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Suiwal S, Wartenberg P, Boehm U, Schmitz F, Schwarz K. A Novel Cre Recombinase Mouse Strain for Cell-Specific Deletion of Floxed Genes in Ribbon Synapse-Forming Retinal Neurons. Int J Mol Sci 2024; 25:1916. [PMID: 38339191 PMCID: PMC10856425 DOI: 10.3390/ijms25031916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/28/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024] Open
Abstract
We generated a novel Cre mouse strain for cell-specific deletion of floxed genes in ribbon synapse-forming retinal neurons. Previous studies have shown that the RIBEYE promotor targets the expression of recombinant proteins such as fluorescently tagged RIBEYE to photoreceptors and retinal bipolar cells and generates fluorescent synaptic ribbons in situ in these neurons. Here, we used the same promotor to generate a novel transgenic mouse strain in which the RIBEYE promotor controls the expression of a Cre-ER(T2) recombinase (RIBEYE-Cre). To visualize Cre expression, the RIBEYE-Cre animals were crossed with ROSA26 tau-GFP (R26-τGFP) reporter mice. In the resulting RIBEYE-Cre/R26 τGFP animals, Cre-mediated removal of a transcriptional STOP cassette results in the expression of green fluorescent tau protein (tau-GFP) that binds to cellular microtubules. We detected robust tau-GFP expression in retinal bipolar cells. Surprisingly, we did not find fluorescent tau-GFP expression in mouse photoreceptors. The lack of tau-GFP reporter protein in these cells could be based on the previously reported absence of tau protein in mouse photoreceptors which could lead to the degradation of the recombinant tau protein. Consistent with this, we detected Cre and tau-GFP mRNA in mouse photoreceptor slices by RT-PCR. The transgenic RIBEYE-Cre mouse strain provides a new tool to study the deletion of floxed genes in ribbon synapse-forming neurons of the retina and will also allow for analyzing gene deletions that are lethal if globally deleted in neurons.
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Affiliation(s)
- Shweta Suiwal
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Medical School, Saarland University, 66421 Homburg, Germany;
| | - Philipp Wartenberg
- Institute of Clinical and Experimental Pharmacology, Center for Molecular Signaling (PZMS) and Center for Gender-Specific Biology and Medicine (CGBM), Medical School, Saarland University, 66421 Homburg, Germany; (P.W.); (U.B.)
| | - Ulrich Boehm
- Institute of Clinical and Experimental Pharmacology, Center for Molecular Signaling (PZMS) and Center for Gender-Specific Biology and Medicine (CGBM), Medical School, Saarland University, 66421 Homburg, Germany; (P.W.); (U.B.)
| | - Frank Schmitz
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Medical School, Saarland University, 66421 Homburg, Germany;
| | - Karin Schwarz
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Medical School, Saarland University, 66421 Homburg, Germany;
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Lavekar SS, Harkin J, Hernandez M, Gomes C, Patil S, Huang KC, Puntambekar SS, Lamb BT, Meyer JS. Development of a three-dimensional organoid model to explore early retinal phenotypes associated with Alzheimer's disease. Sci Rep 2023; 13:13827. [PMID: 37620502 PMCID: PMC10449801 DOI: 10.1038/s41598-023-40382-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 08/09/2023] [Indexed: 08/26/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of Aβ plaques and neurofibrillary tangles, resulting in synaptic loss and neurodegeneration. The retina is an extension of the central nervous system within the eye, sharing many structural similarities with the brain, and previous studies have observed AD-related phenotypes within the retina. Three-dimensional retinal organoids differentiated from human pluripotent stem cells (hPSCs) can effectively model some of the earliest manifestations of disease states, yet early AD-associated phenotypes have not yet been examined. Thus, the current study focused upon the differentiation of hPSCs into retinal organoids for the analysis of early AD-associated alterations. Results demonstrated the robust differentiation of retinal organoids from both familial AD and unaffected control cell lines, with familial AD retinal organoids exhibiting a significant increase in the Aβ42:Aβ40 ratio as well as phosphorylated Tau protein, characteristic of AD pathology. Further, transcriptional analyses demonstrated the differential expression of many genes and cellular pathways, including those associated with synaptic dysfunction. Taken together, the current study demonstrates the ability of retinal organoids to serve as a powerful model for the identification of some of the earliest retinal alterations associated with AD.
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Affiliation(s)
- Sailee S Lavekar
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jade Harkin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Melody Hernandez
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Cátia Gomes
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Shruti Patil
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Kang-Chieh Huang
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Shweta S Puntambekar
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jason S Meyer
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Ophthalmology, Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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Inoue C, Takeuchi T, Shiota A, Kondo M, Nshizawa Y. A rat model for retinitis pigmentosa with rapid retinal degeneration enables drug evaluation in vivo. Biol Proced Online 2021; 23:11. [PMID: 34088267 PMCID: PMC8176615 DOI: 10.1186/s12575-021-00150-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/18/2021] [Indexed: 11/10/2022] Open
Abstract
Background Although retinitis pigmentosa (RP) is most frequently studied in mouse models, rats, rabbits, and pigs are also used as animal models of RP. However, no studies have reported postnatal photoreceptor cell loss before complete development in these models. Here, we generated a transgenic rat strain, named the P347L rat, in which proline at position 347 in the rhodopsin protein was replaced with leucine. Results A pathological analysis of photoreceptor cells in the P347L rat model was performed, and drugs with potential use as therapeutic agents against RP were investigated. The data clearly showed rapid degeneration and elimination of the outer nuclear layer even before the photoreceptor cells were fully established in P347L rats. To test the usefulness of the P347L rat in the search for new therapeutic agents against RP, the effects of rapamycin on RP were investigated in this rat strain. The findings suggest that rapamycin promotes autophagy and autophagosomal uptake of the rhodopsin that has accumulated abnormally in the cytoplasm, thereby alleviating stress and delaying photoreceptor cell death. Conclusions In this RP model, the time to onset of retinal degeneration was less than that of previously reported RP models with other rhodopsin mutations, enabling quicker in vivo evaluation of drug efficacy. Administration of rapamycin delayed the photoreceptor cell degeneration by approximately 1 day. Supplementary Information The online version contains supplementary material available at 10.1186/s12575-021-00150-y.
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Affiliation(s)
- Chisato Inoue
- Center for Clinical Examination Practicum Supp, ort, Chubu University, Kasugai, Aichi, 4878501, Japan.
| | - Tamaki Takeuchi
- College of Life and Health Sciences, Chubu University, Kasugai, Aichi, 4878501, Japan
| | - Akira Shiota
- Institute of Immunology Co., LTD, Utsunomiya, Tochigi, 3290512, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Mie, 5148507, Japan
| | - Yuji Nshizawa
- Department of Biomedical Sciences, Chubu University, Kasugai, Aichi, 4878501, Japan
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Noor A, Zafar S, Zerr I. Neurodegenerative Proteinopathies in the Proteoform Spectrum-Tools and Challenges. Int J Mol Sci 2021; 22:1085. [PMID: 33499319 PMCID: PMC7865347 DOI: 10.3390/ijms22031085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/11/2022] Open
Abstract
Proteinopathy refers to a group of disorders defined by depositions of amyloids within living tissue. Neurodegenerative proteinopathies, including Alzheimer's disease, Parkinson's disease, Creutzfeldt-Jakob disease, and others, constitute a large fraction of these disorders. Amyloids are highly insoluble, ordered, stable, beta-sheet rich proteins. The emerging theory about the pathophysiology of neurodegenerative proteinopathies suggests that the primary amyloid-forming proteins, also known as the prion-like proteins, may exist as multiple proteoforms that contribute differentially towards the disease prognosis. It is therefore necessary to resolve these disorders on the level of proteoforms rather than the proteome. The transient and hydrophobic nature of amyloid-forming proteins and the minor post-translational alterations that lead to the formation of proteoforms require the use of highly sensitive and specialized techniques. Several conventional techniques, like gel electrophoresis and conventional mass spectrometry, have been modified to accommodate the proteoform theory and prion-like proteins. Several new ones, like imaging mass spectrometry, have also emerged. This review aims to discuss the proteoform theory of neurodegenerative disorders along with the utility of these proteomic techniques for the study of highly insoluble proteins and their associated proteoforms.
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Affiliation(s)
- Aneeqa Noor
- Department of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany; (A.N.); (I.Z.)
- German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany
| | - Saima Zafar
- Department of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany; (A.N.); (I.Z.)
- German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany
- Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Bolan Road, H-12, 44000 Islamabad, Pakistan
| | - Inga Zerr
- Department of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany; (A.N.); (I.Z.)
- German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany
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Liu Y, Wang C, Destin G, Szaro BG. Microtubule-associated protein tau promotes neuronal class II β-tubulin microtubule formation and axon elongation in embryonic Xenopus laevis. Eur J Neurosci 2015; 41:1263-75. [PMID: 25656701 DOI: 10.1111/ejn.12848] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/13/2014] [Accepted: 01/07/2015] [Indexed: 01/06/2023]
Abstract
Compared with its roles in neurodegeneration, much less is known about microtubule-associated protein tau's normal functions in vivo, especially during development. The external development and ease of manipulating gene expression of Xenopus laevis embryos make them especially useful for studying gene function during early development. To study tau's functions in axon outgrowth, we characterized the most prominent tau isoforms of Xenopus embryos and manipulated their expression. None of these four isoforms were strictly analogous to those commonly studied in mammals, as all constitutively contained exon 10, which is preferentially removed from mammalian fetal tau isoforms, as well as exon 8, which in mammals is rare. Nonetheless, like mammalian tau, Xenopus tau exhibited alternative splicing of exon 4a, which in mammals distinguishes 'big' tau of peripheral neurons, and exon 6. Strongly suppressing tau expression with antisense morpholino oligonucleotides only modestly compromised peripheral nerve outgrowth of intact tadpoles, but severely disrupted neuronal microtubules containing class II β-tubulins while leaving other microtubules largely unperturbed. Thus, the relatively mild dependence of axon development on tau likely resulted from having only a single class of microtubules disrupted by its loss. Also, consistent with its greater expression in long peripheral axons, boosting expression of 'big' tau increased neurite outgrowth significantly and enhanced tubulin acetylation more so than did the smaller isoform. These data demonstrate the utility of Xenopus as a tool to gain new insights into tau's functions in vivo.
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Affiliation(s)
- Yuanyuan Liu
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Chen Wang
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Giovanny Destin
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Ben G Szaro
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
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