Human genetics and neuropathology suggest a link between miR-218 and amyotrophic lateral sclerosis pathophysiology

Motor neuron–specific microRNA-218 (miR-218) has recently received attention because of its roles in mouse development. However, miR-218 relevance to human motor neuron disease was not yet explored. Here, we demonstrate by neuropathology that miR-218 is abundant in healthy human motor neurons. However, in amyotrophic lateral sclerosis (ALS) motor neurons, miR-218 is down-regulated and its mRNA targets are reciprocally up-regulated (derepressed). We further identify the potassium channel Kv10.1 as a new miR-218 direct target that controls neuronal activity. In addition, we screened thousands of ALS genomes and identified six rare variants in the human miR-218-2 sequence. miR-218 gene variants fail to regulate neuron activity, suggesting the importance of this small endogenous RNA for neuronal robustness. The underlying mechanisms involve inhibition of miR-218 biogenesis and reduced processing by DICER. Therefore, miR-218 activity in motor neurons may be susceptible to failure in human ALS, suggesting that miR-218 may be a potential therapeutic target in motor neuron disease

Supplementary Material for: Elevated Global DNA Methylation Is Not Exclusive to Amyotrophic Lateral Sclerosis and Is Also Observed in Spinocerebellar Ataxia Types 1 and 2

Adult-onset neurological disorders are caused and influenced by a multitude of different factors, including epigenetic modifications. Here, using an ELISA kit selected upon careful testing, we investigated global 5-methylcytosine (5-mC) levels in sporadic and familial amyotrophic lateral sclerosis (sALS and fALS), spinocerebellar ataxia types 1 and 2 (SCA1 and SCA2), Huntington’s disease, Friedreich’s ataxia, and myotonic dystrophy type 1. We report a significant elevation in global 5-mC levels of about 2–7% on average for sALS (<i>p</i> < 0.01 [F(1, 243) = 9.159, <i>p</i> = 0.0027]) and various forms of fALS along with SCA1 (<i>p</i> < 0.01 [F(1, 83) = 11.285], <i>p</i> = 0.0012) and SCA2 (<i>p</i> < 0.001 [F(1, 122) = 29.996, <i>p</i> = 0.0001]) when compared to age- and sex-matched healthy controls. <i>C9orf72</i> expansion carrier ALS patients exhibit the highest global 5-mC levels along with <i>C9orf72</i> promoter hypermethylation. We failed to measure global 5-hydroxymethylcytosine (5-hmC) levels in blood, probably due to the very low levels of 5-hmC and the limitations of the commercially available ELISA kits. Our results point towards a role for epigenetics modification in ALS, SCA1, and SCA2, and help conclude a dispute on the global 5-mC levels in sALS blood

Using global team science to identify genetic Parkinson's disease worldwide

Talks on rare diseases in the field of neurology often start with a statement like this: “About 80% of all rare diseases have a neurologic manifestation and about 80% of those are genetic in origin.” Although these numbers probably represent more of an estimate than well‐documented evidence, rapidly advancing and cost‐effective sequencing technologies have led to the quickly growing identification of patients with hereditary neurological diseases..