Viral mediated knockdown of GATA6 in SMA iPSC-derived astrocytes prevents motor neuron loss and microglial activation.

Spinal muscular atrophy (SMA), a pediatric genetic disorder, is characterized by the profound loss of spinal cord motor neurons and subsequent muscle atrophy and death. Although the mechanisms underlying motor neuron loss are not entirely clear, data from our work and others support the idea that glial cells contribute to disease pathology. GATA6, a transcription factor that we have previously shown to be upregulated in SMA astrocytes, is negatively regulated by SMN (survival motor neuron) and can increase the expression of inflammatory regulator NFκB. In this study, we identified upregulated GATA6 as a contributor to increased activation, pro-inflammatory ligand production, and neurotoxicity in spinal-cord patterned astrocytes differentiated from SMA patient induced pluripotent stem cells. Reducing GATA6 expression in SMA astrocytes via lentiviral infection ameliorated these effects to healthy control levels. Additionally, we found that SMA astrocytes contribute to SMA microglial phagocytosis, which was again decreased by lentiviral-mediated knockdown of GATA6. Together these data identify a role of GATA6 in SMA astrocyte pathology and further highlight glia as important targets of therapeutic intervention in SMA.

Eficacia y seguridad de risdiplam en pacientes pediátricos con atrofia muscular espinal tipo 2 o tipo 3 / Efficacy and safety of risdiplam in pediatric patients with spinal muscular atrophy type 2 or type 3

ANTECEDENTES: En el marco de la metodología ad hoc para evaluar solicitudes de tecnologías sanitarias, aprobada mediante Resolución de Instituto de Evaluación de Tecnologías en Salud e Investigación N° 111-IETSI-ESSALUD-2021 y ampliada mediante Resolución de Instituto de Evaluación de Tecnologías en Salud e Investigación N° 97-IETSI-ESSALUD2022, se ha elaborado el presente dictamen, el cual expone la evaluación de la eficacia y seguridad de risdiplam en pacientes pediátricos con atrofia muscular espinal 5q tipo 2 y tipo 3. Así, Elizabeth Ruth Espíritu Rojas y Katherine Joyce Ramos, médicos especialistas en neurología pediátrica del Hospital Nacional Edgardo Rebagliati Martins (HNERM) siguiendo la Directiva N° 003-IETSI-ESSALUD-2016, enviaron a través del comité farmacoterapéutico del HNERM al Instituto de Evaluación de Tecnologías en Salud e Investigación - IETSI la solicitud de autorización de uso del producto farmacéutico risdiplam no incluido en el Petitorio Farmacológico del EsSalud. ASPECTOS GENERALES: La atrofia muscular espinal (AME) es un conjunto de enfermedades neuromusculares raras con una base genética caracterizada por la degeneración de las células de la asta anterior de la médula espinal y de los núcleos motores en el tronco encefálico inferior, que lleva a una debilidad muscular proximal simétrica difusa y atrofia progresiva. La condición genética del AME se asocia al cromosoma 5 brazo q, y se hereda de forma autosómica recesiva. Los diferentes tipos del AME son causados por deleciones o mutaciones puntuales en el gen SMN1, lo que ocasiona un déficit de la proteína SMN, generando alteración en la síntesis de ARNm en tejido cerebral, motoneuronas y en la médula espinal, estos cambios se relacionan directamente con la fisiopatología del AME. Sin embargo, debido a que los genes SMN1 y SMN2 presentan homología en un 99 % en la secuencia de sus nucleátidos, la proteína SMN se compensa parcialmente mediante la síntesis de la SMN2 (mayo, ©2023 UpToDate) (Ferrari et al. 2010). Así, el inicio y la gravedad de la enfermedad se correlacionan principalmente con el número de copias del gen SMN2, lo cual también permite la clasificación clínica de la AME en fenotipos del O al 4 (Russman B, 2007; Munsat T, 1992). METODOLOGÍA: Se llevó a cabo una búsqueda bibliográfica exhaustiva, sistemática y jerárquica de la literatura con el objetivo de identificar la mejor evidencia sobre la eficacia y seguridad de risdiplam en pacientes pediátricos con AME 5q tipo 2 o tipo 3. La búsqueda bibliográfica se realizó en las bases de datos PubMed, The Cochrane Library y LILACS. Asimismo, se realizó una búsqueda manual dentro de las páginas web pertenecientes a grupos que realizan evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC) incluyendo National Institute for Health and Care Excellence (NICE), International HTA database, Institut national d'excellence en santé et en services sociaux (INESSS), Canadian Agency for Drugs and Technologies in Health (CADTH), Scottish Medicines Consortium (SMC), Scottish Intercollegiate Guidelines Network (SIGN), Institute for Quality and Efficiency in Healthcare (IQWiG por sus siglas en alemán), International Database of GRADE Guideline, Centro Nacional de Excelencia Tecnológica en Salud (CENETEC), Guidelines International Network (GIN), National Health and Medical Research Council (NHMRC), Comissáo Nacional de IncorporaQáo de Tecnologias no Sistema Único de Saúde (CONITEC), Instituto de Evaluación Tecnológica en Salud (IETS), Red Española de Agencias de Evaluación de Tecnologías Sanitarias y Prestaciones del Sistema Nacional de Salud, Instituto de Efectividad Clínica y Sanitaria (IECS), Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA), Organización Mundial de la Salud (OMS), Ministerio de Salud del Perú (MINSA) e Instituto de Evaluación de Tecnologías en Salud e Investigación (IETSI). Finalmente, se realizó una búsqueda en la página web de registro de ensayos clínicos (EC) www.clinicaltrials.gov, para identificar EC en curso o que no hayan sido publicados aún. Se seleccionaron GPC, ETS, revisiones sistemáticas (RS), y ECA de fase III que abordaran la pregunta PICO del presente dictamen. La selección de documentos se realizó en dos fases. En la primera, se realizó la revisión de títulos y resúmenes de las publicaciones, a través del aplicativo web Rayyan (https://rawan.ai/), por parte de dos evaluadores independientes. En la segunda, uno de los evaluadores revisó los documentos a texto completo incluidos en la primera fase y realizó la selección final de los estúdios. RESULTADOS: Luego de la búsqueda bibliográfica, se logró identificar: una GPC de la Sociedad Peruana de Neurología (GPC- AME 2021); seis ETS elaboradas por HAS 2021, NICE 2021, IQWiG 2021, CADTH 2021, SMC 2022 y CONITEC 2022, y finalmente un ECA III, el estudio SUNFISH (NCT02908685). No se contó con alguna RS que se enfocara en la PICO de interés. CONCLUSIÓN: Por lo expuesto, el Instituto de Evaluación de Tecnologías en Salud e Investigación no aprueba el uso de risdiplam para pacientes pediátricos con AME tipo 2 y tipo 3, como producto farmacéutico no incluido en el Petitorio Farmacológico de EsSalud.

Synthetic Nucleic Acids and Treatment of Neurological Diseases.

IMPORTANCE: The ability to control gene expression with antisense oligonucleotides (ASOs) could provide a new treatment strategy for disease. OBJECTIVE: To review the use of ASOs for the treatment of neurological disorders. EVIDENCE REVIEW: Articles were identified through a search of PubMed references from 2000 to 2016 for articles describing the use of ASOs to treat disease, with specific attention to neurological disease. We concentrated our review on articles pertaining to activation of frataxin expression (Friedreich's ataxia) and production of active survival motor neuron 2 (SMN2, spinal muscular atrophy). FINDINGS: Many neurological diseases are caused by inappropriate expression of a protein. Mutations may reduce expression of a wild-type protein, and strategies to activate expression may provide therapeutic benefit. For other diseases, a mutant protein may be expressed too highly and methods that reduce mutant protein expression might form the basis for drug development. Synthetic ASOs can recognize cellular RNA and control gene expression. Antisense oligonucleotides are not a new concept, but successful clinical development has proceeded at a slow pace. Advances in ASO chemistry, biological understanding, and clinical design are making successful applications more likely. CONCLUSIONS AND RELEVANCE: Both laboratory and clinical studies are demonstrating the potential of ASOs as a source of drugs to treat neurological disease.

Defining the therapeutic window in a severe animal model of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the loss of a single gene, Survival Motor Neuron-1 (SMN1). Administration of a self-complementary Adeno-Associated Virus vector expressing full-length SMN cDNA (scAAV-SMN) has proven an effective means to rescue the SMA phenotype in SMA mice, either by intravenous (IV) or intracerebroventricular (ICV) administration at very early time points. We have recently shown that ICV delivery of scAAV9-SMN is more effective than a similar dose of vector administered via an IV injection, thereby providing an important mechanism to examine a timeline for rescuing the disease and determining the therapeutic window in a severe model of SMA. In this report, we utilized a relatively severe mouse model of SMA, SMNΔ7. Animals were injected with scAAV9-SMN vector via ICV injection on a single day, from P2 through P8. At each delivery point from P2 through P8, scAAV9-SMN decreased disease severity. A near complete rescue was obtained following P2 injection while a P8 injection produced a ∼ 40% extension in survival. Analysis of the underlying neuromuscular junction (NMJ) pathology revealed that late-stage delivery of the vector failed to provide protection from NMJ defects despite robust SMN expression in the central nervous system. While our study demonstrates that a maximal benefit is obtained when treatment is delivered during pre-symptomatic stages, significant therapeutic benefit can still be achieved after the onset of disease symptoms.

Systemic delivery of scAAV9 expressing SMN prolongs survival in a model of spinal muscular atrophy.

Spinal muscular atrophy is one of the most common genetic causes of death in childhood, and there is currently no effective treatment. The disease is caused by mutations in the survival motor neuron gene. Gene therapy aimed at restoring the protein encoded by this gene is a rational therapeutic approach to ameliorate the disease phenotype. We previously reported that intramuscular delivery of a lentiviral vector expressing survival motor neuron increased the life expectancy of transgenic mice with spinal muscular atrophy. The marginal efficacy of this therapeutic approach, however, prompted us to explore different strategies for gene therapy delivery to motor neurons to achieve a more clinically relevant effect. Here, we report that a single injection of self-complementary adeno-associated virus serotype 9 expressing green fluorescent protein or of a codon-optimized version of the survival motor neuron protein into the facial vein 1 day after birth in mice carrying a defective survival motor neuron gene led to widespread gene transfer. Furthermore, this gene therapy resulted in a substantial extension of life span in these animals. These data demonstrate a significant increase in survival in a mouse model of spinal muscular atrophy and provide evidence for effective therapy.