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Distintos genes del complejo de reparación de desajustes establecen la tasa de expansión de la repetición de CAG

Nan Wang¹, Shasha Zhang¹, Peter Langfelder¹

¹Center for Neurobehavioral Genetics, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.

|February 12, 2025

Resumen

Los genes de reparación de desajuste Msh3 y Pms1 rescatan significativamente los fenotipos de la enfermedad de Huntington (HD) en ratones al reducir las expansiones de repetición CAG dañinas en las neuronas. Este hallazgo ofrece nuevos objetivos terapéuticos para la EH.

Área de la Ciencia:

La neurociencia
La genética
Biología molecular

Sus antecedentes:

La patogénesis de la enfermedad de Huntington (HD) implica la agregación mutante de la proteína Huntingtin (mHtt) y la disfunción neuronal.
Los genes de reparación de desajuste (MMR) son modificadores conocidos de la EH, pero sus funciones específicas en el daño neuronal no se comprenden completamente.

Objetivo del estudio:

Investigar el impacto de genes MMR específicos en la patogénesis de la EH en un modelo de ratón.
Elucidar los mecanismos por los que los genes MMR influyen en la expansión somática de la repetición CAG y en los fenotipos neuronales en la EH.

Principales métodos:

Pruebas genéticas de 9 genes de asociación de todo el genoma de la EH (GWAS) / MMR en ratones con Huntingtina mutante Q140 (mHtt).
Análisis de fenotipos, incluida la expansión somática de la repetición de CAG, la transcripción, la agregación de mHtt y las funciones neuronales / sinápticas / locomotoras.
Evaluación de los efectos del knockout genético de la MMR en estos fenotipos relacionados con la EH.

Principales resultados:

El nocaut de Msh3 y Pms1 rescató fuertemente los fenotipos de EH, mientras que Msh2 y Mlh1 mostraron un rescate moderado.
La deficiencia del gen MMR redujo o detuvo significativamente la rápida expansión de la repetición somática de CAG en las neuronas espinosas medianas (MSN).
La deficiencia de Msh3 corregía los déficits sinápticos, astrocíticos y locomotores, y prevenía la agregación de mHtt al limitar la longitud del CAG.

Conclusiones:

Msh3 y Pms1 son factores clave de la rápida expansión somática de la repetición de CAG en las neuronas vulnerables a la EH.
Dirigirse a Msh3 y Pms1 puede ofrecer una estrategia terapéutica para mitigar la progresión de la EH mediante el control de la patogénesis dependiente de la repetición.

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