Biology subjects

Herranz-Martin, S.

Publications and source records attributed to Herranz-Martin, S..

3 recordsLinked to original sources

bioRxiv2024

Glial cell activation precedes neurodegeneration in the cerebellar cortex of the YG8-800 murine model of Friedreich's ataxia

Friedreichs ataxia is a hereditary neurodegenerative disorder resulting from reduced levels of the protein frataxin due to an expanded GAA repeat in the FXN gene. This deficiency causes progressive degeneration of specific neuronal populations in the cerebellum and the consequent loss of movement coordination and equilibrium, some of the main symptoms observed in affected individuals. Similar to other neurodegenerative diseases, previous studies suggest that glial cells could be involved in the neurodegenerative process and disease progression in Friedreichs ataxia. In this work, we have followed and characterized the progression of changes in the cerebellar cortex of the latest Friedreichs ataxia humanized mouse model, the YG8-800 (Fxnnull:YG8s(GAA)>800), which carries a human FXN transgene containing more than 800 GAA repeats. Comparative analyses of behavioral, histopathological, and biochemical parameters were conducted between Y47R control and YG8-800 mice at different time points. Our findings revealed that the YG8-800 mice display an ataxic phenotype, characterized by poor motor coordination, lower body weight, cerebellar atrophy, neuronal loss, and changes in synaptic proteins. Additionally, early activation of glial cells, predominantly astrocytes and microglia, was observed preceding neuronal degeneration along with an increased expression of key pro-inflammatory cytokines and downregulation of neurotrophic factors. Together, our results show how the YG8-800 mouse model exhibits a stronger phenotype than previous experimental murine models, reliably recapitulating some of the features observed in the human condition. Accordingly, this humanized model could represent a valuable tool to study Friedreichs ataxia molecular disease mechanisms and for preclinical evaluation of possible therapies.

neuroscience↗

bioRxiv2022

CLN7 mutation causes aberrant redistribution of protein isoforms and contributes to Batten disease pathobiology

The variant late infantile form of the inherited neurodegenerative Batten disease (BD) is caused by mutations in the CLN7/MFSD8 gene and represents a strong candidate for gene therapy. Post-natal intracerebral administration of AAV9-hCLN7 to Cln7{Delta}ex2 knockout mice resulted in extended lifespan but dose escalation resulted in reduced acuity in neurophysiology tests, cerebral atrophy and elevated neuroinflammation. Comparing patient and control iPSC-derived neural progenitor cells (iNPC) we discovered that CLN7 localizes to the nucleus as well as the endolysosomal network and is differentially distributed in BD iNPC. Proteomics identified a profound nuclear defect in BD iNPC that compounds with mitochondrial and lysosomal metabolic defects resulting in elevated apoptosis. We further identified a 50kDa common nuclear CLN7 isoform and a 37kDa isoform that accumulates only in BD iNPC nuclei. Our findings suggest that successful treatment of CLN7 BD will require combinatorial therapies addressing both loss and aberrant gain of protein function.

cell biology↗

bioRxiv2019

Neonatal brain-directed gene therapy rescues a mouse model of neurodegenerative CLN6 Batten disease

The neuronal ceroid lipofuscinoses (NCLs), more commonly referred to as Batten disease, are a group of inherited lysosomal storage disorders that present with neurodegeneration, loss of vision and premature death. There are at least 13 genetically distinct forms of NCL. Enzyme replacement therapies and preclinical studies on gene supplementation have shown promising results for NCLs caused by lysosomal enzyme deficiencies. The development of gene therapies targeting the brain for NCLs caused by defects in transmembrane proteins has been more challenging and only limited therapeutic effects in animal models have been achieved so far. Here, we describe the development of an adeno-associated virus (AAV)-mediated gene therapy to treat the neurodegeneration in a mouse model of CLN6 disease, a form of NCL with a deficiency in the membrane-bound protein CLN6. We show that neonatal bilateral intracerebroventricular injections with AAV9 carrying CLN6 increase lifespan by more than 90%, maintain motor skills and motor coordination and reduce neuropathological hallmarks of Cln6-deficient mice up to 23 months post vector administration. These data demonstrate that brain-directed gene therapy is a valid strategy to treat the neurodegeneration of CLN6 disease and may be applied to other forms of NCL caused by transmembrane protein deficiencies in the future.

neuroscience↗