Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis
| dc.contributor.author | Nel, Melissa | |
| dc.contributor.author | Prince, Sharon | |
| dc.contributor.author | Heckmann, Jeannine M | |
| dc.date.accessioned | 2019-02-05T12:50:12Z | |
| dc.date.available | 2019-02-05T12:50:12Z | |
| dc.date.issued | 2019-01-29 | |
| dc.date.updated | 2019-02-03T04:17:23Z | |
| dc.description.abstract | Background: While extraocular muscles are affected early in myasthenia gravis (MG), but respond to treatment, we observe a high incidence of treatment-resistant ophthalmoplegia (OP-MG) among MG subjects with African genetic ancestry. Previously, using whole exome sequencing, we reported potentially functional variants which associated with OP-MG. The aim of this study was to profile the expression of genes harbouring the OP-MG associated variants using patient-derived subphenotype-specific ‘myocyte’ cultures. Methods From well-characterised MG patients we developed the ‘myocyte’ culture models by transdifferentiating dermal fibroblasts using an adenovirus expressing MyoD. These myocyte cultures were treated with homologous acetylcholine receptor antibody-positive myasthenic sera to induce muscle transcripts in response to an MG stimulus. Gene expression in myocytes derived from OP-MG (n = 10) and control MG subjects (MG without ophthalmoplegia; n = 6) was quantified using a custom qPCR array profiling 93 potentially relevant genes which included the putative OP-MG susceptibility genes and other previously reported genes of interest in MG and experimental autoimmune myasthenia gravis (EAMG). Results OP-MG myocytes compared to control MG myocytes showed altered expression of four OP-MG susceptibility genes (PPP6R2, CANX, FAM136A and FAM69A) as well as several MG and EAMG genes (p < 0.05). A correlation matrix of gene pair expression levels revealed that 15% of gene pairs were strongly correlated in OP-MG samples (r > 0.78, p < 0.01), but not in control MG samples. OP-MG susceptibility genes and MG-associated genes accounted for the top three significantly correlated gene pairs (r ≥ 0.98, p < 1 × 10− 6) reflecting crosstalk between OP-MG and myasthenia pathways, which was not evident in control MG cells. The genes with altered expression dynamics between the two subphenotypes included those with a known role in gangliosphingolipid biosynthesis, mitochondrial metabolism and the IGF1-signalling pathway. Conclusion Using a surrogate cell culture model our findings suggest that muscle gene expression and co-expression differ between OP-MG and control MG individuals. These findings implicate pathways not previously considered in extraocular muscle involvement in myasthenia gravis and will inform future studies. | |
| dc.identifier.apacitation | Nel, M., Prince, S., & Heckmann, J. M. (2019). Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis. http://hdl.handle.net/11427/29335 | en_ZA |
| dc.identifier.chicagocitation | Nel, Melissa, Sharon Prince, and Jeannine M Heckmann "Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis." (2019) http://hdl.handle.net/11427/29335 | en_ZA |
| dc.identifier.citation | Nel, M., Prince, S., & Heckmann, J. M. 2019. Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis. Journal of Rare Diseases. 14(1):24 | |
| dc.identifier.ris | TY - Journal Article AU - Nel, Melissa AU - Prince, Sharon AU - Heckmann, Jeannine M AB - Background: While extraocular muscles are affected early in myasthenia gravis (MG), but respond to treatment, we observe a high incidence of treatment-resistant ophthalmoplegia (OP-MG) among MG subjects with African genetic ancestry. Previously, using whole exome sequencing, we reported potentially functional variants which associated with OP-MG. The aim of this study was to profile the expression of genes harbouring the OP-MG associated variants using patient-derived subphenotype-specific ‘myocyte’ cultures. Methods From well-characterised MG patients we developed the ‘myocyte’ culture models by transdifferentiating dermal fibroblasts using an adenovirus expressing MyoD. These myocyte cultures were treated with homologous acetylcholine receptor antibody-positive myasthenic sera to induce muscle transcripts in response to an MG stimulus. Gene expression in myocytes derived from OP-MG (n = 10) and control MG subjects (MG without ophthalmoplegia; n = 6) was quantified using a custom qPCR array profiling 93 potentially relevant genes which included the putative OP-MG susceptibility genes and other previously reported genes of interest in MG and experimental autoimmune myasthenia gravis (EAMG). Results OP-MG myocytes compared to control MG myocytes showed altered expression of four OP-MG susceptibility genes (PPP6R2, CANX, FAM136A and FAM69A) as well as several MG and EAMG genes (p < 0.05). A correlation matrix of gene pair expression levels revealed that 15% of gene pairs were strongly correlated in OP-MG samples (r > 0.78, p < 0.01), but not in control MG samples. OP-MG susceptibility genes and MG-associated genes accounted for the top three significantly correlated gene pairs (r ≥ 0.98, p < 1 × 10− 6) reflecting crosstalk between OP-MG and myasthenia pathways, which was not evident in control MG cells. The genes with altered expression dynamics between the two subphenotypes included those with a known role in gangliosphingolipid biosynthesis, mitochondrial metabolism and the IGF1-signalling pathway. Conclusion Using a surrogate cell culture model our findings suggest that muscle gene expression and co-expression differ between OP-MG and control MG individuals. These findings implicate pathways not previously considered in extraocular muscle involvement in myasthenia gravis and will inform future studies. DA - 2019-01-29 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PY - 2019 T1 - Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis TI - Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis UR - http://hdl.handle.net/11427/29335 ER - | en_ZA |
| dc.identifier.uri | https://doi.org/10.1186/s13023-019-1003-y | |
| dc.identifier.uri | http://hdl.handle.net/11427/29335 | |
| dc.identifier.vancouvercitation | Nel M, Prince S, Heckmann JM. Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis. 2019; http://hdl.handle.net/11427/29335. | en_ZA |
| dc.language.iso | en | |
| dc.publisher | BioMed Central | |
| dc.rights.holder | The Author(s). | |
| dc.subject.other | Myasthenia gravis | |
| dc.subject.other | Ophthalmoplegia | |
| dc.subject.other | Gene expression | |
| dc.subject.other | Transdifferentiation | |
| dc.subject.other | Subphenotype | |
| dc.subject.other | Myotranscriptome | |
| dc.title | Profiling of patient-specific myocytes identifies altered gene expression in the ophthalmoplegic subphenotype of myasthenia gravis | |
| dc.type | Journal Article |