Progress and challenges in CRISPR-mediated therapeutic genome editing for monogenic diseases

There are an estimated 10000 monogenic diseases affecting tens of millions of individuals worldwide.The application of CRISPR/Cas genome editing tools to treat monogenic diseases is an emerging strategy with the potential to generate personalized treatment approaches for these patients.CRISPR/Cas-based systems are programmable and sequence-specific genome editing tools with the capacity to generate base pair resolution manipulations to DNA or RNA.The complexity of genomic insults resulting in heritable disease requires patientspecific genome editing strategies with consideration of DNA repair pathways,and CRISPR/Cas systems of different types,species,and those with additional enzymatic capacity and/or delivery methods.In this review we aim to discuss broad and multifaceted therapeutic applications of CRISPR/Cas gene editing systems including in harnessing of homology directed repair,non-homologous end joining,microhomology-mediated end joining,and base editing to permanently correct diverse monogenic diseases.

The Antinociceptive Effect of Sympathetic Block is Mediated by Transforming Growth Factor β in a Mouse Model of Radiculopathy

Although sympathetic blockade is clinically used to treat pain,the underlying mechanisms remain unclear.We developed a localized microsympathectomy(mSYMPX),by cutting the grey rami entering the spinal nerves near the rodent lumbar dorsal root ganglia(DRG).In a chemotherapy-induced peripheral neuropathy model,mSYMPX attenuated pain behaviors via DRG macrophages and the anti-inflammatory actions of transforming growth factor-β(TGF-β)and its receptor TGF-βR1.Here,we examined the role of TGF-βin sympathetic-mediated radiculopathy produced by local inflammation of the DRG(LID).Mice showed mechanical hypersensitivity and transcriptional and protein upregulation of TGF-β1 and TGF-βR1 three days after LID.Microsympathectomy prevented mechanical hypersensitivity and further upregulated Tgfb1 and Tgfbr1.Intrathecal delivery of TGF-β1 rapidly relieved the LID-induced mechanical hypersensitivity,and TGF-βR1 antagonists rapidly unmasked the mechanical hypersensitivity after LID+mSYMPX.In situ hybridization showed that Tgfb1 was largely expressed in DRG macrophages,and Tgfbr1 in neurons.We suggest that TGF-βsignaling is a general underlying mechanism of local sympathetic blockade.

Generation of a Hutchinson-Gilford progeria syndrome monkey model by base editing

Many human genetic diseases,including Hutchinson-Gilford progeria syndrome(HGPS),are caused by single point mutations.HGPS is a rare disorder that causes premature aging and is usually caused by a de novo point mutation in the LMNA gene.Base editors(BEs)composed of a cytidine deaminase fused to CRISPR/Cas9 nickase are highly efficient at inducing C to T base conversions in a programmable manner and can be used to generate animal disease models with single amino-acid substitutions.Here,we generated the first HGPS monkey model by delivering a BE mRNA and guide RNA(gRNA)targeting the LMNA gene via microinjection into monkey zygotes.Five out of six newborn monkeys carried the mutation specifically at the target site.HGPS monkeys expressed the toxic form of lamin A,progerin,and recapitulated the typical HGPS phenotypes including growth retardation,bone alterations,and vascular abnormalities.Thus,this monkey model genetically and clinically mimics HGPS in humans,demonstrating that the BE system can efficiently and accurately generate patient-specific disease models in non-human primates.