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Zanier ER, Barzago MM, Vegliante G, Romeo M, Restelli E, Bertani I, Natale C, Colnaghi L, Colombo L, Russo L, Micotti E, Fioriti L, Chiesa R, Diomede L. C. elegans detects toxicity of traumatic brain injury generated tau. Neurobiol Dis 2021; 153:105330. [PMID: 33711491 PMCID: PMC8039186 DOI: 10.1016/j.nbd.2021.105330] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 11/30/2022] Open
Abstract
Traumatic brain injury (TBI) is associated with widespread tau pathology in about 30% of patients surviving late after injury. We previously found that TBI in mice induces the formation of an abnormal form of tau (tauTBI) which progressively spreads from the site of injury to remote brain regions. Intracerebral inoculation of TBI brain homogenates into naïve mice induced progressive tau pathology, synaptic loss and late cognitive decline, suggesting a pivotal role of tauTBI in post-TBI neurodegeneration. However, the possibility that tauTBI was a marker of TBI-associated neurodegeneration rather than a toxic driver of functional decline could not be excluded. Here we employed the nematode C. elegans as a biosensor to test the pathogenic role of TBI generated tau. The motility of this nematode depends on efficient neuromuscular transmission and is exceptionally sensitive to the toxicity of amyloidogenic proteins, providing a tractable model for our tests. We found that worms exposed to brain homogenates from chronic but not acute TBI mice, or from mice in which tauTBI had been transmitted by intracerebral inoculation, had impaired motility and neuromuscular synaptic transmission. Results were similar when worms were given brain homogenates from transgenic mice overexpressing tau P301L, a tauopathy mouse model, suggesting that TBI-induced and mutant tau have similar toxic properties. P301L brain homogenate toxicity was similar in wild-type and ptl-1 knock-out worms, indicating that the nematode tau homolog protein PTL-1 was not required to mediate the toxic effect. Harsh protease digestion to eliminate the protein component of the homogenates, pre-incubation with anti-tau antibodies or tau depletion by immunoprecipitation, abolished the toxicity. Homogenates of chronic TBI brains from tau knock-out mice were not toxic to C. elegans, whereas oligomeric recombinant tau was sufficient to impair their motility. This study indicates that tauTBI impairs motor activity and synaptic transmission in C. elegans and supports a pathogenic role of tauTBI in the long-term consequences of TBI. It also sets the groundwork for the development of a C. elegans-based platform for screening anti-tau compounds. Traumatic brain injury (TBI) in mice induces a progressive tau pathology. Brain-injured tissue from chronic but not acute TBI mice impairs C. elegans motility. TBI tissue immunodepleted of tau or from tau knock-out mice has no toxic effect. Brain-injured tissue from TBI mice impairs neuromuscular transmission in worms. C. elegans is a tractable model for investigating tau toxicity generated by TBI.
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Affiliation(s)
- Elisa R Zanier
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy.
| | - Maria Monica Barzago
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Gloria Vegliante
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Margherita Romeo
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elena Restelli
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Ilaria Bertani
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Carmina Natale
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy; Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Luca Colnaghi
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy; Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Laura Colombo
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Luca Russo
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Edoardo Micotti
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Luana Fioriti
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Roberto Chiesa
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy.
| | - Luisa Diomede
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy.
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Caenorhabditis elegans Models to Investigate the Mechanisms Underlying Tau Toxicity in Tauopathies. Brain Sci 2020; 10:brainsci10110838. [PMID: 33187241 PMCID: PMC7697895 DOI: 10.3390/brainsci10110838] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
The understanding of the genetic, biochemical, and structural determinants underlying tau aggregation is pivotal in the elucidation of the pathogenic process driving tauopathies and the design of effective therapies. Relevant information on the molecular basis of human neurodegeneration in vivo can be obtained using the nematode Caenorhabditis elegans (C. elegans). To this end, two main approaches can be applied: the overexpression of genes/proteins leading to neuronal dysfunction and death, and studies in which proteins prone to misfolding are exogenously administered to induce a neurotoxic phenotype. Thanks to the easy generation of transgenic strains expressing human disease genes, C. elegans allows the identification of genes and/or proteins specifically associated with pathology and the specific disruptions of cellular processes involved in disease. Several transgenic strains expressing human wild-type or mutated tau have been developed and offer significant information concerning whether transgene expression regulates protein production and aggregation in soluble or insoluble form, onset of the disease, and the degenerative process. C. elegans is able to specifically react to the toxic assemblies of tau, thus developing a neurodegenerative phenotype that, even when exogenously administered, opens up the use of this assay to investigate in vivo the relationship between the tau sequence, its folding, and its proteotoxicity. These approaches can be employed to screen drugs and small molecules that can interact with the biogenesis and dynamics of formation of tau aggregates and to analyze their interactions with other cellular proteins.
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V363I and V363A mutated tau affect aggregation and neuronal dysfunction differently in C. elegans. Neurobiol Dis 2018; 117:226-234. [PMID: 29936232 DOI: 10.1016/j.nbd.2018.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 06/18/2018] [Accepted: 06/20/2018] [Indexed: 11/24/2022] Open
Abstract
Mutations in the microtubule-associated protein tau (MAPT) gene have been linked to a heterogeneous group of progressive neurodegenerative disorders commonly called tauopathies. From patients with frontotemporal lobar degeneration with distinct atypical clinical phenotypes, we recently identified two new mutations on the same codon, in position 363 of the MAPT gene, which resulted in the production of Val-to-Ala (tauV363A) or Val-to-Ile (tauV363I) mutated tau. These substitutions specifically affected microtubule polymerization and propensity of tau to aggregate in vitro suggesting that single amino acid modification may dictate the fate of the neuropathology. To clarify whether tauV363A and tauV363I affect protein misfolding differently in vivo driving certain phenotypes, we generated new transgenic C. elegans strains. Human 2N4R tau carrying the mutation was expressed in all the neurons of worms. The behavioral defects, misfolding and proteotoxicity caused by the tauV363A and tauV363I mutated proteins were compared to that induced by the expression of wild-type tau (tauwt). Pan-neuronal expression of human 2N4R tauWT in worms resulted in a neuromuscular defect with characteristics of a neurodegenerative phenotype. This defect was worsened by the expression of mutated proteins which drive distinct neuronal dysfunctions and synaptic impairments involving, in transgenic worms expressing tauV363A (V363A) also a pharyngeal defect never linked before to other mutations. The two mutations differently affected the tau phosphorylation and misfolding propensities: tauV363I was highly phosphorylated on epitopes corresponding to Thr231 and Ser202/Thr205, and accumulated as insoluble tau assemblies whereas tauV363A showed a greater propensity to form soluble oligomeric assemblies. These findings uphold the role of a single amino acid substitution in specifically affecting the ability of tau to form soluble and insoluble assemblies, opening up new perspectives in the pathogenic mechanism underlying tauopathies.
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Fruhmann G, Seynnaeve D, Zheng J, Ven K, Molenberghs S, Wilms T, Liu B, Winderickx J, Franssens V. Yeast buddies helping to unravel the complexity of neurodegenerative disorders. Mech Ageing Dev 2017; 161:288-305. [DOI: 10.1016/j.mad.2016.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/22/2016] [Accepted: 05/02/2016] [Indexed: 12/31/2022]
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Guthrie CR, Greenup L, Leverenz JB, Kraemer BC. MSUT2 is a determinant of susceptibility to tau neurotoxicity. Hum Mol Genet 2011; 20:1989-99. [PMID: 21355046 DOI: 10.1093/hmg/ddr079] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Lesions containing abnormal aggregated tau protein are one of the diagnostic hallmarks of Alzheimer's disease (AD) and related tauopathy disorders. How aggregated tau leads to dementia remains enigmatic, although neuronal dysfunction and loss clearly contribute. We previously identified sut-2 as a gene required for tau neurotoxicity in a transgenic Caenorhabditis elegans model of tauopathy. Here, we further explore the role of sut-2 and show that overexpression of SUT-2 protein enhances tau-induced neuronal dysfunction, neurotoxicity and accumulation of insoluble tau. We also explore the relationship between sut-2 and its human homolog, mammalian SUT-2 (MSUT2) and find both proteins to be predominantly nuclear and localized to SC35-positive nuclear speckles. Using a cell culture model for the accumulation of pathological tau, we find that high tau levels lead to increased expression of MSUT2 protein. We analyzed MSUT2 protein in age-matched post-mortem brain samples from AD patients and observe a marked decrease in overall MSUT2 levels in the temporal lobe of AD patients. Analysis of post-mortem tissue from AD cases shows a clear reduction in neuronal MSUT2 levels in brain regions affected by tau pathology, but little change in regions lacking tau pathology. RNAi knockdown of MSUT2 in cultured human cells overexpressing tau causes a marked decrease in tau aggregation. Both cell culture and post-mortem tissue studies suggest that MSUT2 levels may influence neuronal vulnerability to tau toxicity and aggregation. Thus, neuroprotective strategies targeting MSUT2 may be of therapeutic interest for tauopathy disorders.
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Affiliation(s)
- Chris R Guthrie
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle Division, Seattle, WA 98108, USA
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Dimitriadi M, Hart AC. Neurodegenerative disorders: insights from the nematode Caenorhabditis elegans. Neurobiol Dis 2010; 40:4-11. [PMID: 20493260 DOI: 10.1016/j.nbd.2010.05.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 05/06/2010] [Accepted: 05/11/2010] [Indexed: 10/19/2022] Open
Abstract
Neurodegenerative diseases impose a burden on society, yet for the most part, the mechanisms underlying neuronal dysfunction and death in these disorders remain unclear despite the identification of relevant disease genes. Given the molecular conservation in neuronal signaling pathways across vertebrate and invertebrate species, many researchers have turned to the nematode Caenorhabditis elegans to identify the mechanisms underlying neurodegenerative disease pathology. C. elegans can be engineered to express human proteins associated with neurodegeneration; additionally, the function of C. elegans orthologs of human neurodegenerative disease genes can be dissected. Herein, we examine major C. elegans neurodegeneration models that recapitulate many aspects of human neurodegenerative disease and we survey the screens that have identified modifier genes. This review highlights how the C. elegans community has used this versatile organism to model several aspects of human neurodegeneration and how these studies have contributed to our understanding of human disease.
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Affiliation(s)
- Maria Dimitriadi
- Department of Neuroscience, Brown University, 185 Meeting Street, Providence, RI 02912, USA
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McColl G, Roberts BR, Gunn AP, Perez KA, Tew DJ, Masters CL, Barnham KJ, Cherny RA, Bush AI. The Caenorhabditis elegans A beta 1-42 model of Alzheimer disease predominantly expresses A beta 3-42. J Biol Chem 2009; 284:22697-702. [PMID: 19574211 DOI: 10.1074/jbc.c109.028514] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transgenic expression of human amyloid beta (A beta) peptide in body wall muscle cells of Caenorhabditis elegans has been used to better understand aspects of Alzheimer disease (AD). In human aging and AD, A beta undergoes post-translational changes including covalent modifications, truncations, and oligomerization. Amino truncated A beta is increasingly recognized as potentially contributing to AD pathogenesis. Here we describe surface-enhanced laser desorption ionization-time of flight mass spectrometry mass spectrometry of A beta peptide in established transgenic C. elegans lines. Surprisingly, the A beta being expressed is not full-length 1-42 (amino acids) as expected but rather a 3-42 truncation product. In vitro analysis demonstrates that A beta(3-42) self-aggregates like A beta(1-42), but more rapidly, and forms fibrillar structures. Similarly, A beta(3-42) is also the more potent initiator of A beta(1-40) aggregation. Seeded aggregation via A beta(3-42) is further enhanced via co-incubation with the transition metal Cu(II). Although unexpected, the C. elegans model of A beta expression can now be co-opted to study the proteotoxic effects and processing of A beta(3-42).
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Affiliation(s)
- Gawain McColl
- Mental Health Research Institute, Parkville, Victoria 3052, Australia
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