Engineered AAVs for non-invasive gene delivery to rodent and non-human primate nervous systems

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非人灵长类肿瘤模型研究进展(英文)

癌症是人类第二大致死的疾病。将体外细胞模型获得的癌症研究结果向临床转化过程中,动物活体实验是必不可少的一个环节。现在的肿瘤活体实验绝大部分采用啮齿类实验动物如小鼠和大鼠,这是因为它们具有个体小、繁殖迅速、遗传背景清楚、转基因技术成熟等优势。但是啮齿类和人的亲缘关系比较远,许多从啮齿类动物模型获得的研究结果不能在人体重现。非人灵长类动物在遗传进化、免疫、生理和代谢等诸多方面与人类高度近似,理论上更加适合癌症研究。本文对现有的非人灵长类肿瘤研究做一综述,主要集中介绍用化学和生物致癌剂在不同的非人灵长类动物诱导肿瘤的研究,为将来用非人灵长类动物研究人类癌症奠定基础。     

DNA sequencing of 13 cytokine gene fragments of Aotus infulatus and Saimiri sciureus, two non-human primate models for malaria

Aotus and Saimiri are non-human primate models recommended by the World Health Organization for experimental studies in malaria, especially for vaccine pre-clinical trials. However, research using these primates is hindered by the lack of specific reagents to evaluate immune responses to infection or vaccination. As a step toward developing molecular tools for cytokine expression studies in these species, primer pairs for 18 cytokine gene fragments were designed based on human DNA sequences and used to amplify the corresponding genes in Aotus infulatus and Saimiri sciureus genomic DNA samples. IFNγ, TNFα, LTA, IL2, IL3, IL4, IL5, IL6, IL10, IL12, IL13, CSF2 and TGFβ2 gene fragments were amplified and sequenced. Primer pairs for IL8, IL17, IL18, IL27 and MIF failed to generate amplification products. When compared to the available corresponding human and non-human primate sequences, most--except IL3 and IL4--showed identity degrees above 90%. Small variations in sequence can help to explain the failure to amplify certain genes or the amplification only at lower annealing temperatures as compared to human DNA samples for several primer pairs. The sequences made available provide the basis for designing molecular tools such as primers for real time PCR specific for A. infulatus and/or S. sciureus. The nucleotide sequences reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned accession numbers DQ985386 to DQ985389, DQ989356 to DQ989369, FJ89020 to FJ89024, and FJ89029.     

DNA sequencing of 13 cytokine gene fragments of Aotus infulatus and Saimiri sciureus,two non-human primate models for malaria

Aotus and Saimiri are non-human primate models recommended by the World Health Organization for experimental studies in malaria, especially for vaccine pre-clinical trials. However, research using these primates is hindered by the lack of specific reagents to evaluate immune responses to infection or vaccination. As a step toward developing molecular tools for cytokine expression studies in these species, primer pairs for 18 cytokine gene fragments were designed based on human DNA sequences and used to amplify the corresponding genes in Aotus infulatus and Saimiri sciureus genomic DNA samples. IFNγ, TNFα, LTA, IL2, IL3, IL4, IL5, IL6, IL10, IL12, IL13, CSF2 and TGFβ2 gene fragments were amplified and sequenced. Primer pairs for IL8, IL17, IL18, IL27 and MIF failed to generate amplification products. When compared to the available corresponding human and non-human primate sequences, most – except IL3 and IL4 – showed identity degrees above 90%. Small variations in sequence can help to explain the failure to amplify certain genes or the amplification only at lower annealing temperatures as compared to human DNA samples for several primer pairs. The sequences made available provide the basis for designing molecular tools such as primers for real time PCR specific for A. infulatus and/or S. sciureus.The nucleotide sequences reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned accession numbers DQ985386 to DQ985389, DQ989356 to DQ989369, FJ89020 to FJ89024 and FJ89029.     

Murine, canine and non-human primate models of Krabbe disease

Globoid cell leukodystrophy (GLD) or Krabbe disease is an autosomal recessively inherited neurological disease caused by mutations in the gene coding for the lysosomal enzyme galacto-cerebrosidase (GALC). GALC is responsible for the degradation of specific galactolipids, including several that are important in the production of compact, stable myelin. A failure to adequately degrade galactosylceramide and psychosine (galactosylsphingosine) results in the characteristic pathological findings observed in tissue from humans and animals affected with GLD. These galactosphingolipids are normally synthesized during active myelination, and psychosine accumulates in individuals with very low GALC activity. Psychosine is highly toxic to the myelin-forming oligodendrocytes, causing their death and the paucity of myelin found on autopsy. While most human patients present with symptoms before six months of age and die before 18 months of age, older children and adults can also be diagnosed with GLD[1,2]. The cloning of both the human GALC cDNA and the GALC gene opened the way for the identification of mutations causing GLD in humans and animals and the development of novel strategies to treat this severe and fatal disease[3]. The pheno-typic differences between human patients result from the wide range of mutations identified, as well as additional unknown factors. Treatment of late-onset patients and pre-symptomatic individuals (identified either because prenatal testing was not requested or a fetus predicted to be affected was not aborted) by hemato-poietic stem cell transplantation (HSCT) resulted in a less severe phenotype than was predicted and, in some cases, a significant delay in the onset of symptoms[4]. Attempts to treat this disorder by in utero HSCT have not been successful[5].GLD in dogs     

Analysis of non-human primate models for evaluating prion disease therapeutic efficacy

Prion disease is a fatal neurodegenerative disease caused by the conformational corruption of the prion protein (PrP), encoded by the prion protein gene (PRNP). While no disease-modifying therapy is currently available, genetic and pharmacological proofs of concept support development of therapies that lower PrP levels in the brain. In light of proposals for clinical testing of such drugs in presymptomatic individuals at risk for genetic prion disease, extensive nonclinical data are likely to be required, with extra attention paid to choice of animal models. Uniquely, the entire prion disease process can be faithfully modeled through transmission of human prions to non-human primates (NHPs), raising the question of whether NHP models should be used to assess therapeutic efficacy. Here we systematically aggregate data from N = 883 prion-inoculated animals spanning six decades of research studies. Using this dataset, we assess prion strain, route of administration, endpoint, and passage number to characterize the relationship of tested models to currently prevalent human subtypes of prion disease. We analyze the incubation times observed across diverse models and perform power calculations to assess the practicability of testing prion disease therapeutic efficacy in NHPs. We find that while some models may theoretically be able to support therapeutic efficacy studies, pilot studies would be required to confirm incubation time and attack rate before pivotal studies could be designed, cumulatively requiring several years. The models with the shortest and most tightly distributed incubation times are those with smaller brains and weaker homology to humans. Our findings indicate that it would be challenging to conduct efficacy studies in NHPs in a paradigm that honors the potential advantages of NHPs over other available models, on a timeframe that would not risk unduly delaying patient access to promising drug candidates.     

Induction of transplantation tolerance in non-human primate preclinical models

Short-term outcomes following organ transplantation have improved considerably since the availability of cyclosporine ushered in the modern era of immunosuppression. In spite of this, many of the current limitations to progress in the field are directly related to the existing practice of relatively non-specific immunosuppression. These include increased risks of opportunistic infection and cancer, and toxicity associated with long-term immunosuppressive drug exposure. In addition, long-term graft loss continues to result in part from a failure to adequately control the anti-donor immune response. The development of a safe and reliable means of inducing tolerance would ameliorate these issues and improve the lives of transplant recipients, yet given the improving clinical standard of care, the translation of new therapies has become appropriately more cautious and dependent on increasingly predictive preclinical models. While convenient and easy to use, rodent tolerance models have not to date been reliably capable of predicting a therapy's potential efficacy in humans. Non-human primates possess an immune system that more closely approximates that found in humans, and have served as a more rigorous preclinical testing ground for novel therapies. Prior to clinical adaptation therefore, tolerance regimens should be vetted in non-human primates to ensure that there is sufficient potential for efficacy to justify the risk of its application.     

The non-human primate model of tuberculosis

Non-human primates (NHPs) are used to model human disease owing to their remarkably similar genomes, physiology, and immune systems. Recently, there has been an increased interest in modeling tuberculosis (TB) in NHPs. Macaques are susceptible to infection with different strains of Mycobacterium tuberculosis (Mtb), producing the full spectrum of disease conditions, including latent infection, chronic progressive infection, and acute TB, depending on the route and dose of infection. Clearly, NHPs are an excellent model of human TB. While the initial aim of the NHP model was to allow preclinical testing of candidate vaccines and drugs, it is now also being used to study pathogenesis and immune correlates of protection. Recent advances in this field are discussed in this review. Key questions such as the effect of hypoxia on the biology of Mtb and the basis of reactivation of latent TB can now be investigated through the use of this model.     

Stem and progenitor cell therapies: insights from non-human primate models

Genetic marking strategies in the non-human primate model have elucidated a number of principles relevant to implementation of clinical stem cell therapies, including the lineage potential, number and lifespan of hematopoietic stem and progenitor cells, and differences in the functional properties of marrow cells mobilized into the peripheral blood utilizing different regimens.     

A non-human primate model for gluten sensitivity

Background and Aims

Gluten sensitivity is widespread among humans. For example, in celiac disease patients, an inflammatory response to dietary gluten leads to enteropathy, malabsorption, circulating antibodies against gluten and transglutaminase 2, and clinical symptoms such as diarrhea. There is a growing need in fundamental and translational research for animal models that exhibit aspects of human gluten sensitivity.

Methods

Using ELISA-based antibody assays, we screened a population of captive rhesus macaques with chronic diarrhea of non-infectious origin to estimate the incidence of gluten sensitivity. A selected animal with elevated anti-gliadin antibodies and a matched control were extensively studied through alternating periods of gluten-free diet and gluten challenge. Blinded clinical and histological evaluations were conducted to seek evidence for gluten sensitivity.

Results

When fed with a gluten-containing diet, gluten-sensitive macaques showed signs and symptoms of celiac disease including chronic diarrhea, malabsorptive steatorrhea, intestinal lesions and anti-gliadin antibodies. A gluten-free diet reversed these clinical, histological and serological features, while reintroduction of dietary gluten caused rapid relapse.

Conclusions

Gluten-sensitive rhesus macaques may be an attractive resource for investigating both the pathogenesis and the treatment of celiac disease.     

A song for the unsung: The relevance of Plasmodium vinckei as a laboratory rodent malaria system

Rodent malaria parasites (RMPs) allow the study of malaria parasite biology across its entire life cycle through a vertebrate host and a mosquito vector under laboratory conditions. Among the four RMPs originally collected from wild thicket rats in sub-Saharan Central Africa and adapted to laboratory mice, Plasmodium vinckei has the largest geographical range and includes the largest number of sub-species, demonstrating its deep genetic diversity. Despite affording the same advantages as other RMP species and additionally displaying a large degree of phenotypic and genotypic diversity, P. vinckei has seen limited use in the laboratory. Here, we review the contribution of P. vinckei to our understanding of malaria and highlight the areas where it could offer an advantage over other RMP species in future studies.     

The amygdala and autism: implications from non-human primate studies

Brothers (1990 ) has proposed that the amygdala is an important component of the neural network that underlies social behavior. Kemper and Bauman (1993 ) identified neuropathology in the amygdala of the postmortem autistic brain. These findings, along with recent functional neuroimaging data, have led Baron-Cohen et al. (2000 ) to propose that dysfunction of the amygdala may be responsible, in part, for the impairment of social behavior that is a hallmark feature of autism. Recent data from studies in our laboratory on the effects of amygdala lesions in the adult and infant macaque monkey do not support a fundamental role for the amygdala in social behavior. If the amygdala is not essential for the component processes of social behavior, as seems to be case in both non-human primates and selected patients with bilateral amygdala damage, then it is unlikely to be the primary substrate for the impaired social behavior of autism. However, damage to the amygdala does have an effect on a monkey's response to normally fear-inducing stimuli, such as snakes, and removes a natural reluctance to engage novel conspecifics in social interactions. These findings lead to the conclusion that an important role for the amygdala is in the detection of threats and mobilizing an appropriate behavioral response, part of which is fear. Interestingly, an important comorbid feature of autism is anxiety ( Muris et al. 1998 ). If the amygdala is pathological in subjects with autism, it may contribute to their abnormal fears and increased anxiety rather than their abnormal social behavior.     

Of mice and malaria mutants: unravelling the genetics of drug resistance using rodent malaria models

It is well recognized that drug resistance is the most significant obstacle to gaining effective malaria control. Despite the enormous advances in the knowledge of the biochemistry and molecular biology of malaria parasites, only a few genes determining resistance to the commonly used drugs have been identified. The idea that rodent malaria parasites should be exploited more widely for such work, in view of the practical problems of studying this subject experimentally in human malaria, is presented.     

Gene expression patterns associated with infertility in humans and rodent models

Modern genomic technologies such as DNA arrays provide the means to investigate molecular interactions at an unprecedented level, and arrays have been used to carry out gene expression profiling as a means of identifying candidate genes involved in molecular mechanisms underlying a variety of phenotypes. By comparing gene expression profiles from normal and abnormal human testes with those from comparable infertile mouse models, we endeavored to identify genes and gene networks critical for male fertility. We used commercially available filter-based DNA arrays to analyze testicular gene expression from eight human testis biopsies and three different infertile mouse models (atrichosis mutation, ataxia telangiectasia knockout and CREMtau knockout). Forty-seven mouse genes exhibited differential testicular gene expression (P <0.01) associated with male infertility. These included genes involved in DNA repair (Vim, Rad23A, Rad23B), glutathione metabolism (Gsr, Gstp 1, Mgst1), proteolysis (Ace, Casp1, Ctsd), spermatogenesis (Prlr, Tmsb4 and Zfp-37) and stress response (Hsp 1, Osp94). The expression of 19 human genes was different (P<0.05) between normal and abnormal samples, including those associated with apoptosis (GADD45), gonad development (SOX9), proteolysis (PSMC3, SPINK2, TIMP3, UBE213) and signal transduction (DLK1, NAP4, S100A10). Direct comparison of differentially expressed human and mouse genes identified glucose phosphate isomerase, and the highly similar human tissue inhibitor of metalloproteinase 3 (TIMP3) and mouse Timp2. Using DNA microarrays to profile gene expression in testes from infertile animal models and humans will be useful for understanding congenital infertility, and also infertility caused by environmental exposures where the same genes and molecular mechanisms are involved.