Patient-specific iPSC-derived cellular models of LGMDR1.

Limb-girdle muscular dystrophy recessive 1 (LGMDR1) represents one of the most common types of LGMD in the population, where patients develop a progressive muscle degeneration. The disease is caused by mutations in calpain 3 gene, with over 500 mutations reported to date. However, the molecular events that lead to muscle wasting are not clear, nor the reasons for the great clinical variability among patients, and this has so far hindered the development of effective therapies. Here we generate human induced pluripotent stem cells (iPSCs) from skin fibroblasts of 2 healthy controls and 4 LGMDR1 patients with different mutations. The generated lines were able to differentiate into myogenic progenitors and myotubes in vitro and in vivo, upon a transient PAX7 overexpressing protocol. Thus, we have generated myogenic cellular models of LGMDR1 that harbor different CAPN3 mutations within a human genetic background, and which do not derive from muscular biopsies. These models will allow us to investigate disease mechanisms and test therapies. Despite the variability found among iPSC lines that was unrelated to CAPN3 mutations, we found that patient-derived myogenic progenitors and myotubes express lower levels of DMD, which codes a key protein in satellite cell regulation and myotube maturation.

Advanced cell-based modeling of the royal disease: characterization of the mutated F9 mRNA.

Essentials The Royal disease (RD) is a form of hemophilia B predicted to be caused by a splicing mutation. We generated an iPSC-based model of the disease allowing mechanistic studies at the RNA level. F9 mRNA analysis in iPSC-derived hepatocyte-like cells showed the predicted abnormal splicing. Mutated F9 mRNA level was very low but we also found traces of wild type transcripts. SUMMARY: Background The royal disease is a form of hemophilia B (HB) that affected many descendants of Queen Victoria in the 19th and 20th centuries. It was found to be caused by the mutation F9 c.278-3A>G. Objective To generate a physiological cell model of the disease and to study F9 expression at the RNA level. Methods Using fibroblasts from skin biopsies of a previously identified hemophilic patient bearing the F9 c.278-3A>G mutation and his mother, we generated induced pluripotent stem cells (iPSCs). Both the patient's and mother's iPSCs were differentiated into hepatocyte-like cells (HLCs) and their F9 mRNA was analyzed using next-generation sequencing (NGS). Results and Conclusion We demonstrated the previously predicted aberrant splicing of the F9 transcript as a result of an intronic nucleotide substitution leading to a frameshift and the generation of a premature termination codon (PTC). The F9 mRNA level in the patient's HLCs was significantly reduced compared with that of his mother, suggesting that mutated transcripts undergo nonsense-mediated decay (NMD), a cellular mechanism that degrades PTC-containing mRNAs. We also detected small proportions of correctly spliced transcripts in the patient's HLCs, which, combined with genetic variability in splicing and NMD machineries, could partially explain some clinical variability among affected members of the European royal families who had lifespans above the average. This work allowed the demonstration of the pathologic consequences of an intronic mutation in the F9 gene and represents the first bona fide cellular model of HB allowing the study of rare mutations at the RNA level.

[Effectiveness of a program of early instillation single chemotherapy in patients with bladder cancer]. / Efectividad de un programa de instilación de quimioterapia precoz en pacientes con cáncer de vejiga.

OBJECTIVE: To determine the effectiveness of early intravesical chemotherapy intervention for patients with non-muscle invasive bladder cancer, before and after a training and inter-professional communication plan. METHOD: Non-experimental prospective longitudinal study of a cohort of 349 patients with endoscopic diagnosis of a non-muscle invasive bladder tumour in Northern Area Health Management of Cadiz between 2010 and 2013 and amenable to postoperative treatment with mitomycin C. RESULTS: The mean rate of patients included in the program was 53.9%. The inclusion rate rose by 79.3% at 3 years. The absolute risk reduction of recurrence for patients receiving treatment is 18.1% (95% CI; 8.81% - 27.48%, p<.001), and the number of patients needed to treat was 5.5 (95% CI; 3.6 - 11.3, p<.001). CONCLUSIONS: A program of early postoperative chemotherapy that includes a plan for evaluation and dissemination of results has achieved a good level of adherence among professionals, obtaining the expected impact on the reduction of early recurrence of non-muscle invasive bladder cancer.