Establishing resources and increasing awareness to advance research on Dentatorubral-pallidoluysian atrophy toward a treatment: a patient organization perspective.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an ultra-rare neurodegenerative disorder characterized by ataxia, cognitive decline, myoclonus, chorea, epilepsy, and psychiatric manifestations. This article delves into the multifaceted efforts of CureDRPLA, a family-driven non-profit organization, in advancing research, raising awareness, and developing therapeutic strategies for this complex condition. CureDRPLA's inception in 2019 led to the establishment of the DRPLA Research Program, and since then have funded research projects to advance the understanding of DRPLA including but not limited to human cellular and mouse models, a natural history and biomarkers study, and a patient registry. There are currently no disease-modifying treatments for DRPLA, motivating a concerted effort on behalf of CureDRPLA to hasten their development by funding and coordinating preclinical studies of therapies in multiple modalities. Of particular interest are therapies focused on lowering the expression (or downregulation) of ATN1, the mutant gene that causes DRPLA, in hopes of tackling the pathology at its root. As with many ultra-rare diseases, a key challenge in DRPLA remains the complexity of coordinating both basic and clinical research efforts across multiple sites around the world. Finally, despite the generous financial support provided by CureDRPLA, more funding and collective efforts are still required to advance research toward the clinic and develop effective treatments for individuals with DRPLA.

Funding research projects and activities to advance research towards treatments for dentatorubral-pallidoluysian atrophy (DRPLA) This article describes the journey of CureDRPLA, a family-driven non-profit organization dedicated to making strides against dentatorubral-pallidoluysian atrophy (DRPLA), an ultra-rare brain disorder. It describes CureDRPLA's tireless efforts to understand, treat, and raise awareness about DRPLA, a condition marked by movement difficulties (ataxia), intellectual disability, uncontrollable jerky movements (myoclonus), involuntary or irregular muscle movements (chorea) and seizures. This disorder is caused by a mutation in a gene called ATN1. The gene produces a protein called atrophin-1, and when the DRPLA-causing mutation is present, the protein becomes abnormal and can build up in the brain, affecting its normal functions. Since its founding in 2019, CureDRPLA has funded research projects to unravel the mysteries of the disease and provide support for affected individuals. CureDRPLA has funded projects to create models of DRPLA using human cells and mice, which helps scientists study the disease and test potential treatments. We have started a study to learn more about how DRPLA progresses in people and are building a global database of information from individuals with DRPLA. Due to the absence of a treatment or cure, CureDRPLA is focused on testing treatments. We are particularly interested in exploring different approaches to lower the levels of the abnormal protein in the brain. CureDRPLA is actively involving the DRPLA community worldwide, raising awareness through events, conferences, and social media. We aim to connect with medical professionals, researchers, and affected families to build a strong community focused on understanding and managing DRPLA. In summary, CureDRPLA is working hard to better understand DRPLA, support affected families, and accelerate the development of treatments for this challenging condition. Our collaborative efforts and dedication underscore the importance of a united global approach to address the complexities of DRPLA.

Understanding dentatorubral-pallidoluysian atrophy (DRPLA) symptoms and impacts on daily life: a qualitative interview study with patients and caregivers.

Background: Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare, neurodegenerative disorder with no disease-modifying treatments. There is a dearth of information in the literature about the patient and caregiver experience living with DRPLA. Objectives: This study aimed to (1) understand symptoms experienced by adult- and juvenile-onset DRPLA populations and their impact on daily life and (2) explore patient and caregiver treatment goals and clinical trial participation preferences. Design: The study was a qualitative interview study. Methods: Interviews were conducted remotely with adult patients with DRPLA and caregivers. Participants described patient symptoms and the impact of those symptoms on daily life, and they discussed treatment goals and potential clinical trial participation. There were 18 patients described in the interviews with two patients and seven caregivers. Some participants were caregivers to multiple patients with DRPLA. Results: Interview transcripts were coded for themes, and reported symptoms were summarized with descriptive statistics. Adult-onset patients (N = 7) experienced difficulty with ataxia (100%), cognition (100%), fine motor skills (100%), gross motor skills (100%), speech (100%), personality changes (100%), and seizures (57%). Juvenile-onset patients (N = 11) experienced difficulty with ataxia (100%), sleep (100%), speech (100%), jerking/twitching (83%), behavior (82%), cognition (82%), fine motor skills (82%), gross motor skills (82%), sensory sensitivity (75%), and seizures (64%). When considering aspects of DRPLA to target for future treatment, patients prioritized ataxia/mobility (100%), juvenile-onset caregivers prioritized ataxia/mobility (60%) and independence (60%), and adult-onset caregivers prioritized personality (60%). Almost all patients (93%) would participate in a clinical trial if given the opportunity, but travel to a clinical site could pose a participation barrier for half. Conclusion: This study found that there are symptom domains that are relevant across the DRPLA population, but there is heterogeneity within each domain based on the age of symptom onset and disease stage, which has implications for clinical trial design.

Understanding dentatorubral-pallidoluysian atrophy (DRPLA) symptoms and impacts on daily life through interviews with patients and caregivers Why was the study done? Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare and progressive brain disorder. Little is known about the patient and caregiver experience living with DRPLA and this lack of information has hindered the development of patient-focused treatments and the measurement of outcomes that are most meaningful to caregivers and patients. What did the researchers do? To address this problem, researchers conducted interviews with patients and caregivers of DRPLA to (1) better understand symptoms experienced by adult- and juvenile-onset DRPLA populations and their impact on daily life and (2) explore patient and caregiver treatment goals and clinical trial participation preferences. What did the researchers find? Eighteen patients were described in the interviews. Adult-onset patients (onset at age 20 or older) experienced difficulty with coordination, cognition, motor skills, speech, personality changes, and seizures. Juvenile-onset patients (onset before age 20) experienced difficulty with coordination, sleep, speech, jerking/twitching, behavior, cognition, motor skills, sensory sensitivity, and seizures. When considering symptoms to prioritize for future treatment, patients and caregivers identified coordination/mobility, independence, and personality as important. Nearly all participants indicated they would participate in a clinical trial if given an opportunity, however half expressed that travel to a clinical site could pose a barrier. What do the findings mean? This study provides a better understanding of the symptoms experienced by DRPLA patients and their impact on daily life. Additionally, it identifies important targets for treatment and considerations when designing clinical trials for DRPLA such as the barrier caused by travel to a clinical site.

The vestibular calyceal junction is dismantled following subchronic streptomycin in rats and sensory epithelium stress in humans.

Hair cell (HC) loss by epithelial extrusion has been described to occur in the rodent vestibular system during chronic 3,3'-iminodipropionitrile (IDPN) ototoxicity. This is preceded by dismantlement of the calyceal junction in the contact between type I HC (HCI) and calyx afferent terminals. Here, we evaluated whether these phenomena have wider significance. First, we studied rats receiving seven different doses of streptomycin, ranging from 100 to 800 mg/kg/day, for 3-8 weeks. Streptomycin caused loss of vestibular function associated with partial loss of HCI and decreased expression of contactin-associated protein (CASPR1), denoting calyceal junction dismantlement, in the calyces encasing the surviving HCI. Additional molecular and ultrastructural data supported the conclusion that HC-calyx detachment precede HCI loss by extrusion. Animals allowed to survive after the treatment showed functional recuperation and rebuilding of the calyceal junction. Second, we evaluated human sensory epithelia obtained during therapeutic labyrinthectomies and trans-labyrinthine tumour excisions. Some samples showed abnormal CASPR1 label strongly suggestive of calyceal junction dismantlement. Therefore, reversible dismantlement of the vestibular calyceal junction may be a common response triggered by chronic stress, including ototoxic stress, before HCI loss. This may partly explain clinical observations of reversion in function loss after aminoglycoside exposure.

Functional P2X7 Receptors in the Auditory Nerve of Hearing Rodents Localize Exclusively to Peripheral Glia.

P2X7 receptors (P2X7Rs) are associated with numerous pathophysiological mechanisms, and this promotes them as therapeutic targets for certain neurodegenerative conditions. However, the identity of P2X7R-expressing cells in the nervous system remains contentious. Here, we examined P2X7R functionality in auditory nerve cells from rodents of either sex, and determined their functional and anatomic expression pattern. In whole-cell recordings from rat spiral ganglion cultures, the purinergic agonist 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) activated desensitizing currents in spiral ganglion neurons (SGNs) but non-desensitizing currents in glia that were blocked by P2X7R-specific antagonists. In imaging experiments, BzATP gated sustained Ca2+ entry into glial cells. BzATP-gated uptake of the fluorescent dye YO-PRO-1 was reduced and slowed by P2X7R-specific antagonists. In rats, P2X7Rs were immuno-localized predominantly within satellite glial cells (SGCs) and Schwann cells (SCs). P2X7R expression was not detected in the portion of the auditory nerve within the central nervous system. Mouse models allowed further exploration of the distribution of cochlear P2X7Rs. In GENSAT reporter mice, EGFP expression driven via the P2rx7 promoter was evident in SGCs and SCs but was undetectable in SGNs. A second transgenic model showed a comparable cellular distribution of EGFP-tagged P2X7Rs. In wild-type mice the discrete glial expression was confirmed using a P2X7-specific nanobody construct. Our study shows that P2X7Rs are expressed by peripheral glial cells, rather than by afferent neurons. Description of functional signatures and cellular distributions of these enigmatic proteins in the peripheral nervous system (PNS) will help our understanding of ATP-dependent effects contributing to hearing loss and other sensory neuropathies.SIGNIFICANCE STATEMENT P2X7 receptors (P2X7Rs) have been the subject of much scrutiny in recent years. They have been promoted as therapeutic targets in a number of diseases of the nervous system, yet the specific cellular location of these receptors remains the subject of intense debate. In the auditory nerve, connecting the inner ear to the brainstem, we show these multimodal ATP-gated channels localize exclusively to peripheral glial cells rather than the sensory neurons, and are not evident in central glia. Physiologic responses in the peripheral glia display classical hallmarks of P2X7R activation, including the formation of ion-permeable and also macromolecule-permeable pores. These qualities suggest these proteins could contribute to glial-mediated inflammatory processes in the auditory periphery under pathologic disease states.