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A large G4C2-repeat expansion in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Neuronal degeneration associated with this expansion arises from a loss of C9orf72 protein, the accumulation of RNA foci, the expression of dipeptide repeat (DPR) proteins, or all these factors. We report the discovery of a new targeting sequence that is common to all C9orf72 transcripts but enables preferential knockdown of repeat-containing transcripts in multiple cellular models and C9BAC transgenic mice. We optimize stereopure oligonucleotides that act through this site, and we demonstrate that their preferential activity depends on both backbone stereochemistry and asymmetric wing design. In mice, stereopure oligonucleotides produce durable depletion of pathogenic signatures without disrupting protein expression. These oligonucleotides selectively protect motor neurons harboring C9orf72-expansion mutation from glutamate-induced toxicity. We hypothesize that targeting C9orf72 with stereopure oligonucleotides may be a viable therapeutic approach for the treatment of C9orf72-associated neurodegenerative disorders.

Background: VERVE-101 is an investigational in vivo CRISPR base editing medicine designed to alter a single DNA base in the PCSK9 gene, permanently turn off hepatic protein production, and thereby durably lower LDL-cholesterol (LDL-C). We test the efficacy, durability, tolerability, and potential for germline editing of VERVE-101 in studies of non-human primates and a murine F1 progeny study. Methods: Cynomolgus monkeys were dosed with a single intravenous infusion of a vehicle control (N=10) or VERVE-101 at a dose of 0.75 mg/kg (N=4) or 1.5 mg/kg (N=22) with subsequent follow-up out to 476 days. Two studies assessed the potential for germline editing, including sequencing sperm samples from sexually mature male non-human primates treated with VERVE-101 and genotyping offspring from female mice treated with the murine surrogate of VERVE-101 (VERVE-101mu). Results: Liver biopsies 14 days after dosing noted mean PCSK9 editing of 46% and 70% in monkeys treated with VERVE-101 at 0.75 and 1.5 mg/kg, respectively. This translated into mean reductions in blood PCSK9 of 67% and 83% and reductions of LDL-C of 49% and 69% at the 0.75 and 1.5 mg/kg doses, respectively, assessed as time-weighted average change from baseline between day 28 and up to 476 days following dosing. Liver safety monitoring noted a transient rise in ALT and AST concentrations following infusion that fully resolved by day 14 with no accompanying change in total bilirubin. In a subset of monkeys necropsied 1 year after dosing, no findings related to VERVE-101 were identified on macroscopic and histopathologic assessment of the liver and other organs. In the study to assess potential germline editing of male non-human primates, sperm samples collected after VERVE-101 dosing showed no evidence of PCSK9 editing. Among 436 offspring of female mice treated with a saturating dose of VERVE-101mu, the PCSK9 edit was transmitted in 0 of 436 animals. Conclusions: VERVE-101 was well-tolerated in in non-human primates and led to 83% lower blood PCSK9 protein and 69% lower LDL-C with durable effects up to 476 days following dosing. These results have supported initiation of a first-in-human clinical trial in patients with heterozygous familial hypercholesterolemia and atherosclerotic cardiovascular disease.

Kinematic studies of reaching in human infants using two-dimensional (2-D) and three-dimensional (3-D) recordings have complemented behavioral studies of infant handedness by providing additional evidence of early right asymmetries. Right hand reaches have been reported to be straighter and smoother than left hand reaches during the first year. Although reaching has been a popular measure of handedness in primates, there has been no systematic comparison of left and right hand reach kinematics. We investigated reaching in infant rhesus monkeys using the 2-D motion analysis software MaxTRAQ Lite+ (Innovision Systems). Linear mixed-effects models revealed that left hand reaches were smoother, but not straighter, than right hand reaches. An early left bias matches previous findings of a left hand preference for reaching in adult rhesus monkeys. Additional work using this kind of kinematic approach will extend our understanding of primate handedness beyond traditional studies measuring only frequency or bouts of hand use.

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