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1.
Pediatr Res ; 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39122822

RESUMEN

BACKGROUND: Acute kidney injury (AKI) occurs in up to half of infants admitted to the neonatal intensive care unit (NICU) and is associated with increased risks of death and more days of mechanical ventilation, hospitalization, and vasopressor drug support. Our objective was to build a granular relational database to study the impact that AKI has on infants admitted to Level-IV NICUs. METHODS: A relational database was created by linking data from the Children's Hospitals Neonatal Database with AKI-focused data from electronic health records from 9 centers. RESULTS: The current cohort consists of 24,870 infants with a median (IQR) gestational age of birth of 37 weeks (32 weeks, 39 weeks), and a median birth weight of 2.720 kg (1.750 kg, 3.310 kg). There was a male predominance with 14,214 (57%) males. In all, 2434 (9.8%) of the mothers were of Hispanic ethnicity. The maternal race breakdown of the cohort was as follows: 741 (3.0%) Asian, 5911 (24%) Black, and 14,945 (60%) White. Overall mortality was 5.8%. CONCLUSION: The ADVANCE relational database is an innovative research tool to rigorously study the epidemiology of AKI in a large national cohort of infants admitted to Level-IV NICUs involved in the Children's Hospital Neonatal Consortium. IMPACT: We used a biomedical informatics approach to build a relational database to study acute kidney injury in infants. We highlight our methodology linking Children's Hospital Neonatal Consortium and electronic health record data from nine neonatal intensive care units. The ADVANCE relational database is a granular and innovative research tool to study risk factors and in-hospital outcomes of acute kidney injury and mortality in a vulnerable patient population.

2.
JAMA Health Forum ; 5(8): e243397, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39207771

RESUMEN

This JAMA Forum discusses new regulatory requirements for antidiscrimination in artificial intelligence tools used in health care, the dark side of flexible enforcement by agencies, and ways to facilitate meaningful compliance.


Asunto(s)
Inteligencia Artificial , Inteligencia Artificial/legislación & jurisprudencia , Humanos , Estados Unidos , Seguro de Salud/legislación & jurisprudencia
3.
Nature ; 632(8023): 50-54, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39020171

RESUMEN

Giant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations1. These 'hot Jupiter' planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange with a third body followed by tidally driven orbital circularization2,3. The discovery of the extremely eccentric (e = 0.93) giant exoplanet HD 80606 b (ref. 4) provided observational evidence that hot Jupiters may have formed through this high-eccentricity tidal-migration pathway5. However, no similar hot-Jupiter progenitors have been found and simulations predict that one factor affecting the efficacy of this mechanism is exoplanet mass, as low-mass planets are more likely to be tidally disrupted during periastron passage6-8. Here we present spectroscopic and photometric observations of TIC 241249530 b, a high-mass, transiting warm Jupiter with an extreme orbital eccentricity of e = 0.94. The orbit of TIC 241249530 b is consistent with a history of eccentricity oscillations and a future tidal circularization trajectory. Our analysis of the mass and eccentricity distributions of the transiting-warm-Jupiter population further reveals a correlation between high mass and high eccentricity.

4.
J Perinatol ; 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38992239

RESUMEN

OBJECTIVE: Determine short-term outcomes following peritoneal drain (PD), laparotomy (LAP) after PD (PD-LAP), and LAP in extremely low birth weight (ELBW) infants with spontaneous intestinal perforation (SIP). STUDY DESIGN: ELBW infants with SIP were identified using the Children's Hospitals Neonatal Database. Mortality and length of stay (LOS) were compared among groups. RESULTS: Of 729 SIP infants from 6/2010-12/2016, 383(53%) received PD, 61(8%) PD-LAP, and 285(39%) LAP. PD infants had lower GA at birth, at SIP diagnosis and upon admission than PD-LAP or LAP; and higher sepsis rates than LAP. Bivariate analysis and Kaplan-Meier survival estimates suggested PD had increased mortality vs. PD-LAP and LAP (27%, 11.5%, and 15.8% respectively, p < 0.001). However, surgical approach was not significantly associated with mortality in multivariable analysis accounting for GA and illness severity. LOS did not differ by surgical approach. CONCLUSIONS: In ELBW infants with SIP, mortality, and LOS are independent of the initial surgical approach.

5.
JAMA Pediatr ; 178(8): 792-799, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38913368

RESUMEN

Importance: The Centers for Disease Control and Prevention plans to introduce hospital-onset bacteremia (HOB) as a health care-associated infection measure. The epidemiology and clinical characteristics of HOB among infants admitted to the neonatal intensive care unit (NICU) are unknown. Objective: To estimate the rate of HOB among infants admitted to the NICU, measure the association of HOB risk with birth weight group and postnatal age, and estimate HOB-attributable mortality. Design, Setting, and Participants: This retrospective multicenter cohort study and emulated trial from 2016 to 2021 included a convenience sample of 322 NICUs in the United States. Participants were infants admitted to participating NICUs for 4 or more days. Exposures: The primary exposures were birth weight and postnatal age. Additional exposures included small for gestational age and central line presence. Main Outcomes and Measures: The primary study outcomes were HOB and HOB-attributable mortality. Results: Of 451 443 included infants, 250 763 (55.6%) were male, 200 680 (44.4%) were female, and 62 091 (13.8%) were born 1500 g or less. Of 9015 HOB events that occurred among 8356 infants (2%) during 8 163 432 days at risk (unadjusted incidence rate, 1.1 per 1000 patient-days; 95% CI, 1.0-1.2), 4888 HOB events (54.2%) occurred in the absence of a central line. Within the first 2 weeks after birth, the HOB rate was 14.2 per 1000 patient-days (95% CI, 12.6-16.1) among infants born 750 g or less, to 0.4 events per 1000 patient-days among infants born more than 2500 g (95% CI, 0.4-0.5). Among infants born 750 g or less, the relative HOB risk decreased by 90% after day 42 compared with days 4 to 14 (incidence rate ratio [IRR], 0.10; 95% CI, 0.1-0.1). Conversely, among infants born more than 2500 g, the relative HOB risk increased by 50% after day 42 compared with days 4 to 14 (IRR, 1.5, 95% CI, 1.2-1.9). Compared with otherwise similar infants without HOB, infants with HOB had an absolute difference in attributable mortality of 5.5% (95% CI, 4.7-6.3). Conclusions and Relevance: This study found that HOB events in the NICU are associated with increased mortality. Birth weight is an important risk factor for HOB; however, the relative rate of HOB decreases over postnatal age among low-birth-weight infants and increases among infants born more than 2500 g. Identifying strategies to prevent HOB and programs to decrease HOB risk are urgently needed to reduce infant mortality.


Asunto(s)
Bacteriemia , Infección Hospitalaria , Unidades de Cuidado Intensivo Neonatal , Humanos , Unidades de Cuidado Intensivo Neonatal/estadística & datos numéricos , Recién Nacido , Bacteriemia/epidemiología , Bacteriemia/mortalidad , Femenino , Masculino , Estudios Retrospectivos , Infección Hospitalaria/epidemiología , Estados Unidos/epidemiología , Factores de Riesgo , Incidencia , Peso al Nacer
6.
J Sleep Res ; : e14257, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38888109

RESUMEN

Sleep problems are associated with increased risk of obesity. Multiple mechanisms have been identified to support this relationship, including changes in sensory processing and food choice. Taste researchers have recently begun to explore whether changes in taste occur as a result of short-term or long-term sleep habits. A systematic review was conducted to investigate these relationships. A total of 13 studies were included in the review. Heterogeneity in both the sleep and taste measurements used was noted, and most studies failed to assess sour, bitter and umami tastes. Still, the available evidence suggests that sweet taste hedonic perception appears to be undesirably influenced by short sleep when viewed through the lens of health. That is, preferred sweetness concentration increases as sleep duration decreases. Habitual sleep and interventions curtailing sleep had minimal associations or effects on sweet taste sensitivity. Salt taste sensitivity and hedonic responses appear to be relatively unaffected by insufficient sleep, but more work is needed. Solid evidence on other taste qualities is not available at the present time.

7.
Surgeon ; 22(5): 281-285, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38749901

RESUMEN

INTRODUCTION: Medical tourism refers to the process of patients travelling outside of their native country to undergo elective surgical procedures and is a rapidly expanding healthcare phenomenon [1-3]. Whilst a multitude of established Private Healthcare Providers (PHPs) offer cosmetic surgical procedures within the United Kingdom (UK), a growing number of patients are opting to travel outside of the UK to undergo cosmetic surgery. AIM: To assess the number of patients presenting to the Canniesburn Plastic Surgery Unit, with cosmetic surgery tourism complications, from outside of the UK, and the associated costs to NHS Scotland over a five-year period. METHODS: A retrospective case review of a prospectively maintained trauma database, which records all acute referrals, was undertaken analysing patients referred from January 1st 2019 to December 31st 2023 inclusive. RESULTS: 81 patients presented over five years with complications of cosmetic surgery tourism. The most common presenting complaints were wound dehiscence (49.4%) or wound infection (24.7%). The total cost to NHS Scotland was £755,559.68 with an average of £9327.90 per patient. CONCLUSION: This is the largest single centre cohort of cosmetic surgery tourism complications reported within the NHS to date; with rates on the rise, demand grows for increased patient information regarding healthcare tourism risks, a national consensus on the extent of NHS management and urgent international collaboration with policymakers is required to address this issue across borders.


Asunto(s)
Turismo Médico , Medicina Estatal , Humanos , Estudios Retrospectivos , Turismo Médico/economía , Femenino , Medicina Estatal/economía , Masculino , Persona de Mediana Edad , Adulto , Escocia , Anciano , Complicaciones Posoperatorias/economía , Complicaciones Posoperatorias/epidemiología , Reino Unido , Adulto Joven , Procedimientos de Cirugía Plástica/economía , Adolescente , Costos de la Atención en Salud , Cirugía Plástica/economía
8.
Br J Gen Pract ; 74(745): e544-e551, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38806209

RESUMEN

BACKGROUND: UK cancer mortality is worse than in many other high-income countries, partly because of diagnostic delays in primary care. AIM: To understand beliefs and behaviours of GPs, and systems of general practice teams, to inform the Think Cancer! intervention development. DESIGN AND SETTING: An embedded qualitative study guided by behaviour change models (COM-B [Capability, Opportunity, Motivation - Behaviour] and theoretical domains framework [TDF]) in primary care in Wales, UK. METHOD: Twenty qualitative, semi-structured telephone interviews with GPs were undertaken and four face-to-face focus groups held with practice teams. Framework analysis was used and results were mapped to multiple, overlapping components of COM-B and TDF. RESULTS: Three themes illustrate complex, multilevel referral considerations facing GPs and practice teams; external influences and constraints; and the role of practice systems and culture. Tensions emerged between individual considerations of GPs (Capability and Motivation) and context-dependent external pressures (Opportunity). Detecting cancer was guided not only by external requirements, but also by motivational factors GPs described as part of their cancer diagnostics process. External influences on the diagnosis process often resulted from the primary-secondary care interface and social pressures. GPs adapted their behaviour to deal with this disconnect. Positive practice culture and supportive practice-based systems ameliorated these tensions and complexity. CONCLUSION: By exploring individual GP behaviours together with practice systems and culture we contribute new understanding about how cancer diagnosis operates in primary care and how delays can be improved. We highlight commonly overlooked dynamics and tensions that are experienced by GPs as a tension between individual decision making (Capability and Motivation) and external considerations, such as pressures in secondary care (Opportunity).


Asunto(s)
Actitud del Personal de Salud , Detección Precoz del Cáncer , Neoplasias , Atención Primaria de Salud , Investigación Cualitativa , Humanos , Neoplasias/diagnóstico , Grupos Focales , Médicos Generales , Gales , Derivación y Consulta , Motivación , Masculino , Femenino , Medicina General , Pautas de la Práctica en Medicina
9.
Sci Transl Med ; 16(734): eadg7162, 2024 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-38277467

RESUMEN

Functional loss of TDP-43, an RNA binding protein genetically and pathologically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), leads to the inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote the degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. Here, we show that mRNA transcripts harboring cryptic exons generated de novo proteins in TDP-43-depleted human iPSC-derived neurons in vitro, and de novo peptides were found in cerebrospinal fluid (CSF) samples from patients with ALS or FTD. Using coordinated transcriptomic and proteomic studies of TDP-43-depleted human iPSC-derived neurons, we identified 65 peptides that mapped to 12 cryptic exons. Cryptic exons identified in TDP-43-depleted human iPSC-derived neurons were predictive of cryptic exons expressed in postmortem brain tissue from patients with TDP-43 proteinopathy. These cryptic exons produced transcript variants that generated de novo proteins. We found that the inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Last, we showed that 18 de novo peptides across 13 genes were present in CSF samples from patients with ALS/FTD spectrum disorders. The demonstration of cryptic exon translation suggests new mechanisms for ALS/FTD pathophysiology downstream of TDP-43 dysfunction and may provide a potential strategy to assay TDP-43 function in patient CSF.


Asunto(s)
Esclerosis Amiotrófica Lateral , Demencia Frontotemporal , Humanos , Esclerosis Amiotrófica Lateral/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Demencia Frontotemporal/genética , Péptidos , Proteómica
10.
J Perinatol ; 44(1): 100-107, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37805591

RESUMEN

OBJECTIVE: To evaluate the relationship between cholestasis and outcomes in medical and surgical necrotizing enterocolitis (NEC). STUDY DESIGN: A retrospective analysis of prospectively collected data from 1472 infants with NEC [455 medical (mNEC) and 1017 surgical (sNEC)] from the Children's Hospital Neonatal Database. RESULTS: The prevalence of cholestasis was lower in mNEC versus sNEC (38.2% vs 70.1%, p < 0.001). In both groups, cholestasis was associated with lower birth gestational age [mNEC: OR 0.79 (95% CI 0.68-0.92); sNEC: OR 0.86 (95% CI 0.79-0.95)] and increased days of parenteral nutrition [mNEC: OR 1.08 (95% CI 1.04-1.13); sNEC: OR 1.01 (95% CI 1.01-1.02)]. For both groups, the highest direct bilirubin was associated with the composite outcome mortality or length of stay >75th percentile [mNEC: OR 1.21 (95% CI 1.06-1.38); sNEC: OR 1.06 (95% CI 1.03-1.09)]. CONCLUSION: Cholestasis with both medical NEC and surgical NEC is associated with adverse patient outcomes including increased mortality or extreme length of stay.


Asunto(s)
Colestasis , Enterocolitis Necrotizante , Enfermedades del Recién Nacido , Lactante , Niño , Recién Nacido , Humanos , Estudios Retrospectivos , Enterocolitis Necrotizante/epidemiología , Enterocolitis Necrotizante/cirugía , Enterocolitis Necrotizante/etiología , Edad Gestacional , Nutrición Parenteral/efectos adversos , Enfermedades del Recién Nacido/etiología , Colestasis/etiología
11.
Science ; 382(6673): 941-946, 2023 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-37995235

RESUMEN

Policy-makers seeking to limit the impact of coal electricity-generating units (EGUs, also known as power plants) on air quality and climate justify regulations by quantifying the health burden attributable to exposure from these sources. We defined "coal PM2.5" as fine particulate matter associated with coal EGU sulfur dioxide emissions and estimated annual exposure to coal PM2.5 from 480 EGUs in the US. We estimated the number of deaths attributable to coal PM2.5 from 1999 to 2020 using individual-level Medicare death records representing 650 million person-years. Exposure to coal PM2.5 was associated with 2.1 times greater mortality risk than exposure to PM2.5 from all sources. A total of 460,000 deaths were attributable to coal PM2.5, representing 25% of all PM2.5-related Medicare deaths before 2009 and 7% after 2012. Here, we quantify and visualize the contribution of individual EGUs to mortality.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Carbón Mineral , Exposición a Riesgos Ambientales , Mortalidad , Material Particulado , Centrales Eléctricas , Dióxido de Azufre , Anciano , Humanos , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Exposición a Riesgos Ambientales/efectos adversos , Material Particulado/efectos adversos , Material Particulado/toxicidad , Riesgo , Estados Unidos/epidemiología , Dióxido de Azufre/efectos adversos , Dióxido de Azufre/análisis
12.
Cell Rep Methods ; 3(10): 100593, 2023 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-37729920

RESUMEN

Here, we present a standardized, "off-the-shelf" proteomics pipeline working in a single 96-well plate to achieve deep coverage of cellular proteomes with high throughput and scalability. This integrated pipeline streamlines a fully automated sample preparation platform, a data-independent acquisition (DIA) coupled with high-field asymmetric waveform ion mobility spectrometer (FAIMS) interface, and an optimized library-free DIA database search strategy. Our systematic evaluation of FAIMS-DIA showing single compensation voltage (CV) at -35 V not only yields the deepest proteome coverage but also best correlates with DIA without FAIMS. Our in-depth comparison of direct-DIA database search engines shows that Spectronaut outperforms others, providing the highest quantifiable proteins. Next, we apply three common DIA strategies in characterizing human induced pluripotent stem cell (iPSC)-derived neurons and show single-shot mass spectrometry (MS) using single-CV (-35 V)-FAIMS-DIA results in >9,000 quantifiable proteins with <10% missing values, as well as superior reproducibility and accuracy compared with other existing DIA methods.


Asunto(s)
Células Madre Pluripotentes Inducidas , Proteómica , Humanos , Proteómica/métodos , Espectrometría de Masas en Tándem/métodos , Reproducibilidad de los Resultados , Células Madre Pluripotentes Inducidas/química , Proteoma/análisis
14.
Mol Biol Cell ; 34(8): br11, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37163337

RESUMEN

As an important substrate for cell metabolism, the short-chain fatty acid acetate emerges as a regulator of cell fate and function. However, its role in T-cell survival and its underlying mechanisms remain largely unknown. Here, we demonstrate that acetate modulates T-cell apoptosis via potentiation of α-tubulin acetylation. We further show that acetate treatment effectively increases the expression of the tumor necrosis factor receptor (TNFR) family member CD30 by enhancing its gene transcription. Moreover, CD30 physically associates with and stabilizes the deacetylase HDAC6, which deacetylates α-tubulin to decrease microtubule stability. Proteomic profiling of CD30 knockout (Cd30-/-) T-cells reveals elevated expression of anti-apoptotic BCL2 family proteins and thus promotes T-cell survival via a microtubule-Bcl-2 axis. Taken together, our results demonstrate that acetate is a regulator of T-cell survival by controlling levels of acetylated α-tubulin. This suggests that therapeutic manipulation of acetate metabolism may facilitate optimal T-cell responses in pathological conditions.


Asunto(s)
Proteómica , Tubulina (Proteína) , Tubulina (Proteína)/metabolismo , Histona Desacetilasa 6/metabolismo , Supervivencia Celular , Linfocitos T/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Acetatos/farmacología , Ácidos Grasos Volátiles , Acetilación
15.
Proc Natl Acad Sci U S A ; 120(22): e2300773120, 2023 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-37216537

RESUMEN

δ-catenin is expressed in excitatory synapses and functions as an anchor for the glutamatergic AMPA receptor (AMPAR) GluA2 subunit in the postsynaptic density. The glycine 34 to serine (G34S) mutation in the δ-catenin gene has been found in autism spectrum disorder (ASD) patients and results in loss of δ-catenin functions at excitatory synapses, which is presumed to underlie ASD pathogenesis in humans. However, how the G34S mutation causes loss of δ-catenin functions to induce ASD remains unclear. Here, using neuroblastoma cells, we identify that the G34S mutation increases glycogen synthase kinase 3ß (GSK3ß)-dependent δ-catenin degradation to reduce δ-catenin levels, which likely contributes to the loss of δ-catenin functions. Synaptic δ-catenin and GluA2 levels in the cortex are significantly decreased in mice harboring the δ-catenin G34S mutation. The G34S mutation increases glutamatergic activity in cortical excitatory neurons while it is decreased in inhibitory interneurons, indicating changes in cellular excitation and inhibition. δ-catenin G34S mutant mice also exhibit social dysfunction, a common feature of ASD. Most importantly, pharmacological inhibition of GSK3ß activity reverses the G34S-induced loss of δ-catenin function effects in cells and mice. Finally, using δ-catenin knockout mice, we confirm that δ-catenin is required for GSK3ß inhibition-induced restoration of normal social behavior in δ-catenin G34S mutant animals. Taken together, we reveal that the loss of δ-catenin functions arising from the ASD-associated G34S mutation induces social dysfunction via alterations in glutamatergic activity and that GSK3ß inhibition can reverse δ-catenin G34S-induced synaptic and behavioral deficits.


Asunto(s)
Trastorno del Espectro Autista , Trastorno Autístico , Catenina delta , Animales , Humanos , Ratones , Trastorno del Espectro Autista/metabolismo , Trastorno Autístico/genética , Trastorno Autístico/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Ratones Noqueados , Conducta Social , Sinapsis/metabolismo
16.
Ann Intern Med ; 176(4): 563-567, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36972543

RESUMEN

Interpretation of many genetic test results can change over time as new data accumulate. Hence, physicians who order genetic tests may subsequently receive revised reports with important implications for patients' medical treatment-even for patients who are no longer in their care. Several of the ethical principles underlying medical practice suggest an obligation to reach out to former patients with this information. Discharging that obligation can be accomplished, at a minimum, by attempting to contact the former patient with their last known contact information.


Asunto(s)
Médicos , Medicina de Precisión , Humanos
18.
bioRxiv ; 2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36747793

RESUMEN

Functional loss of TDP-43, an RNA-binding protein genetically and pathologically linked to ALS and FTD, leads to inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. However, the possibility of de novo protein synthesis from cryptic exon transcripts has not been explored. Here, we show that mRNA transcripts harboring cryptic exons generate de novo proteins both in TDP-43 deficient cellular models and in disease. Using coordinated transcriptomic and proteomic studies of TDP-43 depleted iPSC-derived neurons, we identified numerous peptides that mapped to cryptic exons. Cryptic exons identified in iPSC models were highly predictive of cryptic exons expressed in brains of patients with TDP-43 proteinopathy, including cryptic transcripts that generated de novo proteins. We discovered that inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Finally, we showed that these de novo peptides were present in CSF from patients with ALS. The demonstration of cryptic exon translation suggests new mechanisms for ALS pathophysiology downstream of TDP-43 dysfunction and may provide a strategy for novel biomarker development.

19.
Elife ; 122023 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-36655987

RESUMEN

Self-cleaving ribozymes are RNA molecules that catalyze the cleavage of their own phosphodiester backbones. These ribozymes are found in all domains of life and are also a tool for biotechnical and synthetic biology applications. Self-cleaving ribozymes are also an important model of sequence-to-function relationships for RNA because their small size simplifies synthesis of genetic variants and self-cleaving activity is an accessible readout of the functional consequence of the mutation. Here, we used a high-throughput experimental approach to determine the relative activity for every possible single and double mutant of five self-cleaving ribozymes. From this data, we comprehensively identified non-additive effects between pairs of mutations (epistasis) for all five ribozymes. We analyzed how changes in activity and trends in epistasis map to the ribozyme structures. The variety of structures studied provided opportunities to observe several examples of common structural elements, and the data was collected under identical experimental conditions to enable direct comparison. Heatmap-based visualization of the data revealed patterns indicating structural features of the ribozymes including paired regions, unpaired loops, non-canonical structures, and tertiary structural contacts. The data also revealed signatures of functionally critical nucleotides involved in catalysis. The results demonstrate that the data sets provide structural information similar to chemical or enzymatic probing experiments, but with additional quantitative functional information. The large-scale data sets can be used for models predicting structure and function and for efforts to engineer self-cleaving ribozymes.


Asunto(s)
ARN Catalítico , ARN Catalítico/metabolismo , ARN , Secuencia de Bases , Nucleótidos , Mutagénesis , Conformación de Ácido Nucleico
20.
bioRxiv ; 2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36711484

RESUMEN

δ-catenin is expressed in excitatory synapses and functions as an anchor for the glutamatergic AMPA receptor (AMPAR) GluA2 subunit in the postsynaptic density. The glycine 34 to serine (G34S) mutation in the δ-catenin gene is found in autism spectrum disorder (ASD) patients and induces loss of δ-catenin functions at excitatory synapses, which is presumed to underlie ASD pathogenesis in humans. However, how the G34S mutation causes loss of δ-catenin functions to induce ASD remains unclear. Here, using neuroblastoma cells, we discover that the G34S mutation generates an additional phosphorylation site for glycogen synthase kinase 3ß (GSK3ß). This promotes δ-catenin degradation and causes the reduction of δ-catenin levels, which likely contributes to the loss of δ-catenin functions. Synaptic δ-catenin and GluA2 levels in the cortex are significantly decreased in mice harboring the δ-catenin G34S mutation. The G34S mutation increases glutamatergic activity in cortical excitatory neurons while it is decreased in inhibitory interneurons, indicating changes in cellular excitation and inhibition. δ-catenin G34S mutant mice also exhibit social dysfunction, a common feature of ASD. Most importantly, inhibition of GSK3ß activity reverses the G34S-induced loss of δ-catenin function effects in cells and mice. Finally, using δ-catenin knockout mice, we confirm that δ-catenin is required for GSK3ß inhibition-induced restoration of normal social behaviors in δ-catenin G34S mutant animals. Taken together, we reveal that the loss of δ-catenin functions arising from the ASD-associated G34S mutation induces social dysfunction via alterations in glutamatergic activity and that GSK3ß inhibition can reverse δ-catenin G34S-induced synaptic and behavioral deficits. Significance Statement: δ-catenin is important for the localization and function of glutamatergic AMPA receptors at synapses in many brain regions. The glycine 34 to serine (G34S) mutation in the δ-catenin gene is found in autism patients and results in the loss of δ-catenin functions. δ-catenin expression is also closely linked to other autism-risk genes involved in synaptic structure and function, further implying that it is important for the autism pathophysiology. Importantly, social dysfunction is a key characteristic of autism. Nonetheless, the links between δ-catenin functions and social behaviors are largely unknown. The significance of the current research is thus predicated on filling this gap by discovering the molecular, cellular, and synaptic underpinnings of the role of δ-catenin in social behaviors.

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