Inhibition of mitochondrial fragmentation diminishes Huntington’s disease–associated neurodegeneration
Xing Guo, … , Daria Mochly-Rosen, Xin Qi
Xing Guo, … , Daria Mochly-Rosen, Xin Qi
Published November 15, 2013
Citation Information: J Clin Invest. 2013;123(12):5371-5388. https://doi.org/10.1172/JCI70911.
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Research Article Neuroscience

Inhibition of mitochondrial fragmentation diminishes Huntington’s disease–associated neurodegeneration

Abstract

Huntington’s disease (HD) is the result of expression of a mutated Huntingtin protein (mtHtt), and is associated with a variety of cellular dysfunctions including excessive mitochondrial fission. Here, we tested whether inhibition of excessive mitochondrial fission prevents mtHtt-induced pathology. We developed a selective inhibitor (P110-TAT) of the mitochondrial fission protein dynamin-related protein 1 (DRP1). We found that P110-TAT inhibited mtHtt-induced excessive mitochondrial fragmentation, improved mitochondrial function, and increased cell viability in HD cell culture models. P110-TAT treatment of fibroblasts from patients with HD and patients with HD with iPS cell–derived neurons reduced mitochondrial fragmentation and corrected mitochondrial dysfunction. P110-TAT treatment also reduced the extent of neurite shortening and cell death in iPS cell–derived neurons in patients with HD. Moreover, treatment of HD transgenic mice with P110-TAT reduced mitochondrial dysfunction, motor deficits, neuropathology, and mortality. We found that p53, a stress gene involved in HD pathogenesis, binds to DRP1 and mediates DRP1-induced mitochondrial and neuronal damage. Furthermore, P110-TAT treatment suppressed mtHtt-induced association of p53 with mitochondria in multiple HD models. These data indicate that inhibition of DRP1-dependent excessive mitochondrial fission with a P110-TAT–like inhibitor may prevent or slow the progression of HD.

Authors

Xing Guo, Marie-Helene Disatnik, Marie Monbureau, Mehrdad Shamloo, Daria Mochly-Rosen, Xin Qi

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Figure 6

P110-TAT treatment reduced neurite shortening of MSNs from HD-iPS cells and corrected mitochondrial damage and cell death in patient neurons.

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P110-TAT treatment reduced neurite shortening of MSNs from HD-iPS cells ...
(A) Representative imaging on MSNs derived from Con- and HD-iPS cells. Top: A single neuron from each experimental group (original magnification, ×40). Bottom: A cluster of neurons at lower magnification (original magnification, ×20). (B) Data represent 3 independent experiments. At least 50 neurons/group were analyzed by an observed blinded to the experimental conditions. (C) Neuronal cells were labeled with TMRM fluorescence dye to indicate MMP. Density of TMRM red fluorescence only in cells with a neuronal-like morphology (multipolar cell bodies with at least 2 processes) was further quantitated as described in ref. 91. (D) Neuronal cells were stained with MitoSOX red, and density was analyzed in cells immunopositive for anti–DARPP-32. (E) Total ATP levels were measured using total lysates of mixed neuronal cells. Data represent 3 independent experiments. At least 50 neurons per group were analyzed. (F) After removal of BDNF for 48 hours, neuronal cell death was determined by the release of lactate dehydrogenase (LDH). Data represent 3 independent experiments. (G) Fluorescence density of EGFP-positive cells from neurons transduced by lentiviral particles containing p53 shRNA or control vector. Data represent 3 independent experiments. At least 50 EGFP-positive neurons per group were analyzed. (H) Neuronal cell death was determined by LDH release 2 days after removal of BNDF. Data are mean ± SEM. *P < 0.05 vs. Con; #P < 0.05 vs. HD.