Contributions
Abstract: EP1466
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: Genetic and environmental factors are known to influence the complex pathogenesis of multiple sclerosis (MS). In recent years, numerous studies have suggested that vitamin D deficiency contributes to MS risk. By means of targeted resequencing (524 MS patients and 546 healthy controls) and subsequent genotyping in an independent cohort (3450 MS patients and 1688 healthy controls), we identified a variant located in the CYP24A1 gene, rs2762943, that was associated with increased MS risk. The CYP24A1 gene encodes a protein that initiates the degradation of the physiologically active form of vitamin D [1,25-dihydroxyvitamin D - 1,25(OH)2-D]. Here, we aimed to assess the functional role of the rs2762943 polymorphism in the pathogenesis of MS.
Methods: By means of chemiluminescent immunoassay technologies, serum levels of 25-hydroxyvitamin D [25(OH)-D] and 1,25(OH)2-D were measured in two independent cohorts of 101 MS patients (30 minor allele - MA carriers, 71 MA non-carriers for rs2762943) and 100 MS patients (26 MA carriers, 74 MA non-carriers for rs2762943) respectively. In addition, peripheral blood mononuclear cells (PBMC) from 16 MS patients (8 MA carriers, 8 MA non-carriers for rs2762943) were cultured with 25(OH)-D (500nM), 1,25(OH)2-D (1nM) or vehicle for 24 h. Total RNA was extracted and CYP24A1 mRNA expression levels were analyzed by RT-PCR.
Results: Serum levels of 1,25(OH)2-D were significantly lower in MA carriers for rs2762943 compared to MA non-carriers (p=0.004), whereas serum 25(OH)-D levels were comparable between MA carriers and non-carriers. After 24 h of 25(OH)-D stimulation, no differences in the CYP24A1 gene expression levels were found in PBMC from MA carriers and non-carriers. Interestingly, a 4-fold higher CYP24A1 mRNA expression was observed in MS patients carrying the MA for rs2762943 compared to MA non-carriers after 24 h of 1,25(OH)2-D treatment.
Conclusions: The decreased 1,25(OH)2-D serum levels observed in MA carriers may be associated with a CYP24A1 gain of function conferred by the rs2762943 variant. Additional functional studies are needed to confirm these initial findings and further explore the implication of the rs2762943 variant in MS pathogenesis.
Disclosure: E. Gil-Varea, R. Ferrer, F. Matesanz, N. Spataro, S. Malhotra, A. Navarro, E. Bosch and A. Alcina report no disclosures.
X. Montalban has received speaking honoraria and travel expenses for scientific meetings, has been a steering committee member of clinical trials or participated in advisory boards of clinical trials in the past years with Bayer Schering Pharma, Biogen Idec, EMD Merck Serono, Genentech, Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
M. Comabella has received compensation for consulting services and speaking honoraria from Bayer Schering Pharma, Merk Serono, Biogen-Idec, Teva Pharmaceuticals, Sanofi-Aventis, Genzyme and Novartis.
O. Fernández has received honoraria as consultant in advisory boards, and as chairmen or lecturer in meetings, and has also participated in clinical trials and other research projects promoted by Biogen-Idec, Bayer-Schering, Merck-Serono, Teva, Novartis, Roche, Allergan and Almirall.
A. Saiz has received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd and Novartis.
Ll. Ramió-Torrentà has received speaking honoraria and travel expenses for scientific meetings and has participated in advisory boards in the past years with Bayer Schering Pharma, Biogen, EMD Merck Serono, Sanofi Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
G. Izquierdo received speaking honoraria from Almirall, Bayer, Biogen, Novartis, Merck and Roche.
Abstract: EP1466
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: Genetic and environmental factors are known to influence the complex pathogenesis of multiple sclerosis (MS). In recent years, numerous studies have suggested that vitamin D deficiency contributes to MS risk. By means of targeted resequencing (524 MS patients and 546 healthy controls) and subsequent genotyping in an independent cohort (3450 MS patients and 1688 healthy controls), we identified a variant located in the CYP24A1 gene, rs2762943, that was associated with increased MS risk. The CYP24A1 gene encodes a protein that initiates the degradation of the physiologically active form of vitamin D [1,25-dihydroxyvitamin D - 1,25(OH)2-D]. Here, we aimed to assess the functional role of the rs2762943 polymorphism in the pathogenesis of MS.
Methods: By means of chemiluminescent immunoassay technologies, serum levels of 25-hydroxyvitamin D [25(OH)-D] and 1,25(OH)2-D were measured in two independent cohorts of 101 MS patients (30 minor allele - MA carriers, 71 MA non-carriers for rs2762943) and 100 MS patients (26 MA carriers, 74 MA non-carriers for rs2762943) respectively. In addition, peripheral blood mononuclear cells (PBMC) from 16 MS patients (8 MA carriers, 8 MA non-carriers for rs2762943) were cultured with 25(OH)-D (500nM), 1,25(OH)2-D (1nM) or vehicle for 24 h. Total RNA was extracted and CYP24A1 mRNA expression levels were analyzed by RT-PCR.
Results: Serum levels of 1,25(OH)2-D were significantly lower in MA carriers for rs2762943 compared to MA non-carriers (p=0.004), whereas serum 25(OH)-D levels were comparable between MA carriers and non-carriers. After 24 h of 25(OH)-D stimulation, no differences in the CYP24A1 gene expression levels were found in PBMC from MA carriers and non-carriers. Interestingly, a 4-fold higher CYP24A1 mRNA expression was observed in MS patients carrying the MA for rs2762943 compared to MA non-carriers after 24 h of 1,25(OH)2-D treatment.
Conclusions: The decreased 1,25(OH)2-D serum levels observed in MA carriers may be associated with a CYP24A1 gain of function conferred by the rs2762943 variant. Additional functional studies are needed to confirm these initial findings and further explore the implication of the rs2762943 variant in MS pathogenesis.
Disclosure: E. Gil-Varea, R. Ferrer, F. Matesanz, N. Spataro, S. Malhotra, A. Navarro, E. Bosch and A. Alcina report no disclosures.
X. Montalban has received speaking honoraria and travel expenses for scientific meetings, has been a steering committee member of clinical trials or participated in advisory boards of clinical trials in the past years with Bayer Schering Pharma, Biogen Idec, EMD Merck Serono, Genentech, Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
M. Comabella has received compensation for consulting services and speaking honoraria from Bayer Schering Pharma, Merk Serono, Biogen-Idec, Teva Pharmaceuticals, Sanofi-Aventis, Genzyme and Novartis.
O. Fernández has received honoraria as consultant in advisory boards, and as chairmen or lecturer in meetings, and has also participated in clinical trials and other research projects promoted by Biogen-Idec, Bayer-Schering, Merck-Serono, Teva, Novartis, Roche, Allergan and Almirall.
A. Saiz has received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd and Novartis.
Ll. Ramió-Torrentà has received speaking honoraria and travel expenses for scientific meetings and has participated in advisory boards in the past years with Bayer Schering Pharma, Biogen, EMD Merck Serono, Sanofi Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
G. Izquierdo received speaking honoraria from Almirall, Bayer, Biogen, Novartis, Merck and Roche.