Publications by authors named "Agnieszka Fiszer"

Article Synopsis
  • Two mouse models, one with translated (HD/100Q) and one with nontranslated (HD/100CAG) human mutant HTT, were created to study their effects on behavior and molecular changes over 21 months.
  • Results showed both models displayed behavioral alterations and gene deregulations, with the nontranslated model exhibiting less severe impairments but notable anxiety increases due to mutant HTT RNA, suggesting its minor role in HD pathogenesis.
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We developed a method that utilizes fluorescent labeling of nuclear envelopes alongside cytometry sorting for the selective isolation of Purkinje cell (PC) nuclei. Beginning with SUN1 reporter mice, we GFP-tagged envelopes to confirm that PC nuclei could be accurately separated from other cell types. We then developed an antibody-based protocol to make PC nuclear isolation more robust and adaptable to cerebellar tissues of any genotypic background.

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Polyglutamine (polyQ)-encoding CAG repeat expansions represent a common disease-causing mutation responsible for several dominant spinocerebellar ataxias (SCAs). PolyQ-expanded SCA proteins are toxic for cerebellar neurons, with Purkinje cells (PCs) being the most vulnerable. RNA interference (RNAi) reagents targeting transcripts with expanded CAG reduce the level of various mutant SCA proteins in an allele-selective manner in vitro and represent promising universal tools for treating multiple CAG/polyQ SCAs.

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Recent research integrates novel technologies and methods from the interface of RNA biology and neuroscience. This advancing integration of both fields creates new opportunities in neuroscience to deepen the understanding of gene expression programs and their regulation that underlies the cellular heterogeneity and physiology of the central nervous system. Currently, transcriptional heterogeneity can be studied in individual neural cell types in health and disease.

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Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare, incurable genetic disease that belongs to the group of polyglutamine (polyQ) diseases. DRPLA is the most common in the Japanese population; however, its global prevalence is also increasing due to better clinical recognition. It is characterized by cerebellar ataxia, myoclonus, epilepsy, dementia, and chorea.

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Article Synopsis
  • The human genome generally has two copies of each gene, but they often express at unequal levels, which is important for understanding genetic disorders, particularly dominant diseases with one normal and one mutant allele.
  • Polyglutamine diseases, like Spinocerebellar ataxia type 3 and Huntington's disease, are caused by CAG repeat expansions in specific genes, making it tough to study their gene expression due to similar CAG sequences.
  • The study employed SNP variants linked to normal or expanded alleles to measure gene expression levels specifically, revealing that differentiation affects mRNA ratios and enabling monitoring of therapeutic strategies in relevant cellular models and a mouse model of Huntington's disease.
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Repeat expansion diseases are a group of more than 40 disorders that affect mainly the nervous and/or muscular system and include myotonic dystrophies, Huntington's disease, and fragile X syndrome. The mutation-driven expanded repeat tract occurs in specific genes and is composed of tri- to dodeca-nucleotide-long units. Mutant mRNA is a pathogenic factor or important contributor to the disease and has great potential as a therapeutic target.

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Introduction: Since the SARS-CoV-2 emergence in 2019/2020, at least 158 million infections with this pathogen have been recorded, of which 3.29 million infected people have died. Due to the non-specific symptoms of SARS-CoV-2 infection, laboratory tests based on RT-PCR (reverse transcription and polymerase chain reaction) are mainly used in the diagnosis of COVID-19 disease.

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Non-coding RNAs (ncRNAs) have been reported to be implicated in cell fate determination and various human diseases. All ncRNA molecules are emerging as key regulators of diverse cellular processes; however, little is known about the regulatory interaction among these various classes of RNAs. It has been proposed that the large-scale regulatory network across the whole transcriptome is mediated by competing endogenous RNA (ceRNA) activity attributed to both protein-coding and ncRNAs.

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Among the main challenges in further advancing therapeutic strategies for Huntington's disease (HD) is the development of biomarkers which must be applied to assess the efficiency of the treatment. HD is a dreadful neurodegenerative disorder which has its source of pathogenesis in the central nervous system (CNS) but is reflected by symptoms in the periphery. Visible symptoms include motor deficits and slight changes in peripheral tissues, which can be used as hallmarks for prognosis of the course of HD, e.

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Huntington's disease (HD) is a genetic disease caused by expanded CAG repeat tract in exon 1 of the HTT gene that codes for huntingtin. Since the first symptoms of the disease the average life expectancy is 15-20 years, when the symptoms resulting from neurodegeneration are progressing. Therefore, there is a great demand for an effective HD treatment method.

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Spinocerebellar ataxia type 3 (SCA3) is a progressive neurodegenerative disorder caused by a CAG repeat expansion in the ATXN3 gene encoding the ataxin-3 protein. Despite extensive research the exact pathogenic mechanisms of SCA3 are still not understood in depth. In the present study, to gain insight into the toxicity induced by the expanded CAG repeats in SCA3, we comprehensively investigated repeat-associated non-ATG (RAN) translation in various cellular models expressing translated or non-canonically translated ATXN3 sequences with an increasing number of CAG repeats.

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Polyglutamine (polyQ) diseases are incurable neurological disorders caused by CAG repeat expansion in the open reading frames (ORFs) of specific genes. This type of mutation in the HTT gene is responsible for Huntington's disease (HD). CAG repeat-targeting artificial miRNAs (art-miRNAs) were shown as attractive therapeutic approach for polyQ disorders as they caused allele-selective decrease in the level of mutant proteins.

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Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is autosomal-dominant neurodegenerative disease caused by an expansion of polyglutamine-encoding CAG repeats in the ATXN3 gene. Here we established IBCHi002-A induced pluripotent stem cells (iPSCs) line generated from SCA3 patient fibroblasts by using non-integrative Sendai-virus delivery system of four reprogramming factors. This cellular model provides a valid platform for study SCA3 pathogenesis and potential therapies for this so far incurable disease.

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Huntington's disease (HD) is a fatal neurodegenerative disorder caused by the expansion of CAG repeats in exon 1 of the huntingtin gene (). Despite its monogenic nature, HD pathogenesis is still not fully understood, and no effective therapy is available to patients. The development of new techniques such as genome engineering has generated new opportunities in the field of disease modeling and enabled the generation of isogenic models with the same genetic background.

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Dentatorubral-pallidoluysian atrophy (DRPLA) is an incurable autosomal dominant disease caused by an expansion of a CAG repeats in ATN1 gene encoding atrophin 1 protein. Here we report the generation of IBCHi001-A, an induced pluripotent stem cell (iPSC) line derived from DRPLA patient fibroblasts using non-integrative reprogramming technology with OCT4, SOX2, cMYC and KLF4 reprogramming factors. The pluripotency of iPSC was confirmed by immunocytochemistry and PCR for pluripotency markers and by the ability to form three germ layers in vitro.

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MicroRNA (miRNA)-mediated crosstalk between coding and non-coding RNAs of various types is known as the competing endogenous RNA (ceRNA) concept. Here, we propose that there is a specific variant of the ceRNA language that takes advantage of simple sequence repeat (SSR) wording. We applied bioinformatics tools to identify human transcripts that may be regarded as repeat-associated ceRNAs (raceRNAs).

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In several human polyglutamine diseases caused by expansions of CAG repeats in the coding sequence of single genes, mutant transcripts are detained in nuclear RNA foci. In polyglutamine disorders, unlike other repeat-associated diseases, both RNA and proteins exert pathogenic effects; therefore, decreases of both RNA and protein toxicity need to be addressed in proposed treatments. A variety of oligonucleotide-based therapeutic approaches have been developed for polyglutamine diseases, but concomitant assays for RNA foci reduction are lacking.

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Spinocerebellar ataxia type 7 (SCA7) is a human neurodegenerative polyglutamine (polyQ) disease caused by a CAG repeat expansion in the open reading frame of the gene. The allele-selective silencing of mutant transcripts using a repeat-targeting strategy has previously been used for several polyQ diseases. Herein, we demonstrate that the selective targeting of a repeat tract in a mutant transcript by RNA interference is a feasible approach and results in an efficient decrease of mutant ataxin-7 protein in patient-derived cells.

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Polyglutamine (polyQ) diseases comprise a group of nine genetic disorders that are caused by the expansion of the CAG triplet repeat, which encodes glutamine, in unrelated single genes. Various oligonucleotide (ON)-based therapeutic approaches have been considered for polyQ diseases. The very attractive CAG repeat-targeting strategy offers selective silencing of the mutant allele by directly targeting the mutation site.

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Considerable advances have been recently made in understanding the molecular aspects of pathogenesis and in developing therapeutic approaches for polyglutamine (polyQ) diseases. Studies on pathogenic mechanisms have extended our knowledge of mutant protein toxicity, confirmed the toxicity of mutant transcript and identified other toxic RNA and protein entities. One very promising therapeutic strategy is targeting the causative gene expression with oligonucleotide (ON) based tools.

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MicroRNAs comprise a large family of short, non-coding RNAs that are present in most eukaryotic organisms and are typically involved in downregulating the expression of protein-coding genes. The detailed mechanisms of miRNA functioning in animals and plants have been under investigation for more than decade. In mammalian cells, miRNA guides the effector complex miRISC to bind with partially complementary sequences, usually within the 3'UTR of mRNAs, and inhibit protein synthesis with or without transcript degradation.

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Huntington's disease (HD) is a neurodegenerative genetic disorder caused by the expansion of the CAG repeat in the translated sequence of the HTT gene. This expansion generates a mutant huntingtin protein that contains an abnormally elongated polyglutamine tract, which, together with mutant transcript, causes cellular dysfunction. Currently, there is no curative treatment available to patients suffering from HD; however, the selective inhibition of the mutant allele expression is a promising therapeutic option.

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