Mitochondrial DNA mutations in Multiple Sclerosis - untangling genotype, immunometabolism and disease activity
ECTRIMS Online Library. Cortes-Figueiredo F. 09/13/19; 278416; P1213
Filipe Cortes-Figueiredo
Filipe Cortes-Figueiredo
Contributions
Abstract

Abstract: P1213

Type: Poster Sessions

Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics

F. Cortes-Figueiredo1,2, S. Asseyer2,3, F.S. Carvalho1, R.M. Gieß2, J. Bellmann-Strobl2,3, F. Paul *2,3, V.A. Morais *1, * co-senior authors

1VMorais Lab - Mitochondria Biology & Neurodegeneration, Instituto de Medicina Molecular | João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal, 2NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, 3Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, Berlin, Germany

Introduction: Multiple Sclerosis (MS) is an autoimmune demyelinating disease of the Central Nervous System (CNS) with a multifactorial undetermined aetiology. Mitochondria have recently emerged as a mediator in MS pathophysiology. Several reports have identified the presence of mitochondrial dysfunction in MS brain samples, and mitochondrial DNA (mtDNA) variants have been associated with MS risk. More recently, impaired mitochondrial activity in T-CD4+ cells from patients with MS (PwMS) has been observed.
Objectives: In order to unravel the role of mtDNA in determining the mitochondrial dysfunction observed in T-CD4+ cells, we are performing a retrospective study with an established cohort of > 50 PwMS and age and gender matched healthy controls (HC). Following this, we will perform a cross-sectional comparison between PwMS shortly after diagnosis and HC, as well as a longitudinal analysis for the same PwMS cohort 3 years after disease onset.
Aims: We aim to assess the correlation between the mitochondrial genotype of T-CD4+ cells and MS triggering and progression.
Methods: We are performing a preliminary analysis on a subset of 20 matched triplets (HC + PwMS at two time points). MtDNA, extracted from T-CD4+ cells isolated by magnetic separation, was sequenced (whole genome sequencing - WGS) without prior long-range PCR enrichment by performing semiconductor sequencing with an amplicon-based library. Reads were aligned to the revised Cambridge Reference Sequence with BWA-MEM and variants were called with mtdna-server.
Results: We observed a statistically significant increase in T-CD4+ cells after magnetic separation: fold change 95% CI [1.62, 2.11]. Genome coverage and mappability were adequate and uniform between subject types: mean coverage 1820 reads/nucleotide and mean mappability (coverage > 100) of 97.8%. Both median and mean number of variants were increased in PwMS (median 30, mean 26) in comparison to HC (median 19, mean 23) - not statistically significant (ns). Male PwMS showed an increased mutational burden, with 80% of PwMS having an increased number of variants in contrast to their matched HC, while only 53% of females showed the same - ns.
Conclusions: We attained a successful T-CD4+ enrichment and subsequent mtDNA WGS. PwMS showed an increased mutational burden in comparison to HC, particularly in males. Due to the preliminary nature of this project, more research is warranted and is ongoing.
Disclosure: Source of funding: Research support for this project was provided by the National Multiple Sclerosis Society of the USA and Merck, while FCF's stipend was paid by Fundação para a Ciência e a Tecnologia (FCT) - reference PD/BD/114122/2015.
Potential conflicts of interest: FCF: nothing to disclose. SA has received speaker honoraria and/or travel grants from Celgene; unrelated to this project. FSC: nothing to disclose. RMG: nothing to disclose. JBS has received speaker honoraria and/or travel grants from Bayer Healthcare, Biogen Idec, Merck Serono, Sanofi Genzyme, Teva Pharmaceuticals, and Novartis. FP serves on the scientific advisory board for Novartis; has received research support from Bayer, Novartis, Biogen Idec, Teva Pharmaceuticals, Sanofi Genzyme, Merck Serono, Alexion, Chugai, Arthur Arnstein Foundation Berlin, and Guthy Jackson Charitable Foundation; has received speaker honoraria and/or travel grants from Bayer, Novartis, Biogen Idec, Teva Pharmaceuticals, Sanofi Genzyme, Merck Serono, Alexion, Chugai, MedImmune, and Shire; has consulted for Sanofi Genzyme, Biogen Idec, MedImmune, Shire, and Alexion; and is a member of the steering committee of the OCTIMS study (Novartis); none of this is related to the present project. VAM: nothing to disclose.

Abstract: P1213

Type: Poster Sessions

Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics

F. Cortes-Figueiredo1,2, S. Asseyer2,3, F.S. Carvalho1, R.M. Gieß2, J. Bellmann-Strobl2,3, F. Paul *2,3, V.A. Morais *1, * co-senior authors

1VMorais Lab - Mitochondria Biology & Neurodegeneration, Instituto de Medicina Molecular | João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal, 2NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, 3Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, Berlin, Germany

Introduction: Multiple Sclerosis (MS) is an autoimmune demyelinating disease of the Central Nervous System (CNS) with a multifactorial undetermined aetiology. Mitochondria have recently emerged as a mediator in MS pathophysiology. Several reports have identified the presence of mitochondrial dysfunction in MS brain samples, and mitochondrial DNA (mtDNA) variants have been associated with MS risk. More recently, impaired mitochondrial activity in T-CD4+ cells from patients with MS (PwMS) has been observed.
Objectives: In order to unravel the role of mtDNA in determining the mitochondrial dysfunction observed in T-CD4+ cells, we are performing a retrospective study with an established cohort of > 50 PwMS and age and gender matched healthy controls (HC). Following this, we will perform a cross-sectional comparison between PwMS shortly after diagnosis and HC, as well as a longitudinal analysis for the same PwMS cohort 3 years after disease onset.
Aims: We aim to assess the correlation between the mitochondrial genotype of T-CD4+ cells and MS triggering and progression.
Methods: We are performing a preliminary analysis on a subset of 20 matched triplets (HC + PwMS at two time points). MtDNA, extracted from T-CD4+ cells isolated by magnetic separation, was sequenced (whole genome sequencing - WGS) without prior long-range PCR enrichment by performing semiconductor sequencing with an amplicon-based library. Reads were aligned to the revised Cambridge Reference Sequence with BWA-MEM and variants were called with mtdna-server.
Results: We observed a statistically significant increase in T-CD4+ cells after magnetic separation: fold change 95% CI [1.62, 2.11]. Genome coverage and mappability were adequate and uniform between subject types: mean coverage 1820 reads/nucleotide and mean mappability (coverage > 100) of 97.8%. Both median and mean number of variants were increased in PwMS (median 30, mean 26) in comparison to HC (median 19, mean 23) - not statistically significant (ns). Male PwMS showed an increased mutational burden, with 80% of PwMS having an increased number of variants in contrast to their matched HC, while only 53% of females showed the same - ns.
Conclusions: We attained a successful T-CD4+ enrichment and subsequent mtDNA WGS. PwMS showed an increased mutational burden in comparison to HC, particularly in males. Due to the preliminary nature of this project, more research is warranted and is ongoing.
Disclosure: Source of funding: Research support for this project was provided by the National Multiple Sclerosis Society of the USA and Merck, while FCF's stipend was paid by Fundação para a Ciência e a Tecnologia (FCT) - reference PD/BD/114122/2015.
Potential conflicts of interest: FCF: nothing to disclose. SA has received speaker honoraria and/or travel grants from Celgene; unrelated to this project. FSC: nothing to disclose. RMG: nothing to disclose. JBS has received speaker honoraria and/or travel grants from Bayer Healthcare, Biogen Idec, Merck Serono, Sanofi Genzyme, Teva Pharmaceuticals, and Novartis. FP serves on the scientific advisory board for Novartis; has received research support from Bayer, Novartis, Biogen Idec, Teva Pharmaceuticals, Sanofi Genzyme, Merck Serono, Alexion, Chugai, Arthur Arnstein Foundation Berlin, and Guthy Jackson Charitable Foundation; has received speaker honoraria and/or travel grants from Bayer, Novartis, Biogen Idec, Teva Pharmaceuticals, Sanofi Genzyme, Merck Serono, Alexion, Chugai, MedImmune, and Shire; has consulted for Sanofi Genzyme, Biogen Idec, MedImmune, Shire, and Alexion; and is a member of the steering committee of the OCTIMS study (Novartis); none of this is related to the present project. VAM: nothing to disclose.

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