2026-02-22 | Long-term efficacy and disease-specific responsiveness to protirelin in patients with spinocerebellar degeneration: A retrospective study.
The thyrotropin-releasing hormone (TRH) analog protirelin has short-term benefits for cerebellar ataxia (CA), but its long-term efficacy and the subtype-specific responsiveness of spinocerebellar degeneration (SCD) patients remain unclear. We retrospectively reviewed the records of 92 SCD patients (273 courses) treated with protirelin between July 2011 and October 2025, including patients with idiopathic CA (IDCA), multiple system atrophy with predominant CA (MSA-C) or parkinsonism (MSA-P), and genetic subtypes including spinocerebellar ataxia (SCA) type 6, SCA31 and dentatorubral-pallidoluysian atrophy (DRPLA). Responders were defined as showing ≥1-point improvement on the Scale for the Assessment and Rating of Ataxia (SARA). Protirelin was effective in 64.1% of subjects, with significant improvement overall (p < 0.001) and significant SARA gains in MSA-C (p = 0.047), IDCA (p = 0.02), and SCA31 (p = 0.01). Change in SARA score (ΔSARA) correlated negatively with age and positively with total protirelin dose in IDCA, and negatively with age and disease duration and positively with baseline SARA score in SCA31. Several IDCA and DRPLA patients maintained clinical benefit for more than 10 years. All MSA-P discontinued protirelin within 2 years and all MSA-C within 5 years; some SCA6, and SCA31 patients continued for ≥5 years. Adverse effects were infrequent (2/92, 2.2%). Protirelin is efficacious in SCD patients and well-tolerated, particularly in slow-progressing phenotypes (IDCA and SCA31); its benefit in rapidly progressing ataxias (MSA-C) may be confined to early disease stages. Prospective studies with standardized dosing and long-term follow-up are warranted to establish evidence-based protocols for TRH-related therapy for CA.
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2026-01-13 | Data in support of: Atrophin-1 antisense oligonucleotide provides robust protection from pathology in a fully humanized DRPLA model
Dentatorubral-pallidoluysian atrophy (DRPLA) is a fatal neurodegenerative disease arising from a CAG repeat expansion in the atrophin-1 (ATN1) gene. Because DRPLA, like many repeat expansion disorders (REDs), arises predominantly from toxic gain-of-function mechanisms, we hypothesized that ATN1 knockdown would have therapeutic potential. To test this, we established the first fully humanized mouse model of a RED, in which one allele of mouse Atn1 is completely replaced by human ATN1, including 112 pure CAG repeats. This novel approach to exploring RED biology provides significant advantages, notably the ability to test sequence-specific therapeutics targeting human sequences, even in introns and untranslated regions of pre-mRNA. We found that our model—the Atn1Q112/+ mouse—recapitulates key features of human DRPLA, including behavioral alterations, reduced brain size, and aggregate accumulation. We treated Atn1Q112/+ mice with antisense oligonucleotides (ASOs) targeting mouse Atn1 (to probe for loss of function concerns), human ATN1, or a combination. Treatment with human, but not mouse, ATN1-targeting ASOs provides remarkable protection from a range of disease-related behavioral phenotypes and marked rescue of transcriptional dysregulation in the cerebellum. These results have helped motivate an ongoing human clinical study of ASOs targeting ATN1 for DRPLA.
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2025-11-27 | ERBB4 colocalizes with phosphorylated tau aggregates in multiple tauopathies.
The neuregulin-ERBB4 pathway is essential for maintaining cellular function. Upon stimulation by its ligand, neuregulin, ERBB4-a receptor tyrosine kinase-triggers multiple cellular responses, including proliferation, apoptosis, differentiation, and neuromuscular junction formation. Previous research has implicated dysregulated ERBB4 signaling in the pathophysiology of several neurodegenerative disorders, such as Alzheimer's disease, progressive supranuclear palsy, amyotrophic lateral sclerosis, and Parkinson's disease. In this study, we examined ERBB4 expression in diseases characterized by phosphorylated tau (MAPT) pathology. We found that ERBB4 colocalized with neuronal and glial phosphorylated tau-positive inclusions in multiple tauopathies, including Pick's disease, Alzheimer's disease, corticobasal degeneration, progressive supranuclear palsy, argyrophilic grain disease, and frontotemporal lobar degeneration with MAPT mutation. Conversely, ERBB4 did not colocalize with α-synuclein aggregates in α-synucleinopathies (Parkinson's disease and multiple system atrophy) or with neuronal intranuclear inclusions in triplet repeat disorders (Huntington's disease and dentatorubral-pallidoluysian atrophy). A co-immunoprecipitation assay indicated that ERBB4 can interact with tau intracellularly. Notably, in corticobasal degeneration, we observed ectopic ERBB4 expression in astrocytes lacking apparent phosphorylated tau aggregates. These findings suggest a potential role for ERBB4 in the pathophysiology of tau-related neurodegenerative diseases.
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