Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways.

Tracey A. Rouault and Nunziata Maio; The Journal of Biological Chemistry 292, 12744-12753. doi: 10.1074/jbc.R117.789537

Fe-S cofactors are composed of iron and inorganic sulfur in various stoichiometries. A complex assembly pathway conducts their initial synthesis and subsequent binding to recipient proteins. In this minireview, we discuss how discovery of the role of the mammalian cytosolic aconitase, known as iron regulatory protein 1 (IRP1), led to the characterization of the function of its Fe-S cluster in sensing and regulating cellular iron homeostasis. Moreover, we present an overview of recent studies that have provided insights into the mechanism of Fe-S cluster transfer to recipient Fe-S proteins.

Peptide SS-31 upregulates frataxin expression and improves the quality of mitochondria: implications in the treatment of Friedreich ataxia

Hongting Zhao, Huihui Li, Shuangying Hao, Jiping Chen, Jing Wu, Chuanhui Song, Meng Zhang, Tong Qiao & Kuanyu Li; Scientific Reports 7, Article number: 9840 (2017) doi:10.1038/s41598-017-10320-2

We demonstrated that treatment with the mitochondrion-targeted peptide SS-31 reduced frataxin deficiency-induced oxidative stress in lymphoblasts and fibroblasts derived from patients. Interestingly, SS-31 treatment translationally upregulated the protein level of frataxin in a dose-dependent manner. Furthermore, SS-31 treatment increased the enzymatic activities of the iron-sulphur enzymes, including aconitase and complex II and III of the respiratory chain. Further evaluation of the quality of mitochondria showed that mitochondrial membrane potential, ATP content, NAD+/NADH, and the morphology of mitochondria all improved. Our results suggest that SS-31 might potentially be a new drug for the early treatment of Friedreich ataxia.
In summary, SS-31 treatment improves the morphology and function of mitochondria in the FRDA patient-derived cells by upregulating the expression of FXN at the translational level and reducing oxidative stress. In addition, SS-31 treatment significantly enhances the ability of patient-derived cells to withstand challenges from exogenous oxidative stress. The mechanism of the translational upregulation in FXN expression by mitochondrion-targeted SS-31 needs to be further addressed. However, improvement in the quality of mitochondria in FRDA patient–derived cells by SS-31 treatment appears promising. It is reasonable to suggest that SS-31 might potentially be a new drug for the early treatment of FRDA.

Overexpression of Drosophila frataxin triggers cell death in an iron-dependent manner

Oliver Edenharter, Janik Clement, Stephan Schneuwly & Juan A. Navarro, Journal of Neurogenetics Vol. 0 , Iss. 0,0; doi:10.1080/01677063.2017.1363200

In this work, we have increased frataxin expression in neurons to elucidate specific roles that frataxin might play in these tissues. Using molecular, biochemical, histological and behavioral methods, we report that frataxin overexpression is sufficient to increase oxidative phosphorylation, modify mitochondrial morphology, alter iron homeostasis and trigger oxidative stress-dependent cell death. Interestingly, genetic manipulation of mitochondrial iron metabolism by silencing mitoferrin successfully improves cell survival under oxidative-attack conditions, although enhancing antioxidant defenses or mitochondrial fusion failed to ameliorate frataxin overexpression phenotypes. This result suggests that cell degeneration is directly related to enhanced incorporation of iron into the mitochondria. Drosophila frataxin overexpression might also provide an alternative approach to identify processes that are important in FRDA such as changes in mitochondrial morphology and oxidative stress induced cell death.

Are Astrocytes the Predominant Cell Type for Activation of Nrf2 in Aging and Neurodegeneration?

Jeffrey R. Liddell, Antioxidants 2017, 6(3), 65; doi:10.3390/antiox6030065

This review describes the evidence for Nrf2 activation in each cell type in prominent neurodegenerative diseases and normal aging in human brain and animal models of neurodegeneration, the response to pharmacological and genetic modulation of Nrf2, and clinical trials involving Nrf2-modifying drugs.

Jupiter Orphan Therapeutics Receives Orphan Drug Designation for its Trans-Resveratrol Product JOTROL for Treatment of Friedreich's Ataxia

JUPITER, Fla., Aug. 22, 2017 /PRNewswire/ -- Jupiter Orphan Therapeutics, Inc. ("JOT"), Jupiter, FL, today announced that it has received notification from the US Food and Drug Administration (FDA) that its Orphan Drug Designation request for trans-Resveratrol has been granted.

"Orphan Drug Designation serves as an important milestone for JOT as it positions our JOTROL™ product as a potential treatment for FA. We are hopeful that JOTROL™ can ultimately provide a meaningful treatment for FA patients around the world based on the earlier Phase II trial, utilizing resveratrol, conducted by our partner Murdoch Children's Research Institute, Melbourne, Australia ("MCRI"). That trial was an open label trial and generated very encouraging results, where 4 out of 5 very important endpoints were met. We, JOT together with MCRI, expect to repeat these results through a larger placebo controlled study utilizing JOTROL™ to avoid the Gastro Intestinal (GI) tolerability issues.

Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells

Daniela Giustarini, Graziano Colombo, Maria Lisa Garavaglia, Emanuela Astori, Nicola Marcello Portinaro, Francesco Reggiani, Salvatore Badalamenti, Anna Maria Aloisi, Annalisa Santucci, Ranieri Rossi, Aldo Milzani, Isabella Dalle-Donne, Free Radical Biology and Medicine, Available online 12 August 2017, ISSN 0891-5849, doi:10.1016/j.freeradbiomed.2017.08.008.

Glutathione (GSH) is the major non-protein thiol in humans and other mammals, which is present in millimolar concentrations within cells, but at much lower concentrations in the blood plasma. GSH and GSH-related enzymes act both to prevent oxidative damage and to detoxify electrophiles. Under oxidative stress, two GSH molecules become linked by a disulphide bridge to form glutathione disulphide (GSSG). Therefore, assessment of the GSH/GSSG ratio may provide an estimation of cellular redox metabolism. Current evidence resulting from studies in human blood, solid tissues, and cultured cells suggests that GSH also plays a prominent role in protein redox regulation via S-glutathionylation.

By immunohistochemistry with anti-GSH antibody, PSSG were also detected in Friedreich's ataxia, an autosomal recessive disorder caused by mutations in the gene encoding frataxin. In particular, in the cervical sections of spinal cord derived from autopsies of individuals with Friedreich's ataxia, immunostaining with anti-GSH antibodies was significantly stronger than in control sections, suggesting a significant increase in PSSG amount in all grey matter neurons, particularly in motor neurons of the anterior horns, as well as in the axonal spinal tracts (mostly in posterior white columns, spinocerebellar and corticospinal tracts). These findings suggest the occurrence of oxidative stress in the spinal cord of patients with Friedreich's ataxia as a consequence of reduced frataxin expression.

European Reference networks for rare diseases: what is the conceptual framework?

Véronique Héon-Klin, Orphanet Journal of Rare Diseases 201712:137 doi:10.1186/s13023-017-0676-3

In February 2017, 24 European Reference Networks (ERNs) were established in a European legal framework, of which 23 are dedicated to rare or low prevalence complex diseases or conditions. More than 300 hospitals and 900 highly specialised teams are participating in the approved ERN.

The ERNs are an opportunity to explore these changes and turn them into assets for patients with unmet needs. If we succeed in promote knowledge exchange in such a way that patients will only be treated in duly justified cases in the “other” MS, then “the European social model in health” can be preserved under the current European treaties.

Advances in Neurological Therapeutics for Friedreich Ataxia and Machado-Joseph Disease

Yabe I, Sasaki H.; Brain Nerve. 2017 Aug;69(8):913-924. doi: 10.11477/mf.1416200842.
[Article in Japanese]
We reviewed advances in therapeutics for both Friedreich ataxia and Machado-Joseph disease. Various clinical trials have been carried out, mainly for Friedreich ataxia; however, the therapeutic reports from these trials have not provided much evidence for success. Some interesting clinical trials have been reported, and further developments are expected. Regenerative therapy using umbilical cord mesenchymal stem cells and a therapeutic study investigating a new pathomechanism in animal and/or cell culture studies were reported. We expect that these results will translate to therapeutic strategies for patients with these disorders. In addition, biomarkers play an important role when novel treatments are discovered and clinical trials are performed: hence at present, a number of biomarkers such as gait analysis by triaxial accelerometers and prism adaptation of hand-reaching movements, are being examined.

Cerebral Abnormalities in Friedreich Ataxia: A Review

Louisa P. Selvadurai, Ian H. Harding, Louise A. Corben, Nellie Georgiou-Karistianis, Neuroscience & Biobehavioral Reviews, Available online 18 August 2017, ISSN 0149-7634, doi:10.1016/j.neubiorev.2017.08.006.

However, cerebral abnormalities in FRDA are being increasingly documented via multiple neuroimaging techniques. Understanding the nature and implications of cerebral abnormalities in FRDA provides more comprehensive knowledge of nervous system involvement in this disorder and increases the prospects of identifying effective treatment targets. We review the cerebellar and the cerebral involvement with a focus on the emerging in vivo human neuroimaging findings suggesting wide-spread cerebral involvement, including aberrant cerebellar-cerebral connectivity. We synthesise the findings by proposing potential mechanisms that may drive these effects. Finally, we identify future research directions which, we argue, will lead to a better understanding of the extent and potential mechanisms of cerebral aberrations in FRDA.

Tocotrienols: the unsaturated sidekick shifting new paradigms in vitamin E therapeutics

Madhu M. Kanchi, Muthu K. Shanmugam, Grishma Rane, Gautam Sethi, Alan P. Kumar, Drug Discovery Today, 2017, ISSN 1359-6446, doi:10.1016/j.drudis.2017.08.001.

Vitamin E family members: tocotrienols and tocopherols are widely known for their health benefits. Decades of research on tocotrienols have shown they have diverse biological activities such as antioxidant, anti-inflammatory, anticancer, neuroprotective and skin protection benefits, as well as improved cognition, bone health, longevity and reduction of cholesterol levels in plasma. Tocotrienols also modulate several intracellular molecular targets and, most importantly, have been shown to improve lipid profiles, reduce total cholesterol and reduce the volume of white matter lesions in human clinical trials. This review provides a comprehensive update on the little-known therapeutic potentials of tocotrienols, which tocopherols lack in a variety of inflammation-driven diseases.

Remarks: EPI-743, sin: alpha-tocotrienol quinone, vatiquinone or Vincerinone. BioElectron Technology Corporation (Edison Pharmaceutical)

Targeting Mitochondrial Dysfunction in Neurodegenerative Disease

The Dana Foundation. By Kayt Sukel, August 15, 2017

It’s long been known that the brain is an energy glutton: Most estimates suggest that it requires about 20 percent of the body’s total energy stores to work effectively. That energy is produced by mitochondria, specialized rod-shaped organelles in every cell in the body. So perhaps it is no surprise that problems with mitochondrial function in neurons have been linked to a host of progressive neurodegenerative disorders—one of which is Friedreich’s ataxia, a rare but devastating disease that progressively kills off nerve cells in the brain and spinal cord. Now, scientists at the University of California, Davis have identified how frataxin, the gene that causes Friedreich’s ataxia, affects mitochondrial function. That understanding may lead to new, more effective potential treatments for Friedreich’s ataxia as well as other forms of neurodegenerative disease.

Cortopassi hopes to take dimethyl fumarate (DMF) to clinical trial for Friedreich’s ataxia patients soon. He also thinks measuring mitochondrial number could be an important biomarker to test the efficacy of treatments for other neurodegenerative disorders as well. Manfredi agrees.

Mechanisms of unexpected death and autopsy findings in Friedreich ataxia

Roger W Byard, , John D Gilbert; Medicine, Science and the Law, First published date: August-13-2017, Doi:10.1177/0025802417723809

A 36-year-old woman with a clinical history of Friedreich ataxia and hypertrophic cardiomyopathy was found unexpectedly dead at her home. Sudden death due to cardiac disease, resulting in presentation for medicolegal autopsy, may be the presenting feature at all ages, including childhood.
The reported case demonstrates sudden death due to cardiac disease in a woman with an established diagnosis of Friedreich ataxia. Death may, however,be due to a wide range of other vascular, pulmonaryor endocrine diseases, which should be checked for at autopsy. Very rarely, sudden cardiac death may be the presenting feature of this condition.

FDA Confirms That Use of mFARS as Primary Endpoint in Part 2 of the MOXIe Trial Can Support Approval of Omaveloxolone in Friedreich’s Ataxia

RVING, Texas, Aug. 14, 2017 (GLOBE NEWSWIRE) -- Reata Pharmaceuticals, Inc. (Nasdaq:RETA) (“Reata” or the “Company”), a clinical-stage biopharmaceutical company, today announced that the U.S. Food and Drug Administration (FDA) confirmed that the modified Friedreich’s Ataxia Rating Scale (mFARS) is an acceptable primary endpoint for Part 2 of the MOXIe trial for omaveloxolone in Friedreich’s ataxia (FA).

Part 2 of the MOXIe trial will be a double-blind, randomized, placebo-controlled, multi-center, international trial designed to evaluate the safety, tolerability, and efficacy of omaveloxolone in patients with FA. The trial will enroll approximately 100 FA patients randomized evenly to either 150 mg of omaveloxolone or placebo. The primary endpoint of the trial will be the change from baseline in mFARS of omaveloxolone compared to placebo at 48 weeks. Additional endpoints will include the change from baseline in peak work during maximal exercise testing, Patient Global Impression of Change, and Clinical Global Impression of Change. The Company has initiated screening patients for Part 2 of MOXIe and plans to randomize the first patient during the second half of 2017.

Mitochondrial biogenesis and neural differentiation of human iPSC is modulated by idebenone in a developmental stage-dependent manner

J. Augustyniak, J. Lenart, M. Zychowicz, P. P. Stepien, L. Buzanska. Biogerontology (2017) 18: 665. doi:10.1007/s10522-017-9718-4

Idebenone, the synthetic analog of coenzyme Q10 can improve electron transport in mitochondria. Therefore, it is used in the treatment of Alzheimer’s disease and other cognitive impairments. However, the mechanism of its action on neurodevelopment is still to be elucidated. Here we demonstrate that the cellular response of human induced pluripotent stem cells (hiPSC) to idebenone depends on the stage of neural differentiation. When: neural stem cells (NSC), early neural progenitors (eNP) and advanced neural progenitors (NP) have been studied a significant stimulation of mitochondrial biogenesis was observed only at the eNP stage of development. This coexists with the enhancement of cell viability and increase in total cell number. In addition, we report novel idebenone properties in a possible regulation of neural stem cells fate decision: only eNP stage responded with up-regulation of both neuronal (MAP2), astrocytic (GFAP) markers, while at NSC and NP stages significant down-regulation of MAP2 expression was observed, promoting astrocyte differentiation. Thus, idebenone targets specific stages of hiPSC differentiation and may influence the neural stem cell fate decision.

Furthermore, the specific for eNP upregulation of all tested genes involved in the mitochondrial biogenesis as well as significant upregulation of viability may suggest that eNP stage is the “developmental window of sensitivity” for the neuroprotective function of the idebenone. More research is needed to elucidate the effect of idebenone on mitochondrial biogenesis and stem cell fate decision during neural differentiation, however, based on the presented results we can strongly support the hypothesis that idebenone protective effect is developmental stage dependent and that future targeted treatment of the selected stage of neural development may exert better therapeutic effect.

Reversible axonal dystrophy by calcium modulation in frataxin-deficient sensory neurons of YG8R mice

Belén Mollá, Diana C. Muñoz-Lasso, Fatima Riveiro1, Arantxa Bolinches-Amorós, Federico V. Pallardó, Angel Fernandez-Vilata, Maria D. Vaya, Francesc Palau and Pilar Gonzalez-Cabo; Front. Mol. Neurosci. doi:10.3389/fnmol.2017.00264

We observed that the deficiency of frataxin in sensory neurons of dorsal root ganglia (DRG) of the YG8R mouse model causes the formation of axonal spheroids which retain dysfunctional mitochondria, shows alterations in the cytoskeleton and it produces impairment of axonal transport and autophagic flux. The homogenous distribution of axonal spheroids along the neurites supports the existence of continues focal damages. This lead us to propose for FRDA a model of distal axonopathy based on axonal focal damages. In addition, we observed the involvement of oxidative stress and dyshomeostasis of calcium in axonal spheroid formation generating axonal injury as a primary cause of pathophysiology. Axonal spheroids may be a consequence of calcium imbalance, thus we propose the quenching or removal extracellular Ca2+ to prevent spheroids formation. In our neuronal model, treatments with BAPTA and o-phenanthroline reverted the axonal dystrophy and the mitochondrial dysmorphic parameters. These results support the hypothesis that axonal pathology is reversible in FRDA by pharmacological manipulation of intracellular Ca2+ with Ca2+ chelators or metalloprotease inhibitors, preventing Ca2+-mediated axonal injury. Thus, the modulation of Ca2+ levels may be a relevant therapeutic target to develop early axonal protection and prevent dying-back neurodegeneration.

Heart and Nervous System Pathology in Compound Heterozygous Friedreich Ataxia

Alyssa B. Becker, BA Jiang Qian, MD, PhD Benjamin B. Gelman, MD, PhD Michele Yang, MD Peter Bauer, MD Arnulf H. Koeppen, MD; Journal of Neuropathology & Experimental Neurology, Volume 76, Issue 8, 1 August 2017, Pages 665–675, doi:10.1093/jnen/nlx047

The pathologic phenotype in homozygous and compound heterozygous FA is determined by residual frataxin levels rather than unique mutations.

Mitochondrial dysfunction in the neuro-degenerative and cardio-degenerative disease, Friedreich's ataxia

Shannon Chiang, Danuta S. Kalinowski, Patric J. Jansson, Des R. Richardson, Michael L.-H. Huang, Friedreich's ataxia, Neurochemistry International, Available online 4 August 2017, ISSN 0197-0186, doi:10.1016/j.neuint.2017.08.002.

Mitochondrial homeostasis is essential for maintaining healthy cellular function and survival. The detrimental involvement of mitochondrial dysfunction in neuro-degenerative diseases has recently been highlighted in human conditions, such as Parkinson's, Alzheimer's and Huntington's disease. Friedreich's ataxia (FA) is another neuro-degenerative, but also cardio-degenerative condition, where mitochondrial dysfunction plays a crucial role in disease progression. Deficient expression of the mitochondrial protein, frataxin, is the primary cause of FA, which leads to adverse alterations in whole cell and mitochondrial iron metabolism. Dys-regulation of iron metabolism in these compartments, results in the accumulation of inorganic iron deposits in the mitochondrial matrix that is thought to potentiate oxidative damage observed in FA. Therefore, the maintenance of mitochondrial homeostasis is crucial in the progression of neuro-degenerative conditions, particularly in FA. In this review, vital mitochondrial homeostatic processes and their roles in FA pathogenesis will be discussed. These include mitochondrial iron processing, mitochondrial dynamics (fusion and fission processes), mitophagy, mitochondrial biogenesis, mitochondrial energy production and calcium metabolism.

Chondrial Announces FDA Orphan Drug Designation for CTI-1601, a Novel Investigational Technology for the Treatment of Friedreich's Ataxia

BALA CYNWYD, Pa., Aug. 3, 2017 /PRNewswire/ -- Chondrial Therapeutics, Inc., an emerging biotechnology company focused on the treatment of rare mitochondrial diseases, announced today that the US Food and Drug Administration (FDA) has granted orphan drug designation to its lead investigational drug candidate, CTI-1601, being developed for the treatment of Friedreich's Ataxia.

The importance of international collaboration for rare diseases research: a European perspective

D Julkowska, C P Austin, C M Cutillo, D Gancberg, C Hager, J Halftermeyer, A H Jonker, L P L Lau, I Norstedt, A Rath, R Schuster, E Simelyte and S van Weely; Gene Therapy advance online publication 27 July 2017; doi: 10.1038/gt.2017.29

Over the last two decades, important contributions were made at national, European and international levels to foster collaboration into rare diseases research. The European Union (EU) has put much effort into funding rare diseases research, encouraging national funding organizations to collaborate together in the E-Rare program, setting up European Reference Networks for rare diseases and complex conditions, and initiating the International Rare Diseases Research Consortium (IRDiRC) together with the National Institutes of Health in the USA. Co-ordination of the activities of funding agencies, academic researchers, companies, regulatory bodies, and patient advocacy organizations and partnerships with, for example, the European Research Infrastructures maximizes the collective impact of global investments in rare diseases research. This contributes to accelerating progress, for example, in faster diagnosis through enhanced discovery of causative genes, better understanding of natural history of rare diseases through creation of common registries and databases and boosting of innovative therapeutic approaches. Several examples of funded pre-clinical and clinical gene therapy projects show that integration of multinational and multidisciplinary expertize generates new knowledge and can result in multicentre gene therapy trials. International collaboration in rare diseases research is key to improve the life of people living with a rare disease.