Most methods for the detection of nucleic acids require many reagents and expensive and bulky instrumentation. Here, we report the development and testing of a graphene-based field-effect transistor that uses clustered regularly interspaced short palindromic repeats (CRISPR) technology to enable the digital detection of a target sequence within intact genomic material. Termed CRISPR-Chip, the biosensor uses the gene-targeting capacity of catalytically deactivated CRISPR-associated protein 9 (Cas9) complexed with a specific single-guide RNA and immobilized on the transistor to yield a label-free nucleic-acid-testing device whose output signal can be measured with a simple handheld reader. We used CRISPR-Chip to analyse DNA samples collected from HEK293T cell lines expressing blue fluorescent protein, and clinical samples of Reprints and permissions information is available at www.nature.com/reprints. * kiana_aran@kgi.edu. Correspondence and requests for materials should be addressed to K.A. Author contributions R.H. optimized the CRISPR-Chip design, performed the CRISPR-Chip DMD experiments, data collection and analysis, LOD optimization, HEK-BFP calibration methodologies in the presence and absence of contamination, and kinetic analysis, and prepared the manuscript. S.B. assisted in optimization of the CRISPR-Chip assay protocols, performed the MB-dRNP studies, DMD patient sample analysis, HEK-BFP PCR experiments and analysis, and prepared the manuscript. T.T. assisted with the initial CRISPR-Chip design, performed initial CRISPR-Chip protocols for HEK-BFP studies, and prepared the manuscript. T.d. performed the synthesis of sgRNA for the bfp and Scram studies, genomic purification and initial system design, and helped with manuscript preparation. J.E. contributed to the design of the DMD-based validation of CRISPR-Chip and provided the PCR and sequencing data for the DMD studies. M.S. contributed to the design of the DMD-based validation of CRISPR-Chip and assisted in manuscript preparation. N.A.W. and J.-Y.C. assisted T.D. with the synthesis of sgRNAs for bfp studies and assisted with sample preparation. J.N. and B.G. assisted with CRISPR-Chip data analysis and manuscript preparation. M.A. and J.P. assisted with manuscript preparation and data analysis. R.P. assisted with the design of threshold experiments, data analysis and CRISPR-Chip validation. N.M. supervised the synthesis of sgRNAs for the bfp and Scram studies. I.M.C. assisted with technology design, DMD validation and manuscript preparation. K.A. designed and developed the technology, planned and supervised the project, analysed, interpreted and integrated the data, and prepared the manuscript.
Heterochronic blood sharing rejuvenates old tissues, and most of the studies on how this works focus on young plasma, its fractions, and a few youthful systemic candidates. However, it was not formally established that young blood is necessary for this multi-tissue rejuvenation. Here, using our recently developed small animal blood exchange process, we replaced half of the plasma in mice with saline containing 5% albumin (terming it a "neutral" age blood exchange, NBE) thus diluting the plasma factors and replenishing the albumin that would be diminished if only saline was used. Our data demonstrate that a single NBE suffices to meet or exceed the rejuvenative effects of enhancing muscle repair, reducing liver adiposity and fibrosis, and increasing hippocampal neurogenesis in old mice, all the key outcomes seen after blood heterochronicity. Comparative proteomic analysis on serum from NBE, and from a similar human clinical procedure of therapeutic plasma exchange (TPE), revealed a molecular re-setting of the systemic signaling milieu, interestingly, elevating the levels of some proteins, which broadly coordinate tissue maintenance and repair and promote immune responses. Moreover, a single TPE yielded functional blood rejuvenation, abrogating the typical old serum inhibition of progenitor cell proliferation. Ectopically added albumin does not seem to be the sole determinant of such rejuvenation, and levels of albumin do not decrease with age nor are increased by NBE/TPE. A model of action (supported by a large body of published data) is that significant dilution of autoregulatory proteins that crosstalk to multiple signaling pathways (with their own feedback loops) would, through changes in gene expression, have long-lasting molecular and functional effects that are consistent with our observations. This work improves our understanding of the systemic paradigms of multi-tissue rejuvenation and suggest a novel and immediate use of the FDA approved TPE for improving the health and resilience of older people.
We hypothesize that altered intensities of a few morphogenic pathways account for most/all the phenotypes of aging. Investigating this has revealed a novel approach to rejuvenate multiple mammalian tissues by defined pharmacology. Specifically, we pursued the simultaneous youthful in vivo calibration of two determinants: TGF-beta which activates ALK5/pSmad 2,3 and goes up with age, and oxytocin (OT) which activates MAPK and diminishes with age. The dose of Alk5 inhibitor (Alk5i) was reduced by 10-fold and the duration of treatment was shortened (to minimize overt skewing of cell-signaling pathways), yet the positive outcomes were broadened, as compared with our previous studies. Alk5i plus OT quickly and robustly enhanced neurogenesis, reduced neuro-inflammation, improved cognitive performance, and rejuvenated livers and muscle in old mice. Interestingly, the combination also diminished the numbers of cells that express the CDK inhibitor and marker of senescence p16 in vivo. Summarily, simultaneously re-normalizing two pathways that change with age in opposite ways (up vs. down) synergistically reverses multiple symptoms of aging.
Skeletal muscle is among the most age-sensitive tissues in mammal organisms. Significant changes in its resident stem cells (i.e., satellite cells, SCs), differentiated cells (i.e., myofibers), and extracellular matrix cause a decline in tissue homeostasis, function, and regenerative capacity. Based on the conservation of aging across tissues and taking advantage of the relatively well-characterization of the myofibers and associated SCs, skeletal muscle emerged as an experimental system to study the decline in function and maintenance of old tissues and to explore rejuvenation strategies. In this review, we summarize the approaches for understanding the aging process and for assaying the success of rejuvenation that use skeletal muscle as the experimental system of choice. We further discuss (and exemplify with studies of skeletal muscle) how conflicting results might be due to variations in the techniques of stem cell isolation, differences in the assays of functional rejuvenation, or deciding on the numbers of replicates and experimental cohorts.
Background Aldehyde dehydrogenases (ALDHs) are key players in cell survival, protection, and differentiation via the metabolism and detoxification of aldehydes. ALDH activity is also a marker of stem cells. The skeletal muscle contains populations of ALDH‐positive cells amenable to use in cell therapy, whose distribution, persistence in aging, and modifications in myopathic context have not been investigated yet. Methods The Aldefluor® (ALDEF) reagent was used to assess the ALDH activity of muscle cell populations, whose phenotypic characterizations were deepened by flow cytometry. The nature of ALDH isoenzymes expressed by the muscle cell populations was identified in complementary ways by flow cytometry, immunohistology, and real‐time PCR ex vivo and in vitro . These populations were compared in healthy, aging, or Duchenne muscular dystrophy (DMD) patients, healthy non‐human primates, and Golden Retriever dogs (healthy vs. muscular dystrophic model, Golden retriever muscular dystrophy [GRMD]). Results ALDEF + cells persisted through muscle aging in humans and were equally represented in several anatomical localizations in healthy non‐human primates. ALDEF + cells were increased in dystrophic individuals in humans (nine patients with DMD vs. five controls: 14.9 ± 1.63% vs. 3.6 ± 0.39%, P = 0.0002) and dogs (three GRMD dogs vs. three controls: 10.9 ± 2.54% vs. 3.7 ± 0.45%, P = 0.049). In DMD patients, such increase was due to the adipogenic ALDEF + /CD34 + populations (11.74 ± 1.5 vs. 2.8 ± 0.4, P = 0.0003), while in GRMD dogs, it was due to the myogenic ALDEF + /CD34 − cells (3.6 ± 0.6% vs. 1.03 ± 0.23%, P = 0.0165). Phenotypic characterization associated the ALDEF + /CD34 − cells with CD9, CD36, CD49a, CD49c, CD49f, CD106, CD146, and CD184, some being associated with myogenic capacities. Cytological and histological analyses distinguished several ALDH isoenzymes (ALDH1A1, 1A2, 1A3, 1B1, 1L1, 2, 3A1, 3A2, 3B1, 3B2, 4A1, 7A1, 8A1, and 9A1) expressed by different cell populations in the skeletal muscle tissue belonging to multinucleated fibres, or myogenic, endothelial, interstitial, and neural lineages, designing them as potential new markers of cell type or of metabolic activity. Important modifications were noted in isoenzyme expression between healthy and DMD muscle tissues. The level of gene expression of some isoenzymes (ALDH1A1, 1A3, 1B1, 2, 3A2, 7A1, 8A1, and 9A1) suggested their specific involvement in muscle stability or regeneration in situ or in vitro . Conclusions ...
For several years, we have studied the effects of microwave field exposure on the white rat. We have previously detected large perturbations of cerebral electrical activity.' Other phenomena, such as "hearing" pulsed microwave fields'." and generation of evoked potentials4 by microwave impulses, strongly suggest a direct action of these fields on cerebral neurons. This investigation was made in an attempt to demonstrate such an action. METHODSWe used albino rats from Charles River (France) breedings. Experimental rats were irradiated for 10 days in a microwave field. Exposures5 were performed in free space conditions inside an anechoic chamber. Our generator produces a 3-GHz pulsed field; pulses were 1 psec long, and the pulse repetition frequency (PRF), between 500 and 600 pps, was selected so that it would be different from the harmonics of the domestic electric current (of which the frequency is 50 Hz in France). The peak field power was 150 kW, and animals were exposed to a 5-mW/ cm2 average power density. Control rats were maintained for the same length of time under identical environmental conditions. After exposure, experimental animals were withdrawn from the field. We recorded occipital electrocorticograms on paper with an Elema-Shonander M800 paper recorder and on magnetic tape with an Ampex SP700 tape recorder. All records were obtained without filters.Magnetic tapes were then processed with a Federal Scientific Ubiquitous U A 6B spectrum analyzer. Analysis is performed between 500 and 600 Hz in 5 sec, with a 0.2-Hz resolution, and the result is displayed on a memory scope, with frequency on the X axis and time on the Y axis. When the record contains a given frequency, it is displayed as a vertical line, of which the brightness is proportional to the energy. RESULTSWe examined 10 control and eight irradiated animals. For control animals, spectrum analysis only revealed noise in this frequency range (cf. FIGURE 1).
This review discusses current bottlenecks in making CRISPR-Cas9-mediated genome editing a therapeutic reality and it outlines recent strategies that aim to overcome these hurdles as well as the scope of current clinical trials that pioneer the medical translation of CRISPR-Cas9. Additionally, this review outlines the specifics of disease-modifying gene editing in recessive versus dominant genetic diseases with the focus on genetic myopathies that are exemplified by Duchenne muscular dystrophy and myotonic dystrophies.
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