Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease; survival in ALS is typically 3–5 years. No treatment extends patient survival by more than three months. Approximately 20% of familial ALS and 1–3% of sporadic ALS patients carry a mutation in the gene encoding superoxide dismutase 1 (SOD1). In a transgenic ALS mouse model expressing the mutant SOD1G93A protein, silencing the SOD1 gene prolongs survival. One study reports a therapeutic effect of silencing the SOD1 gene in systemically treated adult ALS mice; this was achieved with a short hairpin RNA, a silencing molecule that has raised multiple safety concerns, and recombinant adeno-associated virus (rAAV) 9. We report here a silencing method based on an artificial microRNA termed miR-SOD1 systemically delivered using adeno-associated virus rAAVrh10, a serotype with a demonstrated safety profile in CNS clinical trials. Silencing of SOD1 in adult SOD1G93A transgenic mice with this construct profoundly delayed both disease onset and death in the SOD1G93A mice, and significantly preserved muscle strength and motor and respiratory functions. We also document that intrathecal delivery of the same rAAVrh10-miR-SOD1 in nonhuman primates significantly and safely silences SOD1 in lower motor neurons. This study supports the view that rAAVrh10-miR-SOD1 merits further development for the treatment of SOD1-linked ALS in humans.

Glaucoma is a complex neurodegenerative disease characterized by progressive visual dysfunction leading to vision loss. Retinal ganglion cells are the primary affected neuronal population, with a critical insult damaging their axons in the optic nerve head. This insult is typically secondary to harmfully high levels of intraocular pressure (IOP). We have previously determined that early mitochondrial abnormalities within retinal ganglion cells lead to neuronal dysfunction, with age-related declines in NAD (NAD+ and NADH) rendering retinal ganglion cell mitochondria vulnerable to IOP-dependent stresses. The Wallerian degeneration slow allele, WldS, decreases the vulnerability of retinal ganglion cells in eyes with elevated IOP, but the exact mechanism(s) of protection from glaucoma are not determined. Here, we demonstrate that WldS increases retinal NAD levels. Coupled with nicotinamide administration (an NAD precursor), it robustly protects from glaucomatous neurodegeneration in a mouse model of glaucoma (94% of eyes having no glaucoma, more than WldS or nicotinamide alone). Importantly, nicotinamide and WldS protect somal, synaptic, and axonal compartments, prevent loss of anterograde axoplasmic transport, and protect from visual dysfunction as assessed by pattern electroretinogram. Boosting NAD production generally benefits major compartments of retinal ganglion cells, and may be of value in other complex, age-related, axonopathies where multiple neuronal compartments are ultimately affected.

SignificanceChronic obstructive pulmonary disease affects 10% of the worldwide population, and the leading genetic cause is a genetic disease, α-1 antitrypsin (AAT) deficiency. Humans have only one gene that codes for the AAT protein, but mice have up to six, which made it impossible for decades to create a mouse model of the disease. Here we succeeded in creating this mouse model using CRISPR technology to target all of the mouse genes at once. Importantly, this mouse model spontaneously develops lung disease and recapitulates many aspects of the human disease. We anticipate that this model will be highly relevant not only to the preclinical development of therapeutics for AAT deficiency, but also to emphysema and smoking research.

Nicotinamide adenine dinucleotide (NAD) is a key molecule in several cellular processes and is essential for healthy mitochondrial metabolism. We recently reported that mitochondrial dysfunction is among the very first changes to occur within retinal ganglion cells during initiation of glaucoma in DBA/2J mice. Furthermore, we demonstrated that an age-dependent decline of NAD contributes to mitochondrial dysfunction and vulnerability to glaucoma. The decrease in NAD renders retinal ganglion cells vulnerable to a metabolic crisis following periods of high intraocular pressure. Treating mice with the NAD precursor nicotinamide (the amide form of vitamin B3) inhibited many age- and high intraocular pressure- dependent changes with the highest tested dose decreasing the likelihood of developing glaucoma by ∼10-fold. In this communication, we present further evidence of the neuroprotective effects of nicotinamide against glaucoma in mice, including its prevention of optic nerve excavation and axon loss as assessed by histologic analysis and axon counting. We also show analyses of age- and intraocular pressure- dependent changes in transcripts of NAD producing enzymes within retinal ganglion cells and that nicotinamide treatment prevents these transcriptomic changes.