Direct Lineage Reprogramming Reveals Disease-Specific Phenotypes of Motor Neurons from Human ALS Patients

Abstract

SUMMARY Subtype-specific neurons obtained from adult humans will be critical to modeling neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS). Here we show that adult human skin fibroblasts can be directly and efficiently converted into highly pure motor neurons without passing through an induced pluripotent stem cell stage. These adult human induced motor neurons (hiMNs) exhibit the cytological and electrophysiological features of spinal motor neurons and form functional neuromuscular junctions (NMJs) with skeletal muscles. Importantly, hiMNs converted from ALS-patient fibroblasts show disease-specific degeneration manifested through poor survival, soma shrinkage, hypoactivity, and an inability to form NMJs. A chemical screen revealed that the degenerative features of ALS-hiMNs can be remarkably rescued by the small molecule kenpaullone. Taken together, our results define a direct and efficient strategy to obtain disease-relevant neuronal subtypes from adult human patients and reveal their promising value in disease modeling and drug identification.

Small Molecules Modulate Chromatin Accessibility to Promote NEUROG2-Mediated Fibroblast-to-Neuron Reprogramming

“…Unlike the high-efficiency conversion of fetal MRC-5 fibroblasts, NEUROG2 and FD do not functionally or morphologically reprogram adult skin fibroblast lines without additional SOX11 overexpression (Liu et al., 2013). Likewise, the addition of FGF2 and kenpaullone to this reprogramming cocktail promote the survival of reprogrammed neurons (Liu et al., 2013, Liu et al., 2015). As SOX4 and SOX11 exhibit redundant functions in the developing nervous system (Cheung et al., 2000, Miller et al., 2013), we investigated whether an inability to activate this factor hinders adult cell reprogramming efficiency.…”

“…The morphological complexity of these neurons can be significantly enhanced with ISL1 and LHX3 overexpression (Liu et al., 2015). As adult fibroblast lineages exhibit highly defined epigenetic signatures that make these cells less poised for reprogramming, mechanistic studies have predominantly relied on embryonic or fetal fibroblasts (Masserdotti et al., 2015, Wapinski et al., 2013, Gascón et al., 2016).…”

Codon usage affects the structure and function of the Drosophila circadian clock protein PERIOD

“…These diseases include cystic fibrosis, amyotrophic lateral sclerosis (ALS), and Crohn's disease (Bartoszewski et al 2010;Lazrak et al 2013;Bali and Bebok 2015;Liu et al 2016). A single synonymous SNP in the form of a rare codon in the human multidrug resistance 1 (MDR1) gene was found to result in altered drug and inhibitor interactions (Kimchi-Sarfaty et al 2007).…”

Induced dopaminergic neurons: A new promise for Parkinson’s disease

“…This method has been successfully extended to the human system, where fetal and postnatal human fibroblasts are converted to iN with BAM plus NeuroD1 [11]. Many groups have successfully converted mouse, porcine, non-human primate [12] or human fibroblasts into iN, DA neuronal progenitors (iDPs) [13], [14], dopaminergic neurons [8], [15], [16], motor neurons (hiMNs) [17], [18], [19], peripheral sensory neurons [20], striatal medium spiny neurons (MSNs) [21], [22], cholinergic neurons [23], serotonergic neurons [24], [25], GABAergic neurons [26], glutamatergic neurons [27], neural precursor cells [28] and oligodendrocyte progenitor cells [29], [30], with different combinations of transcription factors and media additives (small molecule compounds and growth factors).…”