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Movement Disorders : Official Journal... May 2024Abnormalities in ataxin-2 associated with spinocerebellar ataxia type 2 (SCA2) may lead to widespread disruptions in the proteome. This study was performed to identify...
BACKGROUND
Abnormalities in ataxin-2 associated with spinocerebellar ataxia type 2 (SCA2) may lead to widespread disruptions in the proteome. This study was performed to identify dysregulated proteome in SCA2 and to explore its clinical-radiological correlations.
METHODS
Cerebrospinal fluid (CSF) samples from 21 genetically confirmed SCA2 were subjected to shotgun proteome analysis using mass spectrometry (MS) and tandem mass tag (TMT)-based multiplexing. Proteins with at least 1.5-fold change in abundance were identified. Their relative abundance was measured using parallel reaction monitoring (PRM) and correlated against disease-related factors.
RESULTS
Eleven proteins were significantly upregulated in SCA2. They belonged to the family of cell adhesion molecules and granins. Their fold changes showed significant clinical, genetic, and radiological correlations.
CONCLUSIONS
Significant dysregulation of CSF proteome is seen in SCA2. The dysregulated protein may have potential use in clinical evaluation of patients with SCA2. © 2024 International Parkinson and Movement Disorder Society.
PubMed: 38769639
DOI: 10.1002/mds.29834 -
PLoS Genetics May 2024Ataxin-2 (ATXN2) is a gene implicated in spinocerebellar ataxia type II (SCA2), amyotrophic lateral sclerosis (ALS) and Parkinsonism. The encoded protein is a...
Ataxin-2 (ATXN2) is a gene implicated in spinocerebellar ataxia type II (SCA2), amyotrophic lateral sclerosis (ALS) and Parkinsonism. The encoded protein is a therapeutic target for ALS and related conditions. ATXN2 (or Atx2 in insects) can function in translational activation, translational repression, mRNA stability and in the assembly of mRNP-granules, a process mediated by intrinsically disordered regions (IDRs). Previous work has shown that the LSm (Like-Sm) domain of Atx2, which can help stimulate mRNA translation, antagonizes mRNP-granule assembly. Here we advance these findings through a series of experiments on Drosophila and human Ataxin-2 proteins. Results of Targets of RNA Binding Proteins Identified by Editing (TRIBE), co-localization and immunoprecipitation experiments indicate that a polyA-binding protein (PABP) interacting, PAM2 motif of Ataxin-2 may be a major determinant of the mRNA and protein content of Ataxin-2 mRNP granules. Experiments with transgenic Drosophila indicate that while the Atx2-LSm domain may protect against neurodegeneration, structured PAM2- and unstructured IDR- interactions both support Atx2-induced cytotoxicity. Taken together, the data lead to a proposal for how Ataxin-2 interactions are remodelled during translational control and how structured and non-structured interactions contribute differently to the specificity and efficiency of RNP granule condensation as well as to neurodegeneration.
Topics: Ataxin-2; Animals; Humans; Ribonucleoproteins; Drosophila Proteins; Drosophila melanogaster; RNA, Messenger; Poly(A)-Binding Proteins; Animals, Genetically Modified; Cytoplasmic Granules; Amyotrophic Lateral Sclerosis; Protein Biosynthesis; RNA-Binding Proteins; Intrinsically Disordered Proteins; Nerve Tissue Proteins; DNA-Binding Proteins
PubMed: 38768217
DOI: 10.1371/journal.pgen.1011251 -
Cerebellum (London, England) May 2024The hereditary cerebellar ataxias (HCAs) are rare, progressive neurologic disorders caused by variants in many different genes. Inheritance may follow autosomal... (Review)
Review
The hereditary cerebellar ataxias (HCAs) are rare, progressive neurologic disorders caused by variants in many different genes. Inheritance may follow autosomal dominant, autosomal recessive, X-linked or mitochondrial patterns. The list of genes associated with adult-onset cerebellar ataxia is continuously growing, with several new genes discovered in the last few years. This includes short-tandem repeat (STR) expansions in RFC1, causing cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS), FGF14-GAA causing spinocerebellar ataxia type 27B (SCA27B), and THAP11. In addition, the genetic basis for SCA4, has recently been identified as a STR expansion in ZFHX3. Given the large and growing number of genes, and different gene variant types, the approach to diagnostic testing for adult-onset HCA can be complex. Testing methods include targeted evaluation of STR expansions (e.g. SCAs, Friedreich ataxia, fragile X-associated tremor/ataxia syndrome, dentatorubral-pallidoluysian atrophy), next generation sequencing for conventional variants, which may include targeted gene panels, whole exome, or whole genome sequencing, followed by various potential additional tests. This review proposes a diagnostic approach for clinical testing, highlights the challenges with current testing technologies, and discusses future advances which may overcome these limitations. Implementing long-read sequencing has the potential to transform the diagnostic approach in HCA, with the overall aim to improve the diagnostic yield.
PubMed: 38760634
DOI: 10.1007/s12311-024-01703-z -
Stem Cell Research Jun 2024Spinocerebellar ataxia type 12 (SCA12) is caused by a CAG expansion mutation in PPP2R2B, a gene encoding brain-specific regulatory units of protein phosphatase 2A...
Spinocerebellar ataxia type 12 (SCA12) is caused by a CAG expansion mutation in PPP2R2B, a gene encoding brain-specific regulatory units of protein phosphatase 2A (PP2A); while normal alleles carry 4 to 31 triplets, the disease alleles carry 43 to 78 triplets. Here, by CRISPR/Cas9n genome editing, we have generated a human heterozygous SCA12 iPSC line with 73 triplets for the mutant allele. The heterozygous SCA12 iPSCs have normal karyotype, express pluripotency markers and are able to differentiate into the three germ layers.
Topics: Humans; Induced Pluripotent Stem Cells; Gene Editing; Spinocerebellar Ataxias; Heterozygote; Mutation; Cell Line; CRISPR-Cas Systems; Protein Phosphatase 2; Nerve Tissue Proteins
PubMed: 38759410
DOI: 10.1016/j.scr.2024.103441 -
Gaceta Medica de Mexico 2024Protein interactions participate in many molecular mechanisms involved in cellular processes. The human TATA box binding protein (hTBP) interacts with Antennapedia...
BACKGROUND
Protein interactions participate in many molecular mechanisms involved in cellular processes. The human TATA box binding protein (hTBP) interacts with Antennapedia (Antp) through its N-terminal region, specifically via its glutamine homopeptides. This PolyQ region acts as a binding site for other transcription factors under normal conditions, but when it expands, it generates spinocerebellar ataxia 17 (SCA17), whose protein aggregates in the brain prevent its correct functioning.
OBJECTIVE
To determine whether the hTBP glutamine-rich region is involved in its interaction with homeoproteins and the role it plays in the formation of protein aggregates in SCA17.
MATERIAL AND METHODS
We characterized hTBP interaction with other homeoproteins using BiFC, and modeled SCA17 in Drosophila melanogaster by targeting hTBPQ80 to the fly brain using UAS/GAL4.
RESULTS
There was hTBP interaction with homeoproteins through its glutamine-rich region, and hTBP protein aggregates with expanded glutamines were found to affect the locomotor capacity of flies.
CONCLUSIONS
The study of hTBP interactions opens the possibility for the search for new therapeutic strategies in neurodegenerative pathologies such as SCA17.
Topics: Animals; Drosophila melanogaster; Disease Models, Animal; Spinocerebellar Ataxias; TATA-Box Binding Protein; Humans; Drosophila Proteins; Glutamine; Protein Aggregates; Peptides; Brain
PubMed: 38753562
DOI: 10.24875/GMM.M24000845 -
Neurobiology of Disease Jul 2024Heterogeneity is one of the key features of the healthy brain and selective vulnerability characterizes many, if not all, neurodegenerative diseases. While cerebellum...
Heterogeneity is one of the key features of the healthy brain and selective vulnerability characterizes many, if not all, neurodegenerative diseases. While cerebellum contains majority of brain cells, neither its heterogeneity nor selective vulnerability in disease are well understood. Here we describe molecular, cellular and functional heterogeneity in the context of healthy cerebellum as well as in cerebellar disease Spinocerebellar Ataxia Type 1 (SCA1). We first compared disease pathology in cerebellar vermis and hemispheres across anterior to posterior axis in a knock-in SCA1 mouse model. Using immunohistochemistry, we demonstrated earlier and more severe pathology of PCs and glia in the posterior cerebellar vermis of SCA1 mice. We also demonstrate heterogeneity of Bergmann glia in the unaffected, wild-type mice. Then, using RNA sequencing, we found both shared, as well as, posterior cerebellum-specific molecular mechanisms of pathogenesis that include exacerbated gene dysregulation, increased number of altered signaling pathways, and decreased pathway activity scores in the posterior cerebellum of SCA1 mice. We demonstrated unexpectedly large differences in the gene expression between posterior and anterior cerebellar vermis of wild-type mice, indicative of robust intraregional heterogeneity of gene expression in the healthy cerebellum. Additionally, we found that SCA1 disease profoundly reduces intracerebellar heterogeneity of gene expression. Further, using fiber photometry, we found that population level PC calcium activity was altered in the posterior lobules in SCA1 mice during walking. We also identified regional differences in the population level activity of Purkinje cells (PCs) in unrestrained wild-type mice that were diminished in SCA1 mice.
Topics: Animals; Cerebellum; Spinocerebellar Ataxias; Mice; Ataxin-1; Purkinje Cells; Neuroglia; Disease Models, Animal; Mice, Transgenic; Mice, Inbred C57BL; Male
PubMed: 38750673
DOI: 10.1016/j.nbd.2024.106530 -
Parkinsonism & Related Disorders May 2024Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is the most common subtype of hereditary ataxia (HA), which is characterized by motor... (Review)
Review
Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is the most common subtype of hereditary ataxia (HA), which is characterized by motor deficits and a lack of effective treatments, and imposes a huge physical, mental, and financial burden on patients and their families. Therefore, it is important to study the early pathogenesis of spinal cerebellar ataxia type 3 based on a mouse model for subsequent preventive treatment and seeking new therapeutic targets.
PubMed: 38749872
DOI: 10.1016/j.parkreldis.2024.106991 -
Neurology May 2024
PubMed: 38748969
DOI: 10.1212/WNL.0000000000209455 -
Blood Cancer Discovery Jul 2024Somatic variants in DNA damage response genes such as ATM are widespread in hematologic malignancies. ATM protein is essential for double-strand DNA break repair....
Somatic variants in DNA damage response genes such as ATM are widespread in hematologic malignancies. ATM protein is essential for double-strand DNA break repair. Germline ATM deficiencies underlie ataxia-telangiectasia (A-T), a disease manifested by radiosensitivity, immunodeficiency, and predisposition to lymphoid malignancies. Patients with A-T diagnosed with malignancies have poor tolerance to chemotherapy or radiation. In this study, we investigated chimeric antigen receptor (CAR) T cells using primary T cells from patients with A-T (ATM-/-), heterozygote donors (ATM+/-), and healthy donors. ATM-/- T cells proliferate and can be successfully transduced with CARs, though functional impairment of ATM-/- CAR T-cells was observed. Retroviral transduction of the CAR in ATM-/- T cells resulted in high rates of chromosomal lesions at CAR insertion sites, as confirmed by next-generation long-read sequencing. This work suggests that ATM is essential to preserve genome integrity of CAR T-cells during retroviral manufacturing, and its lack poses a risk of chromosomal translocations and potential leukemogenicity. Significance: CAR T-cells are clinically approved genetically modified cells, but the control of genome integrity remains largely uncharacterized. This study demonstrates that ATM deficiency marginally impairs CAR T-cell function and results in high rates of chromosomal aberrations after retroviral transduction, which may be of concern in patients with DNA repair deficiencies.
Topics: Ataxia Telangiectasia Mutated Proteins; Humans; T-Lymphocytes; Retroviridae; Receptors, Chimeric Antigen; Ataxia Telangiectasia; Transduction, Genetic; DNA Damage; Immunotherapy, Adoptive
PubMed: 38747501
DOI: 10.1158/2643-3230.BCD-23-0268 -
BioRxiv : the Preprint Server For... May 2024Mutations in , which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia type 27 (SCA27), a multisystem disorder...
Mutations in , which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia type 27 (SCA27), a multisystem disorder associated with progressive deficits in motor coordination and cognitive function. Mice ( ) lacking iFGF14 display similar phenotypes, and we have previously shown that the deficits in motor coordination reflect excitability of cerebellar Purkinje neurons, owing to the loss of iFGF14-mediated regulation of the voltage-dependence of inactivation of the fast transient component of the voltage-gated Na (Nav) current, I . Here, we present the results of experiments designed to test the hypothesis that loss of iFGF14 also attenuates the intrinsic excitability of mature hippocampal and cortical pyramidal neurons. Current-clamp recordings from adult mouse hippocampal CA1 pyramidal neurons in acute slices, however, revealed that repetitive firing rates were in , than in wild type (WT), cells. In addition, the waveforms of individual action potentials were altered in hippocampal CA1 pyramidal neurons, and the loss of iFGF14 reduced the time delay between the initiation of axonal and somal action potentials. Voltage-clamp recordings revealed that the loss of iFGF14 altered the voltage-dependence of activation, but not inactivation, of I in CA1 pyramidal neurons. Similar effects of the loss of iFGF14 on firing properties were evident in current-clamp recordings from layer 5 visual cortical pyramidal neurons. Additional experiments demonstrated that the loss of iFGF14 alter the distribution of anti-Nav1.6 or anti-ankyrin G immunofluorescence labeling intensity along the axon initial segments (AIS) of mature hippocampal CA1 or layer 5 visual cortical pyramidal neurons . Taken together, the results demonstrate that, in contrast with results reported for neonatal (rat) hippocampal pyramidal neurons in dissociated cell culture, the loss of iFGF14 does disrupt AIS architecture or Nav1.6 localization/distribution along the AIS of mature hippocampal (or cortical) pyramidal neurons .
PubMed: 38746081
DOI: 10.1101/2024.05.04.592532