Contamination of Mesenchymal Stem-Cells with Fibroblasts Accelerates Neurodegeneration in an Experimental Model of Parkinson’s Disease

Pre-clinical studies have supported the use of mesenchymal stem cells (MSC) to treat highly prevalent neurodegenerative diseases such as Parkinson’s disease (PD) but preliminary trials have reported controversial results. In a rat model of PD induced by MPTP neurotoxin, we first observed a significant bilateral preservation of dopaminergic neurons in the substantia nigra and prevention of motor deficits typically observed in PD such as hypokinesia, catalepsy, and bradykinesia, following intracerebral administration of human umbilical cord-derived MSC (UC-MSC) early after MPTP injury. However, surprisingly, administration of fibroblasts, mesenchymal cells without stem cell properties, as a xenotransplantation control was highly detrimental, causing significant neurodegeneration and motor dysfunction independently of MPTP. This observation prompted us to further investigate the consequences of transplanting a MSC preparation contaminated with fibroblasts, a plausible circumstance in cell therapy since both cell types display similar immunophenotype and can be manipulated in vitro under the same conditions. Here we show for the first time, using the same experimental model and protocol, that transplantation of UC-MSC induced potent neuroprotection in the brain resulting in clinical benefit. However, co-transplantation of UC-MSC with fibroblasts reverted therapeutic efficacy and caused opposite damaging effects, significantly exacerbating neurodegeneration and motor deficits in MPTP-exposed rats. Besides providing a rationale for testing UC-MSC transplantation in early phases of PD aiming at delaying disease progression, our pre-clinical study suggests that fibroblasts may be common cell contaminants affecting purity of MSC preparations and clinical outcome in stem cell therapy protocols, which might also explain discrepant clinical results

Silent polymorphisms in the RYR1 gene do not\ud modify the phenotype of the p.4898 I>T\ud pathogenic mutation in central core disease:\ud a case report

Background: Central core disease is a congenital myopathy, characterized by presence of central core-like areas in\ud muscle fibers. Patients have mild or moderate weakness, hypotonia and motor developmental delay. The disease is\ud caused by mutations in the human ryanodine receptor gene (RYR1), which encodes a calcium-release channel.\ud Since the RYR1 gene is huge, containing 106 exons, mutation screening has been limited to three ‘hot spots’, with\ud particular attention to the C-terminal region. Recent next- generation sequencing methods are now identifying\ud multiple numbers of variants in patients, in which interpretation and phenotype prevision is difficult.\ud Case presentation: In a Brazilian Caucasian family, clinical, histopathological and molecular analysis identified a\ud new case of central core disease in a 48-year female. Sanger sequencing of the C-terminal region of the RYR1\ud gene identified two different missense mutations: c.14256 A > C polymorphism in exon 98 and c.14693 T > C in\ud exon 102, which have already been described as pathogenic. Trans-position of the 2 mutations was confirmed\ud because patient’s daughter, mother and sister carried only the exon 98’s mutation, a synonymous variant that was\ud subsequently found in the frequency of 013–0,05 of alleles. Further next generation sequencing study of the whole\ud RYR1 gene in the patient revealed the presence of additional 5 common silent polymorphisms in homozygosis and\ud 8 polymorphisms in heterozygosis.\ud Conclusions: Considering that patient’s relatives showed no pathologic phenotype, and the phenotype presented\ud by the patient is within the range observed in other central core disease patients with the same mutation, it was\ud concluded that the c.14256 A > C polymorphism alone is not responsible for disease, and the associated additional\ud silent polymorphisms are not acting as modifiers of the primary pathogenic mutation in the affected patient. The\ud case described above illustrates the present reality where new methods for wide genome screening are becoming\ud more accessible and able to identify a great variety of mutations and polymorphisms of unknown function in\ud patients and their families.Fundação de Amparo a Pesquisa do Estado de São Paulo - Centro de Pesquisa, Inovação e Difusão (FAPESP-CEPID)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-INCT)Associação Brasileira de Distrofia Muscular (ABDIM)CAPES-COFECU

Early transplantation of human immature dental pulp stem cells from baby teeth to golden retriever muscular dystrophy (GRMD) dogs: Local or systemic?

<p>Abstract</p> <p>Background</p> <p>The golden retriever muscular dystrophy (GRMD) dogs represent the best available animal model for therapeutic trials aiming at the future treatment of human Duchenne muscular dystrophy (DMD). We have obtained a rare litter of six GRMD dogs (3 males and 3 females) born from an affected male and a carrier female which were submitted to a therapeutic trial with adult human stem cells to investigate their capacity to engraft into dogs muscles by local as compared to systemic injection without any immunosuppression.</p> <p>Methods</p> <p>Human Immature Dental Pulp Stem Cells (hIDPSC) were transplanted into 4 littermate dogs aged 28 to 40 days by either arterial or muscular injections. Two non-injected dogs were kept as controls. Clinical translation effects were analyzed since immune reactions by blood exams and physical scores capacity of each dog. Samples from biopsies were checked by immunohistochemistry (dystrophin markers) and FISH for human probes.</p> <p>Results and Discussion</p> <p>We analyzed the cells' ability in respect to migrate, engraftment, and myogenic potential, and the expression of human dystrophin in affected muscles. Additionally, the efficiency of single and consecutive early transplantation was compared. Chimeric muscle fibers were detected by immunofluorescence and fluorescent <it>in situ </it>hybridisation (FISH) using human antibodies and X and Y DNA probes. No signs of immune rejection were observed and these results suggested that hIDPSC cell transplantation may be done without immunosuppression. We showed that hIDPSC presented significant engraftment in GRMD dog muscles, although human dystrophin expression was modest and limited to several muscle fibers. Better clinical condition was also observed in the dog, which received monthly arterial injections and is still clinically stable at 25 months of age.</p> <p>Conclusion</p> <p>Our data suggested that systemic multiple deliveries seemed more effective than local injections. These findings open important avenues for further researches.</p

Overexpression of KLC2 due to a homozygous deletion in the non-coding region causes SPOAN syndrome

SPOAN syndrome is a neurodegenerative disorder mainly characterized by spastic paraplegia, optic atrophy and neuropathy (SPOAN). Affected patients are wheelchair bound after 15 years old, with progressive joint contractures and spine deformities. SPOAN patients also have sub normal vision secondary to apparently non-progressive congenital optic atrophy. A potential causative gene was mapped at 11q13 ten years ago. Here we performed next-generation sequencing in SPOAN-derived samples. While whole-exome sequencing failed to identify the causative mutation, whole-genome sequencing allowed to detect a homozygous 216-bp deletion (chr11.hg19:g.66,024,557_66,024,773del) located at the non-coding upstream region of the KLC2 gene. Expression assays performed with patient’s fibroblasts and motor neurons derived from SPOAN patients showed KLC2 overexpression. Luciferase assay in constructs with 216-bp deletion confirmed the overexpression of gene reporter, varying from 48 to 74%, as compared with wild-type. Knockdown and overexpression of klc2 in Danio rerio revealed mild to severe curly-tail phenotype, which is suggestive of a neuromuscular disorder. Overexpression of a gene caused by a small deletion in the non-coding region is a novel mechanism, which to the best of our knowledge, was never reported before in a recessive condition. Although the molecular mechanism of KLC2 up-regulation still remains to be uncovered, such example adds to the importance of non-coding regions in human pathologyFil: Melo, Uira S.. Universidade de Sao Paulo; BrasilFil: Macedo Souza, Lucia I.. Universidade de Sao Paulo; BrasilFil: Figueiredo, Thalita. Federal University of Paraiba; Brasil. Paraiba State University; BrasilFil: Muotri, Alysson R. University of California at San Diego; Estados UnidosFil: Gleeson, Joseph G.. The Rockefeller University; Estados UnidosFil: Coux, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Armas, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Calcaterra, Nora Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Kitajima, João P.. Mendelics Genomic Analysis; BrasilFil: Amorim, Simone. Universidade de Sao Paulo; BrasilFil: Olávio, Thiago R.. Universidade de Sao Paulo; BrasilFil: Griesi Oliveira, Karina. Universidade de Sao Paulo; BrasilFil: Coatti, Giuliana C.. Universidade de Sao Paulo; BrasilFil: Rocha, Clarissa R.R. Universidade de Sao Paulo; BrasilFil: Martins Pinheiro, Marinalva. Universidade de Sao Paulo; BrasilFil: Menck, Carlos F.M.. Universidade de Sao Paulo; BrasilFil: Zaki, Maha S.. National Research Center. EL Cairo; EgiptoFil: Kok, Fernando. Universidade de Sao Paulo; BrasilFil: Zatz, Mayana. Universidade de Sao Paulo; BrasilFil: Santos, Silvana. Federal University of Paraiba; Brasil. Paraiba State University; Brasi