Controlling and enhancing CRISPR systems.
- 作者列表："Shivram H","Cress BF","Knott GJ","Doudna JA
:Many bacterial and archaeal organisms use clustered regularly interspaced short palindromic repeats-CRISPR associated (CRISPR-Cas) systems to defend themselves from mobile genetic elements. These CRISPR-Cas systems are classified into six types based on their composition and mechanism. CRISPR-Cas enzymes are widely used for genome editing and offer immense therapeutic opportunity to treat genetic diseases. To realize their full potential, it is important to control the timing, duration, efficiency and specificity of CRISPR-Cas enzyme activities. In this Review we discuss the mechanisms of natural CRISPR-Cas regulatory biomolecules and engineering strategies that enhance or inhibit CRISPR-Cas immunity by altering enzyme function. We also discuss the potential applications of these CRISPR regulators and highlight unanswered questions about their evolution and purpose in nature.
: 许多细菌和古菌生物使用成簇的规则间隔的短回文重复序列-CRISPR相关 (CRISPR-Cas) 系统来保护自己免受移动遗传元件的侵害。这些CRISPR-Cas系统根据其组成和机制分为六种类型。CRISPR-Cas酶广泛用于基因组编辑，并为治疗遗传疾病提供了巨大的治疗机会。为了实现它们的全部潜力，重要的是控制CRISPR-Cas酶活性的时间、持续时间、效率和特异性。在这篇综述中，我们讨论了天然CRISPR-Cas调控生物分子的机制和通过改变酶功能增强或抑制CRISPR-Cas免疫的工程策略。我们还讨论了这些CRISPR调节剂的潜在应用，并强调了关于它们在自然界中的进化和目的的未回答的问题。
METHODS::The ATP binding-cassette superfamily corresponds the mostly transmembrane transporters family found in humans. These proteins actively transport endogenous and exogenous substrates through biological membranes in body tissues, so they have an important role in the regulation of many physiological functions necessary for human homeostasis, as well as in response regulation to several pharmacological substrates. The development of multidrug resistance has become one of the main troubles in conventional chemotherapy in different illnesses including cancer, being the increased efflux of antineoplastic drugs the main reason for this multidrug resistance, with a key role of the ABC superfamily. Likely, the interindividual variability in the pharmacological response among patients is well known, and may be due to intrinsically factors of the disease, genetic and environmental ones. Thus, the understanding of this variability, especially the genetic variability associated with the efficacy and toxicity of drugs, can provide a safer and more effective pharmacological treatment, so ABC genes are considered as important regulators due to their relationship with the reduction in pharmacological response. In this review, updated information about transporters belonging to this superfamily was collected, the possible role of these transporters in cancer, the role of genetic variability in their genes, as well as some therapeutic tools that have been tried to raise against main transporters associated with chemoresistance in cancer.
METHODS:BACKGROUND:Cholinergic neurotransmission regulates neuroinflammation in Parkinson disease (PD). RESEARCH DESIGN AND METHODS:The authors conducted a delayed-start study of donepezil for cognitive decline in non-demented PD patients. The study consisted of a 96-week randomized placebo-controlled double-blind phase 1, followed by a 24-week donepezil extension phase 2. The primary outcome measure was a change in the Mini-Mental State Examination (MMSE) at week 120. RESULTS:A total of 98 patients were randomly allocated to the early-start (donepezil-to-donepezil) and delayed-start (placebo-to-donepezil) groups. Mean (SD) of the baseline MMSE was 27.6 (2.0) and 28.0 (2.1), respectively. MMSE change at week 120 was better in the early-start group than in the delayed-start group, but the difference was not significant. The MMSE declined in apolipoprotein ε4 carriers, but not in non-carriers, and the factor interaction (intervention × ε4 genotype) was highly significant (P < 0.001). Analyzed with the interaction, the difference was significant (group difference 1.95 [0.33 to 3.57], P = 0.018). The MMSE decline slope in phase 1 was significantly better in the early-start group than in the delayed-start group (P = 0.048). CONCLUSIONS:Cognitive function deteriorated in ε4 carriers, but not in non-carriers, and early-start donepezil may postpone cognitive decline in the former.
METHODS::Since the discovery of dental pulp stem cells, a lot of teams have expressed an interest in dental pulp regeneration. Many approaches, experimental models and biological explorations have been developed, each including the use of stem cells and scaffolds with the final goal being clinical application in humans. In this review, the authors' objective was to compare the experimental models and strategies used for the development of biomaterials for tissue engineering of dental pulp with stem cells. Electronic queries were conducted on PubMed using the following terms: pulp regeneration, scaffold, stem cells, tissue engineering and biomaterial. The extracted data included the following information: the strategy envisaged, the type of stem cells, the experimental models, the exploration or analysis methods, the cytotoxicity or viability or proliferation cellular tests, the tests of scaffold antibacterial properties and take into account the vascularization of the regenerated dental pulp. From the 71 selected articles, 59% focused on the "cell-transplantation" strategy, 82% used in vitro experimentation, 58% in vivo animal models and only one described an in vivo in situ human clinical study. 87% used dental pulp stem cells. A majority of the studies reported histology (75%) and immunohistochemistry explorations (66%). 73% mentioned the use of cytotoxicity, proliferation or viability tests. 48% took vascularization into account but only 6% studied the antibacterial properties of the scaffolds. This article gives an overview of the methods used to regenerate dental pulp from stem cells and should help researchers create the best development strategies for research in this field.