Generation of two induced pluripotent stem cell lines (HIMRi006-A and HIMRi007-A) from Pompe patients with infantile and late disease onset

Here we present the generation of HIMRi006-A and HIMRi007-A Pompe disease (PD) patient derived human induced pluripotent stem cell (hiPSC) lines. HIMRi006-A represents an infantile onset disease (IOPD) phenotype caused by a homozygous c.307 T > G mutation in the GAA gene. HIMRi007-A is characterized by heterozygous mutations c.-32-13 T > G/c.1716C > G and is associated with an adult onset of disease symptoms (LOPD). Both lines are generated via lentiviral expression of OCT4, SOX2, KLF4, and c-MYC. The lines display a typical embryonic stem cell morphology, express pluripotency markers, retain a normal karyotype (46, XX/XY) and have the differentiation capacity in all three germ layers. Altogether, both lines provide a resource tool to the community for future in depth molecular studies of PD pathomechanism.

Generation of two hiPSCs lines of two patients carrying truncating mutations in the dimerization domain of filamin C

Here we introduce the human induced pluripotent stem cell lines (hiPSCs), HIMRi004-A and HIMRi005-A from dermal fibroblasts of a 48-year-old female (HIMRi004-A) carrying missense mutation that translate to the first described filamin C isoform p.W2710X and from a 56-year-old female (HIMRi005-A) carrying a recently described mutation in the same domain p.Y2704X. Both lines are generated via lentiviral expression of OCT4, SOX2, KLF4 and c-MYC. The lines display a typical embryonic stem cell-like morphology, express pluripotency markers, retain a normal karyotype (46, XX) and have the differentiation capacity in all three germ layers. The two lines can be used to elucidate the pathomechanisms of FLNC myofibrillar myopathies and to develop novel therapeutic options.

Generation of two human iPSC lines (HIMRi002-A and HIMRi003-A) derived from Caveolinopathy patients with rippling muscle disease

Here we introduce the human induced pluripotent stem cell lines (hiPSCs), HIMRi002-A and HIMRi003-A, generated from cultured dermal fibroblasts of 61-year-old (HIMRi002-A) and 38-year-old (HIMRi003-A) female patients, carrying a known heterozygous pathogenic variant (p.A46T) in the Caveolin 3 (CAV3) gene, via lentiviral expression of OCT4, SOX2, KLF4 and c-MYC. HIMRi002-A and HIMRi003-A display typical embryonic stem cell-like morphology, carry the p.A46T CAV3 gene mutation, express several pluripotent stem cell markers, retain normal karyotype (46, XX) and can differentiate in all three germ layers. We postulate that the HIMRi002-A and HIMRi003-A iPSC lines can be used for the characterization of CAV3-associated pathomechanisms and for developing new therapeutic options.

Generation of a human iPSC line (HIMRi001-A) from a patient with filaminopathy

Here we introduce the human induced pluripotent stem cell (hiPSC) line HIMRi001-A generated from cultured dermal fibroblasts of a 60-year-old male patient with a myofibrillar myopathy, carrying a heterozygous c.4984C > T [p.Q1662X] mutation in the filamin C (FLNC)-gene, via lentiviral expression of OCT4, SOX2, KLF4 and c-MYC. HIMRi001-A displays typical embryonic stem cell-like morphology, carries the c.4984C > T FLNC gene mutation, expressed several pluripotent stem cell makers, retained normal karyotype (46, XY) and holds the potential to differentiate in all three germ layers. We postulate that HIMRi001-A can be used for the elucidation of FLNC-associated pathomechanisms and for developing new therapeutic options.

Diffusion Tensor Imaging Shows Differences Between Myotonic Dystrophy Type 1 and Type 2

BACKGROUND

Myotonic Dystrophies type 1 and type 2 are hereditary myopathies with dystrophic muscle degeneration in varying degrees. Differences in muscle diffusion between both diseases have not been evaluated yet.

OBJECTIVE

To evaluate the ability to of muscle diffusion tensor imaging (mDTI) and Dixon fat-quantification to distinguish between Myotonic dystrophy (DM) type 1 and type 2 and if both diseases show distinct muscle involvement patterns.

METHODS

We evaluated 6 thigh and 7 calf muscles (both legs) of 10 DM 1 and 13 DM 2 and 28 healthy controls (HC) with diffusion tensor imaging, T1w and mDixonquant sequences in a 3T MRI scanner. The quantitative mDTI-values axial diffusivity (λ1), mean diffusivity (MD), radial diffusivity (RD) and fractional anisotropy (FA) as well as fat-fraction were analysed. CTG-Triplett repeat-length of DM 1 patients was correlated to diffusion metrics and fat-fraction.

RESULTS

mDTI showed significant differences between DM 1 and DM 2 vs. healthy controls in diffusion parameters of the thigh (all p < 0.001) except for FA (p = 0.0521 / 0.8337). In calf muscles mDTI showed significant differences between DM 1 and DM 2 patients (all p < 0.0001) as well as between DM 1 patients and controls (all p = 0.0001). Thigh muscles had a significant higher fat-fraction in both groups vs. controls (p < 0.05). There was no correlation of CTG triplet length with mDTI values and fat-fraction.

DISCUSSION

mDTI reveals specific changes of the diffusion parameters and fat-fraction in muscles of DM 1 and DM 2 patients. Thus, the quantitative MRI methods presented in this study provide a powerful tool in differential diagnosis and follow-up of DM 1 and DM 2, however, the data must be validated in larger studies.

Differential proteomic analysis of abnormal intramyoplasmic aggregates in desminopathy

Desminopathy is a subtype of myofibrillar myopathy caused by desmin mutations and characterized by protein aggregates accumulating in muscle fibers. The aim of this study was to assess the protein composition of these aggregates. Aggregates and intact myofiber sections were obtained from skeletal muscle biopsies of five desminopathy patients by laser microdissection and analyzed by a label-free spectral count-based proteomic approach. We identified 397 proteins with 22 showing significantly higher spectral indices in aggregates (ratio >1.8, p<0.05). Fifteen of these proteins not previously reported as specific aggregate components provide new insights regarding pathomechanisms of desminopathy. Results of proteomic analysis were supported by immunolocalization studies and parallel reaction monitoring. Three mutant desmin variants were detected directly on the protein level as components of the aggregates, suggesting their direct involvement in aggregate-formation and demonstrating for the first time that proteomic analysis can be used for direct identification of a disease-causing mutation in myofibrillar myopathy. Comparison of the proteomic results in desminopathy with our previous analysis of aggregate composition in filaminopathy, another myofibrillar myopathy subtype, allows to determine subtype-specific proteomic profile that facilitates identification of the specific disorder.

BIOLOGICAL SIGNIFICANCE

Our proteomic analysis provides essential new insights in the composition of pathological protein aggregates in skeletal muscle fibers of desminopathy patients. The results contribute to a better understanding of pathomechanisms in myofibrillar myopathies and provide the basis for hypothesis-driven studies. The detection of specific proteomic profiles in different myofibrillar myopathy subtypes indicates that proteomic analysis may become a useful tool in differential diagnosis of protein aggregate myopathies.

[Metabolic and mitochondrial myopathies]

Metabolic myopathies include a broad group of diseases involving inherited enzyme defects in the various metabolic pathways and skeletal musculature. They show an extensive phenotypic variability of symptoms and different ages of manifestation. Symptoms often included intolerance to duress or permanent paresis. Some forms of metabolic myopathy, in particular mitochondriopathy, are associated with multsystemic organ participation. The diagnostics must be adjusted to individual cases and carried out in stages. Primary investigations should include blood parameters (e.g. creatine kinase measurement, muscle load tests and determination of the acylcarnitine spectrum) and a second step includes muscle biopsy for histological and enzyme investigations and special molecular genetic tests although the causative enzyme defect cannot be clarified in every case. On the other hand by means of a thorough investigation it is particularly important in patients with load intolerance to differentiate between other causes, in particular psychosomatic diseases. If this is not done there is a danger of classifying the symptoms of a metabolic myopathy as a somatoform disorder. Therapy is mostly symptom-oriented as Pompe disease is the only one which can be treated with enzyme replacement therapy.

[Camptocormia in the differential diagnosis of hyperkyphosis and ankylosing spondylitis]

HISTORY AND ADMISSION FINDINGS

An 83-year-old patient with Parkinson's disease was referred because of pain in the thoracolumbar spine, increasing kyphosis and gait disturbance. Clinically, the main anomaly was a marked hyperkyphosis of the spine during standing and sitting which regressed while recumbent.

INVESTIGATIONS

Radiologically, spondylosis, osteochondrosis, and facet joint arthrosis demonstrated marked degeneration of the spine (diffuse skeletal hyperostosis, DISH). But the postural disorder could not adequately be explained by these pathological changes. The sacroiliac joints were age-appropriate, syndesmophytes or ankylosis typically of AS were not detectable.

DIAGNOSIS, TREATMENT AND COURSE

A diagnosis of camptocormia in connection with the known Parkinson's disease was made together with the neurologist. Intensive physio- and balneotherapy, the administration of non-steroidal anti-inflammatory drugs (NSAIDs) and an intensification of the Parkinson medication led to a slight improvement of gait disturbance and pain, but not of the tendency to hyperkyphosis.

CONCLUSION

In the differential diagnosis of postural disorders in spinal diseases, especially in case of hyperkyphosis, camptocormia is of importance as a rare manifestation of different diseases, such as Parkinson's disease. The treatment of camptocormia is difficult and usually not satisfactory.