2
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      A patient-derived cellular model for Huntington’s disease reveals phenotypes at clinically relevant CAG lengths

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The huntingtin protein participates in several cellular processes that are disrupted when the polyglutamine tract is expanded beyond a threshold of 37 CAG DNA repeats in Huntington’s disease (HD). Cellular biology approaches to understand these functional disruptions in HD have primarily focused on cell lines with synthetically long CAG length alleles that clinically represent outliers in this disease and a more severe form of HD that lacks age onset. Patient-derived fibroblasts are limited to a finite number of passages before succumbing to cellular senescence. We used human telomerase reverse transcriptase (hTERT) to immortalize fibroblasts taken from individuals of varying age, sex, disease onset, and CAG repeat length, which we have termed TruHD cells. TruHD cells display classic HD phenotypes of altered morphology, size and growth rate, increased sensitivity to oxidative stress, aberrant adenosine diphosphate/adenosine triphosphate (ADP/ATP) ratios, and hypophosphorylated huntingtin protein. We additionally observed dysregulated reactive oxygen species (ROS)-dependent huntingtin localization to nuclear speckles in HD cells. We report the generation and characterization of a human, clinically relevant cellular model for investigating disease mechanisms in HD at the single-cell level, which, unlike transformed cell lines, maintains functions critical for huntingtin transcriptional regulation and genomic integrity.

          Related collections

          Most cited references72

          • Record: found
          • Abstract: found
          • Article: not found

          Extension of life-span by introduction of telomerase into normal human cells.

          Normal human cells undergo a finite number of cell divisions and ultimately enter a nondividing state called replicative senescence. It has been proposed that telomere shortening is the molecular clock that triggers senescence. To test this hypothesis, two telomerase-negative normal human cell types, retinal pigment epithelial cells and foreskin fibroblasts, were transfected with vectors encoding the human telomerase catalytic subunit. In contrast to telomerase-negative control clones, which exhibited telomere shortening and senescence, telomerase-expressing clones had elongated telomeres, divided vigorously, and showed reduced straining for beta-galactosidase, a biomarker for senescence. Notably, the telomerase-expressing clones have a normal karyotype and have already exceeded their normal life-span by at least 20 doublings, thus establishing a causal relationship between telomere shortening and in vitro cellular senescence. The ability to maintain normal human cells in a phenotypically youthful state could have important applications in research and medicine.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Rapid single-step induction of functional neurons from human pluripotent stem cells.

            Available methods for differentiating human embryonic stem cells (ESCs) and induced pluripotent cells (iPSCs) into neurons are often cumbersome, slow, and variable. Alternatively, human fibroblasts can be directly converted into induced neuronal (iN) cells. However, with present techniques conversion is inefficient, synapse formation is limited, and only small amounts of neurons can be generated. Here, we show that human ESCs and iPSCs can be converted into functional iN cells with nearly 100% yield and purity in less than 2 weeks by forced expression of a single transcription factor. The resulting ES-iN or iPS-iN cells exhibit quantitatively reproducible properties independent of the cell line of origin, form mature pre- and postsynaptic specializations, and integrate into existing synaptic networks when transplanted into mouse brain. As illustrated by selected examples, our approach enables large-scale studies of human neurons for questions such as analyses of human diseases, examination of human-specific genes, and drug screening. Copyright © 2013 Elsevier Inc. All rights reserved.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Full-length human mutant huntingtin with a stable polyglutamine repeat can elicit progressive and selective neuropathogenesis in BACHD mice.

              To elucidate the pathogenic mechanisms in Huntington's disease (HD) elicited by expression of full-length human mutant huntingtin (fl-mhtt), a bacterial artificial chromosome (BAC)-mediated transgenic mouse model (BACHD) was developed expressing fl-mhtt with 97 glutamine repeats under the control of endogenous htt regulatory machinery on the BAC. BACHD mice exhibit progressive motor deficits, neuronal synaptic dysfunction, and late-onset selective neuropathology, which includes significant cortical and striatal atrophy and striatal dark neuron degeneration. Power analyses reveal the robustness of the behavioral and neuropathological phenotypes, suggesting BACHD as a suitable fl-mhtt mouse model for preclinical studies. Additional analyses of BACHD mice provide novel insights into how mhtt may elicit neuropathogenesis. First, unlike previous fl-mhtt mouse models, BACHD mice reveal that the slowly progressive and selective pathogenic process in HD mouse brains can occur without early and diffuse nuclear accumulation of aggregated mhtt (i.e., as detected by immunostaining with the EM48 antibody). Instead, a relatively steady-state level of predominantly full-length mhtt and a small amount of mhtt N-terminal fragments are sufficient to elicit the disease process. Second, the polyglutamine repeat within fl-mhtt in BACHD mice is encoded by a mixed CAA-CAG repeat, which is stable in both the germline and somatic tissues including the cortex and striatum at the onset of neuropathology. Therefore, our results suggest that somatic repeat instability does not play a necessary role in selective neuropathogenesis in BACHD mice. In summary, the BACHD model constitutes a novel and robust in vivo paradigm for the investigation of HD pathogenesis and treatment.
                Bookmark

                Author and article information

                Contributors
                Role: Monitoring Editor
                Journal
                Mol Biol Cell
                Mol. Biol. Cell
                molbiolcell
                mbc
                mboc
                Molecular Biology of the Cell
                The American Society for Cell Biology
                1059-1524
                1939-4586
                15 November 2018
                : 29
                : 23
                : 2809-2820
                Affiliations
                [a ]Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
                [e ]Stem Cell and Cancer Research Institute, Faculty of Health Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
                [b ]Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114
                [c ]Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
                [d ]Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048
                University of California, Berkeley
                Author notes

                Author contributions: C.L.H. and R.T. created experiments. C.L.H. wrote the manuscript and generated figures. T.M. and R.T. helped with editing. M.F. provided technical assistance. C.L.H. performed all experiments except for the following: V.M., V.K., and K.S. transduced patient cell lines for immortalization. J.V.G., T.G., and V.W. performed CAG repeat sizing. T.L. and J.S. performed qPCR. L.E.B. performed antibody validation experiments. R.G. performed cell viability experiments. S.S. performed nuclear speckle count. T.M. performed superresolution imaging of nuclear speckles.

                The authors declare that there are no conflicts of interest.

                *Address correspondence to: Ray Truant ( truantr@ 123456mcmaster.ca ).
                Article
                E18-09-0590
                10.1091/mbc.E18-09-0590
                6249865
                30256717
                fd983866-23a1-451d-8d0d-626a5fc2ddf0
                © 2018 Hung et al. “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology.

                This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License.

                History
                : 19 September 2018
                : 20 September 2018
                Categories
                Articles
                Cell Biology of Disease

                Molecular biology
                Molecular biology

                Comments

                Comment on this article