Epigenetic editing of PCSK9 for a durable reduction in cholesterol
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Prime editing: therapeutic advances and mechanistic insights
We are often confronted with a simple question, “which gene editing technique is the best?”; the simple answer is “there isn’t one”. In 2021, a year after prime editing first made its mark, we evaluated the landscape of this potentially transformative advance in genome engineering towards getting treatments to the clinic [1]. Nearly 20% of the papers we cited were still in pre-print at the time which serves to indicate how early-stage the knowledge base was at that time. Now, three years later, we take a look at the landscape and ask what has been learnt to ensure this tech is broadly accessible, highlighting some key advances, especially those that push this towards the clinic. A big part of the appeal of prime editing is its ability to precisely edit DNA without double stranded breaks, and to install any of the 12 possible single-nucleotide conversion events as well as small insertions and/or deletions, or essentially any combination thereof. Over the last few decades, other transformative and Nobel prize-winning technologies that rely on Watson-Crick base-pairing such as PCR, site-directed mutagenesis, RNA interference, and one might say, “classic” CRISPR, were swiftly adopted across labs around the world because of the speed with which mechanistic rules governing their efficiency were determined. Whilst this perspective focuses on the context of gene therapy applications of prime editing, we also further look at the recent studies which have increased our understanding of the mechanism of PEs and simultaneously improved the efficiency and diversity of the PE toolbox.
A torpor-like state in mice slows blood epigenetic aging and prolongs healthspan
Torpor and hibernation are extreme physiological adaptations of homeotherms associated with pro-longevity effects. Yet the underlying mechanisms of how torpor affects aging, and whether hypothermic and hypometabolic states can be induced to slow aging and increase healthspan, remain unknown. Here we demonstrate that the activity of a spatially defined neuronal population in the preoptic area, which has previously been identified as a torpor-regulating brain region, is sufficient to induce a torpor-like state (TLS) in mice. Prolonged induction of TLS slows epigenetic aging across multiple tissues and improves healthspan. We isolate the effects of decreased metabolic rate, long-term caloric restriction, and decreased core body temperature (Tb) on blood epigenetic aging and find that the decelerating effect of TLSs on aging is mediated by decreased Tb. Taken together, our findings provide novel mechanistic insight into the decelerating effects of torpor and hibernation on aging and support the growing body of evidence that Tb is an important mediator of the aging processes.
Taking control with RNA
RNA roles RNA seized the global limelight when a modified RNA was used in the vaccine against the virus SARS-CoV-2 that caused a global pandemic.…
SEED-Selection enables high-efficiency enrichment of primary T cells edited at multiple loci
Engineering T cell specificity and function at multiple loci can generate more effective cellular therapies, but current manufacturing methods produce heterogenous mixtures of partially engineered cells. Here we develop a one-step process to enrich unlabeled cells containing knock-ins at multiple target loci using a family of repair templates named synthetic exon expression disruptors (SEEDs). SEEDs associate transgene integration with the disruption of a paired target endogenous surface protein while preserving target expression in nonmodified and partially edited cells to enable their removal (SEED-Selection). We design SEEDs to modify three critical loci encoding T cell specificity, coreceptor expression and major histocompatibility complex expression. The results demonstrate up to 98% purity after selection for individual modifications and up to 90% purity for six simultaneous edits (three knock-ins and three knockouts). This method is compatible with existing clinical manufacturing workflows and can be readily adapted to other loci to facilitate production of complex gene-edited cell therapies.
Modulation of the human GlyT1 by clinical drugs and cholesterol
Glycine transporter 1 (GlyT1) is a key player in shaping extracellular glutamatergic signaling processes and holds promise for treating cognitive impairments associated with schizophrenia by inhibiting its activity and thus enhancing the function of NMDA receptors. Despite its significant role in physiological and pharmacology, its modulation mechanism by clinical drugs and internal lipids remains elusive. Here, we determine cryo-EM structures of GlyT1 in its apo state and in complex with clinical trial drugs iclepertin and sarcosine. The GlyT1 in its apo state is determined in three distinct conformations, exhibiting a conformational equilibrium of the transport cycle. The complex structures with inhibitor iclepertin and sarcosine elucidate their unique binding poses with GlyT1. Three binding sites of cholesterol are determined in GlyT1, two of which are conformation-dependent. Transport kinetics studies reveal that a delicate binding equilibrium for cholesterol is crucial for the conformational transition of GlyT1. This study significantly enhances our understanding of the physiological and pharmacological aspects of GlyT1.
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