Generation of two human iPSC lines, FINCBi002-A and FINCBi003-A, carrying heteroplasmic macrodeletion of mitochondrial DNA causing Pearson's syndrome

Pearson marrow pancreas syndrome (PMPS) is a sporadic mitochondrial disease, resulting from the clonal expansion of a mutated mitochondrial DNA (mtDNA) molecule bearing a macro-deletion, and therefore missing essential genetic information. PMPS is characterized by the presence of deleted (Δ) mtDNA that co-exist with the presence of a variable amount of wild-type mtDNA, a condition termed heteroplasmy. All tissues of the affected individual, including the haemopoietic system and the post-mitotic, highly specialized tissues (brain, skeletal muscle, and heart) contain the large-scale mtDNA deletion in variable amount. We generated human induced pluripotent stem cells (hiPSCs) from two PMPS patients, carrying different type of large-scale deletion

Generation of a human iPSC line, FINCBi001-A, carrying a homoplasmic m.G3460A mutation in MT-ND1 associated with Leber's Hereditary optic Neuropathy (LHON)

Leber's Hereditary Optic Neuropathy (LHON) is a maternally inherited disorder caused by homoplasmic mutations of mitochondrial DNA (mtDNA). LHON is characterized by the selective degeneration of the retinal ganglion cells (RGC). Almost all LHON maternal lineages are homoplasmic mutant (100% mtDNA copies are mutant) for one of three frequent mtDNA mutations now found in over 90% of patients worldwide (m.11778G > A/MT-ND4, m.3460G > A/MT-ND1, m.14484 T > C/MT-ND6). Human induced pluripotent stem cells (hiPSCs) were generated from a patient carrying the homoplasmic m.3460G > A/MT-ND1 mutation using the Sendai virus non-integrating virus

The relevance of mitochondrial DNA variants fluctuation during reprogramming and neuronal differentiation of human iPSCs

The generation of inducible pluripotent stem cells (iPSCs) is a revolutionary technique allowing production of pluripotent patient-specific cell lines used for disease modeling, drug screening, and cell therapy. Integrity of nuclear DNA (nDNA) is mandatory to allow iPSCs utilization, while quality control of mitochondrial DNA (mtDNA) is rarely included in the iPSCs validation process. In this study, we performed mtDNA deep sequencing during the transition from parental fibroblasts to reprogrammed iPSC and to differentiated neuronal precursor cells (NPCs) obtained from controls and patients affected by mitochondrial disorders. At each step, mtDNA variants, including those potentially pathogenic, fluctuate between emerging and disappearing, and some having functional implications. We strongly recommend including mtDNA analysis as an unavoidable assay to obtain fully certified usable iPSCs and NPCs.Peer reviewe

Method for analyzing accident risks at level crossings aiming to increase railway operational safety

O presente artigo propõe um método para análise dos riscos existentes de acidentes em passagens em nível (PN) em ferrovias brasileiras. Assim, foi realizada uma análise em normas nacionais e internacionais para identificar os principais critérios adotados para classificação por tipo de risco e para definição do tipo de sinalização a ser empregado, visando aumentar a segurança desses cruzamentos. Com base no resultado da análise, foi desenvolvido o método proposto e aplicado na malha de uma ferrovia na região sudeste do país. De acordo com os dados históricos, verifica-se que as obras de sinalização implantadas tiveram resultados positivos em segurança (queda de 72% no número de ocorrências entre 2014 e 2019), proporcionou o aumento da velocidade máxima autorizada no trecho, gerando um menor impacto no trânsito (visto que a PN é liberada mais rapidamente), garantindo ganhos para a operação e para a população que precisa transpor as intervenções nessas localidades, diminuindo os ruídos emitidos pelo tráfego e a necessidade de manutenção em locomotivas e vagões.This article proposes a method for analyzing and solving accident risks at grade crossings in the Brazilian railroads. Thus, an analysis was carried out on national and international standards to identify the main criteria adopted for classifying the type of risk and for defining the type of signaling to be used, aiming to increase the safety of these grade crossings. Based on the analysis result, the proposed method was developed and applied to a railroad network in the southeastern region of the country. According to the historical data, one verifies that the implemented signaling works had positive results in safety (drop of 72% in the number of occurrences between 2014 and 2019), provided an increase in the maximum authorized speed on the railroad stretch, generating less impact in traffic (since the grade crossing is released more quickly), assuring gains for the operation and for the population that needs to transpose the railroad in these locations, reducing the noise emitted by traffic and the need for locomotives and wagons maintenance.Este artículo propone un método para analizar los riesgos de accidentes existentes en los pasos a nivel (PN) de los ferrocarriles brasileños. Así, se realizó un análisis en estándares nacionales e internacionales para identificar los principales criterios adoptados para la clasificación por tipo de riesgo y definir el tipo de señalización a utilizar, con el fin de incrementar la seguridad de estos cruces. Con base en el resultado del análisis, se desarrolló el método propuesto y se aplicó a una red ferroviaria en la región sureste del país. Según datos históricos, parece que las obras de señalización implementadas tuvieron resultados positivos en seguridad (caída del 72% en el número de ocurrencias entre 2014 y 2019), siempre que se incremente la velocidad máxima autorizada en el tramo, generando un menor impacto en el tráfico. (ya que la PN se libera más rápidamente), asegurando ganancias para la operación y para la población que necesita superar las intervenciones en estos lugares, reduciendo el ruido emitido por el tráfico y la necesidad de mantenimiento en locomotoras y vagones

Pathological mitophagy disrupts mitochondrial homeostasis in Leber's hereditary optic neuropathy

Leber's hereditary optic neuropathy (LHON), a disease associated with a mitochondrial DNA mutation, is characterized by blindness due to degeneration of retinal ganglion cells (RGCs) and their axons, which form the optic nerve. We show that a sustained pathological autophagy and compartment-specific mitophagy activity affects LHON patient-derived cells and cybrids, as well as induced pluripotent-stem-cell-derived neurons. This is variably counterbalanced by compensatory mitobiogenesis. The aberrant quality control disrupts mitochondrial homeostasis as reflected by defective bioenergetics and excessive reactive oxygen species production, a stress phenotype that ultimately challenges cell viability by increasing the rate of apoptosis. We counteract this pathological mechanism by using autophagy regulators (clozapine and chloroquine) and redox modulators (idebenone), as well as genetically activating mitochondrial biogenesis (PGC1-α overexpression). This study substantially advances our understanding of LHON pathophysiology, providing an integrated paradigm for pathogenesis of mitochondrial diseases and druggable targets for therapy

Genetic variants affecting NQO1 protein levels impact the efficacy of idebenone treatment in Leber hereditary optic neuropathy

Idebenone, the only approved treatment for Leber hereditary optic neuropathy (LHON), promotes recovery of visual function in up to 50% of patients, but we can neither predict nor understand the non -responders. Idebenone is reduced by the cytosolic NAD(P)H oxidoreductase I (NQO1) and directly shuttles electrons to respiratory complex III, bypassing complex I affected in LHON. We show here that two polymorphic variants drastically reduce NQO1 protein levels when homozygous or compound heterozygous. This hampers idebenone reduction. In its oxidized form, idebenone inhibits complex I, decreasing respiratory function in cells. By retrospectively analyzing a large cohort of idebenone-treated LHON patients, classified by their response to therapy, we show that patients with homozygous or compound heterozygous NQO1 variants have the poorest therapy response, particularly if carrying the m.3460G>A/MT-ND1 LHON mutation. These results suggest consideration of patient NQO1 genotype and mitochondrial DNA mutation in the context of idebenone therapy

Generation of two human iPSC lines, HMGUi004-A and FINCBi004-A, from fibroblasts of MPAN patients carrying pathogenic recessive mutations in the gene C19orf12

Mitochondrial membrane Protein-Associated Neurodegeneration (MPAN) is a lethal neurodegenerative disorder caused by mutations in the human gene C19orf12. The molecular mechanisms underlying the disorder are still unclear, and no established therapy is available. Here, we describe the generation and characterization of two human induced pluripotent stem cell (iPSC) lines derived from skin fibroblasts of two MPAN patients carrying homozygous recessive mutations in C19orf12. These iPSC lines represent a useful resource for future investigations on the pathology of MPAN, as well as for the development of successful treatments

Generation of iPSCs from identical twin, one affected by LHON and one unaffected, both carrying a combination of two mitochondrial variants: m.14484 T>C and m.10680G>A

Leber hereditary optic neuropathy (LHON) is one of the most common mitochondrial illness, causing retinal ganglion cell degeneration and central vision loss. It stems from point mutations in mitochondrial DNA (mtDNA), with key mutations being m.3460G > A, m.11778G > A, and m.14484 T > C. Fibroblasts from identical twins, sharing m.14484 T > C and m.10680G > A variants each with 70 % heteroplasmy, were used to generate iPSC lines. Remarkably, one twin, a LHON patient, displayed symptoms, while the other, a carrier, remained asymptomatic. These iPSCs offer a valuable tool for studying factors influencing disease penetrance and unravelling the role of m.10680G > A, which is still debated

Bismuth mobile promoter and cobalt-bismuth nanoparticles in carbon nanotube supported Fischer-Tropsch catalysts with enhanced stability

International audienc