RNA molecules have emerged as a new class of promising therapeutics to expand the range of druggable targets in the genome. In addition to ‘canonical’ protein-coding mRNAs, the emerging richness of sense and antisense long non-coding RNAs (lncRNAs) provides a new reservoir of molecular tools for RNA-based drugs. LncRNAs are composed of modular structural domains with specific activities involving the recruitment of protein cofactors or directly interacting with nucleic acids. A single therapeutic RNA transcript can then be assembled combining domains with defined secondary structures and functions, and antisense sequences specific for the RNA/DNA target of interest. As the first representative molecules of this new pharmacology, we have identified SINEUPs, a new functional class of natural antisense lncRNAs that increase the translation of partially overlapping mRNAs. Their activity is based on the combination of two domains: an embedded mouse inverted SINEB2 element that enhances mRNA translation (effector domain) and an overlapping antisense region that provides specificity for the target sense transcript (binding domain). By genetic engineering, synthetic SINEUPs can potentially target any mRNA of interest increasing translation and therefore the endogenous level of the encoded protein. In this review, we describe the state-of-the-art knowledge of SINEUPs and discuss recent publications showing their potential application in diseases where a physiological increase of endogenous protein expression can be therapeutic.

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. Despite several attempts to ameliorate the life quality of patients that have been tested, current therapeutical approaches are just symptomatic, as no cure is available. Progress in research in the last two decades has identified a vast number of genes involved in HSP etiology, using cellular and animal models generated on purpose. Although unanimously considered invaluable tools for basic research, those systems are rarely predictive for the establishment of a therapeutic approach. The advent of induced pluripotent stem (iPS) cells allowed instead the direct study of morphological and molecular properties of the patient’s affected neurons generated upon in vitro differentiation. In this review, we revisited all the present literature recently published regarding the use of iPS cells to differentiate HSP patient-specific neurons. Most studies have defined patient-derived neurons as a reliable model to faithfully mimic HSP in vitro, discovering original findings through immunological and –omics approaches, and providing a platform to screen novel or repurposed drugs. Thereby, one of the biggest hopes of current HSP research regards the use of patient-derived iPS cells to expand basic knowledge on the disease, while simultaneously establishing new therapeutic treatments for both generalized and personalized approaches in daily medical practice.

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. These methods enable the detection of subtle visual deficits that may precede overt anatomical damage, providing a non-invasive, efficient strategy for early diagnosis and high-throughput drug screening. Importantly, these behavioral tests also serve as sensitive functional readouts to evaluate the efficacy of pharmacological treatments over time. Compared to traditional murine models, zebrafish offer advantages such as lower maintenance costs, faster development, optical transparency for live imaging, and ethical benefits due to reduced use of higher vertebrates. However, variability in experimental protocols highlights the need for standardization to ensure reliability and reproducibility.

Hereditary spastic paraplegias are rare genetic disorders characterized by corticospinal tract impairment. Spastic paraplegia 83 (SPG83) is associated with biallelic mutations in the HPDL gene, leading to varied severities from neonatal to juvenile onset. The function of HPDL is unclear, though it is speculated to play a role in alternative coenzyme Q10 biosynthesis. Here, we report the generation of hiPS lines from primary skin fibroblasts derived from three SPG83 patients with different HPDL mutations, using episomal reprogramming. The patients’ clinical characteristics are carefully listed. The hiPS lines were meticulously characterized, demonstrating typical pluripotent characteristics through immunofluorescence assays for stemness markers (OCT4, TRA1-60, NANOG, and SSEA4) and RT-PCR for endogenous gene expression. Genetic integrity and identity were confirmed via Sanger sequencing and short tandem repeat analysis. These hiPS cells displayed typical pluripotent characteristics and were able to differentiate into neocortical neurons via a dual SMAD inhibition protocol. In addition, HPDL mutant neurons assessed via long-term culturing were able to achieve effective maturation, similarly to their wild-type counterparts. The HPDL hiPS lines we generated will provide a valuable model for studying SPG83, offering insights into its molecular mechanisms and potential for developing targeted therapies.

Hereditary spastic paraplegias (HSPs) a group of rare, clinically, and genetically heterogeneous disorders characterized by progressive degeneration of the corticospinal tract. Among these HSPs, SPG31 is due to autosomal dominant mutations in the receptor expression-enhancing protein 1 (REEP1) gene. Over 80 genes have been associated with HSPs, and the list is constantly growing as research progresses. This study is aimed to create a patient-derived human induced pluripotent stem cell (hiPSC) line with a specific nonsense mutation to better characterize the etiopathogenesis of the disease.

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. With this in mind, we tested dapagliflozin (50 µM), canagliflozin (2.5 µM) and empagliflozin (200 µM) in our epm2a^-/- zebrafish model, investigating their effects on pathological behaviour. In the case of dapagliflozin, we also investigated the possible mechanisms of action. Overall, the gliflozins reduced or rescued neuronal hyperexcitability and locomotor impairment. Dapagliflozin also reduced spontaneous seizure-like events in epm2a^-/- larvae. At the biochemical and molecular level, dapagliflozin was found to slightly reduce glycogen content, and suppress inflammation and oxidative stress. It also ameliorates autophagic homeostasis and improves lysosomal markers. In conclusion, our preclinical study showed that dapagliflozin was able to ameliorate part of the pathological phenotype of epm2a^-/- zebrafish larvae and could potentially be a suitable drug for repurposing in LD. However, since our model does not present Lafora bodies (LBs), at this early disease stage at least, it would be important to use mouse models in order to ascertain whether it is able to prevent or reduce LB formation.