bims-cytox1 2017-09-24 papers

Issue of 2017‒09‒24
three papers selected by
Gavin McStay
New York Institute of Technology

Brain Dev. 2017 Sep 12. pii: S0387-7604(17)30236-X. [Epub ahead of print]

Japanese Leigh syndrome case treated with EPI-743.

Takeshi Kouga, Mariko Takagi, Akihiko Miyauchi, Hiroko Shimbo, Mizue Iai, Sumimasa Yamashita, Kei Murayama, Matthew B Klein, Guy Miller, Tomohide Goto, Hitoshi Osaka.

BACKGROUND: Leigh syndrome is a mitochondrial disease caused by respiratory chain deficiency, and there are no proven effective therapies. EPI-743 is a potent cellular oxidative stress protectant and results of clinical trials for mitochondrial diseases are accumulating.CASE: At 5months, a girl presented with the scarce eye movement and diminished muscle tone. She was diagnosed with Leigh encephalopathy from blood and cerebrospinal fluid lactate elevation and MRI findings. Sequence analysis for mitochondrial DNA revealed a T10158C mutation in the mitochondrial encoded ND3 gene in complex I.
RESULTS: At 8months, succinate was prescribed expected to restore the electron transport chain system. After that her condition got worse and succinate was discontinued. Subsequent administration of EPI-743 improved her eye movement, fine motor movements of the extremities, and bowel movement. She is now 5years old. Although brain atrophy has progressed, she has still respiratory free time.
CONCLUSION: Our patient showed visible improvement with EPI-743 treatment and the only patient surviving after 4years. There is a possibility that EPI-743 is modifying the natural course of the syndrome.

Keywords: EPI-743; Leigh syndrome; Mitochondrial DNA; Succinate

DOI: https://doi.org/10.1016/j.braindev.2017.08.005

Sci Rep. 2017 Sep 15. 7(1): 11733

Therapeutic effects of the mitochondrial ROS-redox modulator KH176 in a mammalian model of Leigh Disease.

Ria de Haas, Devashish Das, Alejandro Garanto, Herma G Renkema, Rick Greupink, Petra van den Broek, Jeanne Pertijs, Rob W J Collin, Peter Willems, Julien Beyrath, Arend Heerschap, Frans G Russel, Jan A Smeitink.

Leigh Disease is a progressive neurometabolic disorder for which a clinical effective treatment is currently still lacking. Here, we report on the therapeutic efficacy of KH176, a new chemical entity derivative of Trolox, in Ndufs4 -/- mice, a mammalian model for Leigh Disease. Using in vivo brain diffusion tensor imaging, we show a loss of brain microstructural coherence in Ndufs4 -/- mice in the cerebral cortex, external capsule and cerebral peduncle. These findings are in line with the white matter diffusivity changes described in mitochondrial disease patients. Long-term KH176 treatment retained brain microstructural coherence in the external capsule in Ndufs4 -/- mice and normalized the increased lipid peroxidation in this area and the cerebral cortex. Furthermore, KH176 treatment was able to significantly improve rotarod and gait performance and reduced the degeneration of retinal ganglion cells in Ndufs4 -/- mice. These in vivo findings show that further development of KH176 as a potential treatment for mitochondrial disorders is worthwhile to pursue. Clinical trial studies to explore the potency, safety and efficacy of KH176 are ongoing.

DOI: https://doi.org/10.1038/s41598-017-09417-5

J Mol Evol. 2017 Sep 15.

Some Liked It Hot: A Hypothesis Regarding Establishment of the Proto-Mitochondrial Endosymbiont During Eukaryogenesis.

Cory D Dunn.

Eukaryotic cells are characterized by a considerable increase in subcellular compartmentalization when compared to prokaryotes. Most evidence suggests that the earliest eukaryotes consisted of mitochondria derived from an α-proteobacterial ancestor enclosed within an archaeal host cell. However, what benefits the archaeal host and the proto-mitochondrial endosymbiont might have obtained at the beginning of this endosymbiotic relationship remains unclear. In this work, I argue that heat generated by the proto-mitochondrion initially permitted an archaeon living at high temperatures to colonize a cooler environment, thereby removing apparent limitations on cellular complexity. Furthermore, heat generation by the endosymbiont would have provided phenotypic flexibility not available through fixed alleles selected for fitness at specific temperatures. Finally, a role for heat production by the proto-mitochondrion bridges a conceptual gap between initial endosymbiont entry to the archaeal host and a later role for mitochondrial ATP production in permitting increased cellular complexity.

Keywords: Archaea; Bioenergetics; Endosymbiosis; Eukaryogenesis; Mitochondria; Temperature

DOI: https://doi.org/10.1007/s00239-017-9809-5