References of "Grünewald, Anne 50010708"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailNovel insights into Parkin-mediated mitochondrial dysfunction and neuroinflammation in Parkinson's disease
Pereira, Sandro L.; Grossmann, Dajana; Delcambre, Sylvie UL et al

in Current Opinion in Neurobiology (2023), 80

Mutations in PRKN cause the second most common genetic form of Parkinson's disease (PD)—a debilitating movement disorder that is on the rise due to population aging in the industrial world. PRKN codes for ... [more ▼]

Mutations in PRKN cause the second most common genetic form of Parkinson's disease (PD)—a debilitating movement disorder that is on the rise due to population aging in the industrial world. PRKN codes for an E3 ubiquitin ligase that has been well established as a key regulator of mitophagy. Together with PTEN-induced kinase 1 (PINK1), Parkin controls the lysosomal degradation of depolarized mitochondria. But Parkin's functions go well beyond mitochondrial clearance: the versatile protein is involved in mitochondria-derived vesicle formation, cellular metabolism, calcium homeostasis, mitochondrial DNA maintenance, mitochondrial biogenesis, and apoptosis induction. Moreover, Parkin can act as a modulator of different inflammatory pathways. In the current review, we summarize the latest literature concerning the diverse roles of Parkin in maintaining a healthy mitochondrial pool. Moreover, we discuss how these recent discoveries may translate into personalized therapeutic approaches not only for PRKN-PD patients but also for a subset of idiopathic cases. [less ▲]

Detailed reference viewed: 32 (0 UL)
Full Text
See detailFrom methylation to myelination: epigenomic and transcriptomic profiling of chronic inactive demyelinated multiple sclerosis lesions 2023.01.12.523740
Tiane, Assia; Schepers, Melissa; Reijnders, Rick A. et al

E-print/Working paper (2023)

Introduction In the progressive phase of multiple sclerosis (MS), the hampered differentiation capacity of oligodendrocyte precursor cells (OPCs) eventually results in remyelination failure. We have ... [more ▼]

Introduction In the progressive phase of multiple sclerosis (MS), the hampered differentiation capacity of oligodendrocyte precursor cells (OPCs) eventually results in remyelination failure. We have previously shown that DNA methylation of Id2/Id4 is highly involved in OPC differentiation and remyelination. In this study, we took an unbiased approach by determining genome-wide DNA methylation patterns within chronically demyelinated MS lesions and investigated how certain epigenetic signatures relate to OPC differentiation capacity.Methods We compared genome-wide DNA methylation and transcriptional profiles between chronically demyelinated MS lesions and matched normal-appearing white matter (NAWM), making use of post-mortem brain tissue (n=9/group). DNA methylation differences that inversely correlated with mRNA expression of their corresponding genes were validated for their cell-type specificity in laser-captured OPCs using pyrosequencing. The CRISPR-dCas9-DNMT3a/TET1 system was used to epigenetically edit human-iPSC-derived oligodendrocytes to assess the effect on cellular differentiation.Results Our data show hypermethylation of CpGs within genes that cluster in gene ontologies related to myelination and axon ensheathment. Cell type-specific validation indicates a region-dependent hypermethylation of MBP, encoding for myelin basic protein, in OPCs obtained from white matter lesions compared to NAWM-derived OPCs. By altering the DNA methylation state of specific CpGs within the promotor region of MBP, using epigenetic editing, we show that cellular differentiation can be bidirectionally manipulated using the CRISPR-dCas9-DNMT3a/TET1 system in vitro.Conclusion Our data indicate that OPCs within chronically demyelinated MS lesions acquire an inhibitory phenotype, which translates into hypermethylation of crucial myelination related genes. Altering the epigenetic status of MBP can restore the differentiation capacity of OPCs and possibly boost (re)myelination.Competing Interest StatementThe authors have declared no competing interest. [less ▲]

Full Text
Peer Reviewed
See detailGeneration of two induced pluripotent stem cell lines and the corresponding isogenic controls from Parkinson's disease patients carrying the heterozygous mutations c.1290A > G (p.T351A) or c.2067A > G (p.T610A) in the RHOT1 gene encoding Miro1.
Chemla, Axel UL; Arena, Giuseppe UL; Saraiva, Claudia UL et al

in Stem cell research (2023), 69

Primary skin fibroblasts from two Parkinson's disease (PD) patients carrying distinct heterozygous mutations in the RHOT1 gene encoding Miro1, namely c.1290A > G (Miro1 p.T351A) and c.2067A > G (Miro1 p ... [more ▼]

Primary skin fibroblasts from two Parkinson's disease (PD) patients carrying distinct heterozygous mutations in the RHOT1 gene encoding Miro1, namely c.1290A > G (Miro1 p.T351A) and c.2067A > G (Miro1 p.T610A), were converted into induced pluripotent stem cells (iPSCs) by episomal reprogramming. The corresponding isogenic gene-corrected lines have been generated using CRISPR/Cas9 technology. Here, we provide a comprehensive characterization and quality assurance of both isogenic pairs, which will be used to study Miro1-related molecular mechanisms underlying neurodegeneration in iPSC-derived neuronal models (e.g., midbrain dopaminergic neurons and astrocytes). [less ▲]

Detailed reference viewed: 142 (3 UL)
Full Text
See detailInteraction of mitochondrial polygenic score and environmental factors in LRRK2 p.Gly2019Ser parkinsonism 2023.01.02.23284113
Lüth, Theresa; Gabbert, Carolin; König, Inke R. et al

E-print/Working paper (2023)

The objective of our study was to investigate the impact of the mitochondrial polygenic score (MGS) and lifestyle/environmental data on age at onset in LRRK2 p.Gly2019Ser parkinsonism (LRRK2-PD) and ... [more ▼]

The objective of our study was to investigate the impact of the mitochondrial polygenic score (MGS) and lifestyle/environmental data on age at onset in LRRK2 p.Gly2019Ser parkinsonism (LRRK2-PD) and idiopathic Parkinson\textquoterights disease (iPD).In this study, we included N=486 patients with LRRK2-PD and N=9259 patients with iPD from AMP-PD, Fox Insight, and a Tunisian Arab-Berber founder population. Genotyping data was utilized to perform the MGS analysis, using 14 Single Nucleotide Polymorphisms (SNPs) from genes causally associated with mitochondrial function and PD risk. Additionally, lifestyle and environmental data were obtained from the PD risk factor questionnaire (PD-RFQ). Correlation analyses and linear regression models were used to assess the relationship between MGS, lifestyle/environment, and AAO.We observed that higher MGS was associated with earlier AAO in patients with LRRK2-PD (p=4.0\texttimes10-4, β=-0.18) but not in patients with iPD. A correlation between MGS and AAO was visibly stronger in European ancestry LRRK2-PD patients (p=0.01, r=-0.16) than in Tunisian Arab-Berber patients (p=0.44, r=-0.05). We found that the MGS interacted with coffee (p=0.03, β=-0.38) and caffeinated soda consumption (p=0.03, β=-0.37) in LRRK2-PD and with caffeine soda consumption (p=0.047, β=-0.22) and pesticide exposure (p=0.02, β=-0.37) in iPD. Thus, patients with a high MGS had an earlier AAO only if they consumed caffeine or were exposed to pesticides.The MGS related to mitochondrial function was associated with AAO in LRRK2-PD but not iPD with an ethnic-specific effect. Caffeine consumption or pesticide exposure interacted with MGS to predict PD AAO. Our study suggests gene-environment interactions as modifiers of AAO in LRRK2-PD.Competing Interest StatementCK serves as a medical advisor to Centogene and Retromer Therapeutics and received speaking honoraria from Desitin. The remaining authors declare no conflict of interest.Funding StatementThis project was supported by the DFG RU ProtectMove (DFG FOR2488), the Michael J. Fox Foundation (MJFF-021227 \& MJFF-019271), and the Else Kroener-Fresenius-Stiftung.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Ethical permission was given by the Ethical Committee of the Institut National de Neurologie and certified by the Ministry of Health, Tunisia.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData sharing is not applicable to this article as no new data were created or analysed in this study. Data used in the preparation of this manuscript were obtained from the Fox Insight database (https://foxinsight-info.michaeljfox.org/insight/explore/insight.jsp) on 18/10/2020. For up-to-date information on the study, visit https://foxinsight-info.michaeljfox.org/insight/explore/insight.jsp. Data used in the preparation of this article were obtained from the Accelerating Medicine Partnership (AMP) Parkinson\textquoterights Disease (AMP PD) Knowledge Platform. For up-to-date information on the study, visit https://www.amp-pd.org. [less ▲]

Full Text
Peer Reviewed
See detailSelective PDE4 subtype inhibition provides new opportunities to intervene in neuroinflammatory versus myelin damaging hallmarks of multiple sclerosis.
Schepers, Melissa; Paes, Dean; Tiane, Assia et al

in Brain, behavior, and immunity (2023), 109

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) characterized by focal inflammatory lesions and prominent demyelination. Even though the currently available ... [more ▼]

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) characterized by focal inflammatory lesions and prominent demyelination. Even though the currently available therapies are effective in treating the initial stages of disease, they are unable to halt or reverse disease progression into the chronic progressive stage. Thus far, no repair-inducing treatments are available for progressive MS patients. Hence, there is an urgent need for the development of new therapeutic strategies either targeting the destructive immunological demyelination or boosting endogenous repair mechanisms. Using in vitro, ex vivo, and in vivo models, we demonstrate that selective inhibition of phosphodiesterase 4 (PDE4), a family of enzymes that hydrolyzes and inactivates cyclic adenosine monophosphate (cAMP), reduces inflammation and promotes myelin repair. More specifically, we segregated the myelination-promoting and anti-inflammatory effects into a PDE4D- and PDE4B-dependent process respectively. We show that inhibition of PDE4D boosts oligodendrocyte progenitor cells (OPC) differentiation and enhances (re)myelination of both murine OPCs and human iPSC-derived OPCs. In addition, PDE4D inhibition promotes in vivo remyelination in the cuprizone model, which is accompanied by improved spatial memory and reduced visual evoked potential latency times. We further identified that PDE4B-specific inhibition exerts anti-inflammatory effects since it lowers in vitro monocytic nitric oxide (NO) production and improves in vivo neurological scores during the early phase of experimental autoimmune encephalomyelitis (EAE). In contrast to the pan PDE4 inhibitor roflumilast, the therapeutic dose of both the PDE4B-specific inhibitor A33 and the PDE4D-specific inhibitor Gebr32a did not trigger emesis-like side effects in rodents. Finally, we report distinct PDE4D isoform expression patterns in human area postrema neurons and human oligodendroglia lineage cells. Using the CRISPR-Cas9 system, we confirmed that pde4d1/2 and pde4d6 are the key targets to induce OPC differentiation. Collectively, these data demonstrate that gene specific PDE4 inhibitors have potential as novel therapeutic agents for targeting the distinct disease processes of MS. [less ▲]

Detailed reference viewed: 23 (1 UL)
Full Text
Peer Reviewed
See detailMolecular phenotypes of mitochondrial dysfunction in clinically non-manifesting heterozygous PRKN variant carriers
Castelo Rueda, Maria Paulina; Zanon, Alessandra; Gilmozzi, Valentina et al

in NPJ Parkinson's Disease (2023)

Homozygous or compound heterozygous (biallelic) variants in PRKN are causal for PD with highly penetrant symptom expression, while the much more common heterozygous variants may predispose to PD with ... [more ▼]

Homozygous or compound heterozygous (biallelic) variants in PRKN are causal for PD with highly penetrant symptom expression, while the much more common heterozygous variants may predispose to PD with highly reduced penetrance, through altered mitochondrial function. In the presence of pathogenic heterozygous variants, it is therefore important to test for mitochondrial alteration in cells derived from variant carriers to establish potential presymptomatic molecular markers. We generated lymphoblasts (LCLs) and human induced pluripotent stem cell (hiPSC)-derived neurons from non-manifesting heterozygous PRKN variant carriers and tested them for mitochondrial functionality. In LCLs, we detected hyperactive mitochondrial respiration, and, although milder compared to a biallelic PRKN-PD patient, hiPSC-derived neurons of non-manifesting heterozygous variant carriers also displayed several phenotypes of altered mitochondrial function. Overall, we identified molecular phenotypes that might be used to monitor heterozygous PRKN variant carriers during the prodromal phase. Such markers might also be useful to identify individuals at greater risk of eventual disease development and for testing potential mitochondrial function-based neuroprotective therapies before neurodegeneration advances [less ▲]

Detailed reference viewed: 10 (0 UL)
Full Text
Peer Reviewed
See detailMitochondrial DNA heteroplasmy distinguishes disease manifestation in PINK1/PRKN-linked Parkinson’s disease
Trinh, Joanne; Hicks, Andrew A.; König, Inke R. et al

in Brain (2022)

Biallelic mutations in PINK1/PRKN cause recessive Parkinson’s disease. Given the established role of PINK1/Parkin in regulating mitochondrial dynamics, we explored mitochondrial DNA (mtDNA) integrity and ... [more ▼]

Biallelic mutations in PINK1/PRKN cause recessive Parkinson’s disease. Given the established role of PINK1/Parkin in regulating mitochondrial dynamics, we explored mitochondrial DNA (mtDNA) integrity and inflammation as disease modifiers in carriers of mutations in these genes. MtDNA integrity was investigated in a large collection of biallelic (n = 84) and monoallelic (n = 170) carriers of PINK1/PRKN mutations, idiopathic Parkinson’s disease patients (n = 67) and controls (n = 90). In addition, we studied global gene expression and serum cytokine levels in a subset. Affected and unaffected PINK1/PRKN monoallelic mutation carriers can be distinguished by heteroplasmic mtDNA variant load (AUC = 0.83, CI:0.74-0.93). Biallelic PINK1/PRKN mutation carriers harbor more heteroplasmic mtDNA variants in blood (p = 0.0006, Z = 3.63) compared to monoallelic mutation carriers. This enrichment was confirmed in iPSC-derived (controls, n = 3; biallelic PRKN mutation carriers, n = 4) and postmortem (control, n = 1; biallelic PRKN mutation carrier, n = 1) midbrain neurons. Lastly, the heteroplasmic mtDNA variant load correlated with IL6 levels in PINK1/PRKN mutation carriers (r = 0.57, p = 0.0074). PINK1/PRKN mutations predispose individuals to mtDNA variant accumulation in a dose- and disease-dependent manner. [less ▲]

Detailed reference viewed: 27 (6 UL)
Full Text
See detailMitochondrial DNA heteroplasmy distinguishes disease manifestation in PINK1- and PRKN-linked Parkinson's disease 2022.05.17.22275087
Trinh, Joanne; Hicks, Andrew A.; Koenig, Inke R. et al

E-print/Working paper (2022)

Biallelic mutations in PINK1 and PRKN cause recessively inherited Parkinson's disease (PD). Though some studies suggest that PINK1/PRKN monoallelic mutations may not contribute to risk, deep phenotyping ... [more ▼]

Biallelic mutations in PINK1 and PRKN cause recessively inherited Parkinson's disease (PD). Though some studies suggest that PINK1/PRKN monoallelic mutations may not contribute to risk, deep phenotyping assessment showed that PINK1 or PRKN monoallelic pathogenic variants were at a significantly higher rate in PD compared to controls. Given the established role of PINK1 and Parkin in regulating mitochondrial dynamics, we explored mitochondrial DNA (mtDNA) integrity and inflammation as potential disease modifiers in carriers of mutations in these genes. MtDNA integrity, global gene expression and serum cytokine levels were investigated in a large collection of biallelic (n=84) and monoallelic (n=170) carriers of PINK1/PRKN mutations, iPD patients (n=67) and controls (n=90). Affected and unaffected PINK1/PRKN monoallelic mutation carriers can be distinguished by heteroplasmic mtDNA variant load (AUC=0.83, CI:0.74-0.93). Biallelic PINK1/PRKN mutation carriers harbor more heteroplasmic mtDNA variants in blood (p=0.0006, Z=3.63) compared to monoallelic mutation carriers. This enrichment was confirmed in iPSC-derived and postmortem midbrain neurons from biallelic PRKN-PD patients. Lastly, the heteroplasmic mtDNA variant load was found to correlate with IL6 levels in PINK1/PRKN mutation carriers (r=0.57, p=0.0074). PINK1/PRKN mutations predispose individuals to mtDNA variant accumulation in a dose- and disease-dependent manner. MtDNA variant load over time is a potential marker of disease manifestation in PINK1/PRKN mutation carriers.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThe authors wish to thank the many patients and their families who volunteered, and the efforts of the many clinical teams involved. Funding has been obtained from the German Research Foundation (ProtectMove; FOR 2488, GR 3731/5-1; SE 2608/2-1; KO 2250/7-1), the Luxembourg National Research Fund in the ATTRACT (Model-IPD, FNR9631103), NCER-PD (FNR11264123) and INTER programmes (ProtectMove, FNR11250962; MiRisk-PD, C17/BM/11676395, NB 4328/2-1), the BMBF (MitoPD), the Hermann and Lilly Schilling Foundation, the European Community (SysMedPD), the Canadian Institutes of Health Research (CIHR), Peter and Traudl Engelhorn Foundation. Initial studies in Tunisia on familial parkinsonism were in collaboration with Lefkos Middleton, Rachel Gibson, and the GlaxoSmithKline PD Programme Team (2002-2005). We would like to thank Dr Helen Tuppen from the Welcome Trust Centre for Mitochondrial Research, Newcastle University, UK for providing us with the plasmid p7D1. Moreover, this project was supported by the high throughput/high content screening platform and HPC facility at the Luxembourg Centre for Systems Biomedicine, and the University of Luxembourg.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:University of Lubeck Ethics CommitteeI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors [less ▲]

Detailed reference viewed: 98 (6 UL)
Full Text
Peer Reviewed
See detailBenchmarking Low-Frequency Variant Calling With Long-Read Data on Mitochondrial DNA
Lüth, Theresa; Schaake, Susen; Grünewald, Anne UL et al

in Frontiers in Genetics (2022), 13

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial ... [more ▼]

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial samples with different haplogroups (i.e., a specific set of mitochondrial variants) to investigate the applicability of nanopore sequencing for low-frequency single nucleotide variant detection.Methods: We investigated the impact of base-calling, alignment/mapping, quality control steps, and variant calling by comparing the results to a previously derived short-read gold standard generated on the Illumina NextSeq. For nanopore sequencing, six mixtures of four different haplotypes were prepared, allowing us to reliably check for expected variants at the predefined 5%, 2%, and 1% mixture levels. We used two different versions of Guppy for base-calling, two aligners (i.e., Minimap2 and Ngmlr), and three variant callers (i.e., Mutserve2, Freebayes, and Nanopanel2) to compare low-frequency variants. We used F<sub>1</sub> score measurements to assess the performance of variant calling.Results: We observed a mean read length of 11 kb and a mean overall read quality of 15. Ngmlr showed not only higher F<sub>1</sub> scores but also higher allele frequencies (AF) of false-positive calls across the mixtures (mean F<sub>1</sub> score = 0.83; false-positive allele frequencies < 0.17) compared to Minimap2 (mean F<sub>1</sub> score = 0.82; false-positive AF < 0.06). Mutserve2 had the highest F<sub>1</sub> scores (5% level: F<sub>1</sub> score >0.99, 2% level: F<sub>1</sub> score >0.54, and 1% level: F<sub>1</sub> score >0.70) across all callers and mixture levels.Conclusion: We here present the benchmarking for low-frequency variant calling with nanopore sequencing by identifying current limitations. [less ▲]

Detailed reference viewed: 83 (3 UL)
Full Text
Peer Reviewed
See detailSingle-cell sequencing of human midbrain reveals glial activation and a Parkinson-specific neuronal state.
Smajic, Semra UL; Prada-Medina, Cesar A.; Landoulsi, Zied UL et al

in Brain : a journal of neurology (2022), 145(3), 964-978

Idiopathic Parkinson's disease is characterized by a progressive loss of dopaminergic neurons, but the exact disease etiology remains largely unknown. To date, Parkinson's disease research has mainly ... [more ▼]

Idiopathic Parkinson's disease is characterized by a progressive loss of dopaminergic neurons, but the exact disease etiology remains largely unknown. To date, Parkinson's disease research has mainly focused on nigral dopaminergic neurons, although recent studies suggest disease-related changes also in non-neuronal cells and in midbrain regions beyond the substantia nigra. While there is some evidence for glial involvement in Parkinson's disease, the molecular mechanisms remain poorly understood. The aim of this study was to characterize the contribution of all cell types of the midbrain to Parkinson's disease pathology by single-nuclei RNA sequencing and to assess the cell type-specific risk for Parkinson's disease employing the latest genome-wide association study. We profiled >41 000 single-nuclei transcriptomes of postmortem midbrain from six idiopathic Parkinson's disease patients and five age-/sex-matched controls. To validate our findings in a spatial context, we utilized immunolabeling of the same tissues. Moreover, we analyzed Parkinson's disease-associated risk enrichment in genes with cell type-specific expression patterns. We discovered a neuronal cell cluster characterized by CADPS2 overexpression and low TH levels, which was exclusively present in IPD midbrains. Validation analyses in laser-microdissected neurons suggest that this cluster represents dysfunctional dopaminergic neurons. With regard to glial cells, we observed an increase in nigral microglia in Parkinson's disease patients. Moreover, nigral idiopathic Parkinson's disease microglia were more amoeboid, indicating an activated state. We also discovered a reduction in idiopathic Parkinson's disease oligodendrocyte numbers with the remaining cells being characterized by a stress-induced upregulation of S100B. Parkinson's disease risk variants were associated with glia- and neuron-specific gene expression patterns in idiopathic Parkinson's disease cases. Furthermore, astrocytes and microglia presented idiopathic Parkinson's disease-specific cell proliferation and dysregulation of genes related to unfolded protein response and cytokine signaling. While reactive patient astrocytes showed CD44 overexpression, idiopathic Parkinson's disease-microglia revealed a pro-inflammatory trajectory characterized by elevated levels of IL1B, GPNMB, and HSP90AA1. Taken together, we generated the first single-nuclei RNA sequencing dataset from the idiopathic Parkinson's disease midbrain, which highlights a disease-specific neuronal cell cluster as well as 'pan-glial' activation as a central mechanism in the pathology of the movement disorder. This finding warrants further research into inflammatory signaling and immunomodulatory treatments in Parkinson's disease. [less ▲]

Detailed reference viewed: 116 (22 UL)
Full Text
Peer Reviewed
See detailParkin Deficiency Impairs Mitochondrial DNA Dynamics and Propagates Inflammation.
Wasner, Kobi; Smajic, Semra UL; Ghelfi, Jenny UL et al

in Movement disorders : official journal of the Movement Disorder Society (2022)

BACKGROUND: Mutations in the E3 ubiquitin ligase parkin cause autosomal recessive Parkinson's disease (PD). Together with PTEN-induced kinase 1 (PINK1), parkin regulates the clearance of dysfunctional ... [more ▼]

BACKGROUND: Mutations in the E3 ubiquitin ligase parkin cause autosomal recessive Parkinson's disease (PD). Together with PTEN-induced kinase 1 (PINK1), parkin regulates the clearance of dysfunctional mitochondria. New mitochondria are generated through an interplay of nuclear- and mitochondrial-encoded proteins, and recent studies suggest that parkin influences this process at both levels. In addition, parkin was shown to prevent mitochondrial membrane permeability, impeding mitochondrial DNA (mtDNA) escape and subsequent neuroinflammation. However, parkin's regulatory roles independent of mitophagy are not well described in patient-derived neurons. OBJECTIVES: We sought to investigate parkin's role in preventing neuronal mtDNA dyshomeostasis, release, and glial activation at the endogenous level. METHODS: We generated induced pluripotent stem cell (iPSC)-derived midbrain neurons from PD patients with parkin (PRKN) mutations and healthy controls. Live-cell imaging, proteomic, mtDNA integrity, and gene expression analyses were employed to investigate mitochondrial biogenesis and genome maintenance. To assess neuroinflammation, we performed single-nuclei RNA sequencing in postmortem tissue and quantified interleukin expression in mtDNA/lipopolysaccharides (LPS)-treated iPSC-derived neuron-microglia co-cultures. RESULTS: Neurons from patients with PRKN mutations revealed deficits in the mitochondrial biogenesis pathway, resulting in mtDNA dyshomeostasis. Moreover, the energy sensor sirtuin 1, which controls mitochondrial biogenesis and clearance, was downregulated in parkin-deficient cells. Linking mtDNA disintegration to neuroinflammation, in postmortem midbrain with PRKN mutations, we confirmed mtDNA dyshomeostasis and detected an upregulation of microglia overexpressing proinflammatory cytokines. Finally, parkin-deficient neuron-microglia co-cultures elicited an enhanced immune response when exposed to mtDNA/LPS. CONCLUSIONS: Our findings suggest that parkin coregulates mitophagy, mitochondrial biogenesis, and mtDNA maintenance pathways, thereby protecting midbrain neurons from neuroinflammation and degeneration. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [less ▲]

Detailed reference viewed: 112 (10 UL)
Full Text
Peer Reviewed
See detailMolecular mechanisms defining penetrance of LRRK2-associated Parkinson’s disease
Trinh, Joanne; Schymanski, Emma UL; Smajic, Semra UL et al

in Medizinische Genetik (2022), 34(2), 103--116

Detailed reference viewed: 59 (3 UL)
Full Text
Peer Reviewed
See detailNeurodegeneration and Neuroinflammation in Parkinson’s Disease: a Self-Sustained Loop
Arena, Giuseppe UL; Sharma, K.; Agyeah, Gideon UL et al

in Current Neurology and Neuroscience Reports (2022), 22(8), 427440

Purpose of Review: Neuroinflammation plays a significant role in Parkinson’s disease (PD) etiology along with mitochondrial dysfunction and impaired proteostasis. In this context, mechanisms related to ... [more ▼]

Purpose of Review: Neuroinflammation plays a significant role in Parkinson’s disease (PD) etiology along with mitochondrial dysfunction and impaired proteostasis. In this context, mechanisms related to immune response can act as modifiers at different steps of the neurodegenerative process and justify the growing interest in anti-inflammatory agents as potential disease-modifying treatments in PD. The discovery of inherited gene mutations in PD has allowed researchers to develop cellular and animal models to study the mechanisms of the underlying biology, but the original cause of neuroinflammation in PD is still debated to date. Recent Findings: Cell autonomous alterations in neuronal cells, including mitochondrial damage and protein aggregation, could play a role, but recent findings also highlighted the importance of intercellular communication at both local and systemic level. This has given rise to debate about the role of non-neuronal cells in PD and reignited intense research into the gut-brain axis and other non-neuronal interactions in the development of the disease. Whatever the original trigger of neuroinflammation in PD, what appears quite clear is that the aberrant activation of glial cells and other components of the immune system creates a vicious circle in which neurodegeneration and neuroinflammation nourish each other. Summary: In this review, we will provide an up-to-date summary of the main cellular alterations underlying neuroinflammation in PD, including those induced by environmental factors (e.g. the gut microbiome) and those related to the genetic background of affected patients. Starting from the lesson provided by familial forms of PD, we will discuss pathophysiological mechanisms linked to inflammation that could also play a role in idiopathic forms. Finally, we will comment on the potential clinical translatability of immunobiomarkers identified in PD patient cohorts and provide an update on current therapeutic strategies aimed at overcoming or preventing inflammation in PD. © 2022, The Author(s). [less ▲]

Detailed reference viewed: 62 (2 UL)
Full Text
Peer Reviewed
See detailCoffee, smoking and aspirin are associated with age at onset in idiopathic Parkinson's disease.
Gabbert, Carolin; König, Inke R.; Lüth, Theresa et al

in Journal of neurology (2022)

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Genetic modifiers, environmental factors and gene-environment interactions have been found to modify PD risk and disease progression ... [more ▼]

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Genetic modifiers, environmental factors and gene-environment interactions have been found to modify PD risk and disease progression. The objective of this study was to evaluate the association of smoking, caffeine and anti-inflammatory drugs with age at onset (AAO) in a large PD cohort. A total of 35,963 American patients with idiopathic PD (iPD) from the Fox Insight Study responded to health and lifestyle questionnaires. We compared the median AAO between different groups using the non-parametric Mann-Whitney U test. Non-parametric Spearman's correlation was used for correlation assessments and regression analysis was used to assess interaction between variables. We found that smoking (p < 0.0001), coffee drinking (p < 0.0001) and aspirin intake (p < 0.0001) show an exploratory association with AAO in PD, that was further supported by multivariate regression models. The association of aspirin with PD AAO was replicated in another cohort (EPIPARK) (n = 237 patients with PD). [less ▲]

Detailed reference viewed: 42 (1 UL)
Full Text
Peer Reviewed
See detailPINK1 Protects against Staurosporine-Induced Apoptosis by Interacting with Beclin1 and Impairing Its Pro-Apoptotic Cleavage.
Brunelli, Francesco; Torosantucci, Liliana; Gelmetti, Vania et al

in Cells (2022), 11(4),

PINK1 is a causative gene for Parkinson's disease and the corresponding protein has been identified as a master regulator of mitophagy-the autophagic degradation of damaged mitochondria. It interacts with ... [more ▼]

PINK1 is a causative gene for Parkinson's disease and the corresponding protein has been identified as a master regulator of mitophagy-the autophagic degradation of damaged mitochondria. It interacts with Beclin1 to regulate autophagy and initiate autophagosome formation, even outside the context of mitophagy. Several other pro-survival functions of this protein have been described and indicate that it might play a role in other disorders, such as cancer and proliferative diseases. In this study, we investigated a novel anti-apoptotic function of PINK1. To do so, we used SH-SY5Y neuroblastoma cells, a neuronal model used in Parkinson's disease and cancer studies, to characterize the pro-survival functions of PINK1 in response to the apoptosis inducer staurosporine. In this setting, we found that staurosporine induces apoptosis but not mitophagy, and we demonstrated that PINK1 protects against staurosporine-induced apoptosis by impairing the pro-apoptotic cleavage of Beclin1. Our data also show that staurosporine-induced apoptosis is preceded by a phase of enhanced autophagy, and that PINK1 in this context regulates the switch from autophagy to apoptosis. PINK1 protein levels progressively decrease after treatment, inducing this switch. The PINK1-Beclin1 interaction is crucial in exerting this function, as mutants that are unable to interact do not show the anti-apoptotic effect. We characterized a new anti-apoptotic function of PINK1 that could provide options for treatment in proliferative or neurodegenerative diseases. [less ▲]

Detailed reference viewed: 70 (3 UL)
Full Text
Peer Reviewed
See detailA genome on shaky ground: exploring the impact of mitochondrial DNA integrity on Parkinson's disease by highlighting the use of cybrid models.
Lang, Martin; Grünewald, Anne UL; Pramstaller, Peter P. et al

in Cellular and molecular life sciences : CMLS (2022), 79(5), 283

Mitochondria play important roles in the regulation of key cellular processes, including energy metabolism, oxidative stress response, and signaling towards cell death or survival, and are distinguished ... [more ▼]

Mitochondria play important roles in the regulation of key cellular processes, including energy metabolism, oxidative stress response, and signaling towards cell death or survival, and are distinguished by carrying their own genome (mtDNA). Mitochondrial dysfunction has emerged as a prominent cellular mechanism involved in neurodegeneration, including Parkinson's disease (PD), a neurodegenerative movement disorder, characterized by progressive loss of dopaminergic neurons and the occurrence of proteinaceous Lewy body inclusions. The contribution of mtDNA variants to PD pathogenesis has long been debated and is still not clearly answered. Cytoplasmic hybrid (cybrid) cell models provided evidence for a contribution of mtDNA variants to the PD phenotype. However, conclusive evidence of mtDNA mutations as genetic cause of PD is still lacking. Several models have shown a role of somatic, rather than inherited mtDNA variants in the impairment of mitochondrial function and neurodegeneration. Accordingly, several nuclear genes driving inherited forms of PD are linked to mtDNA quality control mechanisms, and idiopathic as well as familial PD tissues present increased mtDNA damage. In this review, we highlight the use of cybrids in this PD research field and summarize various aspects of how and to what extent mtDNA variants may contribute to the etiology of PD. [less ▲]

Detailed reference viewed: 52 (1 UL)
Full Text
Peer Reviewed
See detailNanopore Single-Molecule Sequencing for Mitochondrial DNA Methylation Analysis: Investigating Parkin-Associated Parkinsonism as a Proof of Concept
Lüth, Theresa; Wasner, Kobi UL; Klein, Christine et al

in Frontiers in Aging Neuroscience (2021)

Objective: To establish a workflow for mitochondrial DNA (mtDNA) CpG methylation using Nanopore whole-genome sequencing and perform first pilot experiments on affected Parkin biallelic mutation carriers ... [more ▼]

Objective: To establish a workflow for mitochondrial DNA (mtDNA) CpG methylation using Nanopore whole-genome sequencing and perform first pilot experiments on affected Parkin biallelic mutation carriers (Parkin-PD) and healthy controls. Background: Mitochondria, including mtDNA, are established key players in Parkinson's disease (PD) pathogenesis. Mutations in Parkin, essential for degradation of damaged mitochondria, cause early-onset PD. However, mtDNA methylation and its implication in PD is understudied. Herein, we establish a workflow using Nanopore sequencing to directly detect mtDNA CpG methylation and compare mtDNA methylation between Parkin-related PD and healthy individuals. Methods: To obtain mtDNA, whole-genome Nanopore sequencing was performed on blood-derived from five Parkin-PD and three control subjects. In addition, induced pluripotent stem cell (iPSC)-derived midbrain neurons from four of these patients with PD and the three control subjects were investigated. The workflow was validated, using methylated and unmethylated 897 bp synthetic DNA samples at different dilution ratios (0, 50, 100% methylation) and mtDNA without methylation. MtDNA CpG methylation frequency (MF) was detected using Nanopolish and Megalodon. Results: Across all blood-derived samples, we obtained a mean coverage of 250.3X (SD ± 80.5X) and across all neuron-derived samples 830X (SD ± 465X) of the mitochondrial genome. We detected overall low-level CpG methylation from the blood-derived DNA (mean MF ± SD = 0.029 ± 0.041) and neuron-derived DNA (mean MF ± SD = 0.019 ± 0.035). Validation of the workflow, using synthetic DNA samples showed that highly methylated DNA molecules were prone to lower Guppy Phred quality scores and thereby more likely to fail Guppy base-calling. CpG methylation in blood- and neuron-derived DNA was significantly lower in Parkin-PD compared to controls (Mann-Whitney U-test p < 0.05). Conclusion: Nanopore sequencing is a useful method to investigate mtDNA methylation architecture, including Guppy-failed reads is of importance when investigating highly methylated sites. We present a mtDNA methylation workflow and suggest methylation variability across different tissues and between Parkin-PD patients and controls as an initial model to investigate. [less ▲]

Detailed reference viewed: 49 (4 UL)
Full Text
See detailCoffee, smoking and aspirin are associated with age at onset and clinical severity in idiopathic Parkinson’s disease
Gabbert, Carolin; König, Inke; Lüth, Theresa et al

E-print/Working paper (2021)

Detailed reference viewed: 48 (3 UL)
Full Text
Peer Reviewed
See detailiPSC-Derived Microglia as a Model to Study Inflammation in Idiopathic Parkinson's Disease.
Badanjak, Katja UL; Mulica, Patrycja UL; Smajic, Semra UL et al

in Frontiers in cell and developmental biology (2021), 9

Parkinson's disease (PD) is a neurodegenerative disease with unknown cause in the majority of patients, who are therefore considered "idiopathic" (IPD). PD predominantly affects dopaminergic neurons in ... [more ▼]

Parkinson's disease (PD) is a neurodegenerative disease with unknown cause in the majority of patients, who are therefore considered "idiopathic" (IPD). PD predominantly affects dopaminergic neurons in the substantia nigra pars compacta (SNpc), yet the pathology is not limited to this cell type. Advancing age is considered the main risk factor for the development of IPD and greatly influences the function of microglia, the immune cells of the brain. With increasing age, microglia become dysfunctional and release pro-inflammatory factors into the extracellular space, which promote neuronal cell death. Accordingly, neuroinflammation has also been described as a feature of PD. So far, studies exploring inflammatory pathways in IPD patient samples have primarily focused on blood-derived immune cells or brain sections, but rarely investigated patient microglia in vitro. Accordingly, we decided to explore the contribution of microglia to IPD in a comparative manner using, both, iPSC-derived cultures and postmortem tissue. Our meta-analysis of published RNAseq datasets indicated an upregulation of IL10 and IL1B in nigral tissue from IPD patients. We observed increased expression levels of these cytokines in microglia compared to neurons using our single-cell midbrain atlas. Moreover, IL10 and IL1B were upregulated in IPD compared to control microglia. Next, to validate these findings in vitro, we generated IPD patient microglia from iPSCs using an established differentiation protocol. IPD microglia were more readily primed as indicated by elevated IL1B and IL10 gene expression and higher mRNA and protein levels of NLRP3 after LPS treatment. In addition, IPD microglia had higher phagocytic capacity under basal conditions-a phenotype that was further exacerbated upon stimulation with LPS, suggesting an aberrant microglial function. Our results demonstrate the significance of microglia as the key player in the neuroinflammation process in IPD. While our study highlights the importance of microglia-mediated inflammatory signaling in IPD, further investigations will be needed to explore particular disease mechanisms in these cells. [less ▲]

Detailed reference viewed: 131 (19 UL)