Eyes Wide Open: Assessing Early Visual Behavior in Zebrafish Larvae.

Early diagnosis is critical for the effective management of neurodegenerative disorders, and retinal alterations have emerged as promising early biomarkers due to the retina's close developmental and functional link to the brain. The zebrafish (Danio rerio), with its rapid development, transparent embryos, and evolutionarily conserved visual system, represents a powerful and versatile model for studying retinal degeneration. This review discusses a range of behavioral assays-including visual adaptation, motion detection, and color discrimination-that are employed to evaluate retinal function in zebrafish.

HPDL Biallelic Variants in Cerebral Palsy and Childhood-Onset Hereditary Spastic Paraplegia: Human and Zebrafish Insights.

Background: The human 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL) has been linked to hereditary spastic paraplegia (HSP) with potential roles in neurogenesis and energy metabolism. However, the prevalence of HPDL variants in childhood-onset motor impairments remains unclear.

Objective: This study set out to characterize new patients with biallelic HPDL variants, and to explore the role of this protein both in vitro and in vivo.

Long-term benefits of TUDCA supplement in ARSACS zebrafish model.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodevelopmental and neurodegenerative disorder characterized by ataxia, spasticity, and peripheral neuropathy. However, several studies have highlighted that some patients also experience cognitive, emotional and social deficits, suggesting a more complex clinical picture that extends beyond motor symptoms. Building on these findings, this study aimed to: (i) investigate locomotor, social and cognitive deficits in adult sacs zebrafish versus wild-type (WT) controls through behavioural tests; (ii) identify molecular patterns associated with the adult disease phenotype using transcriptomic and proteomic analyses of sacs and WT brains; (iii) evaluate the effectiveness of long-term treatment with tauroursodeoxycholic acid (TUDCA) on behavioural outcomes and omics profiles in the zebrafish sacs model.

Whole Blood DNA Methylation Analysis Reveals Epigenetic Changes Associated with ARSACS.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare inherited condition described worldwide and characterized by a wide spectrum of heterogeneity in terms of genotype and phenotype. How sacsin loss leads to neurodegeneration is still unclear, and current knowledge indicates that sacsin is involved in multiple functional mechanisms. We hence hypothesized the existence of epigenetic factors, in particular alterations in methylation patterns, that could contribute to ARSACS pathogenesis and explain the pleiotropic effects of SACS further than pathogenic mutations.

Modeling sacsin depletion in Danio Rerio offers new insight on retinal defects in ARSACS.

Biallelic mutations in the SACS gene, encoding sacsin, cause early-onset autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), a neurodegenerative disease also characterized by unique and poorly understood retinal abnormalities. While two murine models replicate the phenotypic and neuronal features observed in patients, no retinal phenotype has been described so far. In a zebrafish knock-out strain that faithfully mirrors the main aspects of ARSACS, we observed impaired visual function due to photoreceptor degeneration, likely caused by cell cycle defects in progenitor cells.

Dapagliflozin ameliorates Lafora disease phenotype in a zebrafish model.

Lafora disease (LD) is an ultra-rare and still incurable neurodegenerative condition. Although several therapeutic strategies are being explored, including gene therapy, there are currently no treatments that can alleviate the course of the disease and slow its progression. Recently, gliflozins, a series of SGLT2 transporter inhibitors approved for use in type 2 diabetes mellitus, heart failure and chronic kidney disease, have been proposed as possible repositioning drugs for the treatment of LD.

Delving into the Complexity of Valproate-Induced Autism Spectrum Disorder: The Use of Zebrafish Models.

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental condition with several identified risk factors, both genetic and non-genetic. Among these, prenatal exposure to valproic acid (VPA) has been extensively associated with the development of the disorder. The zebrafish, a cost- and time-effective model, is useful for studying ASD features.

SCAR32: Functional characterization and expansion of the clinical-genetic spectrum.

Objective: Biallelic mutations in PRDX3 have been linked to autosomal recessive spinocerebellar ataxia type 32. In this study, which aims to contribute to the growing body of knowledge on this rare disease, we identified two unrelated patients with mutations in PRDX3. We explored the impact of PRDX3 mutation in patient skin fibroblasts and the role of the gene in neurodevelopment.

Pluripotent Stem Cells as a Preclinical Cellular Model for Studying Hereditary Spastic Paraplegias.

Hereditary spastic paraplegias (HSPs) comprise a family of degenerative diseases mostly hitting descending axons of corticospinal neurons. Depending on the gene and mutation involved, the disease could present as a pure form with limb spasticity, or a complex form associated with cerebellar and/or cortical signs such as ataxia, dysarthria, epilepsy, and intellectual disability. The progressive nature of HSPs invariably leads patients to require walking canes or wheelchairs over time.

Converging Role for REEP1/SPG31 in Oxidative Stress.

Mutations in the receptor expression-enhancing protein 1 gene are associated with hereditary spastic paraplegia type 31 (SPG31), a neurological disorder characterized by length-dependent degeneration of upper motor neuron axons. Mitochondrial dysfunctions have been observed in patients harboring pathogenic variants in , suggesting a key role of bioenergetics in disease-related manifestations. Nevertheless, the regulation of mitochondrial function in SPG31 remains unclear.

A Review on the Bioactivity of Cannabinoids on Zebrafish Models: Emphasis on Neurodevelopment.

For centuries, the cannabis plant has been used as a source of food, fiber, and medicine. Recently, scientific interest in cannabis has increased considerably, as its bioactive compounds have shown promising potential in the treatment of numerous musculoskeletal and neurological diseases in humans. However, the mechanisms that underlie its possible effects on neurodevelopment and nervous-system functioning remain poorly understood and need to be further investigated.

Oxytocin Receptor Gene Polymorphism in Lactating Dogs.

Genetic variations in the oxytocinergic system, known to regulate social behavior throughout the evolution of mammals, are believed to account for differences in mammalian social behavior. Particularly, polymorphic variants of the oxytocin receptor () gene have been associated with behavioral variations in both humans and dogs. In this study, we offered evidence of the correlation between levels of salivary oxytocin (sOXT), maternal behavior and a single-nucleotide gene variant in (8679684) in nineteen lactating Labrador Retriever dogs.

Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in , which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays.

β-Glucans as Dietary Supplement to Improve Locomotion and Mitochondrial Respiration in a Model of Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration. A lack of dystrophin in DMD leads to inflammatory response, autophagic dysregulation, and oxidative stress in skeletal muscle fibers that play a key role in the progression of the pathology. β-glucans can modulate immune function by modifying the phagocytic activity of immunocompetent cells, notably macrophages.

New pathogenic variants in COQ4 cause ataxia and neurodevelopmental disorder without detectable CoQ deficiency in muscle or skin fibroblasts.

COQ4 is a component of an enzyme complex involved in the biosynthesis of coenzyme Q (CoQ), a molecule with primary importance in cell metabolism. Mutations in the COQ4 gene are responsible for mitochondrial diseases showing heterogeneous age at onset, clinical presentations and association with CoQ deficiency. We herein expand the phenotypic and genetic spectrum of COQ4-related diseases, by reporting two patients harboring bi-allelic variants but not showing CoQ deficiency.

Social Preference Tests in Zebrafish: A Systematic Review.

The use of animal models in biology research continues to be necessary for the development of new technologies and medicines, and therefore crucial for enhancing human and animal health. In this context, the need to ensure the compliance of research with the principles Replacement, Reduction and Refinement (the 3 Rs), which underpin the ethical and human approach to husbandry and experimental design, has become a central issue. The zebrafish () is becoming a widely used model in the field of behavioral neuroscience.

The Stemness Gene Mex3A Is a Key Regulator of Neuroblast Proliferation During Neurogenesis.

Mex3A is an RNA binding protein that can also act as an E3 ubiquitin ligase to control gene expression at the post-transcriptional level. In intestinal adult stem cells, MEX3A is required for cell self-renewal and when overexpressed, MEX3A can contribute to support the proliferation of different cancer cell types. In a completely different context, we found among the genes expressed in neurogenic niches of the embryonic and adult fish brain and, notably, its expression was downregulated during brain aging.

Loss of ap4s1 in zebrafish leads to neurodevelopmental defects resembling spastic paraplegia 52.

Autosomal recessive spastic paraplegia 52 is caused by biallelic mutations in AP4S1 which encodes a subunit of the adaptor protein complex 4 (AP-4). Using next-generation sequencing, we identified three novel unrelated SPG52 patients from a cohort of patients with cerebral palsy. The discovered variants in AP4S1 lead to reduced AP-4 complex formation in patient-derived fibroblasts.

: Zebrafish Modeling of Complicated Forms of Hereditary Spastic Paraplegia and Spastic Ataxia.

Hereditary spastic paraplegia (HSP) and hereditary ataxia (HA) are two groups of disorders characterized, respectively, by progressive dysfunction or degeneration of the pyramidal tracts (HSP) and of the Purkinje cells and spinocerebellar tracts (HA). Although HSP and HA are generally shown to have distinct clinical-genetic profiles, in several cases the clinical presentation, the causative genes, and the cellular pathways and mechanisms involved overlap between the two forms. Genetic analyses in humans in combination with and studies using model systems have greatly expanded our knowledge of spinocerebellar degenerative disorders.

Fishing in the Cell Powerhouse: Zebrafish as A Tool for Exploration of Mitochondrial Defects Affecting the Nervous System.

The zebrafish () is a small vertebrate ideally suited to the modeling of human diseases. Large numbers of genetic alterations have now been modeled and could be used to study organ development by means of a genetic approach. To date, limited attention has been paid to the possible use of the zebrafish toolbox in studying human mitochondrial disorders affecting the nervous system.

PDGF-B: The missing piece in the mosaic of PDGF family role in craniofacial development.

Background: The platelet-derived growth factor (PDGF) family consists of four ligands (PDGF-A, PDGF-B, PDGF-C, PDGF-D) and two tyrosine kinase receptors (PDGFR-α and PDGFR-β). In vertebrates, PDGF signaling influences cell proliferation, migration, and matrix deposition, and its up-regulation is implicated in cancer progression. Despite this evidence, the role of each family member during embryogenesis is still incomplete and partially controversial.

The age-regulated zinc finger factor ZNF367 is a new modulator of neuroblast proliferation during embryonic neurogenesis.

Global population aging is one of the major social and economic challenges of contemporary society. During aging the progressive decline in physiological functions has serious consequences for all organs including brain. The age-related incidence of neurodegenerative diseases coincides with the sharp decline of the amount and functionality of adult neural stem cells.