We describe the first case of anti-CV2 paraneoplastic polyneuropathy associated with lung adenocarcinoma. Our patient presented with progressive unsteadiness and numbness involving bilateral upper and lower limbs. He had symmetrical length-dependent lower motor neuron pattern of weakness and numbness involving both small and large fibres with prominent sensory ataxia. An extended workup for the polyneuropathy involving a serum paraneoplastic antineuronal antibody panel showed a positive reaction for anti-CV2 antibody. CT scan of the thorax, abdomen and pelvis revealed a right upper lung nodule and histopathological examination of the nodule revealed lung adenocarcinoma. He was scheduled for chemotherapy following his discharge and there was improvement of his sensorimotor polyneuropathy following his chemotherapy.

Opsoclonus-myoclonus-ataxia syndrome (OMAS) in children is most often of paraneoplastic origin, but it can also result from infectious processes, toxic and metabolic disorders, and organic events that cause damage to the brainstem or cerebellum. Post-vaccination OMAS has also been reported. We report the case of a 15-year-old girl who developed OMAS 24 hours after her first dose of mRNA COVID-19 (BioNTech) vaccine.

Intracerebral drug delivery is an emerging treatment strategy aiming to manage seizures in patients with systemic drug-resistant epilepsies. In rat seizure and epilepsy models, the GABAA receptor agonist muscimol has shown powerful antiseizure potential when injected acutely into the subthalamic nucleus (STN), known for its capacity to provide remote control of different seizure types. However, chronic intrasubthalamic muscimol delivery required for long-term seizure suppression has not yet been investigated. We tested the hypothesis that chronic convection-enhanced delivery (CED) of muscimol into the STN produces long-lasting antiseizure effects in the intravenous pentylenetetrazole seizure threshold test in female rats. Acute microinjection was included to verify efficacy of intrasubthalamic muscimol delivery in this seizure model and caused significant antiseizure effects at 30 and 60 ng per hemisphere with a dose-dependent increase of responders and efficacy and only mild adverse effects compared to controls. For the chronic study, muscimol was bilaterally infused into the STN over three weeks at daily doses of 60, 300, or 600 ng per hemisphere using an implantable pump and cannula system. Chronic intrasubthalamic CED of muscimol caused significant long-lasting antiseizure effects for up to three weeks at 300 and 600 ng daily. Drug responder rate increased dose-dependently, as did drug tolerance rates. Transient ataxia and body weight loss were the main adverse effects. Drug distribution was comparable (about 2-3 mm) between acute and chronic delivery. This is the first study providing proof-of-concept that not only acute, but also chronic, continuous CED of muscimol into the STN raises seizure thresholds.

A 7-year-old, male neutered French Bulldog was referred to a specialist veterinary hospital for evaluation of a progressive paraparesis of 6-months' duration. The owners reported both faecal and urinary incontinence at home.

Ataxia telangiectasia and Rad3‑related (ATR) is a kinase that repairs DNA damage. Although inhibitors that selectively target ATR have been developed, their effectiveness in colorectal cancer has not been widely reported. The present study hypothesized that anticancer agents that effectively act in the S phase before the G2/M checkpoint may be ideal agents for concomitant use with ATR inhibitors, which act at the G2/M checkpoint. Therefore, the present study examined the combined effects of AZD6738, an ATR inhibitor, and trifluridine (FTD), which acts in the S phase and has a high DNA uptake rate. In vitro cell viability assays, flow cytometry and western blotting were performed to evaluate cell viability, and changes in cell cycle localization and protein expression. The results revealed that in colorectal cancer cells, the combination of AZD6738 and FTD inhibited cell viability, cell cycle arrest at the G2/M checkpoint and Chk1 phosphorylation, and increased apoptotic protein expression levels more than that when treated with FTD alone. HT29, a BRAF‑mutant cell line known to be resistant to anticancer drugs, was used to induce tumors in vivo. Since FTD does not have sufficient efficacy when administered orally, it was mixed with tipiracil to prevent degradation; this mixture is known as TAS‑102. TAS‑102 alone exerted minimal tumor suppressive effects; however, when used in combination with AZD6738, tumor suppression was observed, suggesting that AZD6738 may increase the effectiveness of a weakly effective drug. Although ATR inhibitors are effective against p53 mutants, the present study demonstrated that these inhibitors were also effective against the p53 wild‑type HCT116 colorectal cancer cell line. In conclusion, combination therapy with AZD6738 and FTD enhanced the inhibition of tumor proliferation in vitro and in vivo. In the future, we aim to investigate the potentiating effect of AZD6738 on 5‑fluouracil‑resistant cell lines that are difficult to treat.

Spinocerebellar Ataxia Type 3 (SCA3) is a member of the family of polyglutamine (polyQ) diseases that are caused by anomalous CAG triplet repeat expansions in several genes. SCA3 results from abnormal polyQ expansion in the deubiquitinase (DUB), ataxin-3 (Atxn3). To understand the role of the different domains of mutant Atxn3 on its pathogenicity, with the hope that they can be explored for therapeutic interventions, we have systematically studied their individual and collective effects on its toxicity. One such domain is ubiquitin-binding site 1 (UbS1) on the catalytic domain of Atxn3; UbS1 is necessary for the enzymatic activity of Atxn3. Here, we investigated the importance of UbS1 on the toxicity of pathogenic Atxn3. We generated transgenic Drosophila melanogaster lines that express polyQ-expanded Atxn3 with and without a functional UbS1. We found that mutating UbS1 markedly exacerbates the toxicity of pathogenic Atxn3. Additional studies indicated that UbS1 regulates the toxicity of Atxn3 not by affecting its aggregation or sub-cellular localization, but by impacting its role in ubiquitin processing. Our findings provide additional insights into the role of Atxn3's domains in the pathogenicity of SCA3.

Alpha-particle emitters have recently been explored as valuable therapeutic radionuclides. Yet, toxicity to healthy organs and cancer radioresistance limit the efficacy of targeted alpha-particle therapy (TAT). Identification of the radiation-activated mechanisms, which drive cancer cell survival, provides opportunities to develop new points for therapeutic interference to improve efficacy and safety of TAT. Methods: Quantitative phosphoproteomics and matching proteomics followed by the bioinformatics analysis were employed to identify alterations in the signaling networks in response to TAT with actinium-225 labeled minigastrin analogue 225Ac-PP-F11N in A431 cells, which overexpress cholecystokinin B receptor (CCKBR). Western blot (WB) analysis and microscopy verified the activation of the selected signaling pathways. Small-molecule inhibitors were used to validate the potential of the radio-sensitizing combinatory treatments both in vitro and in A431/CCKBR tumor-bearing nude mice. Results: TAT-induced alterations involved in DNA damage response (DDR), cell cycle regulation, signal transduction as well as RNA transcription and processing, cell morphology and transport. WB analysis and microscopy confirmed increased phosphorylations of the key proteins involved in DDR and carcinogenesis including P53, P53BP1 histone deacetylases (HDACs) and H2AX. Inhibition of HDAC class II, ataxia-telangiectasia mutated (ATM) and p38 kinases by TMP269, AZD1390 and SB202190, respectively, sensitized A431/CCKBR cells to 225Ac-PP-F11N. Combination of 225Ac-PP-F11N with HDAC inhibitor vorinostat (SAHA) showed significantly reduced viability and increased DNA damage of A431/CCKBR cells as well as the most pronounced tumor growth inhibition and the extended mean survival of A431/CCKBR xenografted nude mice as compared to the control and monotherapies. Conclusion: Our study revealed the cellular responses to TAT and demonstrated the radiosensitizing potential of HDAC inhibitors to 225Ac-PP-F11N in CCKBR-positive tumors. This proof-of-concept study recommends development of the novel radiosensitizing strategies by targeting TAT-activated and survival-promoting signaling pathways.

β-III-spectrin is a key cytoskeletal protein that localizes to the soma and dendrites of cerebellar Purkinje cells, and is required for dendritic arborization and signaling. A spinocerebellar ataxia type 5 (SCA5) L253P mutation in the cytoskeletal protein β-III-spectrin causes high-affinity actin binding. Previously we reported a cell-based fluorescence assay for identification of small molecule actin-binding modulators of the L253P mutant β-III-spectrin. Here we describe a complementary, in vitro, fluorescence resonance energy transfer (FRET) assay that uses purified L253P β-III-spectrin actin-binding domain (ABD) and F-actin. To validate the assay for high-throughput compatibility, we first confirmed that our 50% FRET signal was responsive to Swinholide A, an actin-severing compound, and that this yielded excellent assay quality with a Z' value > 0.77. Secondly, we screened a 2,684-compound library of FDA-approved drugs. Importantly, the screening identified numerous compounds that decreased FRET between fluorescently labeled L253P ABD and F-actin. The activity and target of multiple Hit compounds were confirmed in orthologous co-sedimentation actin-binding assays. Through future medicinal chemistry, the Hit compounds can potentially be developed into a SCA5-specific therapeutic. Furthermore, our validated FRET-based in vitro high-throughput screening (HTS) platform is poised for screening large compound libraries for β-III-spectrin ABD modulators.

The cardiovascular system requires iron to maintain its high energy demands and metabolic activity. Iron plays a critical role in oxygen transport and storage, mitochondrial function, and enzyme activity. However, excess iron is also cardiotoxic due to its ability to catalyze the formation of reactive oxygen species and promote oxidative damage. While mammalian cells have several redundant iron import mechanisms, they are equipped with a single iron-exporting protein, which makes the cardiovascular system particularly sensitive to iron overload. As a result, iron levels are tightly regulated at many levels to maintain homeostasis. Iron dysregulation ranges from iron deficiency to iron overload and is seen in many types of cardiovascular disease, including heart failure, myocardial infarction, anthracycline-induced cardiotoxicity, and Friedreich's ataxia. Recently, the use of intravenous iron therapy has been advocated in patients with heart failure and certain criteria for iron deficiency. Here, we provide an overview of systemic and cellular iron homeostasis in the context of cardiovascular physiology, iron deficiency, and iron overload in cardiovascular disease, current therapeutic strategies, and future perspectives.

Neurodegenerative diseases are a major global health burden particularly with the increasing ageing population. Hereditary predisposition and environmental risk factors contribute to the heterogeneity of existing pathological phenotypes. Traditional clinical interventions focused on the use of small drugs have often led to failures due to the difficulties of crossing the blood-brain-barrier and reaching brain. In this regard, nanosystems can specifically deliver drugs and improve their bioavailability, overcoming some of the major challenges in neurodegenerative diseases treatment. This review focuses on the use of nanosystems as an encouraging therapeutic approach targeting molecular pathways involved in localized and systematic neurodegenerative diseases. Among this latter, Friedreich's ataxia is an untreatable complex multisystemic disorder and the most spread type of ataxia, that represents a test case to validate the clinical potential of therapeutic strategies based on nanoparticles with pleiotropic effects.

There are few causes of treatable neurodevelopmental diseases described to date. Branched Chain Ketoacid Dehydrogenase Kinase (BCKDK) deficiency causes branched-chain amino acid (BCAA) depletion and is linked to a neurodevelopmental disorder characterized by autism, intellectual disability, and microcephaly. We report the largest cohort of patients studied, broadening the phenotypic and genotypic spectrum. Moreover, this is the first study to present newborn screening findings and mid-term clinical outcome. In this cross-sectional study, patients with a diagnosis of BCKDK deficiency were recruited via investigators' practices through a MetabERN initiative. Clinical, biochemical and genetic data were collected. Dried blood spot (DBS) newborn screening (NBS) amino acid profiles were retrieved from collaborating centers and compared to a healthy newborn reference population. Twenty-one patients with BCKDK mutations were included from 13 families. Patients were diagnosed between 8 months and 16 years (mean: 5.8 years, 43% female). At diagnosis, BCAA levels (leucine, valine, and isoleucine) were below reference values in plasma and in cerebrospinal fluid. All patients had global neurodevelopmental delay; 18/21 had gross motor function (GMF) impairment with GMF III or worse in 5/18, 16/16 intellectual disability, 17/17 language impairment, 12/17 autism spectrum disorder, 9/21 epilepsy, 12/15 clumsiness, 3/21 had sensorineural hearing loss and 4/20 feeding difficulties. No microcephaly was observed at birth, but 17/20 developed microcephaly during follow-up. Regression was reported in 6 patients. Movement disorder was observed in 3/21 patients: hyperkinetic movements (1), truncal ataxia (1) and dystonia (2). After treatment with high protein diet (≥ 2 g/kg/day) and BCAA supplementation (100-250 mg/kg/day), plasma BCAA increased significantly (p < 0.001), motor functions and head circumference stabilized/improved in 13/13 and in 11/15 patients, respectively. Amongst cases with follow-up data, none of the 3 patients starting treatment before 2 years of age developed autism at follow-up. The patient with the earliest age of treatment initiation (8 months) showed normal development at 3 years of age. NBS in DBS identified BCAA levels significantly lower than those of the normal population. This work highlights the potential benefits of dietetic treatment, in particular early introduction of BCAA. Therefore, it is of utmost importance to increase awareness about this treatable disease and consider it as a candidate for early detection by NBS programs.

Modeling paraneoplastic neurological diseases to understand the immune mechanisms leading to neuronal death is a major challenge given the rarity and terminal access of patients' autopsies. Here, we present a pilot study aiming at modeling paraneoplastic cerebellar degeneration with Yo autoantibodies (Yo-PCD). Female mice were implanted with an ovarian carcinoma cell line expressing CDR2 and CDR2L, the known antigens recognized by anti-Yo antibodies. To boost the immune response, we also immunized the mice by injecting antigens with diverse adjuvants and immune checkpoint inhibitors. Ataxia and gait instability were assessed in treated mice as well as autoantibody levels, Purkinje cell density, and immune infiltration in the cerebellum. We observed the production of anti-Yo antibodies in the CSF and serum of all immunized mice. Brain immunoreaction varied depending on the site of implantation of the tumor, with subcutaneous administration leading to a massive infiltration of immune cells in the meningeal spaces, choroid plexus, and cerebellar parenchyma. However, we did not observe massive Purkinje cell death nor any motor impairments in any of the experimental groups. Self-sustained neuro-inflammation might require a longer time to build up in our model. Unusual tumor antigen presentation and/or intrinsic, species-specific factors required for pro-inflammatory engagement in the brain may also constitute strong limitations to achieve massive recruitment of antigen-specific T-cells and killing of antigen-expressing neurons in this mouse model.

A 68-year-old woman with positional dizziness and progressive imbalance presented for vestibular evaluation. Examination was notable for spontaneous downbeat nystagmus (DBN), horizontal and vertical gaze-evoked nystagmus (GEN) with centripetal and rebound nystagmus, and positional apogeotropic nystagmus. There was also mild-moderate slowing of saccades horizontally and vertically and poor fast phases with an optokinetic stimulus. Further consultation by a movement disorder specialist uncovered asymmetric decrementing bradykinesia and rigidity, masked facies, and a wide-based stance without camptocormia. Screening serum laboratory results for metabolic, rheumatologic, infectious, heavy metal, endocrine, or vitamin abnormalities was normal. Surveillance imaging for neoplasms was unremarkable, and cerebrospinal fluid (CSF) analysis was negative for 14-3-3 and real-time quaking-induced conversion (RT-QuIC). However, her anti-glutamic acid decarboxylase-65 (GAD65) immunoglobulin G (IgG) level was markedly elevated in serum to 426,202 IU/mL (reference range 0-5 IU/mL) and in CSF to 18.1 nmol/L (reference range <0.03 nmol/L). No other autoantibodies were identified on the expanded paraneoplastic panel. The patient was referred to neuroimmunology, where torso rigidity, spasticity, and significant paravertebral muscle spasms were noted. Overall, the clinical presentation, examination findings, and extensive workup were consistent with a diagnosis of anti-GAD65-associated stiff person syndrome-plus (musculoskeletal plus cerebellar and/or brainstem involvement). She was subsequently treated with intravenous immunoglobulin (IVIg) and has been stable since commencing this therapy. In patients with centripetal nystagmus, especially in association with other cerebellar findings, an autoimmune cerebellar workup should be considered.

Altered autophagy is a hallmark of neurodegeneration but how autophagy is regulated in the brain and dysfunctional autophagy leads to neuronal death has remained cryptic. Being a key cellular waste-recycling and housekeeping system, autophagy is implicated in a range of brain disorders and altering autophagy flux could be an effective therapeutic strategy and has the potential for clinical applications down the road. Tight regulation of proteins and organelles in order to meet the needs of complex neuronal physiology suggests that there is distinct regulatory pattern of neuronal autophagy as compared to non-neuronal cells and nervous system might have its own separate regulator of autophagy. Evidence has shown that circRNAs participates in the biological processes of autophagosome assembly. The regulatory networks between circRNAs, autophagy, and neurodegeneration remains unknown and warrants further investigation. Understanding the interplay between autophagy, circRNAs and neurodegeneration requires a knowledge of the multiple steps and regulatory interactions involved in the autophagy pathway which might provide a valuable resource for the diagnosis and therapy of neurodegenerative diseases. In this review, we aimed to summarize the latest studies on the role of brain-protective mechanisms of autophagy associated circRNAs in neurodegenerative diseases (including Alzheimer's disease, Parkinson's disease, Huntington's disease, Spinal Muscular Atrophy, Amyotrophic Lateral Sclerosis, and Friedreich's ataxia) and how this knowledge can be leveraged for the development of novel therapeutics against them. Autophagy stimulation might be potential one-size-fits-all therapy for neurodegenerative disease as per considerable body of evidence, therefore future research on brain-protective mechanisms of autophagy associated circRNAs will illuminate an important feature of nervous system biology and will open the door to new approaches for treating neurodegenerative diseases.

Targeted alpha therapy (TAT) is a promising approach for addressing unmet needs in oncology. Inherent properties make α-emitting radionuclides well suited to cancer therapy, including high linear energy transfer (LET), penetration range of 2-10 cell layers, induction of complex double-stranded DNA breaks, and immune-stimulatory effects. Several alpha radionuclides, including radium-223 (223Ra), actinium-225 (225Ac), and thorium-227 (227Th), have been investigated. Conjugation of tumor targeting modalities, such as antibodies and small molecules, with a chelator moiety and subsequent radiolabeling with α-emitters enables specific delivery of cytotoxic payloads to different tumor types. 223Ra dichloride, approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) with bone-metastatic disease and no visceral metastasis, is the only approved and commercialized alpha therapy. However, 223Ra dichloride cannot currently be complexed to targeting moieties. In contrast to 223Ra, 227Th may be readily chelated, which allows radiolabeling of tumor targeting moieties to produce targeted thorium conjugates (TTCs), facilitating delivery to a broad range of tumors. TTCs have shown promise in pre-clinical studies across a range of tumor-cell expressing antigens. A clinical study in hematological malignancy targeting CD22 has demonstrated early signs of activity. Furthermore, pre-clinical studies show additive or synergistic effects when TTCs are combined with established anti-cancer therapies, for example androgen receptor inhibitors (ARI), DNA damage response inhibitors such as poly (ADP)-ribose polymerase inhibitors or ataxia telangiectasia and Rad3-related kinase inhibitors, as well as immune checkpoint inhibitors.

Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5' untranslated region of FMR1.

Spinocerebellar ataxia type 1 (SCA1) is an adult-onset, dominantly inherited neurodegenerative disease caused by the expanded polyQ tract in the protein ATAXIN1 (ATXN1) and characterized by progressive motor and cognitive impairments. There are no disease-modifying treatments or cures for SCA1. Brain-derived neurotrophic factor (BDNF) plays important role in cerebellar physiology and has shown therapeutic potential for cerebellar pathology in the transgenic mouse model of SCA1, ATXN1[82Q] line that overexpress mutant ATXN1 under a cerebellar Purkinje-cell-specific promoter. Here we demonstrate decreased expression of brain derived neurotrophic factor (BDNF) in the cerebellum and medulla of patients with SCA1. Early stages of disease seem most amenable to therapy. Thus, we next quantified Bdnf expression in Atxn1154Q/2Q mice, a knock-in mouse model of SCA1, during the early symptomatic disease stage in four clinically relevant brain regions: cerebellum, medulla, hippocampus and motor cortex. We found that during the early stages of disease, Bdnf mRNA expression is reduced in the hippocampus and cerebellum, while it is increased in the cortex and brainstem. Importantly, we observed that pharmacological delivery of recombinant BDNF improved motor and cognitive performance, and mitigated pathology in the cerebellum and hippocampus of Atxn1154Q/2Q mice. Our findings demonstrate brain-region specific deficiency of BDNF in SCA1 and show that reversal of low BDNF levels offers the potential for meaningful treatment of motor and cognitive deficits in SCA1.

Cancer treatments targeting DNA repair deficiencies often encounter drug resistance, possibly due to alternative metabolic pathways that counteract the most damaging effects. To identify such alternative pathways, we screened for metabolic pathways exhibiting synthetic lethality with inhibition of the DNA damage response kinase Ataxia-telangiectasia-mutated (ATM) using a metabolism-centered Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 library. Our data revealed Kelch-like ECH-associated protein 1 (KEAP1) as a key factor involved in desensitizing cancer cells to ATM inhibition both in vitro and in vivo. Cells depleted of KEAP1 exhibited an aberrant overexpression of the cystine transporter SLC7A11, robustly accumulated cystine inducing disulfide stress, and became hypersensitive to ATM inhibition. These hallmarks were reversed in a reducing cellular environment indicating that disulfide stress was a crucial factor. In The Cancer Genome Atlas (TCGA) pan-cancer datasets, we found that ATM levels negatively correlated with KEAP1 levels across multiple solid malignancies. Together, our results unveil ATM and KEAP1 as new targetable vulnerabilities in solid tumors.

Otitis media (OM) in dogs can occur as a primary condition instead of as an extension of an otitis externa (OE), characterized by the presence of fluid in the middle ear (ME) referred to as OM with effusion (OME). OME has been reported in a brachycephalic breed (boxer), and the same condition is described as primary secretory OM in Cavalier King Charles Spaniels. These dogs can be asymptomatic or present with pain, facial nerve paralysis and reduced hearing. This report describes two cases of OME with associated neurologic signs in Boston terriers with no previous history of OE, normal external ear canals and tympanic membranes. Neurologic evaluation revealed right head tilt along with vestibular ataxia and frequent walking tight circles to the right in case 1, and a dull mentation with a right-sided head tilt and torticollis, vestibular tetra-ataxia, ambulatory tetraparesis and circling to the right in case 2. MRI imaging of the brain was performed. Results showed bilateral OM with right-sided otitis interna and equivocal associated otogenic meningitis in case 1 and right-sided OM in case 2. Myringotomy was performed, and both dogs' ME sampled for cytology that only revealed inflammatory cells; and bacterial cultures which revealed a light growth of Pseudomonas aeruginosa in case 1. ME were flushed with sterile saline. Oral glucocorticoids and antibiotics based on the susceptibility results, and a compound antibiotic and glucocorticoid ear solution were prescribed to case 1. Neurologic improvement was observed a few days after the appointment, but a mild right-sided head tilt remained evident. Owner of case two elected humane euthanasia due to patient respiratory difficulties upon anaesthetic recovery and other concurrent healthy concerns. Current findings reinforce that brachycephalic dogs may be prone to develop OME, and advanced imaging tests are key to the diagnosis.

Arginase deficiency is an autosomal recessive urea cycle disorder caused by pathogenic variants in the ARG1 gene. The clinical features of the disease include spasticity, tremour, ataxia, hypotonia, microcephaly and seizures. Growth delay can also be observed in the affected individuals. Here we describe the results from molecular-genetic analysis of two patients with arginase deficiency. In the first case, we reported a novel homozygous missense variant c.775G>A p.(Gly259Ser) in a patient with Bulgarian ethnic origin. In the second case, a novel homozygous splice site variant c.329+1G>A was detected in a patient from a consanguineous family of Roma ethnic origin. A hundred samples of newborns of Roma origin were screened for variant c.329+1G>A and one individual was found to be a heterozygous carrier of variant c.329+1G> A. The results from this study indicated the necessity for screening of the Roma population with respect to the disease arginase deficiency in Bulgaria.