Nonhuman primate models of focal cerebral ischemia

Rodents have been widely used in the production of cerebral ischemia models. However, successful therapies have been proven on experimental rodent stroke model, and they have often failed to be effective when tested clinically. Therefore, nonhuman primates were recommended as the ideal alternatives, owing to their similarities with the human cerebrovascular system, brain metabolism, grey to white matter ratio and even their rich behavioral repertoire. The present review is a thorough summary of ten methods that establish nonhuman primate models of focal cerebral ischemia; electrocoagulation, endothelin-1-induced occlusion, microvascular clip occlusion, autologous blood clot embolization, balloon inflation, microcatheter embolization, coil embolization, surgical suture embolization, suture, and photochemical induction methods. This review addresses the advantages and disadvantages of each method, as well as precautions for each model, compared nonhuman primates with rodents, different species of nonhuman primates and different modeling methods. Finally it discusses various factors that need to be considered when modelling and the method of evaluation after modelling. These are critical for understanding their respective strengths and weaknesses and underlie the selection of the optimum model.

Generation of nonhuman primate retinitis pigmentosa model by in situ knockout of RHO in rhesus macaque retina

Retinitis pigmentosa(RP)is a form of inherited retinal degenerative diseases that ultimately involves the macula,which is present in primates but not in the rodents.Therefore,creating nonhuman primate(NHP)models of RP is of critical importance to study its mechanism of pathogenesis and to evaluate potential therapeutic options in the future.Here we applied adeno-associated virus(AAV)-delivered CRISPR/SaCas9 technology to knockout the RHO gene in the retinae of the adult rhesus macaque(Macaca mulatta)to investigate the hypothesis whether non-germline mutation of the RHO gene is sufficient to recapitulate RP.Through a series of studies,we were able to demonstrate successful somatic editing of the RHO gene and reduced RHO protein expression.More importantly,the mutant macaque retinae displayed clinical RP phenotypes,including photoreceptor degeneration,retinal thinning,abnormal rod subcellular structures,and reduced photoresponse.Therefore,we suggest somatic editing of the RHO gene is able to phenocopy RP,and the reduced time span in generating NHP mutant accelerates RP research and expands the utility of NHP model for human disease study.

Induction of core symptoms of autism spectrum disorder by in vivo CRISPR/Cas9-based gene editing in the brain of adolescent rhesus monkeys

Although CRISPR/Cas9-mediated gene editing is widely applied to mimic human disorders,whether acute manipulation of disease-causing genes in the brain leads to behavioral abnormalities in non-human primates remains to be determined.Here we induced genetic mutations in MECP2,a critical gene linked to Rett syndrome(RTT)and autism spectrum disorders(ASD),in the hippocampus(DG and CA1–4)of adolescent rhesus monkeys(Macaca mulatta)in vivo via adeno-associated virus(AAV)-delivered Staphylococcus aureus Cas9 with small guide RNAs(sg RNAs)targeting MECP2.In comparison to monkeys injected with AAV-Sa Cas9 alone(n=4),numerous autistic-like behavioral abnormalities were identified in the AAV-Sa Cas9-sg MECP2-injected monkeys(n=7),including social interaction deficits,abnormal sleep patterns,insensitivity to aversive stimuli,abnormal hand motions,and defective social reward behaviors.Furthermore,some aspects of ASD and RTT,such as stereotypic behaviors,did not appear in the MECP2 gene-edited monkeys,suggesting that different brain areas likely contribute to distinct ASD symptoms.This study showed that acute manipulation of disease-causing genes via in vivo gene editing directly led to behavioral changes in adolescent primates,paving the way for the rapid generation of genetically engineered non-human primate models for neurobiological studies and therapeutic development.