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1.
Biochem J ; 481(13): 865-881, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38958472

ABSTRACT

Filamin A is an essential protein in the cell cytoskeleton because of its actin binding properties and unique homodimer rod-shaped structure, which organises actin into three-dimensional orthogonal networks imperative to cell motility, spreading and adhesion. Filamin A is subject to extensive posttranslational modification (PTM) which serves to co-ordinate cellular architecture and to modulate its large protein-protein interaction network which is key to the protein's role as a cellular signalling hub. Characterised PTMs include phosphorylation, irreversible cleavage, ubiquitin mediated degradation, hydroxylation and O-GlcNAcylation, with preliminary evidence of tyrosylation, carbonylation and acetylation. Each modification and its relation to filamin A function will be described here. These modifications are often aberrantly applied in a range of diseases including, but not limited to, cancer, cardiovascular disease and neurological disease and we discuss the concept of target specific PTMs with novel therapeutic modalities. In summary, our review represents a topical 'one-stop-shop' that enables understanding of filamin A function in cell homeostasis and provides insight into how a variety of modifications add an extra level of Filamin A control.


Subject(s)
Filamins , Protein Processing, Post-Translational , Filamins/metabolism , Humans , Animals , Phosphorylation , Neoplasms/metabolism
2.
Rev Sci Instrum ; 95(7)2024 Jul 01.
Article in English | MEDLINE | ID: mdl-39037303

ABSTRACT

There are few techniques available for chemists to obtain time-to-explosion data with known temperature inputs at the early stages of the design and synthesis of new explosives. In the 1960s, a technique was developed to rapidly heat milligram-quantities of confined explosives to ∼1000 K on microsecond timescales. Wenograd [Trans. Faraday Soc. 57, 1612 (1961)] loaded explosives inside stainless steel hypodermic needles, connected them to a fireset and rapidly discharged a capacitor through the steel. He obtained the temperature by measuring the needle resistance in a Wheatstone bridge arrangement and the time to explosion from a needle rupture. However, owing to the narrow-gauge needles used in the original research, the experiment was only possible with melt-castable explosives; it was never replicated, and modern diagnostics are now available with advances beyond the 1960s. Here, we report the development of the High Explosives Initiation Time (HEIT) test, which utilizes a 250 J pulsed power system to heat the needles. This work extends the Wenograd approach by using optical diagnostics, computational modeling, and advanced techniques to measure needle resistance and needle rupture. Preliminary rate information for pentaerythritol tetranitrate (PETN) will be presented.

3.
Org Biomol Chem ; 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39037740

ABSTRACT

Amide bonds are one of the most prevalent phenomena in nature and are utilized frequently in drug and material design. However, forming amide bonds is not always efficient or high yielding, particularly when the amine used to conjugate to a carboxylic acid is a weak nucleophile. This limitation precludes many useful amino compounds from participating in conjugation reactions to form amides. A particularly valuable amino compound, which is also a very weak nucleophile, is the amino porphyrin, valued for its role as a photosensitizer, fluorescent agent, catalyst, or, upon metalation, even a very efficient contrast agent for magnetic resonance imaging (MRI). In this work, we propose fast and high-yield coupling of an unreactive amine - the amino porphyrin - to carboxylic acid via isothiocyanate conjugation. Reactions can be achieved in one step at room temperature in one hour, achieving quantitative conversion and near perfect selectivity. Both metalated and unmetalated porphyrin, as well as fluorescein isothiocyanate (FITC), demonstrated efficient conjugation. To illustrate the value of the proposed method, we created a new blood-pool MRI contrast agent that reversibly binds to serum albumin. This new blood-pool agent, known as MITC-Deox (MRI isothiocyanate that links with deoxycholic acid), substantially reduced T1 relaxation times in blood vessels in mice, remained stable for 1 hour, cleared from blood by 24 hours, and was eliminated from the body after 4 days. The proposed method for efficient amide formation is a superior alternative to existing coupling methods, opening a door to novel synthesis of MRI contrast agents and beyond.

4.
Cell Rep ; 43(8): 114503, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39018245

ABSTRACT

Synaptic plasticities, such as long-term potentiation (LTP) and depression (LTD), tune synaptic efficacy and are essential for learning and memory. Current studies of synaptic plasticity in humans are limited by a lack of adequate human models. Here, we modeled the thalamocortical system by fusing human induced pluripotent stem cell-derived thalamic and cortical organoids. Single-nucleus RNA sequencing revealed that >80% of cells in thalamic organoids were glutamatergic neurons. When fused to form thalamocortical assembloids, thalamic and cortical organoids formed reciprocal long-range axonal projections and reciprocal synapses detectable by light and electron microscopy, respectively. Using whole-cell patch-clamp electrophysiology and two-photon imaging, we characterized glutamatergic synaptic transmission. Thalamocortical and corticothalamic synapses displayed short-term plasticity analogous to that in animal models. LTP and LTD were reliably induced at both synapses; however, their mechanisms differed from those previously described in rodents. Thus, thalamocortical assembloids provide a model system for exploring synaptic plasticity in human circuits.

5.
Biochem Biophys Rep ; 39: 101765, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39040543

ABSTRACT

Primary Hyperoxaluria Type 3 (PH3) results from 4-hydroxy-2-oxoglutarate (HOG) aldolase (HOGA) deficiency, which causes an increase in endogenous oxalate synthesis leading to calcium oxalate kidney stone disease. The mechanisms underlying HOG metabolism and increased oxalate synthesis in PH3 are not well understood. We used a Hoga1 knock-out mouse model of PH3 to investigate two aspects of HOG metabolism: reduction to dihydroxyglutarate (DHG), a pathway that may limit oxalate synthesis in PH3, and metabolism to glyoxylate, which is a direct precursor to oxalate. The metabolism of HOG to DHG was highest in liver and kidney cortical tissue, enhanced in the cytosolic compartment of the liver, and preferred NADPH as a cofactor. In the absence of HOGA, HOG to glyoxylate aldolase activity was highest in liver mitoplasts, with no activity present in brain tissue lysates. These findings will assist in the identification of enzymes responsible for the metabolism of HOG to DHG and glyoxylate, which may lead to novel therapeutic approaches to limit oxalate synthesis in those afflicted with PH3.

6.
Brain Behav Immun ; 2024 Jul 25.
Article in English | MEDLINE | ID: mdl-39067620

ABSTRACT

Prebiotic galactooligosaccharides (GOS) reduce anxiety-like behaviors in mice and humans. However, the biological pathways behind these behavioral changes are not well understood. To begin to study these pathways, we utilized C57BL/6 mice that were fed a standard diet with or without GOS supplementation for 3 weeks prior to testing on the open field. After behavioral testing, colonic contents and serum were collected for bacteriome (16S rRNA gene sequencing, colonic contents only) and metabolome (UPLC-MS, colonic contents and serum data) analyses. As expected, GOS significantly reduced anxiety-like behavior (i.e., increased time in the center) and decreased cytokine gene expression (Tnfa and Ccl2) in the prefrontal cortex. Notably, time in the center of the open field was significantly correlated with serum methyl-indole-3-acetic acid (methyl-IAA). This metabolite is a methylated form of indole-3-acetic acid (IAA) that is derived from bacterial metabolism of tryptophan. Sequencing analyses showed that GOS significantly increased Lachnospiraceae UCG006 and Akkermansia; these taxa are known to metabolize both GOS and tryptophan. To determine the extent to which methyl-IAA can affect anxiety-like behavior, mice were intraperitoneally injected with methyl-IAA. Mice given methyl-IAA had a reduction in anxiety-like behavior in the open field, along with lower Tnfa in the prefrontal cortex. Methyl-IAA was also found to reduce TNF-α (as well as CCL2) production by LPS-stimulated BV2 microglia. Together, these data support a novel pathway through which GOS reduces anxiety-like behaviors in mice and suggests that the bacterial metabolite methyl-IAA reduces microglial cytokine and chemokine production, which in turn reduces anxiety-like behavior.

7.
Chem Commun (Camb) ; 2024 Jul 19.
Article in English | MEDLINE | ID: mdl-39028006

ABSTRACT

Here we report the synthesis and characterization of diiron complexes containing triaryl N4 and N2S2 ligands derived from o-phenylenediamine. The complexes display significant differences in Fe-Fe distances and magnetic properties that depend on the identity of the flanking NMe2 and SMe donor groups.

9.
ACS Omega ; 9(29): 32097-32106, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39072092

ABSTRACT

Pentaerythritol tetranitrate (PETN) has been used extensively in commercial detonators and other explosive applications for many decades. Here, we show the results of a comprehensive 1.5 year aging study of PETN in commercial detonators, addressing batch-to-batch variations, surface area changes, and comparisons of aged loose powders side-by-side with identically aged detonators. Function time analysis of the aged detonators has also been provided and discussed in the context of powder aging. This large-scale, statistically relevant study addresses long-standing questions on PETN aging without the complications from making comparisons between multiple batches of material. We have evaluated the aging time required to reach the maximum measured amount of PETN coarsening and estimated an activation barrier of ∼123 kJ mol-1, which is higher than literature values reported by Gee et al. It is possible that this discrepancy is due to the fact that that this study cannot quantify the relative contributions of surface diffusion versus sublimation processes. At the lower temperatures of 50 and 60 °C, we assume that surface diffusion dominates over sublimation processes, even at longer aging times. At the higher temperature of 75 °C, we assume that both surface diffusion and sublimation contribute at the early time points, which are included in the Arrhenius analysis for coarsening.

10.
Article in English | MEDLINE | ID: mdl-38981690

ABSTRACT

Intramedullary nails are specialized metal rods inserted into the medullary cavity of a fractured bone and secured to reduce load on the fracture site, provide stability, and permit healing. The purpose of this review is to highlight the biomechanics of orthopaedic intramedullary nailing, as well as discuss the biomechanical considerations that have shaped implant design and fixation technique in veterinary and human medicine. Relevant studies were included from the PubMed database and Google Scholar for discussion on the basic science and nail design of intramedullary nails. Implant design and implementation continues to progress, with new innovative designs currently under investigation. A lack of consensus remains on the superior implant material. Recent studies, particularly in human populations, have supported the use of reaming based on reoperation rates, nonunion rates, and dynamization. Design modifications, such as the expandable intramedullary nails and angle-stable interlocking designs, have been investigated as methods of improving cortical contact and resisting torsional stress. Intramedullary nailing is a valuable stabilization technique for long bone fractures across a variety of species. The technology continues to undergo design improvements in both veterinary and human medicine.

11.
Gut Microbes ; 16(1): 2350150, 2024.
Article in English | MEDLINE | ID: mdl-38841888

ABSTRACT

Comensal Bacteroidota (Bacteroidota) and Enterobacteriacea are often linked to gut inflammation. However, the causes for variability of pro-inflammatory surface antigens that affect gut commensal/opportunistic dualism in Bacteroidota remain unclear. By using the classical lipopolysaccharide/O-antigen 'rfb operon' in Enterobacteriaceae as a surface antigen model (5-rfb-gene-cluster rfbABCDX), and a recent rfbA-typing strategy for strain classification, we characterized the integrity and conservancy of the entire rfb operon in Bacteroidota. Through exploratory analysis of complete genomes and metagenomes, we discovered that most Bacteroidota have the rfb operon fragmented into nonrandom patterns of gene-singlets and doublets/triplets, termed 'rfb-gene-clusters', or rfb-'minioperons' if predicted as transcriptional. To reflect global operon integrity, contiguity, duplication, and fragmentation principles, we propose a six-category (infra/supra-numerary) cataloging system and a Global Operon Profiling System for bacteria. Mechanistically, genomic sequence analyses revealed that operon fragmentation is driven by intra-operon insertions of predominantly Bacteroides-DNA (thetaiotaomicron/fragilis) and likely natural selection in gut-wall specific micro-niches or micropathologies. Bacteroides-insertions, also detected in other antigenic operons (fimbriae), but not in operons deemed essential (ribosomal), could explain why Bacteroidota have fewer KEGG-pathways despite large genomes. DNA insertions, overrepresenting DNA-exchange-avid (Bacteroides) species, impact our interpretation of functional metagenomics data by inflating by inflating gene-based pathway inference and by overestimating 'extra-species' abundance. Of disease relevance, Bacteroidota species isolated from cavitating/cavernous fistulous tract (CavFT) microlesions in Crohn's Disease have supra-numerary fragmented operons, stimulate TNF-alpha from macrophages with low potency, and do not induce hyperacute peritonitis in mice compared to CavFT Enterobacteriaceae. The impact of 'foreign-DNA' insertions on pro-inflammatory operons, metagenomics, and commensalism/opportunism requires further studies to elucidate their potential for novel diagnostics and therapeutics, and to elucidate the role of co-existing pathobionts in Crohn's disease microlesions.


Subject(s)
Crohn Disease , Gastrointestinal Microbiome , Metagenomics , Operon , Mice , Animals , Humans , Crohn Disease/microbiology , Crohn Disease/genetics , Bacteroidetes/genetics , Bacteroidetes/classification , Antigens, Bacterial/genetics , Genome, Bacterial , Enterobacteriaceae/genetics , Enterobacteriaceae/classification
12.
Pediatr Obes ; 19(8): e13143, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38886982

ABSTRACT

BACKGROUND: Anti-obesity medications (AOMs) are promising lifestyle modification (LSM) adjuncts for obesity treatment, and phentermine is commonly prescribed in paediatric weight management clinics. Determining 'real-world' AOM effectiveness and characteristics predicting response is important. OBJECTIVES: We sought to describe phentermine plus LSM effectiveness and identify baseline characteristics predicting response. METHODS: This was a retrospective cohort study among youth seen in a US academic-based weight management clinic from 2012 to 2020. Baseline characteristics (e.g., body mass index (BMI), liver transaminases, eating-related behaviours) and outcomes (%BMI of 95th percentile (%BMIp95), BMI, %BMI change, weight) were determined through electronic health records and intake surveys. RESULTS: Among 91 youth prescribed phentermine plus LSM over 8 years (mean %BMIp95 150%), %BMIp95 was statistically significantly reduced at 1.5, 3, 6 and 12 months (peak reduction 10.9 percentage points at 6 months; p < 0.001). Considering multiple comparisons, the presence of baseline elevated alanine aminotransferase was associated with statistically significant smaller 1.5-month %BMIp95 reductions (p = 0.001) and higher food responsiveness with smaller 3- (p = 0.001) and 6-month (p < 0.001) reductions. CONCLUSIONS: Phentermine plus LSM reduced %BMIp95 among youth in a weight management clinic, and baseline characteristics may help determine those more or less likely to respond. Prospective studies are needed to further characterize effectiveness and confirm response predictors.


Subject(s)
Pediatric Obesity , Phentermine , Weight Loss , Humans , Female , Male , Retrospective Studies , Pediatric Obesity/epidemiology , Pediatric Obesity/therapy , Phentermine/therapeutic use , Child , Adolescent , Anti-Obesity Agents/therapeutic use , Treatment Outcome , Body Mass Index , Risk Reduction Behavior , Life Style
13.
JAMA Pediatr ; 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38884967

ABSTRACT

Importance: Adolescent severe obesity is usually not effectively treated with traditional lifestyle modification therapy. Meal replacement therapy (MRT) shows short-term efficacy for body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) reduction in adolescents, and financial incentives (FIs) may be an appropriate adjunct intervention to enhance long-term efficacy. Objective: To evaluate the effect of MRT plus FIs vs MRT alone on BMI, body fat, and cardiometabolic risk factors in adolescents with severe obesity. Design, Setting, and Participants: This was a randomized clinical trial of MRT plus FIs vs MRT alone at a large academic health center in the Midwest conducted from 2018 to 2022. Participants were adolescents (ages 13-17 y) with severe obesity (≥120% of the 95th BMI percentile based on sex and age or ≥35 BMI, whichever was lower) who were unaware of the FI component of the trial until they were randomized to MRT plus FIs or until the end of the trial. Study staff members collecting clinical measures were blinded to treatment condition. Data were analyzed from March 2022 to February 2024. Interventions: MRT included provision of preportioned, calorie-controlled meals (~1200 kcals/d). In the MRT plus FI group, incentives were provided based on reduction in body weight from baseline. Main Outcomes and Measures: The primary end point was mean BMI percentage change from randomization to 52 weeks. Secondary end points included total body fat and cardiometabolic risk factors: blood pressure, triglyceride to high-density lipoprotein ratio, heart rate variability, and arterial stiffness. Cost-effectiveness was additionally evaluated. Safety was assessed through monthly adverse event monitoring and frequent assessment of unhealthy weight-control behaviors. Results: Among 126 adolescents with severe obesity (73 female [57.9%]; mean [SD] age, 15.3 [1.2] years), 63 participants received MRT plus FIs and 63 participants received only MRT. At 52 weeks, the mean BMI reduction was greater by -5.9 percentage points (95% CI, -9.9 to -1.9 percentage points; P = .004) in the MRT plus FI compared with the MRT group. The MRT plus FI group had a greater reduction in mean total body fat mass by -4.8 kg (95% CI, -9.1 to -0.6 kg; P = .03) and was cost-effective (incremental cost-effectiveness ratio, $39 178 per quality-adjusted life year) compared with MRT alone. There were no significant differences in cardiometabolic risk factors or unhealthy weight-control behaviors between groups. Conclusions and Relevance: In this study, adding FIs to MRT resulted in greater reductions in BMI and total body fat in adolescents with severe obesity without increased unhealthy weight-control behaviors. FIs were cost-effective and possibly promoted adherence to health behaviors. Trial Registration: ClinicalTrials.gov Identifier: NCT03137433.

14.
BMJ Open ; 14(6): e075110, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38830741

ABSTRACT

INTRODUCTION: Screening for atrial fibrillation (AF) in the general population may help identify individuals at risk, enabling further assessment of risk factors and institution of appropriate treatment. Algorithms deployed on wearable technologies such as smartwatches and fitness bands may be trained to screen for such arrhythmias. However, their performance needs to be assessed for safety and accuracy prior to wide-scale implementation. METHODS AND ANALYSIS: This study will assess the ability of the WHOOP strap to detect AF using its WHOOP Arrhythmia Notification Feature (WARN) algorithm in an enriched cohort with a 2:1 distribution of previously diagnosed AF (persistent and paroxysmal) and healthy controls. Recruited participants will collect data for 7 days with the WHOOP wrist-strap and BioTel ePatch (electrocardiography gold-standard). Primary outcome will be participant level sensitivity and specificity of the WARN algorithm in detecting AF in analysable windows compared with the ECG gold-standard. Similar analyses will be performed on an available epoch-level basis as well as comparison of these findings in important subgroups. ETHICS AND DISSEMINATION: The study was approved by the ethics board at the study site. Participants will be enrolled after signing an online informed consent document. Updates will be shared via clinicaltrials.gov. The data obtained from the conclusion of this study will be presented in national and international conferences with publication in clinical research journals. TRIAL REGISTRATION NUMBER: NCT05809362.


Subject(s)
Algorithms , Atrial Fibrillation , Wearable Electronic Devices , Humans , Atrial Fibrillation/diagnosis , Electrocardiography , Male , Female , Observational Studies as Topic , Middle Aged , Adult , Arrhythmias, Cardiac/diagnosis
15.
Mol Genet Metab ; 142(4): 108513, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38917675

ABSTRACT

INTRODUCTION: Congenital disorders of glycosylation (CDG) are a continuously expanding group of monogenic disorders that disrupt glycoprotein and glycolipid biosynthesis, leading to multi-systemic manifestations. These disorders are categorized into various groups depending on which part of the glycosylation process is impaired. The cardiac manifestations in CDG can significantly differ, not only across different types but also among individuals with the same genetic cause of CDG. Cardiomyopathy is an important phenotype in CDG. The clinical manifestations and progression of cardiomyopathy in CDG patients have not been well characterized. This study aims to delineate common patterns of cardiomyopathy across a range of genetic causes of CDG and to propose baseline screening and follow-up evaluation for this patient population. METHODS: Patients with molecular confirmation of CDG who were enrolled in the prospective or memorial arms of the Frontiers in Congenital Disorders of Glycosylation Consortium (FCDGC) natural history study were ascertained for the presence of cardiomyopathy based on a retrospective review of their medical records. All patients were evaluated by clinical geneticists who are members of FCDGC at their respective academic centers. Patients were screened for cardiomyopathy, and detailed data were retrospectively collected. We analyzed their clinical and molecular history, imaging characteristics of cardiac involvement, type of cardiomyopathy, age at initial presentation of cardiomyopathy, additional cardiac features, the treatments administered, and their clinical outcomes. RESULTS: Of the 305 patients with molecularly confirmed CDG participating in the FCDGC natural history study as of June 2023, 17 individuals, nine females and eight males, were identified with concurrent diagnoses of cardiomyopathy. Most of these patients were diagnosed with PMM2-CDG (n = 10). However, cardiomyopathy was also observed in other diagnoses, including PGM1-CDG (n = 3), ALG3-CDG (n = 1), DPM1-CDG (n = 1), DPAGT1-CDG (n = 1), and SSR4-CDG (n = 1). All PMM2-CDG patients were reported to have hypertrophic cardiomyopathy. Dilated cardiomyopathy was observed in three patients, two with PGM1-CDG and one with ALG3-CDG; left ventricular non-compaction cardiomyopathy was diagnosed in two patients, one with PGM1-CDG and one with DPAGT1-CDG; two patients, one with DPM1-CDG and one with SSR4-CDG, were diagnosed with non-ischemic cardiomyopathy. The estimated median age of diagnosis for cardiomyopathy was 5 months (range: prenatal-27 years). Cardiac improvement was observed in three patients with PMM2-CDG. Five patients showed a progressive course of cardiomyopathy, while the condition remained unchanged in eight individuals. Six patients demonstrated pericardial effusion, with three patients exhibiting cardiac tamponade. One patient with SSR4-CDG has been recently diagnosed with cardiomyopathy; thus, the progression of the disease is yet to be determined. One patient with PGM1-CDG underwent cardiac transplantation. Seven patients were deceased, including five with PMM2-CDG, one with DPAGT1-CDG, and one with ALG3-CDG. Two patients died of cardiac tamponade from pericardial effusion; for the remaining patients, cardiomyopathy was not necessarily the primary cause of death. CONCLUSIONS: In this retrospective study, cardiomyopathy was identified in ∼6% of patients with CDG. Notably, the majority, including all those with PMM2-CDG, exhibited hypertrophic cardiomyopathy. Some cases did not show progression, yet pericardial effusions were commonly observed, especially in PMM2-CDG patients, occasionally escalating to life-threatening cardiac tamponade. It is recommended that clinicians managing CDG patients, particularly those with PMM2-CDG and PGM1-CDG, be vigilant of the cardiomyopathy risk and risk for potentially life-threatening pericardial effusions. Cardiac surveillance, including an echocardiogram and EKG, should be conducted at the time of diagnosis, annually throughout the first 5 years, followed by check-ups every 2-3 years if no concerns arise until adulthood. Subsequently, routine cardiac examinations every five years are advisable. Additionally, patients with diagnosed cardiomyopathy should receive ongoing cardiac care to ensure the effective management and monitoring of their condition. A prospective study will be required to determine the true prevalence of cardiomyopathy in CDG.


Subject(s)
Cardiomyopathies , Congenital Disorders of Glycosylation , Phenotype , Humans , Congenital Disorders of Glycosylation/genetics , Congenital Disorders of Glycosylation/diagnosis , Congenital Disorders of Glycosylation/pathology , Female , Male , Cardiomyopathies/genetics , Cardiomyopathies/diagnosis , Child , Child, Preschool , Adolescent , Infant , Glycosylation , Follow-Up Studies , Adult , Retrospective Studies , Young Adult , Prospective Studies , Infant, Newborn
16.
Nucleic Acids Res ; 52(12): 6733-6747, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38828787

ABSTRACT

Adenosine Deaminases Acting on RNA (ADARs) are enzymes that catalyze the conversion of adenosine to inosine in RNA duplexes. These enzymes can be harnessed to correct disease-causing G-to-A mutations in the transcriptome because inosine is translated as guanosine. Guide RNAs (gRNAs) can be used to direct the ADAR reaction to specific sites. Chemical modification of ADAR guide strands is required to facilitate delivery, increase metabolic stability, and increase the efficiency and selectivity of the editing reaction. Here, we show the ADAR reaction is highly sensitive to ribose modifications (e.g. 4'-C-methylation and Locked Nucleic Acid (LNA) substitution) at specific positions within the guide strand. Our studies were enabled by the synthesis of RNA containing a new, ribose-modified nucleoside analog (4'-C-methyladenosine). Importantly, the ADAR reaction is potently inhibited by LNA or 4'-C-methylation at different positions in the ADAR guide. While LNA at guide strand positions -1 and -2 block the ADAR reaction, 4'-C-methylation only inhibits at the -2 position. These effects are rationalized using high-resolution structures of ADAR-RNA complexes. This work sheds additional light on the mechanism of ADAR deamination and aids in the design of highly selective ADAR guide strands for therapeutic editing using chemically modified RNA.


Subject(s)
Adenosine Deaminase , RNA Editing , Ribose , Adenosine Deaminase/metabolism , Adenosine Deaminase/genetics , Adenosine Deaminase/chemistry , Ribose/chemistry , Ribose/metabolism , Humans , Oligonucleotides/chemistry , Oligonucleotides/metabolism , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/chemistry , Methylation , Adenosine/analogs & derivatives , Adenosine/metabolism , Adenosine/chemistry , Nucleosides/chemistry , Nucleosides/metabolism , RNA/metabolism , RNA/chemistry , Inosine/metabolism , Inosine/chemistry
17.
Biology (Basel) ; 13(6)2024 May 29.
Article in English | MEDLINE | ID: mdl-38927271

ABSTRACT

Methyltransferases are a wide-ranging, yet well-conserved, class of molecules that have been found to modify a wide variety of substrates. Interest in RNA methylation has surged in recent years with the identification of the major eukaryotic mRNA m6A methyltransferase METTL3. METTL16 has also been identified as an RNA m6A methyltransferase; however, much less is known about its targets and actions. Interestingly, in addition to their catalytic activities, both METTL3 and METTL16 also have "methylation-independent" functions, including translational regulation, which have been discovered. However, evidence suggests that METTL16's role as an RNA-binding protein may be more significant than is currently recognized. In this review, we will introduce RNA methylation, specifically m6A, and the enzymes responsible for its deposition. We will discuss the varying roles that these enzymes perform and delve deeper into their RNA targets and possible roles as methylation-independent RNA binding proteins. Finally, we will touch upon the many open questions still remaining.

18.
Sci Total Environ ; 945: 173706, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-38866169

ABSTRACT

BACKGROUND: Air pollution is a modifiable risk factor for dementia. Yet, studies on specific sources of air pollution (i.e., toxic chemical emissions from industrial facilities) and dementia risk are scarce. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. METHODS: Participants (n = 2770) were ≥ 65 years old (Mean = 75.3, SD = 5.1 years) from the Cardiovascular Health Cognition Study (1992-1999). Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants' baseline census tract, averaged across 1988-1992, and log2-transformed. Dementia status was clinically adjudicated in 1998-1999 and categorized by subtype (Alzheimer's, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with 1) odds of prevalent dementia and 2) incident dementia risk by subtype. RESULTS: After adjusting for individual and census-tract level covariates, a doubling in toxicity-weighted concentrations was associated with 9 % higher odds of prevalent dementia (OR = 1.09, 95 % CI: 1.00, 1.19). In discrete-time survival models, each doubling in toxicity-weighted concentrations was associated with a 16 % greater hazard of vascular dementia (HR = 1.16, 95 % CI: 1.01, 1.34) but was not significantly associated with all-cause, Alzheimer's disease, or mixed dementia (p's > 0.05). DISCUSSION: Living in regions with higher toxicity-weighted concentrations was associated with higher odds of prevalent dementia and a higher risk of incident vascular dementia in this large, community-based cohort of older adults. These findings support the need for additional studies to examine whether toxic chemical emissions from industrial and federal facilities may be a modifiable target for dementia prevention.


Subject(s)
Air Pollutants , Air Pollution , Dementia , Environmental Exposure , Humans , Dementia/epidemiology , Aged , Male , Female , Air Pollutants/analysis , Air Pollution/statistics & numerical data , Environmental Exposure/statistics & numerical data , Risk Factors , Aged, 80 and over
19.
Expert Opin Ther Pat ; 34(4): 211-229, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38742308

ABSTRACT

INTRODUCTION: SMARCA2 and SMARCA4 are subunits of the SWI/SNF complex which is a chromatin remodeling complex and a key epigenetic regulator that facilitates gene expression. Tumors with loss of function mutations in SMARCA4 rely on SMARCA2 for cell survival and this synthetic lethality is a potential therapeutic strategy to treat cancer. AREAS COVERED: The current review focuses on patent applications that claim proteolysis-targeting chimeras (PROTAC) degraders that bind the bromodomain site of SMARCA2 and are published between January 2019-June 2023. A total of 29 applications from 9 different applicants were evaluated. EXPERT OPINION: SMARCA2/4 bromodomain inhibitors do not lead to desired effects on cancer proliferation; however, companies have converted bromodomain binders into PROTACs to degrade the protein, with a preference for SMARCA2 over SMARCA4. Selective degradation of SMARCA2 is most likely required to be efficacious in the SMARCA4-deficient setting, while allowing for sufficient safety margin in normal tissues. With several patent applications disclosed recently, interest in targeting SMARCA2 should continue, especially with a selective SMARCA2 PROTAC now in the clinic from Prelude Therapeutics. The outcome of the clinical trials will influence the evolution of selective SMARCA2 PROTACs development.


Subject(s)
Antineoplastic Agents , DNA Helicases , Neoplasms , Nuclear Proteins , Patents as Topic , Synthetic Lethal Mutations , Transcription Factors , Humans , Transcription Factors/metabolism , Neoplasms/drug therapy , Neoplasms/pathology , Neoplasms/genetics , Neoplasms/metabolism , Nuclear Proteins/metabolism , Nuclear Proteins/antagonists & inhibitors , Animals , DNA Helicases/metabolism , Antineoplastic Agents/pharmacology , Proteolysis/drug effects , Histone Acetyltransferases/metabolism , Histone Acetyltransferases/antagonists & inhibitors , Molecular Targeted Therapy
20.
Article in English | MEDLINE | ID: mdl-38777885

ABSTRACT

BACKGROUND: Neighborhood walkability may encourage greater out-of-home travel (ie, community mobility) to support independent functioning in later life. We examined associations between a novel walkability audit index and Global Positioning System (GPS)-derived community mobility in community-dwelling older adults. We compared associations with the validated Environmental Protection Agency (EPA) National Walkability Index and further examined moderation by clinical walking speed. METHODS: Participants were 146 older adults (Mean = 77.0 ±â€…6.5 years, 68% women) at baseline of a randomized trial to improve walking speed. A walkability index (range: 0-5; eg, land-use mix, crosswalks, and so on) was created using Google Street View audits within 1/8-mile of the home. Participants carried a GPS device for 5-7 days to derive objective measures of community mobility (eg, time spent out of home, accumulated distance from home). RESULTS: Each 1 SD (~1.3-point) greater walkability audit score was associated with a median 2.16% more time spent out of home (95% confidence interval [95% CI]: 0.30-4.03, p = .023), adjusting for individual demographics/health and neighborhood socioeconomic status. For slower walkers (4-m walking speed <1 m/s), each 1 SD greater audit score was also associated with a median 4.54 km greater accumulated distance from home (95% CI: 0.01-9.07, p (interaction) = .034). No significant associations were found for the EPA walkability index. CONCLUSIONS: Walkability immediately outside the home was related to greater community mobility, especially for older adults with slower walking speeds. Results emphasize the need to consider the joint influence of local environment and individual functioning when addressing community mobility in older populations.


Subject(s)
Geographic Information Systems , Independent Living , Walking , Humans , Aged , Male , Female , Walking/physiology , Environment Design , Neighborhood Characteristics , Residence Characteristics , Aged, 80 and over , Walking Speed/physiology
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