribute to the mean age at onset in the late teen years or even reduced penetrance in some THAP1 mutation carriers.
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Vulinovic F, Lohmann K, Rakovic A, Capetian P, Alvarez-Fischer D, Schmidt A, Weißbach A, Erogullari A, Kaiser FJ, Wiegers K, Ferbert A, Rolfs A, Klein C, Seibler P. Unraveling cellular phenotypes of novel TorsinA/TOR1A mutations. Hum Mutat 2014; 35:1114-22. [PMID: 24931141 DOI: 10.1002/humu.22604] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/04/2014] [Indexed: 01/17/2023]
Abstract
A three-nucleotide (GAG) deletion (ΔE) in TorsinA (TOR1A) has been identified as the most common cause of dominantly inherited early-onset torsion dystonia (DYT1). TOR1A encodes a chaperone-like AAA+-protein localized in the endoplasmic reticulum. Currently, only three additional, likely mutations have been reported in single dystonia patients. Here, we report two new, putative TOR1A mutations (p.A14_P15del and p.E121K) that we examined functionally in comparison with wild-type (WT) protein and two known mutations (ΔE and p.R288Q). While inclusion formation is a characteristic feature for ΔE TOR1A, elevated levels of aggregates for other mutations were not observed when compared with WT TOR1A. WT and mutant TOR1A showed preferred degradation through the autophagy-lysosome pathway, which is most pronounced for p.A14_P15del, p.R288Q, and ΔE TOR1A. Notably, blocking of the autophagy pathway with bafilomycin resulted in a significant increase in inclusion formation in p.E121K TOR1A. In addition, all variants had an influence on protein stability. Although the p.A14_P15del mutation affects the proposed oligomerization domain of TOR1A, this mutation did not disturb the ability to dimerize. Our findings demonstrate functional changes for all four mutations on different levels. Thus, both diagnostic and research genetic screening of dystonia patients should not be limited to testing for the ∆E mutation.
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Jandric S, Rakovic A, Stijepic I. Handball and angular knee deformities in schoolgirls. Ann Phys Rehabil Med 2014. [DOI: 10.1016/j.rehab.2014.03.729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Deuse T, Hua X, Wang D, Maegdefessel L, Heeren J, Scheja L, Bolaños JP, Rakovic A, Spin JM, Stubbendorff M, Ikeno F, Länger F, Zeller T, Schulte-Uentrop L, Stoehr A, Itagaki R, Haddad F, Eschenhagen T, Blankenberg S, Kiefmann R, Reichenspurner H, Velden J, Klein C, Yeung A, Robbins RC, Tsao PS, Schrepfer S. Dichloroacetate prevents restenosis in preclinical animal models of vessel injury. Nature 2014; 509:641-4. [PMID: 24747400 DOI: 10.1038/nature13232] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 03/06/2014] [Indexed: 11/09/2022]
Abstract
Despite the introduction of antiproliferative drug-eluting stents, coronary heart disease remains the leading cause of death in the United States. In-stent restenosis and bypass graft failure are characterized by excessive smooth muscle cell (SMC) proliferation and concomitant myointima formation with luminal obliteration. Here we show that during the development of myointimal hyperplasia in human arteries, SMCs show hyperpolarization of their mitochondrial membrane potential (ΔΨm) and acquire a temporary state with a high proliferative rate and resistance to apoptosis. Pyruvate dehydrogenase kinase isoform 2 (PDK2) was identified as a key regulatory protein, and its activation proved necessary for relevant myointima formation. Pharmacologic PDK2 blockade with dichloroacetate or lentiviral PDK2 knockdown prevented ΔΨm hyperpolarization, facilitated apoptosis and reduced myointima formation in injured human mammary and coronary arteries, rat aortas, rabbit iliac arteries and swine (pig) coronary arteries. In contrast to several commonly used antiproliferative drugs, dichloroacetate did not prevent vessel re-endothelialization. Targeting myointimal ΔΨm and alleviating apoptosis resistance is a novel strategy for the prevention of proliferative vascular diseases.
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Lohmann K, Wilcox RA, Winkler S, Ramirez A, Rakovic A, Park JS, Arns B, Lohnau T, Groen J, Kasten M, Brüggemann N, Hagenah J, Schmidt A, Kaiser FJ, Kumar KR, Zschiedrich K, Alvarez-Fischer D, Altenmüller E, Ferbert A, Lang AE, Münchau A, Kostic V, Simonyan K, Agzarian M, Ozelius LJ, Langeveld APM, Sue CM, Tijssen MAJ, Klein C. Whispering dysphonia (DYT4 dystonia) is caused by a mutation in the TUBB4 gene. Ann Neurol 2013; 73:537-45. [PMID: 23595291 DOI: 10.1002/ana.23829] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/13/2012] [Accepted: 11/30/2012] [Indexed: 12/19/2022]
Abstract
OBJECTIVE A study was undertaken to identify the gene underlying DYT4 dystonia, a dominantly inherited form of spasmodic dysphonia combined with other focal or generalized dystonia and a characteristic facies and body habitus, in an Australian family. METHODS Genome-wide linkage analysis was carried out in 14 family members followed by genome sequencing in 2 individuals. The index patient underwent a detailed neurological follow-up examination, including electrophysiological studies and magnetic resonance imaging scanning. Biopsies of the skin and olfactory mucosa were obtained, and expression levels of TUBB4 mRNA were determined by quantitative real-time polymerase chain reaction in 3 different cell types. All exons of TUBB4 were screened for mutations in 394 unrelated dystonia patients. RESULTS The disease-causing gene was mapped to a 23cM region on chromosome 19p13.3-p13.2 with a maximum multipoint LOD score of 5.338 at markers D9S427 and D9S1034. Genome sequencing revealed a missense variant in the TUBB4 (tubulin beta-4; Arg2Gly) gene as the likely cause of disease. Sequencing of TUBB4 in 394 unrelated dystonia patients revealed another missense variant (Ala271Thr) in a familial case of segmental dystonia with spasmodic dysphonia. mRNA expression studies demonstrated significantly reduced levels of mutant TUBB4 mRNA in different cell types from a heterozygous Arg2Gly mutation carrier compared to controls. INTERPRETATION A mutation in TUBB4 causes DYT4 dystonia in this Australian family with so-called whispering dysphonia, and other mutations in TUBB4 may contribute to spasmodic dysphonia. Given that TUBB4 is a neuronally expressed tubulin, our results imply abnormal microtubule function as a novel mechanism in the pathophysiology of dystonia.
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Rakovic A, Shurkewitsch K, Seibler P, Grünewald A, Zanon A, Hagenah J, Krainc D, Klein C. Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1)-dependent ubiquitination of endogenous Parkin attenuates mitophagy: study in human primary fibroblasts and induced pluripotent stem cell-derived neurons. J Biol Chem 2012; 288:2223-37. [PMID: 23212910 DOI: 10.1074/jbc.m112.391680] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mutations in the E3 ubiquitin ligase Parkin and the mitochondrial PTEN-induced putative kinase 1 (PINK1) have been identified to cause autosomal recessive forms of familial Parkinson disease, with PINK1 functioning upstream of Parkin in a pathway important for the maintenance of mitochondrial function and morphology. Upon the loss of the mitochondrial membrane potential, Parkin translocates to mitochondria in a PINK1-dependent manner to ubiquitinate mitochondrial proteins. Parkin-mediated polyubiquitination of outer mitochondrial membrane (OMM) proteins recruits the ubiquitin- and LC3-binding adaptor protein p62 to mitochondria and induces mitophagy. Although previous studies examined mitophagy in established cell lines through overexpression approaches, there is an imperative to study the role of endogenous Parkin and PINK1 in human-derived and biologically relevant cell models. Here, we demonstrate in human primary fibroblasts and induced pluripotent stem-derived neurons from controls and PINK1 mutation carriers that endogenous levels of Parkin are not sufficient to initiate mitophagy upon loss of the mitochondrial membrane potential, caused by its (self-)ubiquitination, followed by degradation via the ubiquitin proteasome system. Next, we showed differential PINK1-dependent, Parkin-mediated ubiquitination of OMM proteins, which is Parkin dose-dependent and affects primarily OMM proteins of higher molecular mass. In contrast to the situation fibroblasts, we did not detect mitophagy in induced pluripotent stem-derived neurons even upon overexpression of Parkin. Taken together, our data demonstrate that mitophagy differs between human non-neuronal and neuronal cells and between "endogenous" and "Parkin-overexpressing" cellular models.
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Deuse T, Hua X, Länger F, Gossler T, Stubbendorff M, Rakovic A, Klein C, Sutendra G, Dromparis P, Maegdefessel L, Tsao P, Velden J, Reichenspurner H, Robbins R, Haddad F, Michelakis E, Schrepfer S. 356 Pyruvate Dehydrogenase Kinase 2 Controls Vascular Remodeling. J Heart Lung Transplant 2012. [DOI: 10.1016/j.healun.2012.01.365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Deuse T, Hua X, Laenger F, Gossler T, Stubbendorff M, Rakovic A, Klein C, Sutendra G, Dromparis P, Maegdefessel L, Tsao PS, Velden J, Reichenspurner H, Robbins RC, Haddad F, Michelakis E, Schrepfer S. Pyruvate dehydrogenase kinase 2 controls the development of intimal hyperplasia. Thorac Cardiovasc Surg 2012. [DOI: 10.1055/s-0031-1297433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Grünewald A, Arns B, Seibler P, Rakovic A, Münchau A, Ramirez A, Sue CM, Klein C. ATP13A2 mutations impair mitochondrial function in fibroblasts from patients with Kufor-Rakeb syndrome. Neurobiol Aging 2012; 33:1843.e1-7. [PMID: 22296644 DOI: 10.1016/j.neurobiolaging.2011.12.035] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 12/13/2011] [Accepted: 12/28/2011] [Indexed: 11/29/2022]
Abstract
Mutations in ATP13A2 cause autosomal-recessive parkinsonism (Kufor-Rakeb syndrome; KRS). Because several other parkinsonism-associated proteins have been connected to mitochondrial function and mitophagy, we studied the impact of endogenous mutations in ATPase type 13A2 (ATP13A2) on mitochondria in fibroblasts from KRS patients compared with controls. In patients, we detected decreased adenosine triphosphate (ATP) synthesis rates, increased mitochondrial DNA levels, a higher frequency of mitochondrial DNA lesions, increased oxygen consumption rates, and increased fragmentation of the mitochondrial network. Importantly, overexpression of wild-type ATP13A2 rescued the respiration phenotype. These findings collectively suggest that ATP13A2 contributes to the maintenance of a healthy mitochondrial pool, supporting the hypothesis that impaired mitochondrial clearance represents an important pathogenic mechanism underlying KRS.
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Radovanovic D, Ponorac N, Ignjatovic A, Stojiljkovic N, Popovic T, Rakovic A. Specific alterations of physiological parameters in competitive race walkers. ACTA PHYSIOLOGICA HUNGARICA 2011; 98:449-455. [PMID: 22173026 DOI: 10.1556/aphysiol.98.2011.4.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Race walking is the technical and athletic expression of fast walking and it can be considered as a type of endurance performance. The purpose of this study was to examine whether 12 weeks of a specially designed training program results in the further training enhancement of endurance performance and the related physiological parameters in already well-trained race walkers competing at the national and international level. The investigation protocol consisted of determining the maximal oxygen uptake (VO2peak) and related gas exchange values using an automated cardiopulmonary exercise system and of determining blood lactate variables (aerobic threshold - LTAer and the maximal lactate steady state - MLSS) during walking with proper technique at 8, 10, 12 and 14 km·h-1 for 4 minutes without rest in between. Thereafter, the speed on the treadmill was increased by 0.5 km·h-1 every two minutes until exhaustion to determine VO2peak. After 12 weeks of a specially designed endurance training, statistically significant increases in VO2peak (61.8±8.5 mL·kg-1·min-1 pre vs. 66.9±9.5 mL·kg-1·min-1 post training; p<0.05) and blood lactate variables (VO2-LTAer and VO2-MLSS; p<0.05) were noted. The obtained results suggest that the applied training program can improve endurance and race performance in previously well trained race walkers.
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Osmanovic A, Dendorfer A, Erogullari A, Uflacker N, Braunholz D, Rakovic A, Vierke G, Gil-Rodríguez C, Münchau A, Albrecht M, Brüggemann N, Gillessen-Kaesbach G, Klein C, Lohmann K, Kaiser FJ. Truncating mutations in THAP1 define the nuclear localization signal. Mov Disord 2011; 26:1565-7. [PMID: 21495072 DOI: 10.1002/mds.23611] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 10/26/2010] [Accepted: 11/29/2010] [Indexed: 11/10/2022] Open
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Rakovic A, Grünewald A, Voges L, Hofmann S, Orolicki S, Lohmann K, Klein C. PINK1-Interacting Proteins: Proteomic Analysis of Overexpressed PINK1. PARKINSONS DISEASE 2011; 2011:153979. [PMID: 21437181 PMCID: PMC3062077 DOI: 10.4061/2011/153979] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 12/22/2010] [Indexed: 11/20/2022]
Abstract
Recent publications suggest that the Parkinson's disease- (PD-) related PINK1/Parkin pathway promotes elimination of dysfunctional mitochondria by autophagy. We used tandem affinity purification (TAP), SDS-PAGE, and mass spectrometry as a first step towards identification of possible substrates for PINK1. The cellular abundance of selected identified interactors was investigated by Western blotting. Furthermore, one candidate gene was sequenced in 46 patients with atypical PD. In addition to two known binding partners (HSP90, CDC37), 12 proteins were identified using the TAP assay; four of which are mitochondrially localized (GRP75, HSP60, LRPPRC, and TUFM). Western blot analysis showed no differences in cellular abundance of these proteins comparing PINK1 mutant and control fibroblasts. When sequencing LRPPRC, four exonic synonymous changes and 20 polymorphisms in noncoding regions were detected. Our study provides a list of putative PINK1 binding partners, confirming previously described interactions, but also introducing novel mitochondrial proteins as potential components of the PINK1/Parkin mitophagy pathway.
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Kaiser FJ, Osmanoric A, Rakovic A, Erogullari A, Uflacker N, Braunholz D, Lohnau T, Orolicki S, Albrecht M, Gillessen-Kaesbach G, Klein C, Lohmann K. The dystonia gene DYT1 is repressed by the transcription factor THAP1 (DYT6). Ann Neurol 2010; 68:554-9. [DOI: 10.1002/ana.22157] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Grünewald A, Voges L, Rakovic A, Kasten M, Vandebona H, Hemmelmann C, Lohmann K, Orolicki S, Ramirez A, Schapira AHV, Pramstaller PP, Sue CM, Klein C. Mutant Parkin impairs mitochondrial function and morphology in human fibroblasts. PLoS One 2010; 5:e12962. [PMID: 20885945 PMCID: PMC2946349 DOI: 10.1371/journal.pone.0012962] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 09/02/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Mutations in Parkin are the most common cause of autosomal recessive Parkinson disease (PD). The mitochondrially localized E3 ubiquitin-protein ligase Parkin has been reported to be involved in respiratory chain function and mitochondrial dynamics. More recent publications also described a link between Parkin and mitophagy. METHODOLOGY/PRINCIPAL FINDINGS In this study, we investigated the impact of Parkin mutations on mitochondrial function and morphology in a human cellular model. Fibroblasts were obtained from three members of an Italian PD family with two mutations in Parkin (homozygous c.1072delT, homozygous delEx7, compound-heterozygous c.1072delT/delEx7), as well as from two relatives without mutations. Furthermore, three unrelated compound-heterozygous patients (delEx3-4/duplEx7-12, delEx4/c.924C>T and delEx1/c.924C>T) and three unrelated age-matched controls were included. Fibroblasts were cultured under basal or paraquat-induced oxidative stress conditions. ATP synthesis rates and cellular levels were detected luminometrically. Activities of complexes I-IV and citrate synthase were measured spectrophotometrically in mitochondrial preparations or cell lysates. The mitochondrial membrane potential was measured with 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide. Oxidative stress levels were investigated with the OxyBlot technique. The mitochondrial network was investigated immunocytochemically and the degree of branching was determined with image processing methods. We observed a decrease in the production and overall concentration of ATP coinciding with increased mitochondrial mass in Parkin-mutant fibroblasts. After an oxidative insult, the membrane potential decreased in patient cells but not in controls. We further determined higher levels of oxidized proteins in the mutants both under basal and stress conditions. The degree of mitochondrial network branching was comparable in mutants and controls under basal conditions and decreased to a similar extent under paraquat-induced stress. CONCLUSIONS Our results indicate that Parkin mutations cause abnormal mitochondrial function and morphology in non-neuronal human cells.
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Rakovic A, Grünewald A, Seibler P, Ramirez A, Kock N, Orolicki S, Lohmann K, Klein C. Effect of endogenous mutant and wild-type PINK1 on Parkin in fibroblasts from Parkinson disease patients. Hum Mol Genet 2010; 19:3124-37. [PMID: 20508036 DOI: 10.1093/hmg/ddq215] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mutations in the PTEN-induced putative kinase 1 (PINK1), a mitochondrial serine-threonine kinase, and Parkin, an E3 ubiquitin ligase, are associated with autosomal-recessive forms of Parkinson disease (PD). Both are involved in the maintenance of mitochondrial integrity and protection from multiple stressors. Recently, Parkin was demonstrated to be recruited to impaired mitochondria in a PINK1-dependent manner, where it triggers mitophagy. Using primary human dermal fibroblasts originating from PD patients with various PINK1 mutations, we showed at the endogenous level that (i) PINK1 regulates the stress-induced decrease of endogenous Parkin; (ii) mitochondrially localized PINK1 mediates the stress-induced mitochondrial translocation of Parkin; (iii) endogenous PINK1 is stabilized on depolarized mitochondria; and (iv) mitochondrial accumulation of full-length PINK1 is sufficient but not necessary for the stress-induced loss of Parkin signal and its mitochondrial translocation. Furthermore, we showed that different stressors, depolarizing or non-depolarizing, led to the same effect on detectable Parkin levels and its mitochondrial targeting. Although this effect on Parkin was independent of the mitochondrial membrane potential, we demonstrate a differential effect of depolarizing versus non-depolarizing stressors on endogenous levels of PINK1. Our study shows the necessity to introduce an environmental factor, i.e. stress, to visualize the differences in the interaction of PINK1 and Parkin in mutants versus controls. Establishing human fibroblasts as a suitable model for studying this interaction, we extend data from animal and other cellular models and provide experimental evidence for the generally held notion of PD as a condition with a combined genetic and environmental etiology.
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Orolicki S, Grunewald A, Rakovic A, Seibler P, Lohmann K, Kock N, Klein C. Evidence for a role of the Bcl-2 family in the pathophysiology of Parkin-associated parkinsonism using a human fibroblast model. AKTUELLE NEUROLOGIE 2009. [DOI: 10.1055/s-0029-1238561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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