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1.
medRxiv ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38947084

RESUMO

The pathophysiology underlying various manifestations of cerebral small vessel disease (cSVD) remains obscure. Using cerebrospinal fluid proximity extension assays and co-expression network analysis of 2,943 proteins, we found common and distinct proteomic signatures between white matter lesions (WML), microbleeds and infarcts measured in 856 living patients, and validated WML-associated proteins in three additional datasets. Proteins indicative of extracellular matrix dysregulation and vascular remodeling, including ELN, POSTN, CCN2 and MMP12 were elevated across all cSVD manifestations, with MMP12 emerging as an early cSVD indicator. cSVD-associated proteins formed a co-abundance network linked to metabolism and enriched in endothelial and arterial smooth muscle cells, showing elevated levels at early disease manifestations. Later disease stages involved changes in microglial proteins, associated with longitudinal WML progression, and changes in neuronal proteins mediating WML-associated cognitive decline. These findings provide an atlas of novel cSVD biomarkers and a promising roadmap for the next generation of cSVD therapeutics.

2.
Sci Rep ; 14(1): 15292, 2024 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-38961134

RESUMO

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system and a leading cause of neurological disability in young adults. Clinical presentation and disease course are highly heterogeneous. Typically, disease progression occurs over time and is characterized by the gradual accumulation of disability. The risk of developing MS is driven by complex interactions between genetic and environmental factors, including the gut microbiome. How the commensal gut microbiota impacts disease severity and progression over time remains unknown. In a longitudinal study, disability status and associated clinical features in 58 MS patients were tracked over 4.2 ± 0.98 years, and the baseline fecal gut microbiome was characterized via 16S amplicon sequencing. Progressor status, defined as patients with an increase in Expanded Disability Status Scale (EDSS), were correlated with features of the gut microbiome to determine candidate microbiota associated with risk of MS disease progression. We found no overt differences in microbial community diversity and overall structure between MS patients exhibiting disease progression and non-progressors. However, a total of 41 bacterial species were associated with worsening disease, including a marked depletion in Akkermansia, Lachnospiraceae, and Oscillospiraceae, with an expansion of Alloprevotella, Prevotella-9, and Rhodospirillales. Analysis of the metabolic potential of the inferred metagenome from taxa associated with progression revealed enrichment in oxidative stress-inducing aerobic respiration at the expense of microbial vitamin K2 production (linked to Akkermansia), and a depletion in SCFA metabolism (linked to Oscillospiraceae). Further, as a proof of principle, statistical modeling demonstrated that microbiota composition and clinical features were sufficient to predict disease progression. Additionally, we found that constipation, a frequent gastrointestinal comorbidity among MS patients, exhibited a divergent microbial signature compared with progressor status. These results demonstrate a proof of principle for the utility of the gut microbiome for predicting disease progression in MS in a small well-defined cohort. Further, analysis of the inferred metagenome suggested that oxidative stress, vitamin K2, and SCFAs are associated with progression, warranting future functional validation and mechanistic study.


Assuntos
Progressão da Doença , Microbioma Gastrointestinal , Esclerose Múltipla , Humanos , Microbioma Gastrointestinal/genética , Esclerose Múltipla/microbiologia , Esclerose Múltipla/patologia , Masculino , Feminino , Adulto , Estudos Longitudinais , Fezes/microbiologia , Pessoa de Meia-Idade , Índice de Gravidade de Doença , RNA Ribossômico 16S/genética
3.
bioRxiv ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38948774

RESUMO

CRISPR screens are powerful tools to identify key genes that underlie biological processes. One important type of screen uses fluorescence activated cell sorting (FACS) to sort perturbed cells into bins based on the expression level of marker genes, followed by guide RNA (gRNA) sequencing. Analysis of these data presents several statistical challenges due to multiple factors including the discrete nature of the bins and typically small numbers of replicate experiments. To address these challenges, we developed a robust and powerful Bayesian random effects model and software package called Waterbear. Furthermore, we used Waterbear to explore how various experimental design parameters affect statistical power to establish principled guidelines for future screens. Finally, we experimentally validated our experimental design model findings that, when using Waterbear for analysis, high power is maintained even at low cell coverage and a high multiplicity of infection. We anticipate that Waterbear will be of broad utility for analyzing FACS-based CRISPR screens.

4.
Proc Natl Acad Sci U S A ; 121(25): e2219137121, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38861593

RESUMO

Cortical arealization arises during neurodevelopment from the confluence of molecular gradients representing patterned expression of morphogens and transcription factors. However, whether similar gradients are maintained in the adult brain remains unknown. Here, we uncover three axes of topographic variation in gene expression in the adult human brain that specifically capture previously identified rostral-caudal, dorsal-ventral, and medial-lateral axes of early developmental patterning. The interaction of these spatiomolecular gradients i) accurately reconstructs the position of brain tissue samples, ii) delineates known functional territories, and iii) can model the topographical variation of diverse cortical features. The spatiomolecular gradients are distinct from canonical cortical axes differentiating the primary sensory cortex from the association cortex, but radiate in parallel with the axes traversed by local field potentials along the cortex. We replicate all three molecular gradients in three independent human datasets as well as two nonhuman primate datasets and find that each gradient shows a distinct developmental trajectory across the lifespan. The gradients are composed of several well-known transcription factors (e.g., PAX6 and SIX3), and a small set of genes shared across gradients are strongly enriched for multiple diseases. Together, these results provide insight into the developmental sculpting of functionally distinct brain regions, governed by three robust transcriptomic axes embedded within brain parenchyma.


Assuntos
Encéfalo , Humanos , Encéfalo/metabolismo , Animais , Adulto , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Fator de Transcrição PAX6/metabolismo , Fator de Transcrição PAX6/genética , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Padronização Corporal/genética , Feminino , Proteínas do Tecido Nervoso/metabolismo , Proteínas do Tecido Nervoso/genética
5.
Nat Commun ; 15(1): 5133, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38879548

RESUMO

Lewy body (LB) diseases, characterized by the aggregation of misfolded α-synuclein proteins, exhibit notable clinical heterogeneity. This may be due to variations in accumulation patterns of LB neuropathology. Here we apply a data-driven disease progression model to regional neuropathological LB density scores from 814 brain donors with Lewy pathology. We describe three inferred trajectories of LB pathology that are characterized by differing clinicopathological presentation and longitudinal antemortem clinical progression. Most donors (81.9%) show earliest pathology in the olfactory bulb, followed by accumulation in either limbic (60.8%) or brainstem (21.1%) regions. The remaining donors (18.1%) initially exhibit abnormalities in brainstem regions. Early limbic pathology is associated with Alzheimer's disease-associated characteristics while early brainstem pathology is associated with progressive motor impairment and substantial LB pathology outside of the brain. Our data provides evidence for heterogeneity in the temporal spread of LB pathology, possibly explaining some of the clinical disparities observed in Lewy body disease.


Assuntos
Progressão da Doença , Corpos de Lewy , Doença por Corpos de Lewy , alfa-Sinucleína , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , alfa-Sinucleína/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/metabolismo , Encéfalo/patologia , Encéfalo/metabolismo , Tronco Encefálico/patologia , Tronco Encefálico/metabolismo , Corpos de Lewy/patologia , Corpos de Lewy/metabolismo , Doença por Corpos de Lewy/patologia , Doença por Corpos de Lewy/metabolismo , Bulbo Olfatório/patologia , Bulbo Olfatório/metabolismo
6.
J Glaucoma ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38874528

RESUMO

PRCIS: About 1/4th of survey respondents from an ASCRS database initiate treatment for primary open-angle glaucoma (POAG) with laser trabeculoplasty. Factors impacting physicians' choice of laser versus topical treatment for POAG were explored. PURPOSE: To characterize primary treatment preferences (topical medication vs. laser trabeculoplasty or intracameral sustained release implants) in primary open-angle glaucoma (POAG) patients and determine factors related to primary intervention selection. METHODS: A 33-question survey was distributed to an American Society of Cataract and Refractive Surgery database on treatment choices made by ophthalmologists for POAG. Data collected included country of practice, years of practice, completion of glaucoma fellowship training, type of practice, and preference for first line of treatment of POAG. Multiple logit regression was used to compare the effect of covariates on physicians' choice of either topical medication or laser trabeculoplasty for POAG. RESULTS: A total of 252/19,246 (1.3%) of surveys were returned. Almost three-quarters of respondents utilized topical medication as first line of treatment for POAG (73.6%) while 26.4% preferred to start with laser treatment. Significant variables associated with the selection of laser (vs. drops) are practicing in the U.S. (odds ratio [OR] 2.85, 95% confidence interval [CI] 1.33-6.10), more recent completion of ophthalmology residency (OR 1.95, 95% CI 1.00-3.77), greater volume of minimally invasive glaucoma surgeries (MIGS) (OR 1.68, 95% CI 1.18-2.40), and a glaucoma patient base greater than 25% (OR 2.21, 95% CI 1.09-4.48). CONCLUSIONS: For the first line treatment of POAG, laser trabeculoplasty is more likely to be preferred, over topical drops, by U.S. physicians who are relatively new in practice, who have a larger glaucoma patient base and who perform more MIGS.

7.
Bioscience ; 74(5): 333-339, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38854634

RESUMO

Language is central to the way people learn about the natural world. A salient concern of the biodiversity conservation arena has been to understand how language can be employed by scientists to communicate knowledge to nonexpert audiences and build ecological literacy. The use of analogy and narrative by scientists are prominent techniques. In this article, we consider how these two modes of language-based reasoning extend into ordinary conversational language use by the public, specifically when articulating everyday understanding and experiences of biodiversity. Drawing on a process of public engagement in a UK woodland environment, a typological framework based on principles of analogical and narrative reasoning is developed to characterize the precise character of processes of everyday biodiversity sense making. The implications of the framework are discussed in the context of future biodiversity research, particularly its participatory and educational dimensions.

8.
Front Genet ; 15: 1398123, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38859938

RESUMO

Introduction: Improving ewe longevity is an important breeding and management goal, as death loss and early culling of mature ewes are economic burdens in the sheep industry. Ewe longevity can be improved by selecting for positive reproductive outcomes. However, the breeding approaches for accomplishing this come with the challenge of recording a lifetime trait. Characterizing genetic factors underpinning ewe longevity and related traits could result in the development of genomic selection strategies to improve the stayability of sheep through early, informed selection of replacement ewes. Methods: Towards this aim, a genome-wide association study (GWAS) was performed to identify genetic markers associated with ewe longevity, reproductive, and production traits. Traits evaluated included longevity (i.e., length of time in the flock), parity and the lifetime number of lambs born, lambs born alive, lambs weaned, and weight of lambs weaned. Ewe records from previous studies were used. Specifically, Rambouillet (n = 480), Polypay (n = 404), Suffolk (n = 182), and Columbia (n = 64) breed ewes (N = 1,130) were analyzed against 503,617 SNPs in across-breed and within-breed GWAS conducted with the Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model in R. Results: The across-breed GWAS identified 25 significant SNPs and the within-breed GWAS for Rambouillet, Polypay, and Suffolk ewes identified an additional 19 significant SNPs. The most significant markers were rs411309094 (13:22,467,143) associated with longevity in across-breed GWAS (p-value = 8.3E-13) and rs429525276 (2:148,398,336) associated with both longevity (p-value = 6.4E-15) and parity (p-value = 4.8E-15) in Rambouillet GWAS. Significant SNPs were identified within or in proximity (±50 kb) of genes with known or proposed roles in reproduction, dentition, and the immune system. These genes include ALPL, ANOS1, ARHGEF26, ASIC2, ASTN2, ATP8A2, CAMK2D, CEP89, DISC1, ITGB6, KCNH8, MBNL3, MINDY4, MTSS1, PLEKHA7, PRIM2, RNF43, ROBO2, SLCO1A2, TMEM266, TNFRSF21, and ZNF804B. Discussion: This study proposes multiple SNPs as candidates for use in selection indices and suggests genes for further research towards improving understanding of the genetic factors contributing to longevity, reproductive, and production traits of ewes.

9.
J Exp Biol ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38881304

RESUMO

Digestion can make up a substantial proportion of animal energy budgets, yet our understanding of how it varies with sex, body mass, and ration size is limited. A warming climate may have consequences on animal growth and feeding dynamics that will differentially impact individuals in their ability to efficiently acquire and assimilate meals. Many species, such as walleye (Sander vitreus), exhibit sexual size dimorphism (SSD), whereby one sex is larger than the other, suggesting sex-differences in energy acquisition and/or expenditure. Here we present the first thorough estimates of specific dynamic action (SDA) in adult walleye using intermittent-flow respirometry. We fed male (n=14) and female (n=9) walleye two ration sizes; 2% and 4% of individual body weight, over a range of temperatures from 2 - 20°C. SDA was shorter in duration and reached higher peak rates of oxygen consumption with increasing temperatures. Peak SDA increased with ration size and decreased with body mass. The proportion of digestible energy lost to SDA (i.e., the SDA coefficient) was consistent at 6% and was unrelated to temperature, body mass, sex, or ration size. Our findings suggest that sex has a negligible role in shaping SDA, nor is SDA a contributor to SSD for this species. Standard and maximum metabolic rates were similar between sexes but maximum metabolic rate decreased drastically with body mass. Large fish, which are important for population growth due to reproductive hyperallometry, may therefore face a bioenergetic disadvantage and struggle most to perform optimally in future, warmer waters.

10.
J Clin Med ; 13(9)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38730993

RESUMO

Background: We sought to investigate the differential impact of EVAR (endovascular aneurysm repair) vis-à-vis OSR (open surgical repair) on ruptured AAA (abdominal aortic aneurysm) mortality by sex and geographically. Methods: We performed a retrospective study of administrative data on EVAR from state statistical agencies, vascular registries, and academic publications, as well as ruptured AAA mortality rates from the World Health Organization for 14 14 states across Australasia, East Asia, Europe, and North America. Results: Between 2011-2016, the proportion of treatment of ruptured AAAs by EVAR increased from 26.1 to 43.8 percent among females, and from 25.7 to 41.2 percent among males, and age-adjusted ruptured AAA mortality rates fell from 12.62 to 9.50 per million among females, and from 34.14 to 26.54 per million among males. The association of EVAR with reduced mortality was more than three times larger (2.2 vis-à-vis 0.6 percent of prevalence per 10 percentage point increase in EVAR) among females than males. The association of EVAR with reduced mortality was substantially larger (1.7 vis-à-vis 1.1 percent of prevalence per 10 percentage point increase in EVAR) among East Asian states than European+ states. Conclusions: The increasing adoption of EVAR coincided with a decrease in ruptured AAA mortality. The relationship between EVAR and mortality was more pronounced among females than males, and in East Asian than European+ states. Sex and ethnic heterogeneity should be further investigated.

11.
Nat Genet ; 56(6): 1156-1167, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38811842

RESUMO

Cis-regulatory elements (CREs) interact with trans regulators to orchestrate gene expression, but how transcriptional regulation is coordinated in multi-gene loci has not been experimentally defined. We sought to characterize the CREs controlling dynamic expression of the adjacent costimulatory genes CD28, CTLA4 and ICOS, encoding regulators of T cell-mediated immunity. Tiling CRISPR interference (CRISPRi) screens in primary human T cells, both conventional and regulatory subsets, uncovered gene-, cell subset- and stimulation-specific CREs. Integration with CRISPR knockout screens and assay for transposase-accessible chromatin with sequencing (ATAC-seq) profiling identified trans regulators influencing chromatin states at specific CRISPRi-responsive elements to control costimulatory gene expression. We then discovered a critical CCCTC-binding factor (CTCF) boundary that reinforces CRE interaction with CTLA4 while also preventing promiscuous activation of CD28. By systematically mapping CREs and associated trans regulators directly in primary human T cell subsets, this work overcomes longstanding experimental limitations to decode context-dependent gene regulatory programs in a complex, multi-gene locus critical to immune homeostasis.


Assuntos
Antígenos CD28 , Antígeno CTLA-4 , Cromatina , Regulação da Expressão Gênica , Humanos , Antígeno CTLA-4/genética , Antígenos CD28/genética , Cromatina/genética , Cromatina/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Proteína Coestimuladora de Linfócitos T Induzíveis/genética , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Fator de Ligação a CCCTC/metabolismo , Fator de Ligação a CCCTC/genética , Sistemas CRISPR-Cas
12.
Semin Musculoskelet Radiol ; 28(3): 267-281, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38768592

RESUMO

The prevalence of knee osteoarthritis (OA) is the highest among all joints and likely to increase over the coming decades. Advances in the repertoire of diagnostic capabilities of imaging and an expansion in the availability and range of image-guided interventions has led to development of more advanced interventional procedures targeting pain related to OA pain while improving the function of patients presenting with this debilitating condition. We review the spectrum of established advanced interventional procedures for knee OA, describe the techniques used to perform these procedures safely, and discuss the clinical evidence supporting each of them.


Assuntos
Osteoartrite do Joelho , Humanos , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/terapia , Radiografia Intervencionista/métodos , Injeções Intra-Articulares/métodos
13.
Front Med (Lausanne) ; 11: 1381123, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38813376

RESUMO

Meningitis caused by Acinetobacter species is a rare complication of neurosurgical procedures, although it is associated with high morbidity and mortality. Carbapenem-resistant Acinetobacter is particularly difficult to treat, considering the limited selection and tolerability of effective antimicrobials. Sulbactam-durlobactam was approved by the FDA in 2023 for treatment of hospital-acquired and ventilator-associated pneumonia due to susceptible strains of Acinetobacter, including carbapenem-resistant Acinetobacter baumannii. Here, we present a case of carbapenem-resistant Acinetobacter baumannii neurosurgical infection and meningitis successfully treated with sulbactam-durlobactam combination therapy.

14.
Health Aff Sch ; 2(4): qxae036, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38756175

RESUMO

People eligible for both Medicare and Medicaid coverage ("dually eligible individuals") have lower levels of income and assets and often higher health care needs and costs than those eligible for Medicare but not Medicaid coverage. Their 3 most common Medicare coverage options are Medicare Advantage (MA) Dual Eligible Special Needs Plans (D-SNPs), non-D-SNP MA plans, and fee-for-service (FFS) Medicare with a stand-alone prescription drug plan. No prior study has examined clinical quality of care for dually eligible individuals across these 3 coverage types. To fill that void, we used logistic regression to compare these coverage types on 6 HEDIS measures of clinical quality of care that were available for both MA and FFS (constructed from claims files). D-SNPs and non-D-SNP MA plans significantly outperformed FFS for all 6 measures for dually eligible individuals, by approximately 5 percentage points for 2 measures and by 18-34 percentage points for the other 4 measures. For the 4 measures with the greatest advantage over FFS, performance was 3-8 percentage points higher in D-SNPs than in non-D-SNP MA plans.

15.
Org Biomol Chem ; 22(20): 4157-4162, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38715527

RESUMO

This article describes the synthesis and photophysical properties of a series of BODIPY photosensitisers that feature tellurophene motifs appended at the boron centre. These compounds were obtained via nucleophilic substitution of various F-BODIPYs with lithiated tellurophene. The synthetic scope, photophysical characteristics and photosensitisation properties are discussed. Structural modifications around the BODIPY core resulted in an eight-fold improvement in light IC50 values compared to previous designs.

16.
J Fish Biol ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38720527

RESUMO

Bioenergetics is informative for a range of fundamental and applied resource management questions, but findings are often constrained by a lack of ecological realism due to the challenges of remotely estimating key parameters such as metabolic rate. To enable field applications, we conducted a calibration study with smallmouth bass (Micropterus dolomieu, 0.7-2 kg) surgically implanted with accelerometer transmitters and exposed to a ramp-Ucrit swimming protocol in a swim tunnel respirometer across a range of water temperatures (6, 12, 18, and 24°C). There was an exponential increase in fish acceleration with swimming speed, and acceleration per speed was higher in smaller fish and female fish, and at colder temperatures. Mass-specific fish metabolic rate (MO2; mg O2 kg-1 h-1) increased with swimming speed, acceleration, and temperature, and decreased with fish mass, which when combined were strong predictors of MO2. Maximum metabolic rate (MMR) was estimated to peak at 22°C, but maximum sustained swimming speed (Ucrit) remained high at c. 90-100 m s-1 above 20°C, based on second-order polynomial functions. Aerobic scope (AS) estimates peaked at 20°C (>90% AS at 17-24°C; >50% AS at 11-28°C). Males exhibited marginally higher MMR, AS, and Ucrit than females at higher temperatures. Larger fish generally exhibited higher Ucrit, but smaller fish had a marginally broader performance range (AS, Ucrit) among temperatures, benefiting from higher MMR despite a steeper increase in resting metabolic rate with temperature. These findings enable field studies to estimate metabolic metrics of smallmouth bass in situ to characterize their ecological energetics and inform bioenergetics models.

17.
J Orthop Res ; 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38605593

RESUMO

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty-six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K-wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16-week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10-week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose-dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals.

18.
Methods Mol Biol ; 2788: 287-294, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38656521

RESUMO

CRISPR/Cas9 stands as a revolutionary and versatile gene editing technology. At its core, the Cas9 DNA endonuclease is guided with precision by a specifically designed single-guide RNA (gRNA). This guidance system facilitates the introduction of double-stranded breaks (DSBs) within the DNA. Subsequent imprecise repairs, mainly through the non-homologous end-joining (NHEJ) pathway, yield insertions or deletions, resulting in frameshift mutations. These mutations are instrumental in achieving the successful knockout of the target gene. In this chapter, we describe all necessary steps to create and design a gRNA for a gene knockout to a target gene before to transfer it to a target plant.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Técnicas de Inativação de Genes , RNA Guia de Sistemas CRISPR-Cas , RNA Guia de Sistemas CRISPR-Cas/genética , Técnicas de Inativação de Genes/métodos , Edição de Genes/métodos , Simulação por Computador , Reparo do DNA por Junção de Extremidades/genética
19.
Methods Mol Biol ; 2788: 295-316, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38656522

RESUMO

This protocol outlines the construction of a plant transformation plasmid to express both the Cas9 nuclease and individual guide RNA (gRNA), facilitating the induction of double-stranded breaks (DSBs) in DNA and subsequent imprecise repair via the non-homologous end-joining (NHEJ) pathway. The gRNA expression cassettes are assembled from three components. First, the Medicago truncatula U6.6 (MtU6) promoter (352 bp) and scaffold (83 bp) sequences are amplified from a pUC-based plasmid. Additionally, a third fragment, corresponding to the target sequence, is synthesized as an oligonucleotide. The three gRNA expression fragments are then loosely assembled in a ligation-free cloning reaction and used as a template for an additional PCR step to amplify a single gRNA expression construct, ready for assembly into the transformation vector. The benefits of this design include cost efficiency, as subsequent cloning reactions only require 59 oligonucleotides and standard cloning reagents. Researchers engaged in CRISPR/Cas9-mediated genome editing in plants will find this protocol a clear and resource-efficient approach to create transformation plasmids for their experiments.


Assuntos
Sistemas CRISPR-Cas , Técnicas de Inativação de Genes , Vetores Genéticos , RNA Guia de Sistemas CRISPR-Cas , Vetores Genéticos/genética , RNA Guia de Sistemas CRISPR-Cas/genética , Técnicas de Inativação de Genes/métodos , Plasmídeos/genética , Medicago truncatula/genética , Edição de Genes/métodos , Plantas Geneticamente Modificadas/genética , Clonagem Molecular/métodos , Regiões Promotoras Genéticas/genética , Reparo do DNA por Junção de Extremidades/genética , Transformação Genética
20.
bioRxiv ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38659905

RESUMO

Lipid nanoparticles (LNPs) have emerged as the dominant platform for RNA delivery, based on their success in the COVID-19 vaccines and late-stage clinical studies in other indications. However, we and others have shown that LNPs induce severe inflammation, and massively aggravate pre-existing inflammation. Here, using structure-function screening of lipids and analyses of signaling pathways, we elucidate the mechanisms of LNP-associated inflammation and demonstrate solutions. We show that LNPs' hallmark feature, endosomal escape, which is necessary for RNA expression, also directly triggers inflammation by causing endosomal membrane damage. Large, irreparable, endosomal holes are recognized by cytosolic proteins called galectins, which bind to sugars on the inner endosomal membrane and then regulate downstream inflammation. We find that inhibition of galectins abrogates LNP-associated inflammation, both in vitro and in vivo . We show that rapidly biodegradable ionizable lipids can preferentially create endosomal holes that are smaller in size and reparable by the endosomal sorting complex required for transport (ESCRT) pathway. Ionizable lipids producing such ESCRT-recruiting endosomal holes can produce high expression from cargo mRNA with minimal inflammation. Finally, we show that both routes to non-inflammatory LNPs, either galectin inhibition or ESCRT-recruiting ionizable lipids, are compatible with therapeutic mRNAs that ameliorate inflammation in disease models. LNPs without galectin inhibition or biodegradable ionizable lipids lead to severe exacerbation of inflammation in these models. In summary, endosomal escape induces endosomal membrane damage that can lead to inflammation. However, the inflammation can be controlled by inhibiting galectins (large hole detectors) or by using biodegradable lipids, which create smaller holes that are reparable by the ESCRT pathway. These strategies should lead to generally safer LNPs that can be used to treat inflammatory diseases.

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