Monday, October 29, 2018

The impact of histone post-translational modifications in neurodegenerative diseases

Samantha N. Cobos, Seth A. Bennett, Mariana P. Torrente, Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2018, ISSN 0925-4439, doi:10.1016/j.bbadis.2018.10.019.

Several histone PTMs have been associated with FRDA. One of the main causes of FRDA is the triplet repeat expansion GAA responsible for the transcriptional silencing of the FXN gene. Lymphoid cell lines from FRDA patients revealed that H3K4me2 and H3K4me marks decreased in the area surrounding the triplet repeat expansion when compared to unaffected cells. Moreover, both human tissues and a transgenic mice model showed an overall decrease in H3K9ac levels accompanied by increases in H3K9me2 and H3K9me3 levels. Collectively, these changes in histone marks would lead to lowered transcription, strongly suggesting that this is part of the mechanism that defines FRDA pathology.
In FRDA, treatment with nicotinamide (vitamin B3), an HDAC inhibitor, resulted in upregulation of the FXN gene by way of decreasing H3K9me3 and H3K27me3 at the FXN gene, and consequently increasing histone acetylation in both H3 and H4. This revels a possible treatment for FRDA, especially when considering the widespread availability, tolerability and affordability of vitamin B3.

Non-invasive Focal Mechanical Vibrations Delivered by Wearable Devices: An Open-Label Pilot Study in Childhood Ataxia

Schirinzi, T., Romano, A., Favetta, M., Sancesario, A., Burattini, R., Summa, S., Della Bella, G., Castelli, E., Bertini, E., Petrarca, M., … Vasco, G. (2018). Frontiers in neurology, 9, 849. doi:10.3389/fneur.2018.00849

Non-invasive focal mechanical vibrations (NIFMV) now represent a strategy of increasing interest to improve motor control in different neurological diseases. Nanotechnology allowed the creation of wearable devices transforming thermal variations into mechanical energy with focal vibrations. This kind of wearable stimulators (WS) has produced encouraging preliminary results when used in the treatment of movement disorders and ataxia in adults. In this open label pilot study we first evaluated the feasibility, safety and effectiveness of NIFMV by WS in a cohort of 10 patients with childhood ataxia, a phenomenological category including different conditions still lacking of effective symptomatic therapies. Through the assessment of both clinical rating scales and spatio-temporal gait parameters via standardized gait analysis, we observed that a 4 weeks long treatment with WS Equistasi® was safe and provided significantly different effects in stride features of patients with slow/non-progressive cerebellar ataxia and Friedreich's Ataxia.

A case series of hereditary cerebellar ataxias in a highly consanguineous population from Northeast Brazil

Deborah Moreira Rangel, Paulo Ribeiro Nóbrega, Maria Luiza Saraiva-Pereira, Laura Bannach Jardim, Pedro Braga-Neto, Parkinsonism & Related Disorders, 2018, ISSN 1353-8020, doi:10.1016/j.parkreldis.2018.10.027.

A total of 47 patients had ataxia as the main symptom. A high prevalence of consanguinity was found in the population studied (40.4%); The most prevalent diseases were: Friedreich's ataxia in 35% (n = 7), Niemann-Pick type C (NPC) in 15% (n = 3), and ataxia with oculomotor apraxia type 2 in 15% (n = 3).
In contrast with other studies, our prevalence of recessive ataxias was much higher than that of dominant ataxias. These findings might be explained by the high number of patients living in rural areas with a higher rate of consanguineous marriages, absence of a dominant ataxia founder effect or difficult access to healthcare system.